Pipe vibration

[yz250roost]

Hey guys I recently got a new PC platinum pipe for my 98 YZ 250, every thing is great and the response is Awesome but now after I let off the throttle or when I'm going down a hill that forces the RPM's up the pipe makes an audible vibrating sound, both of the rubber mounting brackets are new, what could be my problem area? thanks in advance
Jeff

 

[RGalesi]

Jeff,

The thinner walls of the PC pipe (when compared to the stock unit) make it more sensible to ressonation. It's kind of a trade-off, One thing might help: either change the pipe springs to new ones, or envolves them with garden hose, in order to avoid their vibration. Or better yet, do both things. Good luck...

 

[yz250roost]

Thanks RG I'll try that, I did notice that the PC pipe is lighter than the stock and the Works pipe I have, that must be the reason, I love the sound it makes though, sounds real crisp and clean.

 

[mxmike38]

mine does the same thing. I never got it to stop. let me know what works okay :thumb:
thanks
mike

 

[Shift-MX]

maybe try getting some new or larger o-rings. Where the pipe goes into the exhaust port that is. This may help your problem.

 

[bigred455]

Did you put on new springs,and does the pipe have a gasket like the kx in the exhaust port of the cylinder.

 

[Lorin]

A short piece of fuel line placed over the spring will help a little. Have you thought about putting a pipe guard on the pipe at all? The extra mass (not much) helps to dampen \ change the tone of the pipe. I have even seen a few people that will take a section of inner tube and place that between the pipe and guard to further dampen vibration. On a second note, did you notice a large difference between the stock pipe and Pro Circuit (other than the sound)? If so, where and how did it change or move the power?

 

[yz250roost]

I didn't replace the springs when I replaced the pipe so maybe that's my problem area, I'll try the different coatings around the springs as well and post on what came of it, ---Lorin, I can't tell you for sure how the perfomance changed over the stock pipe, because I was given that pipe when I bought the bike, so I never rode it with the stock on, it came with a PC works pipe which was getting ugly, but had only a few dents, I purchased the platinum pipe and the first time out I noticed that the bike was noticeably more responsive and the pipe seemed to rev up sooner. spots on the track where I usually bogged the engine a little, were now fewer, the pipe made the bike seem more crisp and clean for sure, and that's what I can tell, and that's just over the PC works pipe! hope that helps
Jeff

 

[yz250roost]

I'd say it made the hit of the powerband more noticeable in the midrange, if held open out of a corner it shoots right through the low rpm "lugging" feel and gets right into the meat, so I'd say it improves midrange power.

 

[Jaybird]

I put a PC silencer on my stock pipe and got the vibration thing going on too. It was the sloppy slip over connection between pipe and silencer.
Aluminum muffler tape(as a shim) and silicone took care of it.

 

[Rcannon]

I found one of the springs on my PC pipe (1997 YZ 250) was touching the frame. I added the fuel line and it helped. I also loosened all the mounts and let the pipe find its natural position before I tightened it.

 

[CR-For-Ever]

This Clean sound and power you talk about is probably due to the pipe being clean inside, your old pipe may have been clogged with carbon and what not, however I am sure the pipe does improve performance in other ways not just by being clean, I gotta put mine on it's sittin in my garage crying to be on my CR hehe.

Lata. :thumb:

 

[yz250roost]

thanks guys, tomorrow i'll have the opportunity to look at it in depth while im putting on my new hydraulic clutch kit...I'm stoked!!!