Strange noise preventing power

[Chriskelly]

Really scratching my head,when pulling the throttle to speed up I get to about 22mph and the normal whine the engine makes turns into what I can only describe as a air flapping very fast noise,it jumps between this and the normal whine of the engine speeding up noise every few seconds! I'm thinking either my Cdi is no use at high speed or some issue with piston skirt clearance? Please help also when it is jumping between the two noises when it returns to the normal noise it speeds up for a second.

 

[Deleted member 12676]

air flapping noise at speed does not sound like the engine. sounds like your coat tail

 

[Chriskelly]

Definitely not my coat! It only does it at high rpm under load,it sounds like pressure waves or something,this engine struggles to hit 27 mph on the flat

 

[Deleted member 12676]

probably 4 stroking
click on my signature link and read about it

 

[CrazyDan]

Are your head bolts coming loose? Any other bolts loose elsewhere? These 2 smokers require regular maintenance or else things go bad real fast. Each time before riding check your head, exhaust and mounting bolts minimum. I don't trust 2 strokes, they'll fall apart mid-ride. One way to slow their self-destruction would be to use blue lock tight on every bolt. Make sure the chain and sprocket are lined up, and the engine mounts are solid. This all will reduce vibration (which will limit your top rpm), without modification to the flywheel or piston, but as I'm very sure Jaguar will explain to you, lowering the weight of moving parts and proper balance will make vibration all but disappear. His CDIs are very good from what I've read at further reducing vibration by changing the timing at higher rpms. I'm not the best voice for giving advice to make 2 strokes purr, I owned one and ran to 4 strokes, too busy sometimes to constantly maintain them lil vibrators.

 

[Frankfort MB's]

Definitely not my coat! It only does it at high rpm under load,it sounds like pressure waves or something,this engine struggles to hit 27 mph on the flat

I'm with Jag it sounds like your running a rich fuel mixture causing your bike to four stroke

 

[Chriskelly]

Right guys,ive moved the throttle pin clip to the end groove I believe this is the leanest position,has had no effect on performance or the noise,ive also tried moving the choke with no result,any other suggestions? Is it possible to upload a audio file here as probably best to hear it as it's a hard thing to explain.

 

[LRSimons]

Pull off the airbox/ filter and take it for a spin. The stock one is generally restrictive enough to richen the mixture. With it off you will at least be able to see if you're going in the right direction.

If it does get better but not solved, you'll need a smaller jet. Either buy one or fill yours with solder and drill a smaller hole.

Or start modifying for power. The fuel demand increases with performance increases. Probably best to get your engine running smoothly stock though.


Logan

 

[Deleted member 12676]

they all come with too big a main jet hole. they all need a smaller jet size.
moving the needle doesn't affect the mixture at full throttle, only the main jet does.
and yes if the filter is restrictive then it needs to be replaced with a less restrictive one. but that won't fix the main jet problem.

 

[crassius]

you might try loosening the muffler just a bit (maybe 1/8in gap) to see if something came loose inside it