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RyanWilliamCantrell

Guidance rebuilding the XR650R top-end, please...

31 posts in this topic

Hello,

I've been lurking here for some time, and am using my 1st post because need some guidance with my XR650R...

I purchased it 3 months ago (it's an '01), knowing the compression was a little 'soft'. I'd planned to rebuild it next winter, but after a trip to the dunes, some sand made it past my filter and apparently went through the cylinder... because now it's burning a considerable amount of oil (like a quart in 125 miles of street/trail riding), and the compression is ka-poot.

So... because I'm quite sure I sucked sand through it, I'd like to bore it out and have a new piston in it.

I went to the Honda shop this afternoon, and they were adamant that the XR650R cylinder cannot be bored.

So... that leaves me with 2 questions:

1.) Why not?

2.) What are riders doing then they're moving up to a larger piston? New sleeve?

I’ll likely stay with the 10:1 compression because I’ve read that the 11:1 requires machining to fit correctly? (Is this accurate?), but I’ll move to the stage 1 hot cams.

Please forgive me if I've posted this in the wrong forum, or if there's already a great thread on this subject (please direct me to it)~ I did several searches and couldn't find the answer...

Ryan

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Yes the cylinder is plated not lined,The hard surface is only about 50 thou thick. .050.(better for heat transfer). I'm sure someone else will fill in on the cam question.

Where you at in I DE HOE??

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Nikasil lined = cant be bored as far as I know.

Just rebuilt mine but kept the stock compression and just went to a Wiseco piston.

Ask BWB, I know for sure he's running the 680cc setup.

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Nikasil lined = cant be bored as far as I know.

Just rebuilt mine but kept the stock compression and just went to a Wiseco piston.

Ask BWB, I know for sure he's running the 680cc setup.

Gottcha... but I think I've scratched my wall, so I'm pretty sure the boring will be a 'must'. I'll ask BWB ~ thanks.

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No I mean you can hone it but if you bore it out then the Nikasil is gone. You'll need a new sleeve or jug.

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I just did some research on this. You can sleeve it overbore or you can have it bored and then re-plated by a company like Millennium Technologies.

as far as cost I don't remember details...replating was 7 days turn around with them and shipping times there and back. Harder and less friction than sleeve (some say you won't notice it... I guess depends on application and if your are racing etc...)

On the flip side. if it was overbored and sleeved and something were to happen to the walls like it did with the sand messing up the walls. you have the option to replace the sleeve. With the replating the damage would be directly to the walls and if Honing can't repair it you may not have enough to rebore it anymore.

Ok...this is what I understood of my reading and research. Keep searching and get more details. I'm sure others will chime in as well.

The compression of the piston and clearance...double check no matter the parts but I believe its mainly an issue if you use a cam with more lift than the hotcams...BUT CHECK IT and don't take my word for it.

While its apart...check out the head because the valves and seats may need attention depending on the number of miles. The valves have been known to show wear (beginning signs of mushrooming) and if you have it down and apart you might as well address them.

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J_T is right; you need to get it re-plated. Your not supposed to bore a nikasil coated cylinder because the plating will ruin the boring bar because its so hard.

I sent my cylinder to millenium technologies when I did my rebuild, cost me $100, and when I got it back, the cylinder looked brand new.

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J_T is right; you need to get it re-plated. Your not supposed to bore a nikasil coated cylinder because the plating will ruin the boring bar because its so hard.

I sent my cylinder to millenium technologies when I did my rebuild, cost me $100, and when I got it back, the cylinder looked brand new.

Ruin a boring bar???

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You can search it but to answer one of the smaller questions...NO, K&N air filters are not well liked or widely used on our bikes.

Great for a street bike or car but not ours.

Go UNI or something along those lines.

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You can search it but to answer one of the smaller questions...NO, K&N air filters are not well liked or widely used on our bikes.

Great for a street bike or car but not ours.

Go UNI or something along those lines.

Thanks.

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Well to do this right you probably want to get the HRC kit which is around $1000. You'll definately want to drop the stock carb for a pumper (most liked and best results I've read come from the Edelbrok Qwik Silver which is around $400.

