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J&E HC Piston and Web Cam

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Great weather for riding. No bugs to fly into that big smiling face you must have!

Hoping to do the mods myself this winter.

BTW, do any milage checks yet, or are you still having way to much fun?

Mileage is about the same for me. I have been romping on it most of the time, but I did do some "regular" riding to work last week and it was still yielding mid to high 40s.

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MX-ROB----have you changed the jetting on the 39? could you post your jetting again please, and what plugs are you running? my bike feel a little flat on the upper end. also if on the rev-limiter does the eng studder (miss) or does it just slow down. I'm at 2500--4000ft. might be a little fat. thanks again for your posts. (my bikes eng is set up like yours):bonk:

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That would be quite the project. Hmmm, so that would be a 90.4mm stroke and you might as well go with the 106mm 725cc kit piston so.... 3.14 x 53 x 53 x 90.4= 797cc That should get the front wheel off the ground. Pie R Squared and "exhibition of speed" tickets R rectangle. :ride:

A 108mm is possible. (830cc) Or even more if you want to bore the cases to accept a larger diameter sleeve. I'll be happy to help anybody who wants to try to take it that far.:ride:

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A 108mm is possible. (830cc) Or even more if you want to bore the cases to accept a larger diameter sleeve. I'll be happy to help anybody who wants to try to take it that far.:ride:

I really didn't want to hear about this project, just when I got the 725 done ...:ride:

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A 108mm is possible. (830cc) Or even more if you want to bore the cases to accept a larger diameter sleeve. I'll be happy to help anybody who wants to try to take it that far.:ride:

Isn't that modified DR800 territory?

Do tell...

Manos

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A 108mm is possible. (830cc) Or even more if you want to bore the cases to accept a larger diameter sleeve. I'll be happy to help anybody who wants to try to take it that far.:ride:

Did you get my email Jeff? :ride:

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Did you get my email Jeff? :ride:

Yep, and finally answered. I've been at the Dealer Expo and I'm way behind on emails (and everything else).

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Isn't that modified DR800 territory?

Do tell...

Manos

... please???

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... please???

Sorry, I don't know anything about the DR800. There were never sold here in the US.

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Any cam degreeing necessary with the Web or Pro-Cycle cams?

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Unacceptable. No matter how hard I try I simply can NOT find an excuse to avoid doing this mod...:ride:

Who am I kidding, I ordered all the parts last weekend anyway. :thumbsup:

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Unacceptable. No matter how hard I try I simply can NOT find an excuse to avoid doing this mod...:ride:

:thumbsup:

What's really going to piss you off is when you get it done you'll be saying W*T*F was I thinking not doing this before? :lol::lol:

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What's really going to piss you off is when you get it done you'll be saying W*T*F was I thinking not doing this before? :ride::lol:

It's like you're inside my head... :thumbsup::lol:

Any other tips or tricks to be aware of before undertaking this project? Besides valve jobs, it's been a few decades since I've been inside a top end.

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Any other tips or tricks to be aware of before undertaking this project?

The DR top end is really simple and straightforward to get apart and put back together. One potential 'gotcha' is an error in the factory manual. The manual I have has the head bolt lengths and positions mixed up. If you follow it to the letter you could end up with one head bolt bottomed out in its hole and threads pulled out of the case on another bolt. Just note which hole each bolt cam from and you'll be fine.

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Excellent, thanks :thumbsup: Hopefully that piston will be back in stock tomorrow...

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It's like you're inside my head... :ride::lol:

Any other tips or tricks to be aware of before undertaking this project? Besides valve jobs, it's been a few decades since I've been inside a top end.

Nope, pretty straight forward. Wash the engine down good before taking it apart..... Make sure the frame above it is clean so you don't drop crappola in the cases that way either. Set the engine at TDC on the compression stroke before disassembly. Hold up on the cam chain securely (keep it tight on the crank sprocket) before you turn the engine to DBC to slide the cylinder back on the piston.... otherwise the cam chain can fold over on itself in a wedgie around the crank sprocket! Turning the motor backwards to un-wedgie the chain can be a bummer because of the starter gear one-way bearing. Ring gaps 120 degrees apart. Inspect the tappet cam contact surfaces. No scoring, scratches or gouges allowed. I sprayed my metal base gasket and head gasket with a couple coats of copper coat.... I also sprayed the leak prone cylinder head nut sealing washers with the copper coat. Replace the cam journal end seal/plug. I also replaced the orings and crush washers for the oil lines. Mine is dry as a bone oil tight. :thumbsup:

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...Replace the cam journal end seal/plug....:thumbsup:
D'oh! The one part I haven't ordered. Thanks :ride:

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A 108mm is possible. (830cc) Or even more if you want to bore the cases to accept a larger diameter sleeve. I'll be happy to help anybody who wants to try to take it that far.:thumbsup:

I was just about to pull the trigger on the 725 & cam...

Now you've peaked my interest.... :lol:

What kind of "help" are you willing to offer?

I might be willing to "tinker" a bit... :ride:

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A 108mm is possible. (830cc) Or even more if you want to bore the cases to accept a larger diameter sleeve. I'll be happy to help anybody who wants to try to take it that far.:thumbsup:
I was just about to pull the trigger on the 725 & cam...

Now you've peaked my interest.... :lol:

What kind of "help" are you willing to offer?

I might be willing to "tinker" a bit... :ride:

Help I could provide would be along the lines of custom made piston, sleeve, head & base gaskets & sleeve installation at cost.

The 830cc quoted above was referring to a hypothetical stroker motor. Nobody has really looked hard into whether there is room in the motor for a longer stroke. I understand Lukas may be checking into it. With the stock stroke a 108mm bore will make 751cc. Our existing sleeve could take a 108mm piston (if any existed). If a daring individual wanted to bore the cases to fit a larger OD cylinder sleeve we could probably go 110mm (779cc) or maybe 112mm (808cc) on the bore.

It all depends on how big of a bang you are willing to risk when it all lets go. :lol:

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