When assembling my Horstman HDC-5B (2 disc, whichever model that is…) back on the crank of my KT-100 after re-lubing the bushing, I noticed what I consider to be extreme amounts of free-play — the clutch housing / driver side could be flip-flopped side-to-side by approximately 3/16″ at the exterior rim, enough to notice the chain visibly misaligning. So, my question is:
– How long do the bronze oilite bushings last?
– How do you know when they’re out of spec?
– How much free play should the clutch have on the shaft?
– Is it possible the crank is worn instead of the bushing (or both)
(crank seems fine, no real grooving that I can see or feel.)
I’m considering going to a Patriot or putting on my DXL’s anyhow, but figured I’d ask…I assume I can press in a new oillite bushing and re-test…Thanks,
The bushing in the drive hub is the weak link it will definitely wear out first. The only way the crank could wear is if the bushing disintegrates and you were left with steel on steel. Make sure that you spray between the crank and bushing every time you come off the track that will help with the wear. I use either WD40 or Tri Flo. If you have a lot of side wobble it could be a combination of a worn bushing and or to much clearance between the drum and crank spacer. Below I have put a link to the Horstman Spec and rebuild instructions. I hope this helps.
About 4 races, I usually replace the bushing 1 time. There about $5 and very easy to replace and then the next time replace the entire drum about $65.(Recently I found aftermarket drums from Andrews Racing on eBay for $32) I find that if I go more then 8 races without changing both sprockets and the chain I end up breaking something sometimes the chain gets a bad spot earlier then that.
One other thing I keep a lot of is the shim/spacer between the crank and clutch drum I bought about a 1/2 dozen of the ones for a 10 tooth and another 1/2 dozen for the 11 tooth drums and then filed them all to different thicknesses and put each one through a tie rap with a piece of tape with the size written on them so when I change a bushing or drum I have them on hand for a easy quick swap.