RPM loss on 2019 Alpha ?‍♂️?

[980K]

On two rides this season the RPM’s are down significantly from the last two seasons. Last year and season it was new it always ran 8-8100 peak with stock weights. I ran 70 gram weights around Island Park, Idaho this year and it would hit 7900 briefly then settle down to 7800 while last year in Togwotee(slightly higher average elevation)with same weights it’d run 8-8100. My last trip in Steamboat Lake/Flattops area of Colorado with 68 gram weights it’d briefly hit 7700-7800 then settle down to 7300-7500. Last year it’d pull 8-8100 same area with the same 68 gram weights. I’m puzzled with the lack RPM from one year to the next. The sled only has roughly 900 miles on it too so I wouldn’t think engine would be getting weak already. Primary spring seemed pretty sturdy as well. Any input or advice would be appreciated

 

[tswan]

Start with the simple things first. Clean the clutch every ride or every other one.. Belt then springs. I have a 19 and a 21 seems like belt would fade enough to notice rpm drop at about 750 miles. I did have a secondary clutch spring weaken at about 1000 miles on my 19.

 

[slyrydr]

i doubt that it's internal engine....spark plug change, check power valves going full open....then binding of some sort in clutches...a good cleaning of both will help....and first of all, change your belt

 

[summ8rmk]

1,200 mi on my first belt with zero difference in max RPM from 0 miles.
Only removed because i pulled a small string. u can absolutely swap in a new belt and check if there is a difference on the hill. Super easy to do.

My Primary crapped out at 1,100 miles.
Didn't see any performance loss with the small cracks in it either.

I would replace the primary spring and check weight bushings for excessive play.

Sent it

 

[Suzzy-Q]

Power valve cable adjustment?

 

[Vern]

I’d start with clutch springs. I was having similar issues on my ‘20 after about 800 miles. It would struggle to pull rpm with completely stock clutching. Swapped in new springs, both that were rated about 10-15 lbs stiffer finish rate than stock, and now it’s holding rpm no problem. Don’t know whether it was simply the new springs, or the extra 10 lbs that made the biggest difference though.

 

[sno*jet]

assuming the sheaves were properly cleaned up while the belt was out for weight changes, the next step would be to pull the helix out of the secondary and make sure everything is in working order.
x2 on checking the apv valves for spec and changing spark plugs if never done. Also throttle cable adjustment. track alignment....check everything over in the book before throwing money at it.

 

[980K]

Thanks for the input guys. Clutch was cleaned before last trip as I changed weights. Changed belt too. It seemed to hit hard on the bottom just falls short on RPM. I’ll be getting new clutch springs ,checking power valves and throttle cable adjustment. I just won’t be able to test it out until next season though

 

[boondocker97]

Might be worth checking ohm readings on the stator. All season I've issues with my sled running warm. Have traced it down to weak stator not supplying enough voltage to the fuel pump and running it lean. This is on the old suzuki, but I'd check it just the same.