after some hard riding this past weekend, (on 110 octane which I now know is a bad idea) my raptor makes a vibration sound when revving in neutral. the gears seem fine, although the quad has since been boggin down. I am gonna re-jet (previous owner had full procircuit exhaust and k&n bought new from factory. I have the itemized list of parts on the original invoice and mentions everything BUT the jets). When i got it from the guy there was some gas in there from last fall. I mixed in 110 and it seemed to run great. But when that gas ran out and i filled w/ 110 the quad now bogs 1/2-3/4 throttle and then revs high and goes really fast.

I have a billet air filter adapter and k&n on order (the k&n he had in there was the stock version that needed the lid) I also ordered an EHS racing lid. I bought a jet kit and plan to re-jet this weekend, but would like to address the vibration issue as well. anny suggestions on what it could be??!?!? Any help is deeply appreciated.

 

You may have detonation on your piston and are probably going to be doing a motor pretty soon is my guess. I would do a compression test. It may be valves also.

 

It may seem obvious, but the condition you described sounds like the rev limiter for reverse or the one for the parking brake is kicking in.

 

I think the bogging down and the rattling (vibration) sound are independent of each other. The rattling only occurs when I rev full throttle in neutral and still rattles until the revs come down. It could be something as simple as a loose skid plate, I havent really had the chance to properly inspect. The bogging down happens when engine is under a heavy load then revs and seems like the engine just hit turbo boost.. lol

My main concern was the rattling being a result of something going wrong in the engine due to running that high octane gas. I could kick myself for listening to a friend who recommended that to clean out the fuel system after having old gas in it.

 

Yeah I wouldnt run no higher than 91 octane in a stock motor. But like you said, it could be something loose. I would definitely find out what is causing both problems before you ride it again.

 

Festa
I had the same rattling problem on my raptor and i thought it might be internal and it was my gyt-r chassis skid plate that was a bit loose, tightened it up and sound was gone. Good luck with prob #2 i wish i could help.
Chris

 

lol same wit my friends their skids came loose n they thought it was internal lol

stand it up on rear grab bar (turn fuel off) n cheak

 

Yeah thats why i am thinking (and praying [img]i/expressions/face-icon-small-wink.gif[/img]) is the case. The guy who i bought it from went nuts and has full skids, savers, handguards, etc. The sound seems to only happen when the motor is being rev'ed high and sound like rattling which continues after I let off the gas until the motor revs downs. The terrain I rode on this past weekend was extremely rocky and i did feel a couple of scrapes so it is most likely the skids. Hearing noise like that always gets me scared tho!

Thanks for all your responses, I will be sure to follow up this thread after the weekend when I (fingers crossed) figure out whats wrong.

 

Turn off the gas and run the carbs dry before you stand it on the grab bar.

 

one time my header heat sheild was loose and it made a sound that scared me.