motor help

[fearlessfred]

Im getting ready to order parts to rebuild my old 250r desertsled. it has a ct pro x 295 cylinder on it ,and it is a long rod motor. This motor doesnt run a spacer plate, so im guessing the early pro x cylinders were cast for a longrod setup.My question is there any combo that can be used with a 4 mm stoker crank with this cylinder. thanks fred

[C-LEIGH RACING]

Best that I know, all the Pro-x cylinders, old or new model, were machined for the short rod crank & if a long rod crank is being used, a spacer plate is needed, so you either have a short rod crank or the head dome has been cut so that the piston can run up into the dome.

It could as well, have a long rod crank, but be using the new model 87/88/89 piston.

A +4mm crank can be used, just a mater of spacing the cylinder proper so the ports are in the right spot or either cutting the head dome so the piston can run up into it.
Neil

[machwon]

C-Leigh is right, getting a .25 spacer or a different dome would work. It would be the best, but it will work. That is what ESR would sell you. The best way to do a 4mm would be to do the porting and dome both for a 4mm at the same time. Using the spacer jacks the ports 2mm which in effect raises the exhaust duration more than the transfer duration. Otherwise with the dome you get an exr cut dome and the piston will travel 2mm below all the ports.

[C-LEIGH RACING]

What would be nice, would be if they would machine the cylinder castings correct to begin with.

Short rod cranks been gone for quite a while now, so why keep machining the castings the same way.

Add the 4.8mm to the base & be done with it.
That way the ports will come up right at BDC & the cylinders can be ported right.
Neil

[fearlessfred]

Iwill tear it down today and take pics and post to see what I have and make a decision on what to do. i know that I need new main bearings,so Im thinking just do a hotrod crank at the same time and why not make it a stroker if its not to much effort and money. any opinions on hodrod cranks and main bearings.I parked my 250r in 2001 and all these different options were just coming around.I have allways used honda oem craks and bearings .thanks for the help fred

[rayman375]

Send that motor over to C-Leigh and let him go to town on it.

[fearlessfred]

well ,Tore it down and it looks like it was on its last bore. the skirts on the cylinder are to thin to chance another bore ,even if there is another larger piston ? still wandering whats up with the longrod and no spacer plate. was the early ct big bores la sleeve and not prox . looks like esr has 330 bolt on allready ported ,for 600.00 and rayman I would not hesitate to use neil at c- leigh if in need. neil is always helping someone out and his work has a good rep. ,but the way i have figured it the cost to resleeve is as much as a bolt on 330. 129.00 labor for sleeving 150.00 for the sleeve ,65.00 to bore 130.00 for the piston and rings 30 .00 for gasket kit plus rematching ports.all for an outdated cylinder.neil tell me if im wrong