Does anyone have reliable info on which cylinder produces the most power, I have a 92 quadracer that someone put an 87 cylinder on, I bought a 92 cylinder and was going to install it because the intake port mapping looks better, but a local engine builder told me that the 87 cylinder is the best because it has a bigger reed cage.

 

A person I know who has done a lot of work with Quadracers also told me that the 87 top end is the best. He said it was because its the same cylinder as the 'Zilla, but with a thicker sleeve to make it a 250. So the reed cage is larger than all the other years. I've noticed that reeds for the 87's are more expensive than all the other years, so that makes sense. He also told me that the 89's have the best bottom end (in case you were wondering).

 

An 87 does not have the same cylinder as a Zilla! Think about it! The sleeve would have to be like an 1 1/2 thick. That's the craziest thing I ever heard. They shared a reed cage in 87 but they also shared a reed cage from 88-90. The 87 design was just different. Look at a 250 cylinder and look at a 500 cylinder, there is a night and day difference. It's funny though, my friend has a ported and polished 91 with a FMF exhaust and his brother had an 87 that was stock except that it also had a FMF exhaust, and the 87 was indeed faster. But it doesn't have a 500 cylinder on it.

 

Hey, I was just going by what I was told by someone who does a lot of good engine work (he weighs about 250 and has the fastest Banshee around here). He has worked on a few of his friend's Quadracers that are setup for racing and said that the sleeve is quite a bit thicker on the 87's...I'm not sure by how much though. But its not just the bore that would be decreased, I'm sure that the stroke is less also. So it wouldn't have to be that much thicker. I don't know, maybe he's full of it, but sometimes I wish I would've bought the 87 instead of the 90 when I was getting one.

 

Zillaman is correct I know the 250 cylinder is about half the size of the 500's, the only thing that is the same are the reed cages. The 87 has a bigger reed cage but the 88-92 has an unbridged intake port and a slightly higher exhaust port for better top end, but I don't know which one has better power potential overall. The 86 RM250 cylinder bolts directly to a 87 - 92 quadracer and has larger transfer and exhaust port, but they seem to be hard to find. If I could find someone who has tried both and could tell me which cylinder to use I would be very happy. The reason I am looking for more power is a bunch of my friends have dropped big money into their 400EX motors, Cam, 416 10.5:1, porting, pipe, and now they can keep up with me, I don't like that.