Topic: New Bike - Running Rough

[bmx4637]

Hey all, just got a "new" 1981 Honda CB650C (my second one is a parts bike which I had difficulty w/ the title).

Anyway, I've been searching around and it seems that other bikes appear to be very touchy and very unique with setups and problems. So it was difficult to see something very similar to my issues other than tons of carb stuff. I'm an aircraft (airframe and powerplant certified) mechanic so these issues don't scare me, however I am just trying to wrap my head around how the whole system operates on these bikes.

If there is another thread/post that you may think of, that I may have missed, to help me out would be great.



Bike starts (after many many tries on cold) with choke pulled up (on?) but runs like a bat with metal balls. I believe there may be multiple issues occurring (which is probably throwing me off of my diagnostic).

1 - Idle is not smooth, I heard exhaust pop only once of my couple of times running it.

2 - After warm up, If I push choke down/in (off?) Engine quits on me.

3 - Metal sounds inside engine while running.



The areas of concern I am currently contemplating are:

Fuel flow/carbs
valves/chains


I'll throw up a video if it helps.

What do you guys think?
Any direction you guys can lead me?

Thanks in advance,
Alex

[bmx4637]

Hey Calj,

I think what you suggested is absolutely spot on. Will definitely move forward with this.

Thanks,
Alex

[flybox1]

check the oil level, remove the tappet covers and adjust the valves. Remove the carbs and fully clean them. Download the manual from here and perform the 3K Mile Service interval.

You should also inspect the interior of the fuel tank and ascertain that it too is super clean. If not, flush it and remove all traces of rust that would inhibit fuel flow. Theres no mystery to these little beauties, and being a mechanic I'm sure you'll be fine tending to it.

+1 to this!!

[flybox1]

I think what you suggested is absolutely spot on.

I only know this because Flybox told me 

hey now! 
Complete your 3K maint, bmx4637, and welcome to this 'Great Hall of SOHC4 Knowledge' 

[bmx4637]

Thanks Flybox and CalJ, I've seen both of you around the forums so I can definitely learn a lot from you guys.

Ok, so according to my maintenance manual (Clymer Honda CB650 fours 1979-1982) there is a 4,000 mile maintenance schedule (The sticky manuals for the CB650 show 3,600 mile but I see some things that might not be for my year bike/general information? Also the owners manual shows a 4,000 mile maintenance schedule. So I will go with the clymer manual I have for my model and year specific bike).


According to the 4,000 mile maintenance schedule tune up, the following applies:

"Because different systems in an engine interact, the procedures should be done in the following order"

1-Clean or replace air cleaner element
2-Adjust the camshaft chain tension
3-Check and adjust valve clearance
4-Compression Pressure test
5-Inspect spark plugs type or replace if necessary
6-Check and adjust ignition timing
7-Check and adjust/synchronize the carburetors, idle speed, and accelerator pump
8-Ignition timing light


The remaining items consist of the list in the 4,000 mile maintenance schedule table in no specific order.

9-Change oil and oil filter
10-Check and adjust clutch free play
11-Check and adjust throttle operation and free play
12-Adjust rear brake pedal height and free play
13-Clean fuel shutoff valve and filter
14-Inspect hydraulic brake fluid
15-Inspect brake pads and shoes for wear
16-Inspect crankcase breather hose for cracks or loose hose clamps-drain out all residue
17-Inspect fuel line for chafed, cracked or swollen ends
18-Check engine mounting bolts for tightness
19-Inspect and repack rear swing arm bushings
20-Check all suspension components
21-Lubricate control cables




So, first thing first

List#1 Air filter
http://www.partzilla.com/parts/search/Honda/Motorcycle/1981/CB650C+A/AIR+CLEANER/parts.html
Item #3 - 17211-460-000 - $19.08

List#2 Camshaft chain tension
For the camshaft chain tension - The manual seems very vague on an easy 7 step process to perform this step. It looks easier than an oil change. Do you guys know of a post with someone performing this step?

