Zilla Reving a little slow

[bean86]

Hey guys, I bought a great shape 88 500 last fall and have put a 39 keihin carb, Vforce 3 reeds and a power pros pipe. the base gasket blew but i put a new one in before our little sahara trip last week and it ran great. When we had it apart it basically has a new topend and everything looked extreamly clean in the jug. It rips hard off the bottom end but it doesn't seem to rev as fast as my dads 90 500. My pop's has the same power pros pipe but its running the stock reed cage with boysen reeds and the stock carb. I thought the 39 carb was supposed to make it rev better. I think its my jetting but i don't know what to try. I have a 65 pilot with a 178 main. it rips harder off the bottom end than my dads but my dads just seem to rev out quicker when we were drag racing. Any thoughts would be great It seems a little rich on the top end to me but i am afraid to go leaner because 180 is the general mark where most people are running.Thanks

[FPMXer]

Jet the motor to the plug. What shape is the clutch in and is it adjusted and not slipping? Also when you returned from the sand did you clean and or replace that air filter? A dirty air filter will make a motor fall on it's face.

[burgiebird]

Good point fpmxer. If its all together and jetted right it should act just like dads

[bean86]

The clutch is adjusted properly and i had a clean air filter. I have heard that the clutches are weak on the 500 and i assume that it is all stock because not much has been done to it. I have never fouled a plug since i put all of the parts on. I haven't checked the plug because i don't like to pull it out in the sand if i don't have to. I am back at college now but hopefully I can miss with at home on the dirt.

[pipejob1]

It sounds like the bike is making more power with the mods you have made. I would check to see if the clutch is good. If it is good you should add Barnett heavy duty springs. If it is stock and old do a complete clutch kit it will cost you about $100.00

[FPMXer]

It might sound crazy but dirty oil will cause the clutch to slip. What type do you run and how often do you change it?

[bean86]

We change the oil quite often and we use 10W30 mobile one full synthetic. I know that some people say the full synthetic is bad for a wet clutch system but we have ran it for years in everything we have ever owned and have never had any tranny problems in our 20 year quads so i like it for that reason. I also know that the clutches are not slipping on anything else. My dad runs the same oil in his 500 so i don't think it is the oil. I thought if the clutch was slipping then it would rev up but not go like it should, not the other way around.

[fastman69]

make sure you don't have to much oil in the case. i gave my quad an oil change and then went for a slow ride after about 2 minutes, it felt like the quad was dyin, it would bog and not rev at all. so i drained some oil and it ran great.

[bean86]

It doesn't really bog because it rips hard off the bottom and into the midrange but it just won't rev out all the like it should. its perfect till 3/4 throttle then it just seems to stay there for awile before it finally winds out. Thats why I think its the jetting. Can being to lean on the main cause this?

[fastman69]

Try the power valve. If i was you, I would take it to someone who knows how the engine works and how to adjust the power valve correctly.