running like s**t after short high speed/full throttle runs.


what do you guys think is going on? I know its most likely a carb issue but im not exatly sure what to do. i was in a long straight section of road so i decided to open it up a bit, I rode maybe half a mile at around 3/4 throttle and when i let off to turn around the bike didnt want to idle or rev without cutting out and backfiring. after i rode back to where i started and let the bike idle for about a minute it cleared up and ran fine again. This isnt the first time this has happened so I would really like to get it straightened out.



Check to make sure the tank vent isn't plugged up. If it's plugged or partially plugged it will starve the carb for fuel. Your vent hose may have a kink in it.

the vent is perfectly clear. One thing that is not normal besides starving for fuel after high speed runs is that the bike is somewhat hard to start cold. I'm going to venture to guess that the two issues are related and I plan to clean the carburator and make sure everythings okay in there as soon as possible

hard starting cold is indicative of the valve lash out of spec.

cleaning the carb is always a good idea

cleaned the carb and the problem is still there so i'm checking the valve clearence soon.

First off is this a 2T or 4T?....2T plug is getting fouled, therefor jet changing is req or piston rings are gone. 4T... Had same Prob on Rap, head gasket had a small fatigue in it, and would release fluid into cylinder under high RPM's, have a friend follow and smell for burnt anti-freeze. More proper method, radiator pressure check and Cylinder pressure check.

its a 4T, Suzuki Z400 quad and it does lose a small amount of coolant over time but has been doing it for a while. What would that have to do with hard starts tho? sorry if thats a dumb question im a newb when it comes to the actual internal parts of the motor :smirk:

sometimes if u have a small failure in you head gasket u can get a fluid draw into your jug. mostly after it would sit over night or after a strong motor load. this might not be your case but dont eliminate it as a possible issue. you can smell exhaust after your bike acts up and see if it smells wierd, ie burnt nasty smell. hopefully its just a tuning prob. good luck.

Choke rusted half shut inside carby? when its running lever the choke on & off. If it doesnt make a difference to how the bike idles its rusted or jammed

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