List#9 Oil and oil filter
http://www.pqiamerica.com/apiserviceclass.htm
According to my owners manual, the oil api category should be SE. Since this is now obsolete, would SJ suffice? Since it is still current: https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-v-twin-motorcycle-oil The manual calls for an SE 10W-40, this one is an SJ 20W-50, but should be fine since I live near Miami, FL.
http://www.partzilla.com/parts/search/Honda/Motorcycle/1981/CB650C+A/OIL+FILTER+%2B+OIL+PAN/parts.html
Is there a difference between the 15410-426-010 and 15410-426-000? - Item #4 - $7.31


Thanks,
Alex

[JimJamerino]

The cam chain adjustment is pretty easy. The manual I have says to loosen the cam chain adjuster nut a half turn or so (it's a little acorn nut on the cylinders under the carbs), spin the motor with the starter a few rotations, then tighten the nut.

A suggestion from another forum member is slightly more complex, but has worked better for my bike. Loosen the cam chain adjuster nut, remove the pulser cover on the right side of the engine and spin the crankshaft counter-clockwise to rotate the engine backwards a revolution or two, then clockwise to go forwards a couple revolutions. Then tighten the nut and replace the pulser cover. He said there was something about going backwards that makes the cam chain adjuster work better.

Seemed to work for me.

The CB650 cam chain is a hy-vo style chain like the timing chains on old V-8 engines. It doesn't like to be bent backwards, so adjusting can be a little tricky. When all adjustments (valves, a/f mixture, cam chain, carb sync, etc.) are done correctly, my CB650 engine sounds like an angry sewing machine.

[harisuluv]

sounds like you probably have clogged/semi clogged slow jets.

[bmx4637]

Thanks Jim, Can't wait until mine sounds like an angry sewing machine haha

Yea my manual says to loosen nut, manually turn crank a few times, then tighten. How exactly does that work inside? I'm not able to check if the tension is correct  I guess I just take their word for it that the automatic tensioner should be working.

Any tips for the oil I was mentioning?


Hey Haris,
I'm thinking for sure carbs/fuel flow can be an issue. Is there a way to confirm only slow jets are the issue when I try partial throttle to keep it from dying?

Thanks guys,
Alex

[harisuluv]

Keep in mind there are dozens of things that could be wrong or causing your issues.  Unfortunately if you want to try and eliminate the slow jets as the cause solely the only way to do that is replace them with new OEM.  You can clean out and visually inspect the oem brass you have or buy new aftermarket and that also has different variables for example different aftermarket jets marked the same size are actually not the same size.

Basically, the only for sure option is new OEM.  However, that doesn't exist readily for sale, they are discontinued.  Next best thing would be new 35 jets aftermarket (there are only one or two suppliers making them). 

If it were me I would pull them and clean them, and they would probably work very well.

[bmx4637]

... Remove the carbs and fully clean them...

...If it were me I would pull them and clean them, and they would probably work very well.

Yea, you're #2 to advise me on this, and at least specifically slow jet (I'll clean it all anyway, however). Since you're good with carbs, I have a few questions:

1-I've noticed people having trouble with the removal and replace of the carburetor because of the boots on the head and on the airbox. Do you know of any advice on how to perform this properly/easily without damage? I never knew what they were called but once I looked it up it seemed to maybe solve this issue; pod filters. I read that the main needle would need changing, however I don't intend to change the setup other than stock to at least get it up and running. Only after the bike is running properly do I intend to maybe mess around with a setup.

2-Do you spray clean all the openings of the carbs after disassembly or do you dip the whole unit in carb cleaner at sit for a period of time?


Thanks,
-Alex

[harisuluv]

1. Everything is easier to do with new boots.  With rock hard ones it is a bit of a pain.  You will need a heatgun, soapy water, and something like a broomstick.

2. I never dip carbs in carb cleaner.  I completely disassemble them and soda blast them.  Then ultrasonic clean after.  If the process you described worked as well as what I do then I wouldn't have a job.   

[bmx4637]

List#3 Check and adjust valve clearance
The manual showed an adjusting tool. Would a normal socket suffice? (edit: Honda valve adjusting wrench - part# 07908-323000.)

List#5 Inspect spark plug type or replace if necessary
Plan on using D8EA plugs http://www.partzilla.com/parts/detail/honda/HP-98069-58717.html

1 - The spark plugs have a threaded end on it where the cap goes on; is that for vibration? And is there any special way the caps go on the plugs because of this?

2 - I haven't seen any plug wires set for the bike. I looked around and saw that custom lengths can be made. Has anyone ever done this? The guy who sold me the bike said he bought a set but one of the lengths was too short so one wire is old. I would like to change them all anyway.

-Alex

[bmx4637]

  So... No compression on #1 and #4 cylinder?

less than 0.001" valve clearance on #1 intake and exhaust valves, greater than 0.025" clearance on intake valve on #4 cylinder!?

