Cagiva wmx 125 1987

Will be fun to see

did you sort out your piston height yet?
different ways to change power is port timing and rod length, as in rod to stroke ratio because it moves the wrist pin up or down to accommodate torque vs horsepower, you might have the wrong year rod or piston

Your cases are from a 85 or 86 cagiva. You cylinder is from either a 87-88 or 89. 87-89 used an external water port from the cylinder to the pump. 85-86 used an internal port between the cylinder and the cases. I suspect your cylinder, rod or piston may be from a 89 as they had a different stroke than the 85-88.

Let's see a pic of the heads combustion chamber. I worked on one of these decades ago and remember something being different with the head?

Pre 83 water cooled 125s had a funky looking combustion chamber. 1985-1990 heads all look basically the same except around 88 they omitted the locating pins on he head and made minor revisions to the squish band

Hay sa I got a price from a place in qld to re cote my 125 it was $225 I think how much is it in the uk

You are right on the money there is a long piston and a short piston
I got 2 out of Italy through vertex for my sons 89 125 project
Yamaha yz125k piston fits the 88/89 cagiva as well I got a bit of info from an old tuner who had a lot to do with husky/cagiva in Europe in the mid to late 80s
He had a bit to do with the big hp 125 motor
I asked him if he build me a motor . He still has all the specs for a 35hp motor
I've got nos crank,barrel just need a good set of cases

I bought a 88 wmx125 to restore, I was told by the owner it had a yamaha piston in it, but I have not tore it down yet.

Pretty sure 85-88 uses the same piston. 89 is different piston and rod

I may have an extra set of NOS 88 wmx125 cases. I have several nos wmx125 1985/86 cylinder/piston kits

I have a nos 88 and a nos 89 piston, cylinder, rod, head kits I can measure if need be

Your engine is a 1986.
since 1987 the cylinder has water passage outside.
1985-1988 the bike mounts the short connecting rod and a piston along.
In 1989, the rod extends and the piston is short.
nothing forbids you to mount the coupled piston rod long and short on your 1986.
the motor runs stronger, was done well in competitions.

Just found 3 x Folding gear levers for these. pm me if you want them / one.

Andy

Nice interesting build please keep the pics coming, I remember these Cagiva 125's being raced and doing well.

i'd like to see the Cagiva name come back yours is lookin good hope u havit rippin soon

Bike was put away due to other money pits And the lesser conscious part of my mind suppressed this thread

All i can say is THANKS for the clarification

I was randomly browsing through ebay two days ago and found a cylinder sleeve. After a bit of searching i hit buy now, hoping its the right one

So now there is hope. ooh also got the correct usd forks on