Actually I already bought a CP. The TT Store gave me a really awesome price match deal that made it not much more then the JE when you figure in all the gaskets, which the CP kit I bought comes with. I feel confident the JE and the CP are neck n neck as far as quality. I think the thing that made the difference for me was my conversation with the CP rep. His knowledge and installation advice pretty much mirrored what people like Ron Hamp, Shawn_MC, and others say in posts I found searching for info here. When guys like that say things like you want your rings to break in with the cylinder at heat because thats when it is in it's normal and optimal running shape as for as expansion goes it really makes sense to me. It was much the same regarding dry build. They pretty much say the same thing and again, it makes sense in my mind. Thats just a couple examples. There was a few other things that brought me to the decision to buy CP. Had I not come across a little extra free money I surely would have bought the JE.

Thanks Bruce I really appreciate your help!

Edited by mrmoto35, 17 April 2012 - 09:51 AM.

Let us know what you think of the kit.  I know CP pistons are top notch but they are also providing you with a gasket kit, which I am assuming is going to be aftermarket.  Let us know how the fit and finish is.  I would be interested in a CP 13.0:1 piston kit for $250 since that is what I paid for my JE 12.5:1 piston plus OEM gasket kit when I did my last rebuild.

Did they advise the drybuild?  Which if I read right is not lubing your piston rings during assembly...right?

shanecarr, on 17 April 2012 - 11:27 AM, said:

That is correct. DO NOT oil the ring. And you for sure never want to dunk the piston and rings in oil and the assemble them    Here are some threads I bookmarked before I bought the piston.
Reading those took me way way back to when I was building my VW motor. A 61 rag that would stomp pretty much any prod car off the line. Well built V8's usually got me on the big end though.

http://www.thumperta...__hl__dry build

http://www.thumperta...dry ron__st__20

http://www.thumperta...__hl__dry build

http://www.thumperta...a-break-in-oil/

mrmoto35, on 16 April 2012 - 11:24 AM, said:

http://shop.thumpert...n-p4056615.html

And I just bought one for a customer too.

Well f*** me running , you have to put a period after J and E to locate it via search. And I didn't ask when I bought the CP. My bad for saying they didn't sell them. Doesn't matter for me though as I had my mind made up to buy the CP kit.

I am glad you pointed it out.

what is the weight of a cp piston vs the J&E pro? also i only change the head gst and it is $23 dollars i have not found cp pistons less than $250 that is a lot of difference.also reading the forums i thought i read ron hamp preferred the J&E over any other piston.i do like the dlc coating on the wrist pin on the cp and the skirt coating

I paid less then $250.00.

I have never had the top end off this motor and as far as I know the cylinder has never been off so I am replacing all gaskets no matter what I find. The existing may be ok but it is not something I wanna do. The bike had very few hours when I bought it and I could wait to do the piston but I wanna get in there and have a look so I decided to do it now. Plus the 02 is lower compressed for the cam it has so this will be a nice power addition without demanding an appendage. Not that I need more power... LOL

The JE pro is 255g, and the CP is 249g according to a second CP rep I had talked to. If I remember RH wrote both are good. I think I read something about him using JE as well but I wasn't searching on piston preference when I read things he was saying. I was searching on assembly, dry build, and break-in.

Edited by mrmoto35, 19 April 2012 - 11:28 AM.

j&E piston and gaskets $200 thats a $50 dollars difference and i have had excellent luck with the J&E 13.5;1 with pump gas

Yeah I paid more then $200.00 and a JE would work just as well. I think the tipping poit for me was in the phone calls to CP. Just liked them more.

Do you happen to remember what your cylinder to piston clearence was?

cylinder to piston clearance is 0.020-0.040 mm or 0.0006-0016 (in) if you need any other specs let me know i have the factory manual

Got the new CP piston in today and it fired 3rd kick. Got my first 4t piston replacement under my belt. Many many thanks to everyone here at TT!!!

Going to take it out tomorrow to the dry lake bed and break it in.

It is hard to say how well I like this kit as it is the only one have I installed. The Cometic gaskets lined up perfect except for the head pipe gasket. It is thicker then OEM but is a much smaller diameter so I didn't use it. I used a new OEM. Maybe Cometic put the wrong one in the kit?

I will give an update on how it runs tomorrow when I get home.

Edited by mrmoto35, 04 May 2012 - 06:59 PM.

brucegregory, on 20 April 2012 - 04:26 AM, said:

I measured it for him, he was dead nuts at .0009 after I honed the bore.

I also checked the rod big end gap and it is almost at new spec. I have to admit being that it is an 02 I was worried that I was gonna find $$$ adding up but the previous owner did right by me. Of course I paid next to nothing for it so I guess I couldn't complain if I had found the bike had many more hours then I was told

Edited by mrmoto35, 06 May 2012 - 11:29 PM.

I am stoked!!! The missing link for my '02 has been found. That silly little piston woke my bike up!

I did a dry build using oil on the pin/little end of course and just a smidgen on the skirts. I ended up using Quickseat  on the ring/cylinder as it arrived in the mail just in time, put Rotella T white jug in the motor, and kicked it without the spark plug in approx 50 times to prime it. I could easily tell when it was primed which was really cool.

I took it to the dry lake bed this morning and broke it in. I rode it about 3/4 of normal, did 3/4 throttle acceleration thru all the gears about 6-8 times, and never slowed down without having the clutch disengaged for about 25 minutes. I then changed the oil and then rode it again around the lake bed at around 3/4 of normal, never staying at a steady speed until I had pretty much gone thru a tank of gas. I then drained the oil again and put a new filter in and filled it with Rotalla Synthetic blue jug.
I ate lunch, watched a military drone fly around El Mirage for a while, then rode it again,

I rode it across the lake bed and into the desert and I have to say it pulls so much better now. I would say the biggest and best gain is in the bottom end. It has been a while since I last rode desert but man oh man I am loving it again. The combination of the new piston and the new CRFStuff brakes made it a whole different bike. I was shifting probably 70-75% less then before. Almost all the corners I would have normally down shifted for are now just brake and gas. That added bottom end was there to replace the downshift in many corners. I am running 13/51 gearing so it wasn't hard at all to get it into 5th gear in the smoother straights, and at my age I have no desire to go any faster then that in the dirt.

The bike ran really great, like it had been waiting to have the higher compression. Ran awesome on the usual California 91 pump. I ended up using up all my fuel and If I didn't have the Dunlop 756 on the back I would have made the 30 minute round trip to town and purchased more and kept riding. I was also by myself and there was hardly anybody there so I had to take it a bit easy. One bad crash and I might still be laying out there.

I am sure I would be saying this same thing had I bought a JE but the CP has a bigger skirt the DLC pin which made it more attractive to me. I am glad I pad the extra $30.00 and got the CP.

Edited by mrmoto35, 05 May 2012 - 11:33 PM.

mrmoto35, on 05 May 2012 - 02:35 PM, said:

Good Job