Runs like crap until 4000rpm?

[rider119]

Bike runs like crap, bike fire, bogs, no power, until I get it up to 4 grand then runs great, any ideas?

 

[rider119]

Hard to get it to 4 grand too.

 

[rider119]

Carbs I assume? Maybe timing? 82 with pamco by the way. Cam chain and valves adjusted, carbs cleaned, fresh gas, new plugs.

 

[Sparky]

vacuum leak? spritz around the carbs with carb cleaner or starting fluid. if its sucking air it will run quite differently.

also, check to see if both cylinders are firing.

in my experience, it pretty much wont run at all if you left something out of the carbs, so i think you got that right. have you read one of the multiple carb rebuild manuals floating around here? they are a wealth of info.

 

[rider119]

Alright, I'll give that a shot. Both cylinders are making a spark, have good compression, and getting fuel I assume.
No I have not read any of the carb manual through, glanced through one of them I downloaded however.
Can anyone give me a link or something to a good post, video, manual, or whatever for some good info on setting the timing with my pamco and how to use a timing light?
Thanks

 

[mick71b]

Clogged up pilot jets or bad carb slide diaphragms would be the first thing I would check.

 

[RatyXS]

^^^^ Im with him...

 

[angus67]

wrong pilots if your carbs are truly clean. what intake /exhaust you got? what brass is in your carbs now?
float level is very important.

 

[rider119]

Can't remember on brass, not sure how to check float level. Diaphragms seemed fine from what I remember, but who knows. Have to tear them apart tomorrow maybe if I can find time. Running air pods, xs performance I believe, and two into one straight pipes.

 

[angus67]

first, lose the pods, and get these,
http://www.motorcycle-superstore.co...ID=AvantLink|NA|55963_d3fe7c65&WT.MC_ID=54020
Then find the carb guide and figure it out. it is the carb bible. seems daunting at first, but it is all there.
The xspods don't deliver good air flow, and can make the slide stutter. Those emgo pods are crap for cv carbs, they block the vacuum hole for the slide.
Im pretty sure your pilot is too small.

 

[TwoManyXS1Bs]

If misfiring occurs when manipulating throttle, think carburation.
If misfiring occurs at specific rpms, think ignition and/or exhaust reversion.

 

[rider119]

Ok, still haven't gotten a timing light on my bike but I took my advance mech off and set to tdc and the pin is at 12 o'clock so seems as though cams are in right. Is there another way to check? Other than tearing the head down? My pamco is set all the way clockwise just to get it started. Is that full advance or retard?

 

[rider119]

Also carb diaphragms look good, pilot is 45, needle jet 145, mix screw 3 1/2 out. Does that sound right? I'm by no means carb savy.

 

[scabber]

Turn the mixture screws back in 1 1/2 turns. The main jet is too big. What exhaust do you have on the bike.

 

[rider119]

Back of my advance mech plate, how bad is this? Cause of timing probs?

 

[rider119]

Just straight two into one pipes that dump just under the right foot peg.

 

[rider119]

Another shot of it.

 

[rider119]

You say main, same as needle jet? What would you suggest?

 

[scabber]

That is bad needs to be replaced. Your exhaust is a carb tuners nightmare.

 

[rider119]

Great, I'm by no means a carb tuner, always been my down fall. I will be replacing them with some just straight dumps at some point, not sure if that's any better.