I geared my 2009 HCR from 57/63 to 55/65. Now it seems like I am lacking backshift in the secondary. Dropped 3 grams in the primary weights and it pulls more RPM down the trail, but still falls on its face under heavy load. There is no adjustability in the spring rate on the secondary, so I am looking to convert to an adjustable spring rate helix to increase the spring rate. If that doesn't solve it then I am planning on adding a D&D torsional set-up. Any other suggestions? Is it common to lose backshift when gearing down?
What clutching changes should be made after gearing down?
- Thread starter sledr900
- Start date
Yes, that is the end result. Running a couple grams lighter and a couple degrees shallower helix should get you back on track. Your secondary is now sensing less resistance allowing it to upshift more than it did before, especially noticeable when a quick backshift is needed.
G
geo
Well-known member
Don't confuse upshift and backshift (common mistake).
For the same reasons you upshift quicker (less load), you also backshift easier on the secondary when gearing down.
Helix requirements don't change much (full load squeeze on the belt) because the big paddle track (it hasn't changed) requires a lot of grip from the secondary sheaves. So to get the benefit of gearing down you can lessen the secondary spring pressure ('cause you don't need as much anyway).
If you don't do these changes you will probably lose performance (if you wern't way over geared before) because the front clutch has to work harder (shift through to a higher ratio) to go to the same MPH. That's why the front will need a little less weight.
The lower spinning forces (less primary weight) will require a little less backshift signal from the rear also. Too much backshift is the biggest HP robber in the CVT system. But, darn, we need it perfect in the mountians.
Anyhow, you need to find a new clutch balance when you change gearing. Performance isn't automatic.
Geo
For the same reasons you upshift quicker (less load), you also backshift easier on the secondary when gearing down.
Helix requirements don't change much (full load squeeze on the belt) because the big paddle track (it hasn't changed) requires a lot of grip from the secondary sheaves. So to get the benefit of gearing down you can lessen the secondary spring pressure ('cause you don't need as much anyway).
If you don't do these changes you will probably lose performance (if you wern't way over geared before) because the front clutch has to work harder (shift through to a higher ratio) to go to the same MPH. That's why the front will need a little less weight.
The lower spinning forces (less primary weight) will require a little less backshift signal from the rear also. Too much backshift is the biggest HP robber in the CVT system. But, darn, we need it perfect in the mountians.
Anyhow, you need to find a new clutch balance when you change gearing. Performance isn't automatic.
Geo
S
SLEDIOT
Well-known member
i would put the weight back to your primary and either get a stiffer spring for your secondary or go to an adjustable aftermarket secondary. I geared my 1000 down and had to tighten my RKT secondary 2 notches to a ccomadate the consistant rpm. I found that the rpm's hold more steady now with the lower gearing thus making for easier clutching. Good luck
