Im soon going to be installing the Mikuni Carb,Exhaust,and Have my heads Worked and was wondering which Rev Limiter chip should I go with? All help is greatly appreaciated. I cuurently have a 5100 but kinda think its going to be toooo much for my likings. What are you guy's running?

with only carb, heads, and exhaust run the 4350.

4500!

With shimmed valve springs, decked heads, carb, and exhaust mine ran a 4570 chip. I kept it under 4500.

The 5100 is fine if you shim your valve springs when you have the heads done.. Use .100 or .120 shims.. The rev limiter IS NOT A GOVERNOR.. DO NOT RUN AGAINST IT LIKE A GOV AND YOU WILL HAVE NO PROBLEMS.. If the motor kicks up, roll off the throttle for a second.. Use your head and you won't have a problem with the 5100..

Agree with DB8 4570. Keep it under 4500 rpm's. I think that some of the problems people have with modded motor longevity has to do with case pressure and too much RPM.

X2

I agree but my point was if the heads are off and worked, shim the springs and you don't have to worry about any blips.. The man problem from high revs is valve float.. I know you know that but others might not.. With a .120 shim you move the float to about 5000 and the .2 seconds it hits 5400 won't hurt anything..

Remember that Higher RPM's cause extreme case pressure, as well as valve float, causing problems to occure at the weakest location of the motor. Agree that if the heads are off for work valve shimming should be included. I have a modded 35 to stage 1 and will be keeping my rpm's at around 4-4300. As I have stated in the past I modded for load carrying power and hole shot not so much for speed. My opinion is that Constant or intermitent running at these higher rpm's can be considered extreme for these engines. I would like to keep my motor around for a while.

Maybe we're actually agreeing and still arguing.. lol

Totally agree that SUSTAINED high revs will eat a motor.. I ran mine 5000-5200 for a while and ended up rebuilding.. Instant 1-2 sec blips will not be enough to create the high pressures related to engine failure.. Pooh Bear's got an idea about engines and that's what my initial response is based on.. Some of these guys in here should have a 3500 chip installed..

X2 no argument!!

I can damn near wear a new prop down in less than a month, ( I'm only allowed 3 a year! lol )

I run 4350 WOT with a good prop. Once the prop starts to show wear and my rpms start to climb. I use the smaller rev chip (4570) to remind me to let off the throttle. A modded (Stage 1) motor with a worn prop can run 4800+ steady before you know it. You have to use a little common sense.

4600+ = $'s in the long run. Not worth taking the chance imo.

after 3 rev limiters taking shits on me I gave up and quit wasting my money on them and just rely on my mad driving skills instead.

Most times it works... sometimes in don't. lol

my rev limiter ain't worked in a year