Topic: StrongPerf 550 project! CARB / Pods / battery / tank / tuning thread with pics

[StrongPerf]

Here is a pic of the current look. I'll be doing the pretty stuff soon.

I'm running the 272304 needles. They measure 2.52mm on the large diameter taper. My assumption is that this needs to be a little smaller for that initial fuel needed. I think the 40 mains will do nearly the same thing without requiring me to find different needles.

Thanks

[TwoTired]

Question: What is Throttle Valve cut away or opening?

The bottom of the slide is cut at an angle on the inlet side.  That is the Throttle Valve cut away.  More angle causes more velocity and suction on the jet needle outlet...I think.

Cheers,

[StrongPerf]

Couple of comments and a question or two:

I noticed that when the slide is fully open and the entire throat of the carb is open the slide will continue up quite a way's. This continues to pull the needle up and richens the WOT mixture because no more air is added but more fuel mixture is added do to the needle being further up. I adjusted the throttle stop on the linkage to stop just at the point the throat is fully open and my end result AF ratio is leaner. This is affecting what main jet feels right. The 105 main felt too rich only at WOT till I did this.

How much past a full throat opening is the slide supposed to go up? I haven't been able to find a spec for this anywhere...

My bike pops lots on closed throttle decel no matter what. The main and needle clip posit don't seem to affect it. I think my slows need to be bigger. The spec for IMS is 1.5 turns out. It's taking about 3/4 - 2/3 turns out (richer position than the spec) for the best idle. I'm thinking this is more evidence that I need to go from 38 slow's to 40 slows.


I set my floats to 22mm. My Clymer manuel showed the trick of using the transparent tubing rigged to the draing screw. I tried this to learn something. I placed the tube up the side of the float bowl and measured the fuel level. It was 4.5 mm down from the gasket parting line. Clymer doesn't give a spec for that. I'm assuming 4.5 mm is right if my floats to are set to 22mm. I can see how this could be used to verify all carbs have the same fuel level or to tell if I had a bad float.

Thoughts?

Thanks

[manjisann]

WOW, some good info on cleaning the carbs!  This is a great thread, thanks for taking the time to post it!

Brandon

[OakBehringer]

I set my floats to 22mm. My Clymer manuel showed the trick of using the transparent tubing rigged to the draing screw. I tried this to learn something. I placed the tube up the side of the float bowl and measured the fuel level. It was 4.5 mm down from the gasket parting line. Clymer doesn't give a spec for that. I'm assuming 4.5 mm is right if my floats to are set to 22mm. I can see how this could be used to verify all carbs have the same fuel level or to tell if I had a bad float.

Based on the pictures in your thread you didn't set your floats to 22. The measurement should be taken at the point that the float tab is just touching the pin. It looks like you're measuring from when the floats are resting on the pin, compressing the spring a bit. This will, as a consequence, keep the fuel level lower in your bowls. I don't have a 550, but 4.5mm below the gasket surface sounds quite low. I believe it should at the gasket level.

If your fuel level is low, it will take more suction to pull fuel through the jets.

On Honda twins it's not that hard to adjust the float height with the carbs on. With a four it's a bit harder to do on the inside carbs. On my 350F I have accurately adjusted the floats with the carbs on the bike by working from the inside out. You're going to want to wear a headlamp so you can see where the pins and tabs are just barely touching. This coupled with an acute sense of touch is crucial. Also, since your calipers won't fit in there, use them to cut a rectangle of thin cardboard to 22mm and use that to measure from the gasket surface.

It's worth noting that, without the horrid pain of removing and installing the 350F stock airbox, you might be able to get this done faster by simply removing the carbs.

[StrongPerf]

Based on the pictures in your thread you didn't set your floats to 22. The measurement should be taken at the point that the float tab is just touching the pin. It looks like you're measuring from when the floats are resting on the pin, compressing the spring a bit. 

OB

Thanks for the tip. It has been a while since I set them but I think I did it correctly. It's hard to see in the picture but if I remember correctly, my other finger is holding the float in place where the tang is just touching the tip of the pin. I need to pull the carbs anyway to fix a stripped out screw hole and I need to replace the throttle cables. I'll check it again and make sure it's right!

[OakBehringer]

Someone else should chime in here, but 4.5mm below the gasket surface sounds low to me.

