Topic: Top End Work Complete - Bike Won't Start

[mbspark]

I've been searching on the forums for others who seem have to have the same issues as I have, but all I get is the same symptoms and the user never came back with a solution.

Here is my story and hoping someone can guide me in the right direction.

I tore apart the top end, new Head Gasket, Bought a flex hone brush to deglaze the cylinders, installed new valve stem seals, lapped valves. Yesterday, I got the new base gasket on, installed the cylinder head, valves, and finally the cam shaft and cover.

Through this process I didn't crack the case and had the cam chain always hanging over the edge or head up by a string, so it should never have come off at the bottom.

After putting everything back together, I lined up the timing marks with the notch in the camshaft as stated in the manual and was identical to another 550 I was able to use for reference.

Threw oil in the bike attached the tank to fire it up and hooked up the battery to my jeep with jumper cables so I knew I didn't have a battery issue in starting.

The Bike tries to fire up. It spits a bunch of gas out of the back of the carbs when starting.

Also after it tries to turn over, eventually it sounds like something gives loose and you hear this fast spinning like a drill and then followed by a grinding noise of a gear engaging (My guess after searching the forums is the spinning sound is my starter and it's spinning freely for some reason) The engine is turning, the nut on the points cover is spinning.

Kick starting does nothing. The Bike doesn't even try to start when kick starting, it just coughs with every kick.

I tried to take a video for reference of the sounds and what is going on, but it's very blurry. I'm at work now, but will attempt a 2nd video when I get home.

I feel like all of this would be a fuel issue, seeing as the fuel is spitting out the back of the carbs instead of being sucked in, but it's that letting loose sound followed by a grinding noise that really has me concerned.

[Bankerdanny]

At the very least it sounds like a starter clutch problem.

I suppose you could have the cam off by 180 degrees so that the intake valves are opening during the exaust stroke, blowing air back through the carbs.

You should be able to watch the action of the valves as you rotate the engine my hand to confirm the proper valves are open/closed at TDC

[mbspark]

Thanks for the reply!

To see the action of the valves, should I just open a few tappet covers and see what they are doing?

I get very confused on the matching of the timing marks with the notch of the camshaft vs TDC.

Is it as simple as, through timing "peep hole" T 1-4, equals camshaft notch matched with surface level facing forward, and TDC on 1 & 4?

[dave500]

the cam cannot be 180 out,you can line up with either the front or rear level with the head,for example,line it up with the 1/4 mark and have the notch forward,now rotate the engine 360 degrees to the 1/4 mark again,,where is the cam notch now?its to the rear,make sure the cam is timed properly and recheck the tappet settings and the ignition timing aswell,was the bike running ok before the top end work?the tappet cover went on without fouling valve stems?

[mbspark]

the cam cannot be 180 out,you can line up with either the front or rear level with the head,for example,line it up with the 1/4 mark and have the notch forward,now rotate the engine 360 degrees to the 1/4 mark again,,where is the cam notch now?its to the rear,make sure the cam is timed properly and recheck the tappet settings and the ignition timing aswell,was the bike running ok before the top end work?the tappet cover went on without fouling valve stems?

Bike was running ok before top end work. Reason was it was smoking, so I went to replace the valve seals.

I guess I need to re-read my manual and figure out timing on this thing.

I did not use the rubber band trick for the rockers when putting the tappet cover on. I had a friend help and we pulled them up manually as we set it. The cover didn't sit level, but with little pressure down it would seat. I quite possibly could have buggered up the valve stems during this period.

I'm definitely leaning towards a timing issue seeing as how the gas spits out the back of the carb, but like I said above, that spinning and grinding to a halt noise concerns me as it's never done that before.

[Old Scrambler]

My bet is your 80 to 90-degrees wrong on the cam. When you align the cam in the tower to the correct end- marks...........and the T-mark is dead-on........you have to rotate the cam-sprocket to align with the mounting holes before you slide the chain on.   

[dave500]

hoping not but if you did bend an inlet valve stem and that valve dosent seat itll spit fuel backwards,are all the carbs spitting fuel or just one?

[mbspark]

the gas seems to be spitting out of just 1 & 4, and when I do try to start it, it seems that only 2 or 3 is firing.

I'm going to be out of town for 13 days starting tomorrow, so hopefully tonight I can find some time to check the marks on both the points and the cam sprocket

[Leanier]

Just an easy thing to try is have you tried choking it?  My fresh 750 engines always like the choke to start first, (has similar issues to you, and with the choke it eventually caught.)

[mbspark]

Yea, tried the choke for sure.

Since the gas is coming out the back of the carbs, there is definitely something off with getting gas to the head.

12 more days until I'm back home and can get in my garage :/

[76CB5WI]

I vote funky timing as well.

I would detension all the tappets..put it to 1-4 set the appropriate tappets..then go to 2 -3 and do the same the I would manually rotate the motor with the plugs out and do a static
time with a DC check light to make sure you have firing when 1/4 and 2/3 come around.
You should detension those valves before taking the cover off always.
Sorry if you have done all this...
Best luck hope for no damage.
Chris

[dave500]

it must be set with 1/4 on the compression stroke,rotate the engine and watch the inlet valve go down and watch as it comes up,as its near closed look for the 1/4 mark,or 2/3 mark as you do each pair,some folks get it wrong and just line up the mark but it might be on the exhaust stroke,you can adjust other valves with the engine in this position but i prefer to do them one by one.

