Thumper Racing is developing a 310/320 kit?

I dig it... stroked thumpers sounds beasty. I'm looking forward to seeing the dynos from this kit.

Wonder if they have a stronger rod to use to assuage some of the fears of the motor not being able to handle the heavier piston and increased power

nice... its only a hour ride to there new shop for me
ill pick mine up in person haha

so January kinda is the new date?

skidmarx wrote:

deerHater wrote:

I would go for a sorted 310 kit (reliable and no extra vibration) when my WR250X needs a rebuild. My guess is in 2025.

Only 24 HP? I'd expect well over 30 HP from that...

That's funny. I was going to post that I wouldn't mind doing the 310 when my bike needs a major overhaul, but the way these things run, that would be about...never.

I think 24hp is so ridiculously low for a 350 that I'm going to ignore it.
Maybe they have it breathing through cocktail straws.
My XT350 has more than that and it's air cooled and designed in the '80s

I believe the new KTM Freeride is about that, it's to make more torque or something?

Awww.. they moved... and they moved really far! I was so close to them too.

i am curious to know what are you going to do about the head. 310? thats alot more air and fuel that head would have to move. let alone the machine combustion chamber in the head. you would end up creating corners that the air fuel mixture could hide and you would end up with less of a burn. unless u have your head machined. and in which as some1 once said. you bought the wrong bike. if a 310 was such a great idea. yamaha would have done it already.

Niewski11 wrote:

i am curious to know what are you going to do about the head. 310? thats alot more air and fuel that head would have to move. let alone the machine combustion chamber in the head. you would end up creating corners that the air fuel mixture could hide and you would end up with less of a burn. unless u have your head machined. and in which as some1 once said. you bought the wrong bike. if a 310 was such a great idea. yamaha would have done it already.

Assuming you are referring to me, I don't know what I am going to do. I have already investigated head work and it may be in the cards. Hell, at this point, I don't even know if I'll install the kit. I want to find a spare engine to tinker with first.

As to your comment about buying the wrong bike, I think I'll be the judge of that. I've never owned a single motorcycle that I haven't modified in one way or another. I like to tinker. If my tinkering involves putting a 310 stroker kit in a WR/X, then that is the perfect bike to receive my attention.

BuilderBob wrote:

Niewski11 wrote:

i am curious to know what are you going to do about the head. 310? thats alot more air and fuel that head would have to move. let alone the machine combustion chamber in the head. you would end up creating corners that the air fuel mixture could hide and you would end up with less of a burn. unless u have your head machined. and in which as some1 once said. you bought the wrong bike. if a 310 was such a great idea. yamaha would have done it already.

Assuming you are referring to me, I don't know what I am going to do. I have already investigated head work and it may be in the cards. Hell, at this point, I don't even know if I'll install the kit. I want to find a spare engine to tinker with first.

As to your comment about buying the wrong bike, I think I'll be the judge of that. I've never owned a single motorcycle that I haven't modified in one way or another. I like to tinker. If my tinkering involves putting a 310 stroker kit in a WR/X, then that is the perfect bike to receive my attention.

I can relate to that. I modify everything... I like change.

Hell I've been thinking about putting exhaust on my honda mini van... just because I can.

well i can respect that. i mean i have quite a list of mods to my bike as well. including a 290 kit. i would very interested in knowing what someone has in mind for the head to accept the 310 properly. bc of course the stock head will work. i think you would see more out of cams rather a big bore kit. and also. any mods other than reducing the air restriction in and exhaust restriction will decrease the engine life. for those who may know. im thinkin bout porting and polishing my head this winter. and ima see if i can find some cams as well while im that far.

Read FreeRide. The motor has been tuned down from 45 to 24 hp.
The WR could use more torque! It all depends on your riding style. The WR was a compromise for me - street legal and low maintenance, but way too high geared for the trails around here - (Using 12-48 thinking about going to a 52). I would have bought a Scopra T-ride if I knew I could insure it. The Husqvarna-Te 310 required more maintenance. A 310/320 kit sounds interesting if it proves reliable, but the FreeRide is so much lighter.

well i am running 13-40 sprockets and i have a 290 kit. and my bike is a monster off bottom. so much torque. also have a mega bomb header which helped torque. and my two bros computer programer dumpin fuel in with all its heart helped throttle response. and my k&n filter did about nothing. nothing noticeable that is. i think you will have to do too much when compared to the Athena 290 kit. which is a new jug piston and everything needed to put a new piston in it.