Let us know what happens.

[StrongPerf]

Someone else should chime in here, but 4.5mm below the gasket surface sounds low to me.

Let us know what happens.

Me too. That's why I was asking. I will check it againg and post results. Thanks!

[super pasty white guy]

I just read the slide retraction height yesterday.  It should be even with or less than 1 mm higher than the throat of the carb.

spwg

[StrongPerf]

I just read the slide retraction height yesterday.  It should be even with or less than 1 mm higher than the throat of the carb.

spwg

Great info. Thanks!

[StrongPerf]

Dangit! How many times do we hear to make sure all our tune up is in order before jetting... 

I found my ignition advancer stuck and my intake manifold o-rings shot. It was an extreme difference in power once the was advancer fixed. Also once I replaced the manifold o-rings I needed to step down from 105 mains to 100 mains. This little motor screams now.

I also had a time syncing the carbs. It seem that the little tab connecting the syncing screws for 1-2 and 3-4 holds the syncing assembly in a bind when the jam nut is tightened. As the assembly twists (and held there due to the tab) it changes the sync because it's pivoting pulling the lever up or down. After fighting it forever I finally got pissed and cut the tabs (I have another set). It took a sync and kept it! I know Honda designed those tabs for a reason but unless one of you experts can talk me into using them again, I'm done with them...

I'm getting real close to final carb setup and will post all combo/settins/results.

Thanks for the help guys!

[StrongPerf]

Someone else should chime in here, but 4.5mm below the gasket surface sounds low to me.

Let us know what happens.

I double checked and my floats were set properly at 22mm with the tang just touching the pin. I guess fuel level 4.5mm below the parting line is right. Unless my floats are bad... I doubt it though...

[StrongPerf]

Ok I'm about ready to call this thing properly tuned with one exception. A slight miss-fire between 4500 and 5500 rpm. Mostly at light throttle 1/8 to a little over 1/3 throttle is where I notice it most, but only because that's the only throttle positions that allow me to stay in that RPM range very long. Also if I start accelerating at those throttle positions at say 3000 RPM and just let it accelerate to say 6000 RPM the missifire starts at 4500 and stops at 5500. It's extremely clean at 4000 and 6000, just not between 4500 and 5500. It's real subtle. Like a cylinder down. Maybe even 2 cylinders down. No real surge or anything just a different note to the exaust a slight loss of torque. It doesn't change whether the bike is hot or cold. I drove about 10 minutes in a straight line at 5000 rpm and let it miss. I then stopped and checked the plugs. The were burning clean without loading up with soot. The bike did not feel rich. #4 looked a little fuel wet on the outer perimeter. #1 also but less than #4. #3 looked clean and I didn't check #2. This miss is not load dependent.

With 100 mains and the clip on the richest setting the bike ran perfect (enough for me)except for this... I moved the clip up 1 (leaner) and it changed the feel of things a little but not the miss.

I have new coils/wires/plugs and a Hondaman ignition on the way. Points are new and set and timed properly. The bike absolutly rips! Just a drop in note between 4.5 and 5.5.

I'll get the parts in and check it again this week but looking for things to check...

Thanks

[StrongPerf]

I thought you guys might like to see my other threads on this bike:

Swingarm, Wheels, chain, etc:

http://forums.sohc4.net/index.php?topic=28324.0

And front end swap:

http://forums.sohc4.net/index.php?topic=31582.0

Coming soon: Paint and pretty stuff.

[StrongPerf]

Ok I'm about ready to call this thing properly tuned with one exception. A slight miss-fire between 4500 and 5500 rpm. Mostly at light throttle 1/8 to a little over 1/3 throttle is where I notice it most, but only because that's the only throttle positions that allow me to stay in that RPM range very long. Also if I start accelerating at those throttle positions at say 3000 RPM and just let it accelerate to say 6000 RPM the missifire starts at 4500 and stops at 5500. It's extremely clean at 4000 and 6000, just not between 4500 and 5500. It's real subtle. Like a cylinder down. Maybe even 2 cylinders down. No real surge or anything just a different note to the exaust a slight loss of torque. It doesn't change whether the bike is hot or cold. I drove about 10 minutes in a straight line at 5000 rpm and let it miss. I then stopped and checked the plugs. The were burning clean without loading up with soot. The bike did not feel rich. #4 looked a little fuel wet on the outer perimeter. #1 also but less than #4. #3 looked clean and I didn't check #2. This miss is not load dependent.

