Just picked up an old honda M/C a cm400c (1981).
I'm getting a blow-by on the left front fork seal.
This 81 has 'air' added on top, not like the '80 that I also own.
So, do I need to replace the seals, or could I just go to a heavy fork oil; say a 30 or 40 weight. . . And does adding Air on top increase the chance of "blow-by" (or not)?
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And it looks like the 'fool' that owned it before used regular oil on the drive chain, not the sticky chain lube. (It's all throwing off)
So, can I just strip off the oil with a brake-cleaner and then after it's dry, add the chain-lube. Or will any cleaner I use damage the "o-rings" ?

---thanks

Shade-tree-Mech., September 2010

if the fork seal is leaking replace it,i wouldnt bother adding air to the forks if you want them to be a bit stiffer and have a slower action use 20 weight oil no heavier the standard oil would be 10 weight.clean the chain with clean petrol and a paintbrush that wont hurt it, brake cleaner will also be ok but its not cheap and drys to fast.ps adding air is more likely to make it leak too.

adam bike doctor, September 2010