09 M8 spinning too many RPM's

[1M800]

I'm not sure what is going on with my sled. I bought it here in MN and put in the 77 gram weights it calls for under 3000'. The first time I realized it had a recall on the tach it said 8400+or-. I put in 70 gram weights and took it to the snowies and the highest I saw was 8150 +or-. I got it back home and put the 77's back in and went for a little trail ride and when I checked it again it was 8400+. I understand that it needs heavier weights...but why? This is what it calls for here. I don't even remember what the max RPM's are supposed to be...but this seems too high!

 

[89sandman]

lower elevation=thicker air=more horsepower!!!

 

[1M800]

lower elevation=thicker air=more horsepower!!!

No sh!t! But I am running the weights AC calls for at this elevation. Mine must make about 10 more horsepower than others!

 

[BigRed118]

I would have your tach checked. Some have been off by 2-300rpm.

 

[1M800]

I would have your tach checked. Some have been off by 2-300rpm.

OK, that would make sense. I will have to call the dealer. Thanks.

 

[Runner8]

Idling

I would have your tach checked. Some have been off by 2-300rpm.

Can you check this when idling? I mean, will the tach be more and more off as the rpm rises?
On my BD box, I can read the rpm. But I have only checked at idle...

 

[1M800]

My brother just reminded me about the helix. Does anyone know if it is supposed to have a helix change for low elevation?

 

[BigRed118]

I believe it is supposed to be a straight 36 degree. The higher elevation is 44/40 for 6000ft and higher

 

[jaws136]

Wrong BIGRED 44/40 is what your dealer should of installed if you bought if for flat land country, may not hurt to ask them....I believe your tach is on or near and your turning too many rrr''s in mine 44/40 81g's it is still overrevving to 81-82 midshift but just right on top. this is 0-3k

 

[1M800]

I believe it is supposed to be a straight 36 degree. The higher elevation is 44/40 for 6000ft and higher

I just checked and it looks like it is the opposite of what you are saying. I need a 44/40 for LOW elevation. Any one know how much the helix change would drop my RPM's?

 

[M Turbo]

I've had to run 44/40 helix and 78gram bully dog's at 2000-3000ft to keep my r's down to 7600. Stock 800HCR, and it fly's!!!. Belt deflection is important, to loose is not good. Try a 060 belt or wash and clean yours.

 

[1M800]

Thanks. Looks like I am ordering a helix!

 

[killerrf]

i tried yellow/GREEN primary spring with 77 grams and cat orange sec spring with shift assist and stock 36 helix and it still seemed to rev fine about 7700 rpms. i have the standard gauge.

i also tried 80 gram cat weights with yellow/GREEN pri spring with 42/36 prog, shift assist, d&d gold sec spring with one black shim out and found this works the best for me. both tried at home at 2200 ft. i thought the yel/grn with 80grams would contribute to poor backshifting somewhat or doggy feel but with that 360lbs d&d spring it works good in all conditions i found.

 

[JHG]

Don't adjust RPM's with your secondary. Find a helix that has the shift characteristic's you want and then adjust primary weight to get the right RPM's with it. If you're over-reving and want the shift of a steeper helix then go for it but if you are happy with the the shift of what you've got, work on the primary to get it to pull the RPM range you want.

 

[1M800]

Don't adjust RPM's with your secondary. Find a helix that has the shift characteristic's you want and then adjust primary weight to get the right RPM's with it. If you're over-reving and want the shift of a steeper helix then go for it but if you are happy with the the shift of what you've got, work on the primary to get it to pull the RPM range you want.

Sounds like good advice. But going to the 44/40 helix isn't going to make it more responsive? It might actually make sense for me to put this one in for Minnesota riding. Ditches, forestry roads, trails, etc.

 

[JHG]

Sounds like good advice. But going to the 44/40 helix isn't going to make it more responsive? It might actually make sense for me to put this one in for Minnesota riding. Ditches, forestry roads, trails, etc.

It may, and like I said...If you want to try a different helix go for it but don't pick a helix based on RPM's being low or hi. Usually when you change helix's you have to change primary weight, it's just the way it goes. Run a couple different helix's, decide what you like then dial the primary weight. I like cat weights so I usually buy them a little heavy then grind them down to the weight that works.

 

[1M800]

It may, and like I said...If you want to try a different helix go for it but don't pick a helix based on RPM's being low or hi. Usually when you change helix's you have to change primary weight, it's just the way it goes. Run a couple different helix's, decide what you like then dial the primary weight. I like cat weights so I usually buy them a little heavy then grind them down to the weight that works.

Thanks again! I'm going to try the helix and see if I like it. Man it sure was cheaper messing around with the clutching on my old 2004 1M. Weights and helix's are alot more expensive for the new one!

 

[tcpeterson]

Thanks again! I'm going to try the helix and see if I like it. Man it sure was cheaper messing around with the clutching on my old 2004 1M. Weights and helix's are alot more expensive for the new one!

I'm running an M1000 but i have a 44/40 helix with 75g AC weights and an orange/white spring in the primary. I've been pulling around 7400-7500 rpm's at 3000-6000 feet. I know you are lower than that but just thought i'd share my experience.