With 100 mains and the clip on the richest setting the bike ran perfect (enough for me)except for this... I moved the clip up 1 (leaner) and it changed the feel of things a little but not the miss.

I have new coils/wires/plugs and a Hondaman ignition on the way. Points are new and set and timed properly. The bike absolutly rips! Just a drop in note between 4.5 and 5.5.

I'll get the parts in and check it again this week but looking for things to check...

Thanks

So I got new Dyna 5 ohm coils and a HondaMan ignition. New wires too. She runs so smooth now!

I'm giving up on pods for now though. I thought the previouse set up was great. It was until the motor was fully warm (freeway speeds for more than a few minutes). I've got too much cash into jets and such. Now it comes to needles and I probably couldn't re-sale those if they are not right.

I noticed that with 100 mains and the clip on #5 (full rich) 1/3 to 2/3 throttle posit was great but 0 to 1/3 was a dog (felt rich even with 38 slows) and WOT was rich. I went to clip #4 (leaner) and now the light throttle felt better but after riding this combo on the freeway at 75mph it started surging and showing lean from 1/3 to 3/4 throttle with WOT feeling better. I even tried a .5mm washer shim to put me between #4 and #5 clip. It seems that the needle taper is just wrong. I think maybe not enough taper. I'd like to try the F bike needles since I've got a 4-1 header but it's not stock either. I found some new needles that might work but before I spend lots of cash on maybe's I'll get some dyno time to confirm my feelings. In the mean time the airbox is back in. I really like what works best without getting obsessive.

The real reason I wanted pods is to move my electronics in and put flat side covers on the bike instead of the bulky wide stockers. I'm 5'6" and the wideness of the bike bothers me. I also don't think spending cash on this tuning is wise for now. I'll spend the money on getting the bike nice first. If I do revert to pods I'll post results. I won't do it unless it can be done right. If anyone has got a set of F needles they are willing to part with I'd give them a measure at least. Thanks.

[StrongPerf]

So I've ridden the bike with the stock airbox for a while now. It's still not perfect!

I did put in a new Uni filter, properly oiled and such. I also made sure all the hook ups and lines were correct.

The problem is I still get a difference in exhaust note at low RPM's. With the clip at #4 (stock) the change in exhaust note is from 3800 to 4800 RPM. If I decel (engine brake) gently down to that area and then slightly crack the gas there is a hesitation. This is very annoying  because often I am trail breaking going into a turn and just want to get back into it slightly to power out of a turn. I tried the clip with a .5mm washer under the clip (1/2 clip richer) and it feels the same but now the burble is at 4500 to 5000 RPM (liike when the pods were on it).

I also don't like 3/4 throttle. This was worse with the pods but still isn't great. Not a hesitation her but just a little flat. It seems worse at #4 clip than with the washer under the clip (#4.5). This leads me to believe that the needle is slightly lean at 3/4 throttle. I know it's not from twisting the throttle too quick because it if I twist it real quick to WOT it isn't flat.

I am in the stock set up for this bike (except for the header). 022A/100 mains/38 slows/1 1/2 turns out/clip #4/22mm float setting. I'm running .012 point gap, timing full advance withing the ll (lines). Brand new plugs (then look great), wires, caps, coils, Hondaman ignition, etc.

Any ideas?

[TwoTired]

Cover up your tach face or disconnect it.

Mark your throttle so you can tell what position it is in when you have annoying symptoms.

Warm the engine, then put in clean spark plugs.

Operate the engine at the throttle setting where the annoyance occurs.  (Long enough to make readable deposits on the spark plugs.)
Hit the kill switch and pull in the clutch.
Remove spark plugs and read the deposits. Or, take pictures and post them.  We will need the see the center electrode insulator from tip to recess, and the ground strap in detail.

You can observe if all the plugs "read" identical.  If not you have other issues to correct before focusing on mixture adjustments.

Are you certain that the emulsion tubes are clean and that the throttle valve jet is not worn or altered in shape/size?

Cheers,

[StrongPerf]

Cover up your tach face or disconnect it.

