Is it a bolt on 330 or not?

[JOHNNY FIVE]

Trying to determine if my 330 cylinder is a bolt on or non bolt on.Guy i bought it from told me it was a ct motor with bolt on style cylinder.I talked to ct and they said they never did or ever will do a bolt on cylinder.I swear the guy at ct said something about to do a bolt on they hack off the piston skirts to make them work.I pulled my cylinder off to take a look and it has a new 75.94 piston,the sleeve definitely goes down into the cases at least about an inch with spacer plate,the thickness of sleeve is a little over 3mm.,the one thing i notice is,it looks like the back of piston depth from top of piston to bottom of piston skirt,is about 2 mm shorter than front of piston.Is this what the guy at ct is talking about?Do they alter the piston on a 330 bolt on cylinder compared to non on?

[trx250racer]

sounds like a non bolt on kit. in which case the cases would have been machined to accept the bigger sleeve.
show us a picture, top view of the cylinder stud area.

[JOHNNY FIVE]

I took pictures but cant seem to send them.Throw me an e mail and maybe i can send them that way.

[trx250racer]

send pics to trx250r_acer@yahoo.com
i will see if i can upload them for you.

[Burns310r]

Bolt on cylinders have short skirt sleeves. The pistons are untouched. The only company that makes a bolt on kit is EST.

[JOHNNY FIVE]

Originally posted by trx250racer
send pics to trx250r_acer@yahoo.com
i will see if i can upload them for you. I cant seem to send to your email.saying they cant find your address

[trx250racer]

Originally posted by JOHNNY FIVE
I cant seem to send to your email.saying they cant find your address


did you copy and paste my addy?? because if you didnt, you might be missing the underscore after the trx250r

[JOHNNY FIVE]

Im trying to send them again now.

[trx250racer]

it is a non bolt on kit. you can see that the cases have been machined to accept the big bore sleeve.

http://i1085.photobucket.com/albums/j438/TRX250RACER/1321847199.jpg

http://i1085.photobucket.com/albums/j438/TRX250RACER/1321847203.jpg

http://i1085.photobucket.com/albums/j438/TRX250RACER/1321847194.jpg

http://i1085.photobucket.com/albums/j438/TRX250RACER/1321847207.jpg

http://i1085.photobucket.com/albums/j438/TRX250RACER/1321847222.jpg

[JOHNNY FIVE]

Thanks for your help.Much appreciated!

[jhtrx250r]

That is a good set up but a supper old jug. It looks like the first generation of the Pro cross cylinders.
A word of advise take that top end to a machine shop and have them weld in some support braces to the out side of the intake area. (those are very proned to cracking in that area)

[JOHNNY FIVE]

Who made the cylinder?

[jhtrx250r]

Looks like pro cross ? early design with out intake support
They made all the big bore cylinders back in the old days (except for the duncans well at least they are a difrent casting) Now esr makes their own stuff and it's way cheeper than a pro cross.
Pro cross is what all the top builders used to use LRD, CT, even ESR, Now most of them are CPI or ESR,s new casting.

I enclosed a pic of a LRD pro cross PV i used to run Look at the intake area thats where you need a support.

[C-LEIGH RACING]

Another thing you need to remember about that old model casting.

You'll need to use a reed spacer every time you put the cylinder on, because the reed chamber area not as thick as the newer model castings & if you dont have that reed spacer in place, the tips of the reeds on that Rad Valve will strike the outside of the sleeve & end up busting or splitting the tips off.

I would say, it is mighty lucky that cylinder has lasted till this date & not busted.

We are running one of those old model welded up cylinders right now.
Been quite a few sleeves replaced in that casting as well as every bolt hole heli-coiled,,, BUT its still running.

I want to add a little tip.
When your looking at those pics submitted, looking at the one of the piston & see the darkening on the sides around the wrist pin area.

That darkening comes from port linking, from on the downward stroke of the piston & the aux exhaust port & main transfer port linking together.
The returning wave of the pipe, is pushing spent exhaust back down into the crankcase via the aux exhaust port, through the machining on the side of the piston around the wrist pin area & down into the main transfer port.

Only other time you will see darkening, on the side of a piston in a normal running engine, is if the rings are worn out & blowby being forced past those rings.

All is not lost though.
For years now this problem has been known by CT, LA Sleeve & even Eddie Sanders that used the Pro-x casting for the cylinder kits they offer, & to date ESR is the only one to come up with a cure.
ESR offers a new style machined piston, where the sides around the pistons wrist pin area not machined as much & prevent the port linking from happening.
Now, with this new style piston, we can pull some hp numbers out of these Pro-x cylinders just like those other new model cylinders on the market.

Just thought I would add that so you reading this would know & could pass the info on to others.
Neil

[mx91a]

Hi Neil,

Do the 265 Pro-X jugs have the port linking problems with the pistons or is it only on 295cc and up?

thanks

[JOHNNY FIVE]

Thanks for your insight guys.You made me go pull my cylinder back off,but by doing so i found that one of the clips holding the piston in,was not clipped in all the way.I think the dark color is bad lighting when i took the picture.I pulled the cylinder off to make sure but i think the piston is brand new.

[C-LEIGH RACING]

Originally posted by mx91a
Hi Neil,

Do the 265 Pro-X jugs have the port linking problems with the pistons or is it only on 295cc and up?

thanks

It is dependent on which piston is used to build that 265 & how that piston is machined around the wrist pin area.

A normal CR piston, the machining starts about the center of the wrist pin hole up & then back down around the outside of the hole, preventing the linking, but all brands of piston are not machined alike.
Some cast pistons, the whole side around the pin hole is machined off from front to back, which would allow linking.

It is all in the piston that is causing the problem.
The machining on the casting & sleeve, could be changed to prevent this as well, but would be far more trouble than changing the piston machining process.
Got a new replacement sleeve one time, checking it out how it had been cut, the port holes & such.
The aux exhaust ports had been machined around to far & not even matching the ports up it would cause port linking right to begin with.
Those sleeve port windows are CNC machined in, so its no telling how many had been machined that same way & unsuspecting people got them with no idea at all that there was a problem.
Neil

[Langbolt]

Who machined the OIL grooves around the Piston ??

Is that something CT does for those OLD Pro-X jugs ???

First time i've seen that.

I know Trinity used to do Oil holes in the pistons....but these grooves have intrigued me

:D

[C-LEIGH RACING]

Anything done to the front & back of the piston sides, like grooves or dimples, will cause a non friction point where the metal has been removed & hold oil/gas mix in the void which all together promotes cooling.
Neil

[JOHNNY FIVE]

Im not sure about the grooves,there is also holes on the front of piston.Its my first 250r,and the first time ive ripped into one.I bought the motor complete from a guy,and all i know is he said the guy he got it from had ct build it for him.Supposevily he raced go carts and this was his spare motor.Im hoping shes a runner.