gc_srt
Pro
All,
Playing around last weekend with a new belt (carlisle ultimax xs) and gearing. I went from a 20 tooth to a 19 tooth and stock belt to ultimax xs. My question is, what is everyone running for shifting rpm? I was running around 9100rpm during shift and went up to about 9250 in top end last year and this year I am shifting at approximately 8800rpm. Looking at the dyno graph for full exhaust and k&n, that appears to be the peak hp. Although looking at the graph, the hp is consistent across 8600-9100rpm with the combined k&n and full exhaust that is not snow.
http://www.ty4stroke.com/viewtopic.php?t=62992
What is everyone else shifting at? FYI, I am running an ulmer clutch kit with empty tip and mid.
Playing around last weekend with a new belt (carlisle ultimax xs) and gearing. I went from a 20 tooth to a 19 tooth and stock belt to ultimax xs. My question is, what is everyone running for shifting rpm? I was running around 9100rpm during shift and went up to about 9250 in top end last year and this year I am shifting at approximately 8800rpm. Looking at the dyno graph for full exhaust and k&n, that appears to be the peak hp. Although looking at the graph, the hp is consistent across 8600-9100rpm with the combined k&n and full exhaust that is not snow.
http://www.ty4stroke.com/viewtopic.php?t=62992
What is everyone else shifting at? FYI, I am running an ulmer clutch kit with empty tip and mid.
auto2665
Extreme
How do you know when it shifts?
gc_srt
Pro
There are three rpm's, engagement, shifting, and top end. The engagement rpm is what rpm that the sled starts to move, the shifting rpm is where your primary and secondary shift at, and the final rpm is where the primary and secondary are fully shift (top gear) and the engine pulls to its top speed.
To test shift rpm, hammer the throttle and see what rpm the sled holds during acceleration.
I was hoping someone with similar engine mods (there should be lots of guys) were shifting at.
To test shift rpm, hammer the throttle and see what rpm the sled holds during acceleration.
I was hoping someone with similar engine mods (there should be lots of guys) were shifting at.
Bahr05
Expert
8700-8800 is good, with a top end RPM of 9000-9100. I think at 9300 the rev limiter kicks in. My peak hp on the dyno is at 8900 wit all the add-on in my signature.
gc_srt
Pro
Bahr05 said:
I found some great information in the following thread:
http://www.ty4stroke.com/viewtopic.php? ... c12b0079a2
Allen's graph and table show slightly different numbers for full exhaust and k&n, but it appears shifting between 8700-9000 appears to be ideal (149hp.2 @ 8700rpm to 150hp @ 8900 and 149.8 @ 9000). The graph shows max hp of 147.8 @ 8600rpm.
Bahr05, did you dyno your sled before and after modifications? When looking for Allen's dyno sheet, I found one of your threads indicating that you did but I didn't see any results.
Bahr05
Expert
I didn't not dyno it before. Just after the add-ons. I seem like im always fighting the shift RPM now, plus after the clutch kit, I had a belt come apart, which hasnt happened before.
gc_srt
Pro
Bahr05 said:
Are your clutches hot after running them? If you are running a stock belts, they should last 2000mi (3000km).
gc_srt
Pro
Bahr05 said:
What do you mean by fighting with shifting rpm. The shift rpm will usually be +/-100rpm during acceleration. It will never hold that rpm and will constantly be moving.
auto2665
Extreme
At what speed does the shift rpm take place at? If I'm cruising along at 50 mph, will I be into the shift rpm?
Bahr05
Expert
Shift RPM occurs when you pin the throttle. Your RPM's will jump to say 8700, and hold there while the clutches are shifting. At 50, you should be roughly a 7000-7200 RPM's, depending on gearing and clutching.
Yes, my clutches are hot too. I might be trying something else next year. I can't get consistent results. Either its too low, or two high. Can't find a happy medium.
Yes, my clutches are hot too. I might be trying something else next year. I can't get consistent results. Either its too low, or two high. Can't find a happy medium.
gc_srt
Pro
Bahr05 said:
If your clutches are running hot, you are slipping the belting causing the over-revving; the heat issue is causing your belt to fail prematurely. I was having that issue last year and it was an ingress of snow into the clutches causing the issue. I sealed up whatever I could and it helped greatly. Dumb question but do you still have your belly pan on? I have seen a couple of guys lose their bell pans in transit. Also, how many miles are on your sled? Is it time to rebuild the primary? Your arms may not be sliding smoothly on the rollers or the sliding sheave is not sliding smoothly on the shaft.
Bahr05
Expert
There is 4751 on the sled, and I had the clutch cleaned up and inspected last year. The clutch kit is 2 seasons old. Belly pan is intact.
Im extremely low on $$ this year, and the Nytro needs a good overhauling in the rear suspension. Wheels, slides, bushings, etc... might not hit the trails this year.
Im extremely low on $$ this year, and the Nytro needs a good overhauling in the rear suspension. Wheels, slides, bushings, etc... might not hit the trails this year.