Here is some info on the full HRC kit:

The XR650R HRC Power-Up Kit features a high compression piston (including rings and clips), camshaft assembly with decompressor, cam chain assembly, stiffer clutch springs and all the necessary gaskets to reassemble the engine. Because the Power-Up Kit is designed exclusively for competition, it is sold without warranty. The manufacturer's suggested retail price (MSRP) is $999.99 and the kit can be ordered through any authorized Honda motorcycle dealer while supplies last.

XR650modkit.jpg

XR650modkitpistoncam.jpg

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Another question for you: How hard do you really ride and how much power do you need?

You could do a basic rebuild (which I just did) for under $400.

Piston,rings,clips

Gaksets

Valve guid seals

Torque wrenches/chemicals (which I didnt have)

Fully uncorked you can see 55hp range...thats a lot of juice.

Just a suggestion if you've never ridden the pig when in good health...might want to consider trying it that way first and put all that money where it belongs....in the suspension!

Unless you weigh the perfect 170lbs a $400 rebuild and the rest for suspension work aka Precision Concepts, Barnums or (my preference by miles BWB) will make you much happier with that bike than 60+hp and a crap stock suspension.

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Yes, I can use the extra hp that'll come for the 680cc and stage 1 cam ~ esp the low-end power.

Yes, I do weigh the perfect 170 lbs (actually 166lbs as of this morning), so suspension isn't an issue for me: I need to decrease the pre-load a hair, but other than that... it's dialed in perfectly for me ~ I can truck across the open desert at 45-50mph without any issues (that's no-trail... just cross country riding), and regularly hit 60mph on the double track with it's current suspension. I'd rather put the money into the engine right now, to have the extra hp for the street (Mine is plated) and open gravel roads (which we can run a couple hundred miles of in a day or riding).

The problem with the basic rebuild, is I'd have to have another sleeve because I've scratched mine with the sane that passed through it... so if I have to put in another sleeve... why not put in the 680cc?

Your thoughts?

Another question for you: How hard do you really ride and how much power do you need?

You could do a basic rebuild (which I just did) for under $400.

Piston,rings,clips

Gaksets

Valve guid seals

Torque wrenches/chemicals (which I didnt have)

Fully uncorked you can see 55hp range...thats a lot of juice.

Just a suggestion if you've never ridden the pig when in good health...might want to consider trying it that way first and put all that money where it belongs....in the suspension!

Unless you weigh the perfect 170lbs a $400 rebuild and the rest for suspension work aka Precision Concepts, Barnums or (my preference by miles BWB) will make you much happier with that bike than 60+hp and a crap stock suspension.

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Ouch. That's a whole lot of money for me right now, because I just dumped a grand into my KLR rebuilding it this winter (685cc with stage 2 head work from Shnitz Racing). I can be in the 680cc with the stage 1 cam for around $550... and I think that'll still keep a very reliable XR that maintains a similar maint. schedule as the stock bike.

Well to do this right you probably want to get the HRC kit which is around $1000. You'll definately want to drop the stock carb for a pumper (most liked and best results I've read come from the Edelbrok Qwik Silver which is around $400.

Here is some info on the full HRC kit:

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Ouch. That's a whole lot of money for me right now...

No doubt. Use the hipo cam chain and sprocket from that kit with your 680 build.

As others have said, make sure you check out your top end and make sure it didn't also get screwed up by your sandy antics.

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I've been doing my homework, and found a Wiseco big bore sleeve for $70, a .100 over Wiseco Piston (with rings, etc) for $144, and the gasket set for $23. I'l get the Stage 1 HotCam from the shop here at Thumpertalk ~ does this sound reasonable? I'll also finish this little project off with a Uni filter, in hopes that this never happens again... from what I've read, they've got the best seal?

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Not sure what you would see in improvement with the 680cc kit without upgrading cam, valves and carb. I think BWB said 3mm over was a bit too much but 1mm was kind of needed to realize the gains your paying for.

Also at least upgrade your timing chain. Thats a whole lot of money to put in there and expect the stock chain to hold out.

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