RE: Thumper Racing 340cc upgrade costs and options?
 

Can you explain to a non-machinist likeme why they shy away fromremoving more metaleven though the amount of material remaining is the same once they are finished?

RE: Thumper Racing 340cc upgrade costs and options?
 

Wow, 8000 miles seems pretty low for new piston and rings.....maybe I'll be selling my 300 cylinder and going with Kustom Kraft's full kit. Going to cost me $250 more than the route I was going to take but I'm not interested in doing piston and rings every 1 1/2 to 2 years. No wonder I heard reports of the 340 kit smoking if the rings go that quick.[:'(]

RE: Thumper Racing 340cc upgrade costs and options?
 

I have the 340 kit from T/r and have 700 miles on it. I beat the crap out of this as I ride all sand trails.
I've done a leak down and it was the same as when I first broke it in.
I hardly ever ride on the street, just to skip trails and if it lasts 8,000 miles I'll be 50yrs. by then. I have 769 miles now and at this rate it will be awhile.


Kevin

RE: Thumper Racing 340cc upgrade costs and options?
 

Tremor
In answer to your question. Ifa 330 sleeve is installed in both 250 &300 cylinders the following amount of material will be removed.
A 250 cylinder has .549 removed to install the 330 sleeve.
A 300 cylinder has .310 removed to install the 330 sleeve.
Hopefully this will answer your question.

RE: Thumper Racing 340cc upgrade costs and options?
 

Well I guess what I'm trying to ask is the outer diameterof the two cylinders isthe same, so why are the machine shops concerned with removing more metal from the 249cc?

RE: Thumper Racing 340cc upgrade costs and options?
 

It a time issue it takes longer to remove .549 from the 250 cylinder than it takes to remove .310 form the 300 cylinder

RE: Thumper Racing 340cc upgrade costs and options?
 

Just to make sure everyone is on the same page & comparing apples to Oldsmobiles:

I dont think it was ever said the 250 cylinder could not be bored to 330, 340, etc with a sleeve ala BillBlue.

What has been said was the 250 cylinder could not be bored to 330, 340 etc with a recoating ala Kustom Kraft.

Its my understanding if you sleeve it, you can do whatever you want to whatever cylinder you want (the sleeve goes in to the water jackets). But if you want to just have a coated bore the 300 cylinder is needed, 330 is the max, & the 250 cylinder will not work this way. I have gone to 300 cc myself & had each cylinder in each hand comparing the two--wish I took a pic! But it seems at the time I agreed with the statements made that the 250 cylinder can not go to 330 without a sleeve due to the location of the water jackets.

RE: Thumper Racing 340cc upgrade costs and options?
 

KLXer what do you think of going to just 300cc? Was the difference worth it or are you planning on going on the 330 or 340? I'm really on the fence on overboring as what I ultimately want is a 450, since that will most likely satisfy my desires for power and then some. I'm a bigger guy and want to do wheelies over stuff and through puddles. I can almost do it on my 250, with maybe a bit more practice i can get it. Going to a 300 seems relatively cheap for an displacement upgrade and it might be enough to settle my needs for a few years.

I would just hate to go through all of the overboaring and find out 340 is still just not enough, after having spent that time money and effort.

RE: Thumper Racing 340cc upgrade costs and options?
 

If you want a 450 I think you should get one.
My 340 is alot better but by no means a 450.
I can wheelie at will through puddles in the bottom 3-4 gears but it still doesn't run like a 450.

RE: Thumper Racing 340cc upgrade costs and options?
 

Think going 300 and calling it quits on the mods would be worth it?