As belt drives are a non OEM item, the manufactured clearances are arbitrary between the various manufacturers. I fitted an RGM unit last week, and whist they provide a 5 page set of "information" its rather Microsoft help...it just does not give you any practical tips whatsoever that a compentant home mechanic can follow.
Something that did cause me a running problem was clutch drag when hot. Whilst the splines on the old steel centre were a little notched it certainly did not hang up on the old steel clutch. I had been on a 400Km run, and it got bad toward the end so a strip down was neccesary. What I found was that the OD of the clutch basket bearing boss was rubbing on the ID of the centre and eroding the alloy and binding quite severly. When newly installed, the centre was spinning free in the bearing, thats when cold but that alloy clutch basket does expand, makes contact, make more heat and then the rubbing surfaces get into weld mode. And granulated alloy dust was migrating into the basket so makimg matters worse.
The immediate cure for this was to chuck the centre into the lathe and skim out .020" radial on the ID. Theres no harm in the surface of the bearing boss being eroded of its anodised finish as that area is meant to be non-contact.
As a pre-caution for any new belt drive installs, I recommend you measure up the OD of the bearing boss and the ID of the centre and make sure you can get 0.5 mm (.020") clearance. Add that to the Tension and Alignment issues and you should be good to go.
Something that did cause me a running problem was clutch drag when hot. Whilst the splines on the old steel centre were a little notched it certainly did not hang up on the old steel clutch. I had been on a 400Km run, and it got bad toward the end so a strip down was neccesary. What I found was that the OD of the clutch basket bearing boss was rubbing on the ID of the centre and eroding the alloy and binding quite severly. When newly installed, the centre was spinning free in the bearing, thats when cold but that alloy clutch basket does expand, makes contact, make more heat and then the rubbing surfaces get into weld mode. And granulated alloy dust was migrating into the basket so makimg matters worse.
The immediate cure for this was to chuck the centre into the lathe and skim out .020" radial on the ID. Theres no harm in the surface of the bearing boss being eroded of its anodised finish as that area is meant to be non-contact.
As a pre-caution for any new belt drive installs, I recommend you measure up the OD of the bearing boss and the ID of the centre and make sure you can get 0.5 mm (.020") clearance. Add that to the Tension and Alignment issues and you should be good to go.
