crazypj said:I was going to make Delrin rollers for Marc but he got a Ka at a good price, thats how I have an idea how long they last racing.
The stock rubber rollers are know to break up at sustained 10k plus rpm
gregajo said:Hi All, I am at this point in my motor rebuild of needing the cam chain tensioner. I thought about getting those rollers from the guy in Poland (Pawel). However he has had trouble finding the time to produce more of them. l wondered about the KA slipper model from Bore Tech but saw in their add that there may be some machining needed to make it fit? So, other choices? I hate the idea of putting in the OEM rollers that were historically the Achilles heal of these motors. Thanks Greg
crazypj said:NOS should be fine, it's the heat cycling that screws them up.
I think I have a lower roller here somewhere but I know I don't have the upper one
I was going to look for a needle bearing to fit into them but never got any further after Marc got the Ka
I have some Delrin but not needle bearings or something for pattern
MotorbikeBruno said:I heard the Achilles heel part of it was sustained speeds that it wasn't "designed" to do, and when they sit, they get brittle. If they were used regularly, there wasn't a problem. Can anybody confirm that?
DrJ said:I'd say yes, the hot engine oil keeps the rubber supple making the rollers more absorbent to the stress. When sitting for a long time, the rollers get dry and brittle.
gregajo said:l wondered about the KA slipper model from Bore Tech but saw in their add that there may be some machining needed to make it fit?
rcl5011 said:For those of you still looking for these rollers and has come across this thread, I have brand new chromolly versions of both the upper and lower rollers.