I must be doing something wrong, is that even possible? I started up the bike before I began work on it.

I'll be back, heading over to Sears right now to get a thin walled socket that fits to remove #2 and #3 spark plugs...

[bmx4637]

Hey all, just got the title yesterday so decided to now spend my time on the bike. Wanted to take it slow to learn a little bit about my bike.


List#1 Air filter



Looks look the previous owner installed a new air filter.






Air box had some junk inside. The design looks like the bottom is supposed to be a trap. Similar to sand traps in helicopter air intakes. Also noticed a tube extending out of the bottom of the air box to the underside of the bike?






Wiped it clean.






Pulled #1 plug (Every single plug looked like this). Carbon Foul: "Appearance dull, dry black with fluffy carbon deposits on the insulator tip, electrode and exposed shell. Caused by Fuel/air mixture too rich, plug heat range too cold, weak ignition system, dirty air cleaner, faulty automatic choke, or excessive idling."






Rest of the plug looks brand new. You guys know what those threads are for?






Hard to see. Gap shows 0.024" on #1 plug (between 0.024" and 0.025" on remaining plugs). Spec calls for "0.024" to 0.028"






Now comes a problem. This is my #4 cylinder intake valve clearance.






Valve clearance shows 0.025"  . The exhaust valve on #4 cylinder showed 0.013". #1 cylinder intake and exhaust valves were both less than 0.001" I had no play and my smallest shim didn't fit, which was technically 0.0015". Talk about valve slap! I didn't bother with #2 and #3 until I get the valve adjustment tool. Spec calls for 0.002" Intake, 0.003" Exhaust.




Now there were 2 weird things I encountered while performing work on my bike.

1 - cam timing
2 - compression.




1 - cam timing

When I aligned the 1.4T with the fixed index mark (this pic shows it a bit off, however) I cannot measure the valve clearance (as stated in the procedures: "Rotate crankshaft clockwise...until the ignition timing mark 1.4T aligns with the fixed index mark. The no.1 cylinder must be at TDC on the compression stroke." Check - no.1 cyl. intake and exhaust, no.2 cyl. exhaust only, and no.3 cyl. intake only.)

If I do this according to the procedure, there is always a cam lobe on at least one of the valves on #1 cyl. ( and technically, it doesn't have to be on the compression stroke to check clearance, so long as the cam lobe has not begun its travel on the rocker arm). I had to place the fixed index mark with the 2.3 side to actually get both cam lobes off of the rocker arms on #1 cyl. (indicating to me that the camshaft is a full 180 degrees ass backwards).

Am I wrong with this? I mean I started the bike before performing any work and it idled for a good bit (was gona die a couple of times though), however it did sound rough as hell (living up to the original posts' reputation). Could I be doing something wrong that the procedures in the manual doesn't state?




2 - compression

Compression is always a good indicator for engine health. I've performed this on a couple of older cars I've had. So I had my kit handy.

But I must say, I have to be doing something wrong with this. Even following procedures in the manual.

I had to run to sears for an 18MM spark plug socket to fit in the #2 and #3 plugs. Then proceeded to check all 4 cylinders.

My needle didn't move one bit. It stayed at 0    on every single cylinder.

I first thought the gauge is bad. So I hooked it up to my little air compressor, and the gauge on the compressor and on the compressor tester gauge matched.


I honestly don't know what else to say about this.



Thanks,
-Alex

[evanphi]

that isn't how you measure valve clearance!

You put the feeler gauge under the little screw at the OTHER end of the rocker that is lifted by the valve stem. There's a specific order that you have to check them in. It is in the manual.

http://www.motopsyco.com/2013/10/25/how-to-adjust-valve-lash-1980-honda-cb650-sohc/

I googled and fond this.

[DaveBarbier]

For the 650 that's how you measure the clearance. Makes it much easier and you don't need to bend your feeler gauges.

[bmx4637]

that isn't how you measure valve clearance!

You put the feeler gauge under the little screw at the OTHER end of the rocker that is lifted by the valve stem.

http://www.motopsyco.com/2013/10/25/how-to-adjust-valve-lash-1980-honda-cb650-sohc/

I googled and fond this.

"Check the clearance...by inserting a flat feeler gauge between the rocker arm pad and the camshaft lobe." You saved yourself on this one. I'm sure it may be different with different type bikes, etc.

