Only hitting 8000 RPMs with stock clutching.

[dfinn]

What is backshift? I hear lots of people refer to it but I've got no idea what they are talking about.

Phil, found the markings on the clutch plate. Had to clean them real good and take a close look. Can't see the 3 at all but I can make out the 1 and 2. Thanks.

 

[philsummers21]

Backshift: is the ability for the engine to accelerate to rated rpms, as the load changes. Basically its like gearing down in a car when you come to a steep hill or what not. Say your boondocking through the trees. hit a bump and your front end comes up and you loose a little momentum and traction. Backshift will gear down basically and maintain optimum RPMS.

 

[akvector]

phil, what would you recommend for a 2010 MTX SE 153, ridden from sea level to 2000' with Yamaha's recommended adjustments (22/40 gearing and the sea level kit) ? I spoke with my dealer recently because I was only seeing 8500 rpms in soft snow, and he said to be patient and take note once the engine gets fully broke in, or to try putting more tension on the secondary spring as you mentioned in detail earlier.

Appreciate your input

I run pretty close to you most of the time. I have been around 2500 feet in elevation. I am running 20/40 gears and secodary wind is at 6-3 seems to be working well. although i do not care for tight wind on hard pack. But in the powder its working alot better than last year.

I did not want the 22 gears as yamaha always gears to high.

I tried a 46 helix last year and on the trail it was awesome but as soon as it seen powder it was a turd.

 

[dfinn]

Looks like part of my issue might be my belt. I've got around 850 miles on the stock belt now. Still looks good but it was probably about an 1/8th of an inch or more thinner than the new belt I put on last night. The old belt sat down in the secondary about 5 mm, the new belt sticks up about 2 mm.

I put my secondary back together last night with the stock spring at 90. I'll be out testing tomorrow morning.

 

[philsummers21]

Any updates Dfinn

 

[dfinn]

Yeah, things are definitely heading in the right direction. I saw sustained RPMs right around 8500 and track speeds around 43 mph while climbing a pretty steep hill with about +10" of snow on it.

I'm going to shave a little bit more off of the weights this week. I think the new belt really helped.

Also, I paid more attention to it and it definitely felt like the backshift was much improved running it at 90. I was climbing a less steep hill with a little more snow on it than the hill above, in the middle it had a hump with more hill above it. Normally I would hit that hump, wheelie, land and loose some RPMs/speed from the deep snow impact and uphill landing. That wasn't happening anymore. My sled it's it's RPMs and speed up like nothing had happened. Is there any downside to twisting it up to 120?

edit: it is still frustrating though. compared to my buddies on a poorly running rmk 900 and an older rev 800 I can't go nearly the places they can go when it comes to climbing stuff.

 

[philsummers21]

Run it at 120. Will see more backshift and a little more RPMS. I can beat my buddies M8 all day long in any snow condition. Cousins XP still beats me but not by a whole lot. Hes also about 75lbs lighter then me too tho.

 

[dfinn]

Phil, what year is yours? I've been reading up on attack angles and it sounds like the '10 is a big improvement over past years.

 

[philsummers21]

08 with a 162 CE and TS rear. undertunnel exhaust and some clutching

 

[dfinn]

Does the TS skid change the attack angle?

 

[philsummers21]

I think so. I know you run your limiter straps a little tighter which would help. makes a HUGE difference i do know that. Got a video today of a highmark i put on a hill that my friends M8 Couldn't touch. Needless to say he bought the beer.

 

[fiddlersgreen]

You gotta use lighter rivets in the primary clutch weights. pretty basic & easy stuff.

Hard to use lighter rivets when stock clutching uses no rivets.

DFIN. A gear change is pretty easy if you have any mechanical skills at all. Cost is about $30 for a new gear. I ride the same elevation with a 162 as well. Im running the 18/20 gearing. Buy an arctic cat yellow secondary spring and run it at 30Degrees. Will be a HUGE improvement.

What does the yellow spring do to the secondary as opposed to the Yammy spring?

 

[philsummers21]

Its stiffer then the yamaha springs. So more backshift.