I am feeling like I dont want to run the 690 kit anymore because its digging into my pocket now with my bottom end out. I was wondering if anyone is running the stock bore with a 13:1 Piston and FCR carbs? How has it been doing and how long have you had it? I believe if I do this again (690) I will have the rod replaced as well but then again, will the Piston last? I had a weak piston in mine and dont want to use that again with the FCR's. So I will stay away from JE from now on. What I am mostly looking for is DURABILITY, I do mostly trail riding, duning and a little drag racing now and then and dont want to go through this again.


Any help would be greatly appreciated, I purchased a new bike but if its just going to go out every 6 months then FORGET drag racing for me, I am out.

 

alot of the rods that were lost before were on stock bore rappys,i have heard of 2 or 3 that's why i went to a 686....

I actually ran itto a few fast stock bore bikes this weekend...

 

Sam, Scott told me your running a different piston now because yours took a beating. What did you go with?

 

Anyone else want to comment on this?

Thank you

 

The opinion I have gathered is a slightly lean condition causes the rod too get too hot and fail..."edit" or detonation destroys the piston + creates a hotter cylinder. JE is know for awesome durability and more importantly accuracy. Sorry too hear you got a bad one. My stock bore 10.75/1 JE hasprovided excellent servise....another worry area is most of my local shops are used too boring for WISECO pistons and you throw a JE in and viola...siezure....and of course it was not their fault...boo!

 

I don't think it's the bore size that's the problem. Were you running a 11:1 JE on pump gas?

Anyhow, there are better pistons available now. Craycraft has some Ross pistons that are built much stronger in the webbing than the 11:1 JE. If you are going to replace the rod, it's only a little more money to go Ti. Once you are in that far, then it's only a little more money to do a 727:-)

 

Yeah but the Piston was working great until I ran it with the FCR's. I was told the Piston that I got will not work with the FCR carbs (AFTER 2 MONTHS OF IT INSTALLED) and it causes the Piston to crack and break, well, not soon after that guess what happened???? IT WAS THE SAME @#$%&* day I was told this. Thats what pisses me off, I figured shoot its been running this good for the last two months it should be good to go. If the Rod is going to go easier on a Stock bore then I am just going to enjoy my trail and dune riding from now on.

 

I was running a 12.5:1 on Unical 110. The bike has never ran hot at all.

 

I was told on this forum not to bother with FCR's with what I have done. I've had it for a couple of months and it runs great, and I do ride it hard.

 

Yes I was told the same to as in power wise but when I test rode a bike with the FCR's on a 690 it was a 2 to 3 bike difference. I got them and now I find out all this junk.

So, is anyone running the FCR's with a Stock bore high compression piston ?? I just hate to sell my carbs too. But if I have to I will.

I am going to start listing everything on ebay next week if I cant find a resolution not too.