Running like crap

[One-Industries]

Today i took one of my bikes out (a 200cc 4 stroke) and it was spluttering at high reves in 2 3 4 5 gear it got fairly hot aswell, a friend of mine said i have a air leak in the rubber grommet near the carby making it run lean, i somehow think the carby itself needs cleaning and re-jetting, what could be some other problems that could cause this?

 

[One-Industries]

Also could, timing or valves being sticky or need adjusting be another problem that might cause this?
It is misfiring quite about now, only at high revvs, could it be the spark plug, piston rings or dodgy wiring?
Lol good old chinese ****.

 

[NinetySix]

bikes only need rejetting when you change something (like exhaust or intake) or if they were not jetted real well from the factory. if it ran good when you first got it but not now, then a leaky carb boot is the problem. always a good idea to give the carby a pull down, clean it out thoroughly, make sure the float is set right, and the needle / needle jet are not worn. do that and replace/fix the carb boot then worry about what else it might be

 

[hughesy69]

yh the same thing happened to me it was the carby lid had come off also it could be the throttle adjustment if its screwed out far that can make high revs aswell

 

[One-Industries]

umm might be a dumb question but does a factory cdi have a revv limiter?
beacuse it was mainly at full throttle or close when it started spluttering/miss-firing.

 

[One-Industries]

na, its not the throttle adjustment, its just last time i touched it i put a 1/4 turn throtle on it and havnt experinced it with it on, so i was going full throttle sometimes. aswell i have changed the intake by putting a dual layer foam filter on it, when i first got that bike it had a wire "pod" filter on it and it was running good, the foam filter is like choking it somewhat.

 

[Mack]

Process of elimination is the only way to solve those problems. Breakdown of the top end like that could be heaps of things. Start with the carby first though before going to electrics or mechanical. Also helps to put things back to a previously known good state eg. put the old filter back on, change back any jetting or needle settings, things like that.

 

[sik-pj]

my bikes doing the same thing dont no wat it is as yet but my manifold gasket had a hole in it mabe it was that?? ill check 2moz and get bk to u if ya want

 

[One-Industries]

thats the thing, i dont try to tinker with things i dont know about, so i havent touched anything from electrical to mechanical apart from the air filter so nothing has changed, coudl someone just give me a quick walkthrough things like, jetting, needle settings and how to get it right for this foam filter, im pretty sure the filter is 30mm

 

[One-Industries]

yeah thanks mate, as mack said, elimination ile just go over the things that i think might cause this problem to bring it back to its original state, and i might find some other dodgy things that might help this particular problem. One thing im not sure about what place could get me parts in for a 200cc verticly mounted 4 stroke engine, like rings, valves, cdi whatever i need, if i ever need it.

 

[One-Industries]

ok i just tested it, somone said if i had it in neutral and revved it, if it look longer to come back to idle that means the valves are sticky. well i tried that and it is perfectly normal, ile take the boot off the carby to see if it is damaged in anyway and ile put some of this locktite gasket sealer on it then it wont leak anymore.

 

[mjc85]

Clean your carby out, if that doesn't help. Put the bike in neutral, rev it to full throttle and while its revving at full throttle pull the plug lead off the spark plug, then remove your plug and check the colour. It should be chocolate brown. If it's white then its running lean and the needle may need adjusting or if its a more broad adjustment needed you will have to rejet.

If the plug is black its running to rich at WOT (wide open throttle).

 

[One-Industries]

what is the process to rejet a carby?

 

[NinetySix]

best to do that with the bike in gear and rolling along than in neutral

 

[mjc85]

best to do that with the bike in gear and rolling along than in neutral

Yeh but it shouldn't matter, either way you should get a decent reading. But if you wanna do it that way then that will work too.

 

[NinetySix]

and hitting the killswitch is probably a lot easier than trying to pull the plug lead off

keep the throttle open until the engine has stopped spinning completely too

 

[One-Industries]

Yeah, thanks for the comments guys, ile try to fix it this weekend. Then go out for a burn on my track