Crankshaft stuffing

[OW10]

Hello all, I am a recent new member of this website and have been reading about the TY250 in particular since I bought a 1974 version in very sad condition. It was seized solid in the top end and sat for a few decades with the plug missing. It took every trick I knew to get the cylinder off and when l cleaned up the crankcase I found three or four of the stuffers had come free from the crank. I split the engine cases a few days ago to replace the mains and now I have a chance to replace those plugs. My question is, is it necessary to replace them? Can I use wine bottle corks with a few coats of varnish? Where do I even get these things? Does any of you even know what I’m rambling on about;).

Anyway thanks for any info on this matter, you can never know too much about the internal combustion engine!

[feetupfun]

From my experience those pressed steel caps are only fitted to the outsides of the crankwheels so they are not actually "stuffers" as such because they don't reduce the volume of the crankcase.

Did yours have them on the inside ends of the holes as well as the outside ends?

If you want there is no law against using stuffers in a TY250 so yes you can use cork or balsa stuffers. The usual sealant however is epoxy resin rather than varnish.

I find the standard motor runs amazingly well without stuffers and some people even space the reed cage outwards to increase the crankcase volume so it may not be a good move to fit stuffers if you are not wanting to go out on a limb.

Those steel caps may be there to provide some sort of streamlining of the crankshaft to reduce aerodynamic drag at high RPM. I would say that their presence or lack of presence is not something important for performance. Their presence is definitely a liability for the risk they pose should they come loose

[OW10]

Thanks for your reply. Going off of what came out of the crankcase and what’s left on the crank it looks like only the larger holes had both caps in place, the smaller holes have one one cap which makes me think maybe it’s more of a balance issue rather than reducing volume . Of course it’s the inside one that came off my crank, so I can’t press them back without splitting the crank. It’s such a compact crankshaft with some serious heft, it’s almost a Ducati part

[Tillerman6]

On 4/14/2021 at 11:29 PM, OW10 said:

Hello all, I am a recent new member of this website and have been reading about the TY250 in particular since I bought a 1974 version in very sad condition. It was seized solid in the top end and sat for a few decades with the plug missing. It took every trick I knew to get the cylinder off and when l cleaned up the crankcase I found three or four of the stuffers had come free from the crank. I split the engine cases a few days ago to replace the mains and now I have a chance to replace those plugs. My question is, is it necessary to replace them? Can I use wine bottle corks with a few coats of varnish? Where do I even get these things? Does any of you even know what I’m rambling on about;).

Anyway thanks for any info on this matter, you can never know too much about the internal combustion engine!

If u are in the states it might be easier to just buy another used crank on ebay