There's a specific order that you have to check them in. It is in the manual.

... The no.1 cylinder must be at TDC on the compression stroke." Check - no.1 cyl. intake and exhaust, no.2 cyl. exhaust only, and no.3 cyl. intake only.)

That specific order, which I already mentioned.



But I figured out why my cam timing and compression is off. I verified it just now.

The cam chain adjustment is pretty easy. The manual I have says to loosen the cam chain adjuster nut a half turn or so (it's a little acorn nut on the cylinders under the carbs), spin the motor with the starter a few rotations, then tighten the nut.

A suggestion from another forum member is slightly more complex, but has worked better for my bike. Loosen the cam chain adjuster nut, remove the pulser cover on the right side of the engine and spin the crankshaft counter-clockwise to rotate the engine backwards a revolution or two, then clockwise to go forwards a couple revolutions. Then tighten the nut and replace the pulser cover. He said there was something about going backwards that makes the cam chain adjuster work better.

Seemed to work for me.

The CB650 cam chain is a hy-vo style chain like the timing chains on old V-8 engines. It doesn't like to be bent backwards, so adjusting can be a little tricky. When all adjustments (valves, a/f mixture, cam chain, carb sync, etc.) are done correctly, my CB650 engine sounds like an angry sewing machine.

JimJamerino, the rotating the crank backwards did not work out for me. In fact, upon review, the camshaft did not rotate when I rotated the crank backwards. Not sure why, but I believe since "loosen the cam chain adjuster nut...and spin the crankshaft counter-clockwise" the loosened nut may have made the teeth jump on the cam or on the crank. I am not exactly too familiar with how the guts of this engine design works, but it wouldn't be the first time I performed maintenance and something didn't make sense or sound right.

Since I performed the compression check after the cam chain adjustment

1-Clean or replace air cleaner element
2-Adjust the camshaft chain tension
3-Check and adjust valve clearance
4-Compression Pressure test
...

This explains why I have no compression, since the camshaft is now timed improperly.



I do appreciate the help and the time you guys offer. You guys have more experience than me on these bikes. But please note which model and year specific bike the experience/recommendation is in. Since each bike and procedures are different.

I will lean towards the manuals' procedures from the Japanese engineers.

Thanks,
-Alex

[bmx4637]

Ok so I dove into it

to correct the valve/camshaft timing.




Removed the cylinder head cover and organized the x22 bolts (6-9 FT-LB) so they went back into place.







Got wear?




So I had to follow the procedures in the manual to the T. There was no other way for the removal/installation of the cam chain other than what the procedures stated, which was to remove the chain sprocket. The exception was that I was unable to break the torque of the x2 bolts on the chain sprocket (16-19 FT-LB). the chain tensioner kept giving way and made the entire camshaft walk off the bearings (maybe I will get a light impact wrench for that next time). So I had to pry the chain off the sprocket with a screwdriver and hold the chain up with a zip tie to the center frame. I then removed the camshaft and placed it on my bench vise (with wood in between the jaws) and broke the torque of the two bolts on the cam chain sprocket. Once removed, I placed the loose sprocket and camshaft back on the bearings and rotated the crankshaft to the correct position.





I then rotated the camshaft and sprocket to the correct position, which I would eventually tighten.



The pic above (viewed from Left Hand side, based on rider position) is after I placed the chain on the sprocket and aligned the sprocket with the 2 holes for the  bolts. Tighten the x2 bolts (16-19 FT-LB). (Notice the two punch marks aligned with the same plane as the top of the valve head, as stated in the procedure).





The pic above (viewed from Right Hand side, based on rider position) is the index mark at the end of the camshaft facing the front top surface of the head.

I would like to re-iterate what the manual says here...

CAUTION: VERY EXPENSIVE DAMAGE COULD RESULT FROM IMPROPER CAM AND CHAIN ALIGNMENT. RECHECK YOUR WORK SEVERAL TIMES TO BE SURE ALIGNMENT IS CORRECT.





I put the cylinder head cover back on. x22 bolts (6-9 FT-LB)

Notice the swivel tool I have attached to my 1/4" extension. I highly recommend using that tool.



Also, the way I like to torque things (especially with this many bolts) based on my aircraft experience:
1 - I run the bolts through the threads a few turns so the bolts bite in but are still loose. Do this with all 22 bolts so the threads start biting (as shown in the above pic).
2 - I then hand turn the bolts with the extension (the extension removed from the ratchet) to the point where the bolt begins to touch the head. Do this in the order of tightening sequence (showed in the picture below).

