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Took the XR on it's first and last moto race!

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The XR and I raced our first ever moto on sunday. The XR had more than enough performance to race the "moto" bikes, however we got our asses kicked on the jumps. But, we still finished 9th and 10th. Good times, but I feel like I got hit by a cement truck from hitting mother earth off the jumps. Sorry fellas, but the XR is going to be limited to trails and I am going to go back to the KX for moto racing.

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You actually went to a track and competed with an XR? Yer brave! :)

I've thought about taking mine to a track just to play around a bit, but never to compete :thumbsup:

But hell man congrats on 9th and 10th places.

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YOU HAVE THE BIGGEST BALLS OF THEM ALL !!!!!!!!! (AC/DC song)

LOL

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I had my xr4 at the track last weekend. I couldn't get enough boost to clear some of the big tables and landed flat a couple times from 6-8ft up. I thought I was going to have to pull my kidneys out of my socks! Congrats on the solid finishes...I know right now that my xr4 will never see the start of a moto race!

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So I commend your efforts,at least you had the cajones for getting out there and doing it.I sure hope you kicked some 2 stroke butt along the way.

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So I commend your efforts,at least you had the cajones for getting out there and doing it.I sure hope you kicked some 2 stroke butt along the way.

I was doing that in the woods on Sunday last week when my buddy was on his YZ125.

Then he bought a modded out WR400 and he kicks my ass now..... except on the slow technical hillclimbs, the XR400 still owns him on those :thumbsup:

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But, we still finished 9th and 10th.

So which one finished 9th - you or the 440? :thumbsup: BIG cajones!!:thumbsup:

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If Ive read right,Jay Peterson says his XR400,with 430 kit,pipe and pumper carb,and just about every other little do hickey he can drap on to it,will equal the YZ400s out put,and still has more bottom end,any one else hear of such??

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How do I get in touch with Jay Peterson? I've dumped about 10 grand in my XR400 and am ready to start on the engine now. I sure could use some experienced advice.

XR Bob

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I have several questions that I'm sure have been asked in the past. First, which big bore kit that's still available is the one to go with? Next, does this kit require machining of the center cases to accept the larger sleeve? Also, does anyone still offer a stroker kit? Is it something recommended to go with and why? I ask this because I would prefer to gain displacement by stroking the engine rather than just increasing bore.

Next, I was planning on going with the Black Diamond stainless steel oversized valves with their spring/retainer kit. Anyone have experience with these?

Last, once the engine is pumped up are there any glaring weak points to be careful about? My bike is a '96 and I've read about using a CRF timing chain and the newer XR400 countershaft. Are these upgrades necessary?

Any advice based on experience and not just heresay would be greatly appreciated.

XR Bob

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I have several questions that I'm sure have been asked in the past. First, which big bore kit that's still available is the one to go with? Next, does this kit require machining of the center cases to accept the larger sleeve? Also, does anyone still offer a stroker kit? Is it something recommended to go with and why? I ask this because I would prefer to gain displacement by stroking the engine rather than just increasing bore.

Next, I was planning on going with the Black Diamond stainless steel oversized valves with their spring/retainer kit. Anyone have experience with these?

Last, once the engine is pumped up are there any glaring weak points to be careful about? My bike is a '96 and I've read about using a CRF timing chain and the newer XR400 countershaft. Are these upgrades necessary?

Any advice based on experience and not just heresay would be greatly appreciated.

XR Bob

I want to go with the stroker kit too. Look up Powroll.com. THey make a 440 stroker kit for the xr4. They modify your crank to get most of the increase in displacement fill out the 440 with a 87mm piston. They also send you the base and head gaskets, the piston, pin, and your crank fitted with a new rod, or the old one depending on the shape that it is in.

I like 440 approach because of the use of a smaller bore because i think allows the engine to be more reliable and run cooler because of thicker cylinder walls. Also because you are stroking it, the bike makes more torque and will really pull due to the increased stroke.

http://powroll.com/P_HONDA_XR400R.htm

I would prefer a stroker motor, but here is the 440 kit that i would get if i didn't get the stroker.

http://9sgbt.hyqb9.servertrust.com/product_p/xr400%20to%20440%20big%20bore%20kit.htm

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Never really got stroking this motor. The stock stroke is already REALLY long and IMO stroking in this case is not worth the money unless you're looking to go over 440.

There's a guy on ebay selling JE 88.5mm piston and BB sleeve kits for real cheap. I picked one up for $150 shipped and it's the real deal, quality stuff. The only thing I'll swap out is the head gasket for a Cometic MLS. Nice thing about the 88.5mm piston is you still have one bore left in the sleeve for later. You will not need to bore the case halves to fit the sleeve.

Bigger piston = more rotating mass. The flywheel is huge on these so you can combat the larger piston weight by shaving a few ounces off. If you're worried about loosing low end then stop at 6oz.

You will want to re-anchor your head studs. Any good machine shop can install SS or brass inserts for you. Honda did minimal engineering in this department but the stock studs are plenty strong once they get a good bite in that aluminum.

The Kibblewhite valves are a good choice. The valve spring kit and retainers are a toss up. They're unnecessary unless a) you're going with a large lift cam from webcams or megacycle, :bonk: your stock components are shot. I would not go oversized unless you're going to get some porting done too.

If you're going with a Hotcam they don't make anything truly radical including the stage 3. I've played with the 1 and 2, this time it's going to be stg3. So far I've seen solid results from their products. CRF cam chain is a solid choice.

If you're going oversized valves and porting a full exhaust is desirable and that carb needs a serious update. So far I'm enjoying the BST40SS. For your build I'd stay away from the 36mm pumper from XRs Only. It's just too small and you'll be holding your whole build back.

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Never really got stroking this motor. The stock stroke is already REALLY long and IMO stroking in this case is not worth the money unless you're looking to go over 440.

There's a guy on ebay selling JE 88.5mm piston and BB sleeve kits for real cheap. I picked one up for $150 shipped and it's the real deal, quality stuff. The only thing I'll swap out is the head gasket for a Cometic MLS. Nice thing about the 88.5mm piston is you still have one bore left in the sleeve for later. You will not need to bore the case halves to fit the sleeve.

Bigger piston = more rotating mass. The flywheel is huge on these so you can combat the larger piston weight by shaving a few ounces off. If you're worried about loosing low end then stop at 6oz.

You will want to re-anchor your head studs. Any good machine shop can install SS or brass inserts for you. Honda did minimal engineering in this department but the stock studs are plenty strong once they get a good bite in that aluminum.

The Kibblewhite valves are a good choice. The valve spring kit and retainers are a toss up. They're unnecessary unless a) you're going with a large lift cam from webcams or megacycle, :bonk: your stock components are shot. I would not go oversized unless you're going to get some porting done too.

If you're going with a Hotcam they don't make anything truly radical including the stage 3. I've played with the 1 and 2, this time it's going to be stg3. So far I've seen solid results from their products. CRF cam chain is a solid choice.

If you're going oversized valves and porting a full exhaust is desirable and that carb needs a serious update. So far I'm enjoying the BST40SS. For your build I'd stay away from the 36mm pumper from XRs Only. It's just too small and you'll be holding your whole build back.

I get what you are saying. That's a good point. the bigger slug would benefit from the already long stroke.

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