would there be a huge speed dif

[fritzbat]

Gday lads you have probalby answered this question hundreds of times b4 but I will throw it out there again.I have a decission to make I done my topend in on my cy23 baja i can put the 28.5 top on or buy a whole zen 26 would the zen 26 be a lot faster and punchier than the 23 engine.Any help would be great also when i pulled down the old motor there was a few drag marks on the fan/flywheel from the coil contacts is this normal they were only going halfway around not all the way would that b a sign of it being out of round?
CHEERS

 

[Timmahh]

yes the Zen will have a bit more torque, as its a bigger bore. 32mm for the stock cy23 to 34mm of the Zen. same stroke. yes you can just install 28.5 topend kit and gain even a bit more torque over teh Zen. note: you will lose just a bit topend going from the Zen 260 to the CY 28.5 again due to bigger bore. the Zen as noted above is 34mm and the CY 28.5 is a 36mm bore. all working on a 28mm stroke.

but how did you toast your topend? you bearings maybe an issue if you got dirt/sand into the motor. so be sure to go thru the entire lower half or at the very least flush is very very well before tossing on a new topend. the zen it basically a complete drop in, but you may need to change the flywheel cover. there is a few good threads on HBF concerning isntalling a zen based motor in the baja. if you need a link lmk and i ll get it for you.

sounds lke the coil mounting bolts became loose and dropped down on the flywheel. as long as it not completely fugged up, you should be good to use it.
T