I've got an '88 Fourtrax, and the port job on it is done to the max. (I think if any more material is taked off, there will be holes in my cylinder.) I recently blew a quarter size hole in my Gold Series Fatty. Unfortunately the hole is located under the frame mount, so there is no patching that can be done. I can also see hairline cracks extendng out from the hole. Four of them to be exact. I have heard the FMF SST pipe was the one to get, however with my port job, I'm not sure if I will do better with the pipe that I have now or if it would be wise to go ahead and buy the SST pipe instead. Any one have any info on these, and will I do better with one or the other? I only want to buy a FMF, no Curtis Sparks or Paul Turner. (Can only get deals on the FMF.)

You mentioned you have ported the cylinder to the max. That's one thing.
How about piston size? Do you have a big bore? If so, the amount of exhaust you have with that set up is huge. You need to contact FMF and tell them exactly the set up you have.


Big bore vs regular bore pipes differ quite a bit.

The only other thing I have done to the bike is a clutch and basket. Bore is stock (more reliable) but still fast. All my money is in the suspension. I'll contact FMF though, and see what they say.

Well, that didn't take long. FMF told me that the SST hits a bit harder at the bottom, and hits alot harder in the mid to top end, especially with the port job. So that's the way I think I'm going to go. Time to order a pipe, and get ready for some night rides. Thanks for the info Sandpusher.