Never seen this info sheet before.
I found this in a box of genuine Yamaha .25 OS piston rings I purchased last week here in the UK.


I found this in a box of genuine Yamaha .25 OS piston rings I purchased last week here in the UK.

I couldn't get it to run right.
I bought it from a dealer.
The tank was full of dirt, fuel tap leaking ,yadder yadder.
The fuel pipe was disintegrating.
Sorted all that out.
It would run but you know when that confidence isn't there?
Wether you buy them to ride or restore and look at them, no matter what they are, sooner or later, you'll have to fix them.
99% of maintenance on two stroke engines is preventative. As far as the cylinder ,crank shaft assembies are concerned it is anyway.
To quote Cummins diesel manuals opening statement " knowledge is power"
The Internet is a great tool. Use it.
However, 75% of the stuff out there is baffling! I say that when you see people starting a job with, no workshop manual shite tools and no idea and it will be okay attitudes.
You can call me an arse hole, I don't care !!
I have the right order of piston and rings according to the part numbers .
There's something not right though.
I'm going to see if I still have the original piston and rings see if I can get a comparison.
Anyone seen the buzz box for sale on ebay UK?

Great post Shyted . . .
You aren't the first guy that's had to scratch his head over this issue .... Ha ha
I'm glad you posted this problem that the early flange mounted carbs sometimes suffered from.
I hope to write some more on this topic in the future .... including how to repair it, and how to avoid future reoccurrence.