3 - I then turn with the ratchet, in the sequence given, a couple of turns each bolt. So #1 bolt turn 2-3 times, #2 bolt turn 2-3 times, #3 bolt...etc. back to #1,2,3,...22. Until you start feeling it become a bit tighter than normal.

4 - I do all my torque at the middle of the range given (So the middle of 6-9 ft lb is 7.5 +/- 1.5 ft lbs, or 90 +/- 18 inch lbs). I set my 1/4" torque wrench at HALF the specified torque. In this case I set it at 45 inch lbs. Then tighten in sequence.

5 - I set my torque wrench at 90 inch lbs. Then tighten in sequence.





[click image above to make it bigger]


Once done, with spark plugs removed, I turn the crank with my 1/2" drive ratchet (15/16" socket I believe) to make sure it turns smooth.




I now checked the valve adjustment positions.

The valves are now timed exactly in the position as stated in the manual. Thus my camshaft/valves are properly timed now.

I will post my valve adjustment job and compression test (which I already did today but don't have the time to post it now).


My valves are now adjusted properly. BUT, my compression test shows 85 PSI dry test on #1 cylinder. And no compression on 2,3, and 4 cylinders. Which makes me think that this engine has been running on one cylinder.

I will do a wet test on #1 cylinder and a leak down test with compressed air on all cylinders when I have time.

-Alex

[Tews19]

Great detail. I am not positive but your Cam looks to have some really heavy wear on the lobes.

[bmx4637]

Thanks Tews, yea it definitely does look worn. I will probably need a micrometer to determine if it is out of limits or not. I have an extra from my parts bike but am not sure of the condition.

So after 8 months I'm back at it.

List#9 Oil and oil filter
http://www.pqiamerica.com/apiserviceclass.htm
According to my owners manual, the oil api category should be SE. Since this is now obsolete, would SJ suffice? Since it is still current: https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-v-twin-motorcycle-oil The manual calls for an SE 10W-40, this one is an SJ 20W-50, but should be fine since I live near Miami, FL.
http://www.partzilla.com/parts/search/Honda/Motorcycle/1981/CB650C+A/OIL+FILTER+%2B+OIL+PAN/parts.html
Is there a difference between the 15410-426-010 and 15410-426-000? - Item #4 - $7.31

By the way what kind of oil do you guys normally put? Will the above mentioned be ok?

Thanks,
-Alex

[bmx4637]

Ok my notes from last year showed results from my 2nd compression test (cold, dry):
#1cyl - 85psi
#2,3,4 - 0psi

so I did a Leak Down Test today (no gauge just listened to air):
#1cyl - small leakage through oil cap (piston rings)
#2cyl - large leakage out of exhaust pipe (I also put a note in my notebook that I felt a little air at the top of the head, but wasn't sure if it was air leaking out of the threads/hose or not).
#3cyl - large leakage out of intake
#4cyl - large leakage out of intake and exhaust.

I feared that after my valve train was improperly timed, that I may have bent the edges of the valves while doing the 1st compression test. I believe my fear has come true, as this is precisely the order of the camshaft timing (#2 ex, #3 int, #4 int+ex) when #1 cyl. is at TDC.

I have my other identical bike's valves so I can just replace these if that is the case. However it wouldn't explain why it was running so rough originally, before the valvetrain was moved backwards.

If not bent valves, then I will Re-Lap.



I am now in the process of removing the top end. Currently the valve head is removed, next I will remove the carburetor assembly, exhaust, then cylinder head.

Since #1 cylinder shows bad piston rings, I might as well change all piston rings while I'm at it.....so engine rebuild?

Thanks,
-Alex

[bmx4637]

Hey CalJ,

Thanks for your response, it was very informative. I am usually first to question my work before the bike/car (as I've asked in previous posts if I am doing things correctly, even after going step by step through the manual).

My compression tests were performed late last year and since my bike has sat since, my battery was done. So all the information I have is from memory and notes. I wanted to grab a battery at walmart but decided to just leak test it instead.

When I was able to originally start and run the bike, I didn't have an IR temperature gauge to see if all cylinders were firing. I had suspected misfiring but wanted to ensure that my valve timing was correct first. Which led to this mess.

