290 big bore bikes...

Subject: 290 big bore bikes... Thu Apr 28, 2011 3:59 am

What kind of horse power numbers are people making with the 290 kits on X's?

Subject: Re: 290 big bore bikes... Thu Apr 28, 2011 6:40 am

Check this out:

http://advrider.com/forums/showthread.php?t=621532

No dyno numbers, but an excellent step-by-step on the install. Rider impressions on the results start on page 9.

My 290 kit should be here today! wings

Subject: Re: 290 big bore bikes... Fri Apr 29, 2011 12:53 am

BuilderBob wrote:: My 290 kit should be here today!

well, its today over here dddog

Subject: Re: 290 big bore bikes... Fri Apr 29, 2011 5:58 pm

little squirt wrote:

BuilderBob wrote:: My 290 kit should be here today!

well, its today over here dddog

Crap. Didn't come. They're saying Tuesday now... budah

Subject: Re: 290 big bore bikes... Sat Apr 30, 2011 2:04 am

Gayness, I cant believe nobody has any dyno numbers from a bike with a 290 kit?

Subject: Re: 290 big bore bikes... Sat Apr 30, 2011 5:21 am

Man, that sucks! Expecting it on Friday and now not getting in until Tuesday? There goes your weekend project!

Subject: Re: 290 big bore bikes... Sat Apr 30, 2011 5:53 am

gasmachine85 wrote:: Gayness, I cant believe nobody has any dyno numbers from a bike with a 290 kit?

I'll have them after the install.

Midnite171 wrote:: Man, that sucks! Expecting it on Friday and now not getting in until Tuesday? There goes your weekend project!

I know, right? Not sure that it will be a one-weekend project though. I'm considering sending the head off to have it ported and polished while I have it torn down.

Subject: Re: 290 big bore bikes... Sat Apr 30, 2011 6:40 am

Here's a start.
See post #220:

http://www.supermotojunkie.com/showthread.php?84451-GYTR-290CC-bigbore-for-WR250x!/page5

Subject: Re: 290 big bore bikes... Sat Apr 30, 2011 7:32 am

YZEtc wrote:: Here's a start.
See post #220:

http://www.supermotojunkie.com/showthread.php?84451-GYTR-290CC-bigbore-for-WR250x!/page5

Great info. Thanks! thumb

Subject: Re: 290 big bore bikes... Sun May 01, 2011 4:30 am

Here's a dyno chart from an old post.

Stock

vs.

Athena 290 (GYTR), programmer, with GYTR muffler (I believe)

vs.

Thumper Racing 275, programmer, with FMF muffler and power bomb (I believe)

290 big bore bikes... Dyno_c10

Nice step improvement in the torque curve across the RPM range with either the Thumper Racing or the Athena 290. The Thumper Racing kit apparently runs well at higher RPMs with less vibration due to a lighter weight piston. Thumper Racing kit requires installation of a piston sleeve in the stock cylinder head (mail head in for a few days or get a local machine shop to do it).

I've been strongly considering the Thumper Racing kit.

Subject: ok Mon May 02, 2011 12:39 am

i wish someone would do a comparison of the 2 kits with same bolt ons and a tune. bc it would be a more realistic and fair judgement.

» Riders behind the bikes ... or how about on the bikes?
» Big bore help
» Big Bore and FMF programmer
» possible Big Bore....PSI <40lbs
» Thumper Racing 280 Big Bore kit Long Term Experience?