I think I'm running...something. any help?

A

afiendishthingy

New Member
Alright ladies and gents, I finally got my bike in the road, but am having a couple of problems.
My bike runs great, until it gets to full operating temperature and giving me two specific faults.

1. After a while, when I am at a stop, shift into first and my bike bogs terribly until I stick it out and slowly gain speed, then boom, I'm good to go. Or I have to hold the clutch, rev, then dump the clutch to go.

2. It takes forever to get back down to idle speed (it will stay at around 5000 rpm). The only way I get it to go back down is to just keep it in gear until I almost stop or stop, poor a small load by releasing the clutch a tad, OR by cutting power for a split second (only done while I'm working on it in shop).

A few things, I cleaned and inspected everything in the stock carbs. Everything works great, slides slide without sticking and it seals completely. From what I can tell, the cable/cables work great. They go back to the stops without hesitation.

Only mods are uni pods, stock jetting. I didn't think it would be these, because I had on stockers(dirty ones mind you) and it did the same thing.

Any help would be greatly appreciated. Any jet recommendations would be great too if that is what my problem is.

Thanks!
 
You added more flow...but didn't add any fuel.

You are describing a LEAN condition. Hanging idle is due to the fact that there is a leak (carb boot) or that your mixture screws are set too lean. Generally with just a UNI filter on there (it has to be oiled too!) you can adjust the mixture screws and it will be a happy bike again.

So. Look for leaks at the boots, but I'm almost positive that your mixture screws need a 1 turn or so RICHER, possibly more.

Hope that helps!
 
It did it even when I was running rich(could smell it and also checked the plugs).
After I installed the filters it was running almost perfect(in terms of mixture) according to plugs. So I think I am good on mixture now, but I will definitely make sure to oil and adjust the mixture.

That makes sense. Since I posted this, I was thinking that it only does it when warm, so, the boot may be warming up and changing shape ONLY when warm and not sealing correctly. Makes sense, no?

I will double check everything tonight after work and either get new boots, or seal accordingly. Thanks for the info!
 
afiendishthingy said:
It did it even when I was running rich(could smell it and also checked the plugs).
After I installed the filters it was running almost perfect(in terms of mixture) according to plugs. So I think I am good on mixture now, but I will definitely make sure to oil and adjust the mixture.

That makes sense. Since I posted this, I was thinking that it only does it when warm, so, the boot may be warming up and changing shape ONLY when warm and not sealing correctly. Makes sense, no?

I will double check everything tonight after work and either get new boots, or seal accordingly. Thanks for the info!
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Not typically. Those boots don't deform THAT easily. I just realized that I goofed up and it's the opposite condition for this one. You are too Rich if it's getting worse as you warm up. Ugh...it's Friday.

Sorry about that.

If you haven't synchronized, this can cause the same thing as well. Some of the slides will be more open than others, causing a lag of throttle response and idle to be slow to come down. Just a thought.
 
Ah, I see. It was just a thought I wanted to check. I knew, what you meant with the lean/rich deal.

How would you recommend synching?

I put the carbs on, pulled out the idle until they didn't touch, then adjusted so they barely sat on on the stop, then started adjusting the cables(which were loose during the rest of the process) until both were being pulled equally and at the same time.

I actually brought my carbs to work on at lunch, so if you have any suggestions on what I should check on those I would appreciate it.
 
afiendishthingy said:
Ah, I see. It was just a thought I wanted to check. I knew, what you meant with the lean/rich deal.

How would you recommend synching?

I put the carbs on, pulled out the idle until they didn't touch, then adjusted so they barely sat on on the stop, then started adjusting the cables(which were loose during the rest of the process) until both were being pulled equally and at the same time.

I actually brought my carbs to work on at lunch, so if you have any suggestions on what I should check on those I would appreciate it.
Click to expand...