After adjusting properly and had verified correct timing is when I finally did the compression test (choke 'open'?, throttle open). Unfortunately the bike wasn't starting, so an engine warm up wasn't possible. Also, by the time I hit the 4th cyl. I could tell my battery was going off. Therefore I didn't perform a wet test on all 4. If I did wet then I could possible have gotten 100psi maybe 110. Spec calls for 170 +/-28 so between 142psi and 198psi. Honestly if I had 110 in all four I would be happy and wouldn't touch a thing. But yea even the book says top number isnt as important as comparables between cylinders. Compression tests aren't the most difficult thing to do, but yea maybe I did something wrong.

But I must say, I have to be doing something wrong with this. Even following procedures in the manual.

Having all the correct tools helps, however money is always an issue for everyone who may not perform these specific tests very often. A dedicated testing equipment of decent quality would absolutely be more definitive. But if I can feel air leakage coming out of my exhaust with a shim between the rocker arm and cam lobe to verify no contact is on the valve, then I'm going to take a look at that valve.

I suspect based upon the pictures you posted of your cam, that one of the issues you're having is the cam and rockers more than the rings or bent valves.

What do you suspect? When I took the valve cover off I wanted to see the differences in wear and patterns of the other camshaft I have from my other bike. The camshaft on this bike I'm working on definitely has some heavy wear but I couldn't 'see' anything else wrong' maybe I'm missing something?

While it is certainly possible to bend valves with the wrong cam timing, I suspect based upon the pictures you posted of your cam, that one of the issues you're having is the cam and rockers more than the rings or bent valves. If you pull the head, remove and keep in order all the valves for check on their straightness. But also accurately check the valve guides. If both are still good, a gentle lapping, or better yet, invert the head, and seal the valves, then pour fluid onto the combustion chamber and watch for leakage. That will tell you more than your intuition.

The point I'm making is, too many folks make small mistakes in assembling their engines, then believe a major component or aspect is now at fault. So they tear back into it, and never resolve the actual issue. General diagnosis and specific tests should always be done to truly identify the source of the problem, then fix that issue and assemble correctly. You'll save time, money, and engine parts. 

Yea I agree with you 100% there. I may take everything off and fine no problems which can very well frustrate me more with my diagnosis. It can very well be that my valve springs are unable to provide a proper seal (Which I will measure once removed). But I have no compression and heavy leakage So I'm going to take a quick peak lol 


Thanks,
-Alex

[bmx4637]

Posted by: calj737
To accurately determine cylinder wear, lobe wear, spring fatigue etc you need accurate measuring tools. You cannot "eyeball" these measurements.

Right...

Posted by: bmx4637
It can very well be that my valve springs are unable to provide a proper seal (Which I will measure once removed)...Thanks Tews, yea it (camshaft) definitely does look worn. I will probably need a micrometer to determine if it is out of limits or not.

My previous visual inspection was to look at wear patterns, which the manual says to look for.
I've seen that worn camshafts tend to cause backfire and low compression, however I haven't experienced those symptoms with this bike. Only afterfire and no compression.

As for the leakage at the exhaust, that could easily be down to bad gaskets.

I believe it would have to leak past the valve first then past the exhaust gasket though. If leaking past the head gasket then I would feel/hear the air coming out of the head/block interface instead of the tail pipe.







But I went ahead and moved forward anyway, Removed the exhaust manifold and carb assembly which actually wasn't as bad as I thought it would be. It appears that the previous owner had put a white grease on the rubber seals to facilitate removal/installation.

         



Question:

         
Carb assy removed from bike

         
Carb assy from parts bike. Anyone knows what that little manifold at the top is?




This was the compression tester I used, middle one fits the threads on the bike. Since it's a 2piece system it works very well for leak testing when connecting an air line to the fitting. I have videos of the leak down test with the carb assy and exhaust manifold removed to see a few things better before removing the head. Just haven't uploaded them yet.


         
Image of #4 cylinder intake port.                                                                         Image of #4 cylinder exhaust port.     Camshaft is removed so valves are supposed to be shut.



Out of focus Image of #3 cylinder intake port.


         
Image of #2 cylinder exhaust port.                                                                         Image of #1 cylinder exhaust port. Closed the way it's supposed to be.






         
Cylinder head bolt pattern.                                                                                                                        Cylinder head removal procedures.


         
3" extension 3/8"drive. Very useful for #'s 1-4 bolts because of the center frame. I didn't want to use a 1/2" drive and put too much force without knowing it and break some bolts. Luckily they all came out no problem with some elbow grease.





