HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
dldavis_66

Anybody tried the 100.5mm piston(650L)from XRs only??

8 posts in this topic

Still waiting on their e-mail. I asked them if there might be any issues with honing my sleeve.

100.5mm....not quite sure what to make of the extra half a millimeter. My sleeve is really good shape. I wanna get it honed, but should I just stick with deglazing it???

Share this post


Link to post
Share on other sites

You will for sure need a bore and hone with .5mm over size. Even a .25mm over size needs a bore. Quarter of a millimeter is HUGE in terms of cylinder to wall clearance.

If you can I would stick with a 100mm piston and go with a hone. If you get the OEM piston, usually with the Honda 's the bore needs to be dead on 100mm as the piston is something like 99.97mm. Just in case you want to measure first.

1 person likes this

Share this post


Link to post
Share on other sites

What you really need to do is make some measurements. The piston is relatively easy, but the bore takes more specialized tools. It usually takes a lot of miles to wear out the bore and/or the piston. If it is in good shape there is no reason to bore it out. There is no way to know without taking those measurements.

If you are not replacing the rings do not hone the bore. To check the rings remove the top one and put it back in the bore about 3/4 of an inch from the top. Use the piston to get it in there nice and square. Measure the gap between the ends. If the gap is over spec, it's time for new rings and a hone.

Share this post


Link to post
Share on other sites

If you dont have a good bore gauge like prolly most everyone doesnt, then take it somewhere to have it checked. They should look at 2 measurements really, Ovality and Conicity, Ovality is the round measurement making sure its round and not slightly oval even a little bit isnt good. Conicity is making sure its round all the way up and down, sometimes you can get a cylinder that may be .0005 less at the bottom than it is at top of the cylinder and you want nice and round all the way up and down the cylinder. Just a few things i learned myself when i was rebuilding aircraft gas engines.

A good thing for people to remember also is if they ever have an engine that overheats to prolly ask about having the hardness checked also, not sure if motorcycle manufactures check Rockwell hardness but it definitely is something to consider with an Aluminum cylinder, ive seen em myself get "soft" after an overheat and ive thrown some cylinders in the scrap metal bins.

Share this post


Link to post
Share on other sites

There is no way I'm sticking with the OEM Piston. Nah....I'm getting at least an 11:1 piston.

You think I would go through all the trouble that I'm going through: Web Racing Cam(with hardened rockers), Port and Polish heads, Desmog, Desnorkel, rejet, home-made hi-flo headers, etc...JUST TO PUT AN OEM , 8.3:1 piston back in my bike??? You nuts or something??? Geeze.

Just the way XRsonly has the information on their website layed out, almost like they don't even know what the hell they're talking about. I mean, look at this stuff:

XRs Only Piston Kit - Honda XR650L - 100.5mm / 11:1 / 651cc

PART PRICE: $209.95

PART NUMBER: XRPK-0651

--------------------------------------------------------------------------------

XR's Only performs extensive performance testing for each XR's Only Big Bore Piston Kit it offers to the public to ensure high performance and reliability standards. Available in compression ratios that range from the modest 10:5.1 up to 12:1, XR's Only recommends race gas with any piston kit above 11:1 compression rations or higher.

The XR's Only Piston Kit comes with everything needed for complete top end reassembly and includes a new JE or Ross race piston, rings, a wrist pin, piston clips, Cometic head gasket and Cometic base gasket.

FITS: Honda XR650L (1993-UP)

SPECIAL NOTE: This kit comes with a 10.5:1 JE Piston that is actually closer to 11:1, making it difficult for the bike's electric start to crank the bike. Kicking may be necessary on bikes with older batteries. If you desire a piston kit with less compression, making it easier for your electric start to crank the engine, we recommend the 10.5:1 option.

NOTE: The use of a big bore cylinder sleeve is NOT required on XR650L piston kits with a 100mm or larger bore.

AVAILABLE OPTION: XR's Only offers ceramic coating as an option on all of its performance piston kits, which provides a distinct advantage over conventional pistons because of its heat dissapation properties that contributes to component life, burning cooler and producing greater horsepower.

That was just for the 100.5?? piston kit.

Heres another one for the 101mm, 102mm, and 103mm:

XRs Only Piston Kit - Honda XR650L - 101mm / 10:5.1 / 657cc

PART PRICE: $209.95

PART NUMBER: XRPK-0657

--------------------------------------------------------------------------------

XR's Only performs extensive performance testing for each XR's Only Big Bore Piston Kit it offers to the public to ensure high performance and reliability standards. Available in compression ratios that range from the modest 10:5.1 up to 12:1, XR's Only recommends race gas with any piston kit above 11:1 compression rations or higher.

The XR's Only Piston Kit comes with everything needed for complete top end reassembly and includes a new JE or Ross race piston, rings, a wrist pin, piston clips, Cometic head gasket and Cometic base gasket.

FITS: Honda XR650L (1993-UP)

NOTE: The use of a big bore cylinder sleeve is NOT required on XR650L piston kits with a 100mm or larger bore.

AVAILABLE OPTION: XR's Only offers ceramic coating as an option on all of its performance piston kits, which provides a distinct advantage over conventional pistons because of its heat dissapation properties that contributes to component life, burning cooler and producing greater horsepower.

The only difference between the 2 different ads is the 100.5mm Special Note for the JE Piston being closer to 11:1 and then giving you an option for just a 10.5:1.

And what about the crap saying:

NOTE: The use of a big bore cylinder sleeve is NOT required on XR650L piston kits with a 100mm or larger bore.
shouldn't that be 100mm or smaller???? Or can a stock sleeve be bored out to 104mm, 105 or 106mm???? What the hell are they saying??? I mean...geeze. Do these people at XRsonly know what they're talking about, let alone what they are selling??? Sure is confusing the heck out of me!!!! :busted::worthy::ride:

Share this post


Link to post
Share on other sites

I dont think anyone WANTS you to use a stocker??? Get that hi comp and when you get it done come do mine!!

<---- is lazy, hell im a fat bastard of course im lazzyyyy

Share this post


Link to post
Share on other sites

And what about the crap saying: shouldn't that be 100mm or smaller???? Or can a stock sleeve be bored out to 104mm, 105 or 106mm???? What the hell are they saying??? I mean...geeze. Do these people at XRsonly know what they're talking about, let alone what they are selling??? Sure is confusing the heck out of me!!!!

All that means is that the stock sleeve is capable of being bored out to the required size. If I remember right there is some one out there with a 107mm bore running alcohol on the stock sleeve. I am running a 103mm bore in my L and there is still plenty of meat left in the sleeve.

As far as their 10.5:1 is more like 11:1 is probably true for all the JE piston sizes. I was running a 10.5:1 weisco at 102.4mm and the piston hight compared to the JE 10.5:1 was something like 2.5mm shorter. So yeah I would say someone's measurements are off. Either the weisco is rated higher or the JE is rated lower.

Share this post


Link to post
Share on other sites

I finally got a reply from xrsonly.com. The "100.5mm" listed on their website is just a 100mm...(100.5 is a misprint).

Thanks for clearing up the stuff about the different bore sizes.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0