M1000 not pulling on top end?

[THINairJUNKIE]

I have m1000 with slp pipe, y-pipe, hps can, porting, sno pro air box. rk tech secondary with 38 helix, green secondary spring in 3rd hole and mtx 74g weights on 6 post clutch with no weight in them and yellow white primary spring. 63/57 gears. Ride 8 to 11k. sled pulls 7600 7700 rpms all day long. Pulls really hard bottom and mid then seems to fall off in the top end. Any ideas would be great.

 

[harf69]

Ive got the same thing going on on mine 07 m1000 I had a few people ride it and say the samr thing and i got beat up the hill by my buddies ET900 I sold him.Maybe I should have kept the 900 motor

 

[Outlander800]

My first guess is that you need more weight in the primary. I have a set-up similar to yours (except no porting), and I run 77 grm MTX weights with 1 gram in the outer hole (78 grms total) and at 9000 ft. it runs 7500-7600 RPM consistently and pulls hard. Also my sled seems to pull harder in the 7500 RPM range than it does at 7700.

These big twins only want to spin so fast, and sometimes you can add more weight and lose little if any RPM. On my modded KK I started with 66 grm weights and thought they were just right because I was pulling the RPM I wanted, but it did not pull hard on the top end. Finally I put in 69 gram weights and the RPM remained the same but it pulled much harder on top.

Try adding 2 or 3 grams in the outer hole and see if it pulls hard or not. Won't cost you anything to try.

Are you really running 63/57 gears (higher than stock)? Or are you running 57/63 (M8 gears)?

 

[THINairJUNKIE]

Ya meant 57\63 gears, M8. Im going to put my stock gears back in. I dont think that the lower gears are loading the motor enough. I had more weight in the tips and wasnt pulling rs at 9k plus. If gears dont help im going to take cpc weights with me and put them in. I think the the cpc weights will pull through the top end better.

 

[WyoBoy1000]

mine is doing the same thing, dealer is putting heavier spring and a little lighter weights. he setup another sled with the same thing and it rips.

 

[MarcS]

Mines kinda doing the same thing too. I have some heavy on the end 77's, but i was thinking of putting arctic cat weights back in it...what spring and weights are they putting in your primary Wyoboy?

 

[knzee]

thinairjunkie,
Have a buddy that runs an 08 m1000 nightfire with porting, rkt head, slp single/ypipe set up, and rkt secondary and he is running 80 grams with a d/d white primary spring (135-330). He was running it with the 046 belt and was still hitting the rev limiter. Put the 060 belt on and holds 7700. He will pull three-four sled links in a drag race on my d/d single m1000 set up and most of it comes around midrange and top end, right out of the hole we are pretty even.

Also if you don't have CPC weights let me know i have a set of 70 - 80 never been installed for $125.

 

[RockyMtn.Kris]

What belt are you running? Leave the lower gearing. Lower gearing will load the motor because the secondary can shift out easier. Did you notice this problem after gearing down???? If so drop some primary weight. Stay away from tip loading on your M1k it wont like it. I think the straight 38 is fine. You can go up one hole on the secondary too if needed.

Something you may not have considered. Is your motor running good? Not too rich??. These motors can run seemingly well rich, but will fall off at WOT loaded down if too rich. I spent last season with similar clutching issues. Now that I have the motor running sharp I am back with the clutching I couldnt pull last season.