Thread revival!

So being impatient I e-mailed Thumper Racing via their website inquiring about the new kit for our bikes. Here's the response I got:

Quote :

Hey Dan
We are done. The big bore kit ($550 for 81mm or $595 for 83mm) and stroker ($600 for balanced crank) The reason for the cost is the crank has to be balanced to the bigger piston the price l listed includes balancing. We will balance the crank to any piston setup you would like to run with the crank for the same cost.

If you took the after market crank you are talking about and added it to a big bore kit you would get a substantial increase in vibration.

I have cranks in stock.

Travis

I wrote that I was considering just running the Hod Rods stroker crank and their 280 piston, hence the reference at the end of his message.

I e-mailed him back to confirm that the 83mm piston will retain the double compression ring design of their 280 kits.

So it's looking like $1200 to punch these bikes out to a 306. Just for grins I was looking at their kits for some other machines. One example was their CRF250 kit that brings it up to 300. It makes our kit look like a deal at $2500...

Quick response!

Quote :

Yes the pistons are 3 ring. They are also undercut and lightened.

I will try to get them online in the next week or so. If you would like to order before then please give us a call.

I haven't got $1200 lying around presently, so I'll have to do some saving first.

Niewski11 wrote:

if a 310 was such a great idea. yamaha would have done it already.

If all the great ideas have already been done, that means we will never see another new bike.

millert85 wrote:

if properly tuned the turbo will be easier on the motor. the big bore changes the rotating mass and throws off the crank balance (as indicated by the increased vibes).

I agree on the properly tuned turbo being easier on the engine since the engineering design has not been altered. Changing mass of any rotating part of the engine will change the balance of the assembly & possibly cause more vibration. It would be ideal to take the rotating assembly to a shop that can balance it after swapping the new piston. That could make things much smoother running but it's more work & money to put out. At least with the turbo, you can tune it for conservative power increases & not over tax the engine to maintain reliability. Plus you can just unbolt it & go back to stock if you want.

The 310 kit from Thumper Racing comes pre-balanced. Install it and go! I was told that's part of why it's so pricey; they balance the assembly for you.

Any new information on the bore/stroker kit? Nothing is shown on TR's website.

While you're waiting you can probably buy a used DRZ for about the same amount as it will cost :P Or sell your bike, pair that with the money, and pick up a used KTM640 ;)

nwrider wrote:

Any new information on the bore/stroker kit? Nothing is shown on TR's website.

You have to call them. They said they were trying to get them up on the site a long time ago, but I guess that fell by the wayside. Call 'em up and tell 'em you want the 310 kit!

I was curious as to the final cost of the mods and whether or not they have any dyno runs on this conversion to compare with the 280 kit. I guess I'll have to contact them directly.

Thanks

I think eddie sinerous (sp) (he posted about it on thumpertalk) is advertising 40 hp from the 310 or 320 kit with porting and cams.
You could contact him for prices too.
I'd rather skip the cams and have 35ish hp with more low end tho, I ride off road mostly and want all the low end I can get. The 40hp kit is aimed at the sm guys.

nwrider wrote:

I was curious as to the final cost of the mods and whether or not they have any dyno runs on this conversion to compare with the 280 kit. I guess I'll have to contact them directly.

Thanks

When I was in e-mail contact with them I was told $1200 forr the parts. You'll need some gaskets on top of that for the engine teardown.

I left a message for Thumper Racing several weeks ago. No followup from them. Not what I would call responsive! As it is, I was able to buy a new 280kit with the sleeve already installed in an extra cylinder from a fellow in Kansas. Should get it by the end of the week. It seems like a better compromise for additional low and midrange power vs. $$$.

I would love to hear your thoughts on install etc once you get it. I am very much contemplating this bb kit for this spring. Ive done a lot of reading on the kit as well as other bbs. I think the 280 makes the most sense as the stroker sounds a bit dangerous. Guess Im just looking for that extra "do it" to push me over edge. ;)

Dryer,

I'll try to do that. However, I probably won't get started until later in February. I'm going to try doing it with the engine still in the frame. Follow the link in AdvRider: http://www.advrider.com/forums/showthread.php?t=621532 where Highfive does an excellent job of documenting the process, although he installed a Athena 290 kit. Later in the thread, others who've also done it offered additional suggestions to shorten the process.

My bike is stock, except for a FMF programmer. I'll be happy if it gives the same low rpm performance of my 2002 Honda XR250R.