Bolt position #3, I had to install the extension first then connect the ratchet because the frame wouldn't let it all fit together.


                             
Just make sure that socket/extension doesn't fall into the chain cavity!! *cough*                   Magnet also helps remove the bolts/washers. My #11 bolt actually had 2 washers on it 




         
Cylinder head bolts removed.


Now I am trying to remove the cylinder head only and not the cylinder block. However the entire assembly is loose and I've tapped a ton with my rubber hammer, tried cylinder compression to remove (as noted in manual) and the block keeps trying to come off, but I don't want to remove the block. I want to remove only the head. I don't want to score or pry open the head/block interface and cause out of round/local warp that will make me need to deck the head.

Any tips?

Thanks guys,
Alex

[Tews19]

Alex, non of your pics posted.

[bmx4637]

Are you guys able to see the pics now? I can see them on my comp and phone.

I would have never thought about that rope idea.

[Tews19]

No bud

[bmx4637]

Are you able to see the pics from my prior posts on page 1?

[Tews19]

Yes I can see on page 1.

[bmx4637]

Ok the url's for the images work and it's coded the same as the previous page's images. It shows on my comp and phone. I'm thinking it may be information overload since it is 21 images. I will repost it in 3 posts to give it a try.

[bmx4637]

Posted by: calj737
To accurately determine cylinder wear, lobe wear, spring fatigue etc you need accurate measuring tools. You cannot "eyeball" these measurements.

Right...

Posted by: bmx4637
It can very well be that my valve springs are unable to provide a proper seal (Which I will measure once removed)...Thanks Tews, yea it (camshaft) definitely does look worn. I will probably need a micrometer to determine if it is out of limits or not.

My previous visual inspection was to look at wear patterns, which the manual says to look for.
I've seen that worn camshafts tend to cause backfire and low compression, however I haven't experienced those symptoms with this bike. Only afterfire and no compression.

As for the leakage at the exhaust, that could easily be down to bad gaskets.

I believe it would have to leak past the valve first then past the exhaust gasket though. If leaking past the head gasket then I would feel/hear the air coming out of the head/block interface instead of the tail pipe.







But I went ahead and moved forward anyway, Removed the exhaust manifold and carb assembly which actually wasn't as bad as I thought it would be. It appears that the previous owner had put a white grease on the rubber seals to facilitate removal/installation.

         



Question:

         
Carb assy removed from bike

         
Carb assy from parts bike. Anyone knows what that little manifold at the top is?

[bmx4637]

This was the compression tester I used, middle one fits the threads on the bike. Since it's a 2piece system it works very well for leak testing when connecting an air line to the fitting. I have videos of the leak down test with the carb assy and exhaust manifold removed to see a few things better before removing the head. Just haven't uploaded them yet.


         
Image of #4 cylinder intake port.                                                                         Image of #4 cylinder exhaust port.     Camshaft is removed so valves are supposed to be shut.



Out of focus Image of #3 cylinder intake port.


         
Image of #2 cylinder exhaust port.                                                                         Image of #1 cylinder exhaust port. Closed the way it's supposed to be.

[bmx4637]

         
Cylinder head bolt pattern.                                                                                                                        Cylinder head removal procedures.


         
3" extension 3/8"drive. Very useful for #'s 1-4 bolts because of the center frame. I didn't want to use a 1/2" drive and put too much force without knowing it and break some bolts. Luckily they all came out no problem with some elbow grease.





Bolt position #3, I had to install the extension first then connect the ratchet because the frame wouldn't let it all fit together.


                             
Just make sure that socket/extension doesn't fall into the chain cavity!! *cough*                   Magnet also helps remove the bolts/washers. My #11 bolt actually had 2 washers on it 




         
Cylinder head bolts removed.


Now I am trying to remove the cylinder head only and not the cylinder block. However the entire assembly is loose and I've tapped a ton with my rubber hammer, tried cylinder compression to remove (as noted in manual) and the block keeps trying to come off, but I don't want to remove the block. I want to remove only the head. I don't want to score or pry open the head/block interface and cause out of round/local warp that will make me need to deck the head.

Any tips?

Thanks guys,
Alex

[bmx4637]

I will try the rope in the cylinder idea, but I think it will just move the entire block up anyway, similar to adding compression in the cylinder. Is there any way to hold the block down and pull/push on the head?

Thanks,
-Alex