Look up "bench synchronizing" that's the best you can do without a manometer or sync gauges. If you are into bikes (which you are) you should probably spend a few bucks on them. Here's some great links to ones on sale now. Remember that depending upon your bike, you may need adapters if they don't have a vacuum nipple on there.

http://www.ebay.com/itm/Vacuum-Carburetor-Synchronizer-carb-sync-Gauge-2-cylinder-bike-Honda-CB-CL350-/290721182379?pt=Motors_Automotive_Tools&hash=item43b05532ab&vxp=mtr

This one isn't complete, but cheap!
http://www.ebay.com/itm/Vintage-Carburetor-Carb-Synch-Synchronizer-Sync-Vacuum-Gauge-Tool-/121129271265?pt=Motors_Automotive_Tools&hash=item1c33ddffe1&vxp=mtr

http://www.ebay.com/itm/MOTORCYCLE-4-CYLINDER-CARBURETOR-SYNCHRONIZER-TUNER-/190858347126?pt=Motorcycles_Parts_Accessories&hash=item2c700b4276&vxp=mtr
 
I can actually get one from my work for pretty cheap, thanks!

So to bench sync, I am just getting the butterflies to barely cover(but not entirely) the holes? Seems easy enough. Now once this is done, am I able to adjust the idle via the screws or what? That confused me a little. Also, does this need to be done with the linkage in place? Thanks for the help!
 
afiendishthingy said:
I can actually get one from my work for pretty cheap, thanks!

So to bench sync, I am just getting the butterflies to barely cover(but not entirely) the holes? Seems easy enough. Now once this is done, am I able to adjust the idle via the screws or what? That confused me a little. Also, does this need to be done with the linkage in place? Thanks for the help!
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Ok, so the butterflies are what control the amount of air that can flow through the carb. The holes you see are the PILOT JET holes (or idle jet, whatever you want to call it) You don't have to cover the holes or anything, but for bench syncing it can help "eyeballing" with where they are. Many use the drill bit method.

All the linkage should be in place, other than the throttle and choke cables if it has one.

Then the screws are for the idle, I'm assuming this is a cb350 or something? You never said which bike.
 
Yeah, It is for a cb350. I'm going to have to look it up a bit more. Everything I am finding is for four with a single cable. Mine obviously has two. I'm assuming twins are have a different way of syncing.

Thanks for all your help btw. While on lunch, I was fiddling with them and found that one slide has a sticky spot, which I never noticed before. I'm hoping it is that.

EDIT: It is only a slight stick and not all the time. I am going to clean the bore and slide and maybe this will work.
 
afiendishthingy said:
I am going to. So far I have them to be barely before the hole. They weren't off by too much.
Click to expand...

That gets you close, but each cylinder will be different than the other due to wear, carbs, filters, valves (need I go on... haha) Get that sync gauges as soon as you can my friend. Also, if you haven't double checked, make sure your timing is spot on, those twins will hate you more than an in-line 4 will if they are off a little ;) ::)
 
MotorbikeBruno said:
That gets you close, but each cylinder will be different than the other due to wear, carbs, filters, valves (need I go on... haha) Get that sync gauges as soon as you can my friend. Also, if you haven't double checked, make sure your timing is spot on, those twins will hate you more than an in-line 4 will if they are off a little ;) ::)
Click to expand...

I am beginning to think something is wrong with the carbs. I double checked everything, no air leaks, no sticking slides, no leak in diaphragm, I do need a new battery, but I don't think that will make it do what it is doing, fresh plugs, clean fuel, new petcock(old one didn't have in-tank filter so it kept letting crap get into the screen, I did realize oil is leaking from behind the points(cam oil seal I am assuming?), but the points are clean, oil just runs to the bottom where there is actually a missing piece and leaks out(just realized this as well). I am thinking of just going to stock advance, getting fresh jets, maybe one size up, and starting from there.
 
afiendishthingy said:
I am beginning to think something is wrong with the carbs. I double checked everything, no air leaks, no sticking slides, no leak in diaphragm, I do need a new battery, but I don't think that will make it do what it is doing, fresh plugs, clean fuel, new petcock(old one didn't have in-tank filter so it kept letting crap get into the screen, I did realize oil is leaking from behind the points(cam oil seal I am assuming?), but the points are clean, oil just runs to the bottom where there is actually a missing piece and leaks out(just realized this as well). I am thinking of just going to stock advance, getting fresh jets, maybe one size up, and starting from there.
Click to expand...


One thing I don't remember hitting on: Float height? If it's too high, that can cause a rich condition that you just can't fix without doing that.

Another thing: Coils that have cracked will work when cold, but when they heat up and expand will fail.

How many more things can we throw into the mix eh!? haha I wish you luck sir. Starting over isn't a terrible idea, and doing ONE thing at a time to see what helps!
 
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