Mark your throttle so you can tell what position it is in when you have annoying symptoms.

Warm the engine, then put in clean spark plugs.

Operate the engine at the throttle setting where the annoyance occurs.  (Long enough to make readable deposits on the spark plugs.)
Hit the kill switch and pull in the clutch.
Remove spark plugs and read the deposits. Or, take pictures and post them.  We will need the see the center electrode insulator from tip to recess, and the ground strap in detail.

You can observe if all the plugs "read" identical.  If not you have other issues to correct before focusing on mixture adjustments.

Are you certain that the emulsion tubes are clean and that the throttle valve jet is not worn or altered in shape/size?

Cheers,

Thanks TT 

I've got the throttle marked. So far the change in exhaust note at low RPM has been around 1/8 throttle, however, when I hold the throttle at 1/8 and acclerate, the change in exhaust note starts at 3800 RPM and goes away at 4800 RPM without changing the throttle position (clip #4). It does the same thing at a 1/2 clip richer but starts at 4500 and goes away at 5500.  If I decel into one of these areas where the exhaust sounds different and transition from decel to accel it will hesitate in the first 1/16 throttle (transition really).  I can't seem to keep it there very long though. I'll find a lonely country road and bring my plug wrench, new plugs and a camera.

The 3/4 throttle problem is also hard to keep there due to high speeds. I'll try it on a long hill. It seems to get worse as I lean the needle but not positive about this. I'll do the plug chop after finding a nice hill.

My emulsion tubes and the carbs were very clean when I put it all back together. As earlier in this thread I did have to replace one bent carb body (#4). It is the same 022A. I did check that all the passages are clean in all the carbs. I'm not sure what the throttle valve jet looks like to check it. Is this the orfice at the end of the emulsion tube where the needle goes in?

I looked at my slow jets before. 38 or 40 doesn't seem to feel any different. The holes in some 38's look bigger than some on the 40's. I have run a small strand of copper wire through each to clean them out but they still don't look all the same. I got another set of 38's and have been soaking them for a couple of days. I'll try to get a set that at least looks equal to my naked eye before I do these checks you recommend.

[TwoTired]

I'm not sure what the throttle valve jet looks like to check it. Is this the orfice at the end of the emulsion tube where the needle goes in?

Yes.

[StrongPerf]

You can observe if all the plugs "read" identical.  If not you have other issues to correct before focusing on mixture adjustments.


Are you certain that the emulsion tubes are clean and that the throttle valve jet is not worn or altered in shape/size?

It looks like I have other issues to correct before focusing on mixture. I think these pics will show that not all 4 plugs look the same. #2 looks the lightest and #4 the darkest with #2 and 3 being in between.

I have put in 4 #38 slows that all are clean and look like the same size hole. I have checked all my emulsion tubes. They are all clean and all the same size at the throttle valve. All my needles are the same and not worn. All idle air screws set to 1 1/2.

This was after a 30 minute ride at 1/8 to 1/4 throttle. I started with new plugs. I didn't let it idle and didn't go much past 1/4 throttle at all. I kept it in the area that had the odd exhaust note and felt sluggish.

Edit: #1 on left #4 on right.

[StrongPerf]

Another shot

[StrongPerf]

One more.

[TwoTired]

What's that glossy stuff on #4?  Oil?

Since they are not even in coloration (not awful, mind you), and you can't find overt differences inside the carbs...

Is your compression equal across the cylinders? 
Are all the valves adjusted with spec and even? 
Can you comment about cam wear among the lobes? (do all the valves open the same amount?)
Have you done a leakdown test?
Can you be certain there are no leaks in the induction either before or after the carbs?

This was after a 30 minute ride at 1/8 to 1/4 throttle. I started with new plugs. I didn't let it idle and didn't go much past 1/4 throttle at all. I kept it in the area that had the odd exhaust note and felt sluggish.

The difficult thing about street tuning, in this throttle range, is that the engine is so lightly loaded and not close to making max power at this throttle setting.  Deposits are very slow to show their true colors as peak temps can't be achieved.  One of the valuable things about a dyno vs. street tuning.

I'd like to see into the depths of the spark plug to see how far up the deposits crawl toward the tip.

I didn't reread this whole thread. So, I'll ask if you have vacuum synchronized the carbs.

