Did the ported head give you a big power difference? Does it affect your low end power in anyway or does it help all around?? Thanks

 

Im not Jeffksf but i do have a ported head on my mo. I ported the head myself and it does make more power. Whenever you port a head, in almost every case you will add the power to the upper part of the powerband. Mine really turns on on top because I opened it up a lot and added a bigger carb. Also unless the head is terribly restrictive to start with, a port job is often going to hurt the performance on the bottom end, especially if you really open it up for big power improvements. A mild port job will give you better mid through top power and will probably not effect the bottom very much. If you are wanting to salvage the bottom end dont go with a wild, huge port job.

 

Thanks mojo addict. Do you think I should get a bigger carb also or only if I go with a wild port job? Are the cvk carbs that come with the mojave boreable?

 

When I had it done it was in conjunction with the piston and exhaust and rev limiter so its hard to say exactly what just the porting did but together those mods made a big difference. FST did my work and after describing the type of riding I do most He said that the stock cams are the best low end cams out there and to port it and run the stock cams. But I would recommend porting for any type of riding because its only going to get more air/fuel into the combustion chamber and that = more power. FST also doesn't recommend bigger carbs unless you are going really big on the mods and want most of your gains on top end.

 

A bigger carb will definately hurt the bottom. stock cams are best for low end as well. If your engine is really free flowing with a big port job, big carb, wild cams, free flowing exhaust and etc. then the velocity of the air slows down at low rpms to a point where the fuel is not drawn into the air stream as well, atomizing of the fuel is not as good, and combustion effeciency goes down. At high rpms however, velocity increases and the additional air and fuel make more power.

I have a high compression wiesco piston, big cams, ported head, 38 mm carb, IDS2 exhaust(race series with 26 discs), high rev valve springs and rev limiter removed. It makes much more power on the top end but the very low bottom(just of idle) is not there and low end power is not great. I have to ride it in a lower gear than my other mojave when trail riding to keep it in the powerband. But it will kick but when I get to the fast sections of the trail. The big carb and cams have probably cuased this more than the porting though.

FST ran a stock carb on their racing mojaves for xcountry for this reason. If you race flattrack or fast TT, the big carb and porting with the other mods are great. It all depends on what riding you do. If you want all around better performance I would say run the stock carb or one that is not really bigger and get a mild port job that will give better power throughout the range. If you like to trail ride, I would stick with stock carb and cams for sure.

Porting is kinda expensive if you pay someone like FST to do it. I beleive that your money is better spent on a big bore kit. I would choose a big bore from FST with no porting and a good exhaust and jetting over a ported head and big carb. Of course if you got plenty
of money you can just do it all. A big bore kit will increase power everywhere with no penalties or trade offs.