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what're the "best" 100 performance mods?

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It looks like finding a 150r and swapping my xr100 motor into it is a long term plan. My 100 is a little used, but somewhat tired 82 model. At the point where I'm ready to do this I'd like to have the motor built up a bit.

What is considered the "sweet spot" of modification for these motors? A nice increase without creating a rolling grenade or going to need work every winter.

Stronger, but reliable and going to run for years with little attention. Bike won't get at lot of use, but i'll plan on keeping it forever.

What would you do? 🤣👍

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I would say, a Wiseco 120cc piston, web cam or similar, 200x carb, lightened flywheel, and pipe. That's my $.02. In a 1982 roller, believe me, this is plenty of power.

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i have been looking at a 132cc kit for my 100. not really sure about it though has anyone on here used this or no anyone that has i cant find any posts on it i've looked at a couple different forums but i haven't had any luck on it yet. heres some links to it if someone wants to check it out http://www.hondatrailbikes.com/catalog/product_info.php?cPath=24&products_id=1063

and also

http://www.50stunt.com/product_p/tbw9051.htm

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I would say, a Wiseco 120cc piston, web cam or similar, 200x carb, lightened flywheel, and pipe. That's my $.02. In a 1982 roller, believe me, this is plenty of power.

This sounds like the setup that I'm aiming for myself. What's a ballpark cost on these mods minus the pipe since I already have one. I really want more power for my offroad XR80, but don't have a lot to sink in it and definitely don't want a high maintenance grenade for an engine.

I am assuming that the XR80 pipe will work on the XR100 engine. I have a FMF Powercore. That'll work, right?

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Won't be budget freindly...

$100 Piston

$80 Piston sleeve

$125 or so for sleeve install and boring

$140 Web cam

$40 Valve springs

$50 flywheel lighting

$535 Total approx.

$25-50 add for Carb (ebay)

BBR 120 kit is a little more attractive on a budget, Add a Cam as funds are avaible and a High Comp piston first rebuild.

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I have two 132cc motors. I wouldn't buy another one. They just don't have the power I was expecting. Plus, the reliability thing.

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I would say, a Wiseco 120cc piston, web cam or similar, 200x carb, lightened flywheel, and pipe. That's my $.02. In a 1982 roller, believe me, this is plenty of power.

The motor isn't getting built until it's getting put in a 150R roller!! 👍

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Ohhhhhh, for a conversion I would go bigger using a stroker with one of the buy it off the shelf kits.

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Ohhhhhh, for a conversion I would go bigger using a stroker with one of the buy it off the shelf kits.

How big and what kit is the question. 👍

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when you thought it was going in the old frame, you had specific mods to do. Now it's "whatever" ???

I know the chassis will handle way more than anything the 100 puts out, so it's back to my original question, "what without creating a maintenance nightmare?"

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The old twin shock frame can only handle so much before it becomes scary to ride. A 120 is max without doing major mods to the frame and suspension. Plus, a 120 motor when built right is bullet proof. I've seen some last 10+ years without cracking open the motor . . . ever. Those were GPZ piston ones. Personally I think the GPZ piston is the best piston out there. It's not the lightest or has the smallest skirt like all the new stuff, but it lasts. What's nice is you have the sleeve bored to fit the piston with perfect tolerences and not get some off the shelf kit from (China?) with low standards. You do have to get it machined to work though.

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The old twin shock frame can only handle so much before it becomes scary to ride. A 120 is max without doing major mods to the frame and suspension. Plus, a 120 motor when built right is bullet proof. I've seen some last 10+ years without cracking open the motor . . . ever. Those were GPZ piston ones. Personally I think the GPZ piston is the best piston out there. It's not the lightest or has the smallest skirt like all the new stuff, but it lasts. What's nice is you have the sleeve bored to fit the piston with perfect tolerences and not get some off the shelf kit from (China?) with low standards. You do have to get it machined to work though.

GPZ is a brand? Or old Kawasaki GPZ street bike? Like one of the 550's pistons?

So you think going above 120cc starts to cost you reliability? The Chinese crud metal is what I'm mostly afraid of with the popular kits. Seems like I hear about a fair amount of exploding mini's, but then I don't know how close to the edge they are being run at. 👍

Oh, this will be a trail bike, though he will play at the track when it's empty.🤣

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Yes, the GPZ piston is the kawi 550's. The good thing is your getting a OEM piston that you know isn't junk. Let me tell you, when I blew up my $1100 Kitaco motor, it was very depressing to say the least. Then after I replaced everything, the crank broke. That's why I can't say get a big money kit. (unless you want to fix it)

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socalxr wrote(I have two 132cc motors. I wouldn't buy another one. They just don't have the power I was expecting. Plus, the reliability thing.

socalxr can you elabrate more about the 132 kit what you dont like, what reliability issues? the short skirt thing?or what?

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yes please socalxr. its cheaper then the 120 so im sure its not quite as reliable and the 120 comes with more stuff but for the little extra power it might throw out it seem like a decent deal

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Im starting to think its just as reliable as the bbr 120, plus the ceramic cylinder will outlast the cast iron liner 120, the head gasket requires the correct sealant thats all. I have a year of use on mine and wouldnt hesitate to buy another.

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Im starting to think its just as reliable as the bbr 120, plus the ceramic cylinder will outlast the cast iron liner 120, the head gasket requires the correct sealant thats all. I have a year of use on mine and wouldnt hesitate to buy another.

what sealant ? ive got one coming in the next couple days .

thanks

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GPZ is a brand? Or old Kawasaki GPZ street bike? Like one of the 550's pistons?

So you think going above 120cc starts to cost you reliability? The Chinese crud metal is what I'm mostly afraid of with the popular kits. Seems like I hear about a fair amount of exploding mini's, but then I don't know how close to the edge they are being run at. 👍

Oh, this will be a trail bike, though he will play at the track when it's empty.🤣

I start'd to play with GPZ and KZ 550 pistons after reading all Socal's posts regarding DMC engine kits. A little info can be found here https://thumpertalk.com/forum/showthread.php?t=854201&highlight= I pretty much have it narrowed down-the last version will be a runner. Just to certify for our purposes (stock head'd 100) the GPZ piston aren't necessary and the KZ can be substituted...

There is a difference of about a point of compression between the (stock 550's) GPZ (10:1) and the KZ (9.2:1) is relative to about .100" in dome hight. Which would be needed for a high CR Supper Head. Unfortunately, these pistons are discontinued through Kawi' and there are no aftermarket 58-59mm replacements. Ebay is/may be the only source.

CC's doesn't necessarily contribute to poor relyablity.... Compression, high rpms, and short rods are usually the evil villains. And the condition of use/existing parts, quality of performance parts

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