Cheers,

[StrongPerf]

What's that glossy stuff on #4?  Oil?

Since they are not even in coloration (not awful, mind you), and you can't find overt differences inside the carbs...

Is your compression equal across the cylinders? 
Are all the valves adjusted with spec and even? 
Can you comment about cam wear among the lobes? (do all the valves open the same amount?)
Have you done a leakdown test?
Can you be certain there are no leaks in the induction either before or after the carbs?

This was after a 30 minute ride at 1/8 to 1/4 throttle. I started with new plugs. I didn't let it idle and didn't go much past 1/4 throttle at all. I kept it in the area that had the odd exhaust note and felt sluggish.

The difficult thing about street tuning, in this throttle range, is that the engine is so lightly loaded and not close to making max power at this throttle setting.  Deposits are very slow to show their true colors as peak temps can't be achieved.  One of the valuable things about a dyno vs. street tuning.

I'd like to see into the depths of the spark plug to see how far up the deposits crawl toward the tip.

I didn't reread this whole thread. So, I'll ask if you have vacuum synchronized the carbs.

Cheers,

That's why I rode for 30 continious minutes at this throttle setting. I new it would be hard to get some color...

The glossy stuff on #4 is fairly consistent but doesn't get much worse over time.

Valves have been adjusted and are all even. I lashed the exh at .an extra .001 looser as per Hondaman's recommendations for longevity.

I have done a sync. They synced pretty good. I did it at about 2000 rpm and not at idle. They were pretty close at idle anyway. I can do it again and will just to check.

I had manifold leaks but put in new o-rings. The RPM's don't change when I spray WD-40 anywhere on the intake system. I assume I have no leaks now...

My compression tester and leakdown tester don't have 12mm adapters but I guess I should hunt the stuff down.... I guess that's next because something is still wrong.

I have a CB650 cam to put in it but didn't want to do the swap until I know all is right. I have not measured the old cam lobes. I can pull the cover and measure cam lift with a dial indicator. If the cam is bad at least I have another. I could also check rocker wear at the same time...


Does this sound like a good diagnosis check list?

Re-sync carbs (free)
Compression test and leakdown test (find 12mm adapter)
Check rocker and cam lobe wear


I really cleaned these carbs good but is there any particular passages (air maybe) that I should go back and check?

Here is the shot you asked for. It's #4 plug. I have #1,2,3 if needed.

[HondaMan]

You're battling with the famous 500 flat spot....it was still there on the 650, as I recall.
One suggestion comes to mind, as I didn't see it in the posts I've had time to read:

Have you tried running with the airbox in place, but without the foam filter? (Like, with a paper or K&N or no filter at all?)

And, a comment: the 500/550 bikes always suffered a flat spot in the 4000-5000 RPM range for several additive reasons:
1. Long intake tract. This improved bottom end, but impedes the transition to high end until ramcharging occurs from the length, hence the "spitback" range, as we used to call it.
2. Poor construction of the intake tract right over the intake valve(s). This area needs a pocket, which reduces the flat spot noticeably.
3. Spark advancer rates never matched the cam on these bikes. To smooth out the flat spot for our lady riders, we used to cut off 1/2 to 1 coil on each spring: for the hotrodder we installed softer springs. Either one blended the flat spot into either an extension of the low end (cutting springs) or started the HP sooner (soft springs). Another option was to alter the cam timing, which accomplished the same thing: move it forward to improve midrange at the cost of 1 HP or so up high, or move it later to push the spitback range up toward the  ramcharging end of the intake dynamics. This made it a Johnny-come-lately on the HP, but made an extra 1 HP or so at 8500 RPM, with power starting just over 6000 RPM.  The change was 3-5 degrees on the cam sprocket.

Make sure on those carbs: the air passage from the air horn to the emulsifier tubes must be VERY clean. These collect tiny particles over the years, and are invisible to the user: this is the little brass fitting in the air horn that has a tiny hole in it: that hole goes thru the body to the emulsifier tube, adjacent to the needle jet, right at its base. Even a 25% blockage can cause uneven carb performance. I clean these with mechanic's wire and brake cleaner, then compressed air. Gotta disassemble the carbs to get at them (even remove the needle jet), but I've found it worth the effort, and do it to every bike I rebuild.