[mbspark]

when rotating by hand, the (#4() intake valve starts it's down stroke when TF 1-4 hits through the peep hole. Also, when this happens, rotating by hand becomes very tough and let's up half way and is much easier. Is this the right timing for the bike or am I off 90 degrees?

If I had to take the head off to check for bend valves, do I need to buy a whole new head gasket after just putting a new one on without the engine successfully starting?

This is my first time doing any sort of timing with an engine, so I apologize for any ignorance or lack of knowledge when it comes to this.

[dave500]

rotate it with the spark plugs removed,that toughening up then getting easier feel is the other cylinders compressing then exhausting,keep rotating watching #1 inlet valve,watch it go down then itll start to come up,then cast an eye on the 1/4 mark as you rotate slowly till the tdc mark lines up with the mark on the casing,at this spot the cam notch should be in the forward position flush level with the head suface,,if you already have the tappet cover off the valves wont operate,just rotate to the 1/4 mark and look at the cam notch,,post some pictures for us.

[mbspark]

So here are some pictures. First pictures are when I line up the T. As you can see the notch isn't 90 degrees on the head.

Hope this one is clear enough to see in there. the T mark in " T F 1-4" is lined up.


Camshaft notch when at that position.


2nd view


Pic of Cam chain when T Mark is lined:


Here are pictures of the timing marks when the cam shaft is lined up 90 degrees:

[gsnorcal]

Cam looks off by about 2 teeth, if you are really at "T". At "T", shouldn't the lobes on #1 should be at 5 and 7 o'clock (yours are at 6 and . At least on other bikes (e.g. my 400, my KTM) that's how it is.

Dave

[mbspark]

Cam looks off by about 2 teeth, if you are really at "T". At "T", shouldn't the lobes on #1 should be at 5 and 7 o'clock (yours are at 6 and . At least on other bikes (e.g. my 400, my KTM) that's how it is.

Dave

Here, I turned up the brightness on the one photo. This is where I have it set when the notch is off. Hopefully this helps see what I have going on.

[gsnorcal]

Sometimes when I get stuck or confused about a manual's procedures, I just stop and think about how it must work. If you think about TDC, it helps. When #1 and #4 are at TDC (the "T" mark), one of them should have both valves closed and the other both open. For that to happen, one's lobes need to be at 5 and 7 o'clock (to open both valves), and the other at 11 and 1 (to not open the valves).

At this point, I do not see this being the case in your photos (assuming 1 and 4 are at TDC when you took the cam photos).

So, I think you need to rotate the cam about 2 teeth on the chain so that the lobes are in the correct position at TDC.

Then, you really need the manual to adjust the valves once you button it up. But even then, if you think it through, you can do without. The closed valves are the ones you adjust. So, look at the lobes on the cam, think about how the shaft rotates, and you can see how the Honda engineers managed to write the procedure. Here's the page from the 400 shop manual on the whole thing.



Dave

[dave500]

move the cam so the notch lines up with the head surface,with the "T" mark lined up as you have,with a bit of luck you havent bent valves.

[mbspark]

Well, I done with this thing. Time to get rid of it. Anyone want a 550?

I got everything lined up properly. Installed the valve cover very carefully, I'm very confident not valves are bent.

Bike still wouldn't start.

Exact same characteristics as to what led me to post this thread to begin with.

The real issue, it backfired and me being a complete moron had a rag sitting hear the rear fender I used to clean up gas, and when it backfired it caught the rag on fire and went up in flames. Luckily I had a fire extinguisher and could put it out, but the electronics panel is toast, fender, toast, battery toast, and I don't have enough time or money to do any more work on this thing.

Not a good day.

[Brantley]

I'm pretty confident EVERYONE here has had brainfarts that've lead to steps backward. Not much point in a tech forum otherwise. At least you admit to it and are ok . Walk away. I don't mean forever; just give your blood a chance to return from boiling. Check the classifieds here and put up a wanted post for your toasted stuff. I always keep this in mind (and it's an ex-girlfriend quote at that)- "Another man made it, that's what you are, why can't you fix it? It ain't magic."

[dave500]

anyone close by who could rig up a temporary wiring just to get it running?once you hear it run youll change your mind and stay with it,count to ten,deep breaths,can you post a picture of the entire bike?

[mbspark]

I have another 550 sitting right next to it that my buddy owns. I'm going to see if he is willing to let me transfer some parts to see if I can get it running, I just don't know what's left?? I know the carbs work because they worked on my buddy's bike to get it running. It just won't kick over. I've run out of knowledge or ideas.

Pics:

[Duanob]

Like was said before from your first set of pics your cam timing is off by a tooth or two. That notch on the end of the cam needs to be split by the head surface down the middle when the T 1-4 mark is dead on. This is not government work it can't be close and expect it to run right. Send another pic of the cam timing at T 1-4. Then recheck all your valve tappets again. I did this drill about three times to get it all correct. Then afetr all that you need to adjust the cam chain tensioner. Also your ignition timing may be off by quite a bit too. It doesn't take much of these issues to compound quickly to make the bike run like crap or not run at all. The starter may be a whole seperate issue. Don't give up just yet.

[mbspark]

I got it lined up last night. Had to change it 3 notches, but it looked as perfect as can be. Tightened up the chain tensioner, backed out all my tappets, installed the cover and tightened down the tappets per the manual with the right specs on my feeler gauge.