Suzuki K10

Pushrod Fifty /

I have a 67 Suzuki K10 that I fixed up. Found it on CL it sat for over 30 years. Initially, I gunk soaked the crankcase to free up the crank and cleaned up the top end and replaced all of the seals. It ran fine until it locked up. The crank had locked up and after it cooled down it ran but I could hear the right crank bearing sounding like loose marbles.

I tore it down and had the crank trued, replaced all bearings and seals again, and rebored it.

The right side of the crank has two bearings with a notched spacer between them. The notches line up with a hole in the case that is within the transfer port. The inner bearing is spaced out .5mm from the crank by the shim between, so it doesnt get alot of premix flow through it and out into the outer bearing. Premix flow diagram from the 60s show the mix going through the inner bearing, spacer, them dead ending at the outer bearing and then travelling up the hole through the transfer port on the compression stroke.

It runs fine but after it heats up and runs over 40 mph for a stretch, the outer bearing gets loud. I was thinking that if I chamfered the oil passage hole in the case transfer port, tbe oil might flow better to the outer bearing.

This problem was fixed in the next prod year by adding oil inject, the pump was located on the right end of the crank snd oil was pumped tight into thebearings.

Has anyone had a K10, or can recommend mods to improve lubrication of the right bearings? I am using conventional Valvoline 2 stroke motorcycle oil, 32:1. Stock setup. Runs lousy with more oil.(edited)


Re: Suzuki K10

Wow I have never even seen one of those complete. Interesting.(edited)

Re: Suzuki K10

Super cool looking bike!

Re: Suzuki K10

Brandon Weiss (Detective brandon to you) /

I wonder what would happen if you ran a double rubber sealed bearing with grease inside...hmmm

It would probably fail in a regular moped setup, but maybe the outer bearing being farther away from the premix would allow for a sealed bearing to last, and not be deteriorated by the gasoline/oil?

Probably not the best idea, but it would be an interesting experiment.

Re: Suzuki K10

Pushrod Fifty /

The outer bearing is an oddball size made by Koyo for Suzuki, it is 9mm wide instead of 12mm. I found two of them at a Suzuki shop and have one left.

Re: Suzuki K10

I have one too!!! it runs, but it has a crack in the exhaust. i think mines a 68, since it has the oil injection. i got it to 45 mphs last summer :-)

Re: Suzuki K10

you can use narrower seals usually without issue if ID and OD match - are there any thin ones that size?

Re: Suzuki K10

If I may offer advice... I am sure you are a very talented guy to rebuild the bike as far as you have... Did you set up the oil pump to the engine/throttle? There is a procedure for that as I do it to my T-20. There will be a mark on the arm and another on the pump... it has been so long I do not remember is you set it at no throttle or full throttle.

Also if the pump is not primed this is another cause of the problem too. Now if you take it apart... there is a bolt that is Left hand thread. Do not mess it up taking this one off. LOL! I paid dearly for that mistake.

For priming my T-20... Hold the throttle wide open... remove the plugs and spin the engine with a drill. If you have filled the pump with oil and set it right it will pump the oil required and you are set. Or use premix and bleed the system out and set it while the engine is running? Never did it this way but it might work.

Re: Suzuki K10

Paul Boyer (OFMC) /

Sweet bike!!!

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