1972 Gt 380 rings

[husky99]

I'm putting my cylinders back on with NOS rings (part # 12140-33010) I bought off ebay. I put the rings in the cylinder bore (after honing) and they had the proper gap. Bike has 5,000 original miles. The bottom ring fits perfect, letters up on the rings. But I'm having problems getting the top ring on. It won't close all the way against the stop, like the bottom ring does. I have scraped and lightly sanded the ring grove and still no go. I was able to get one cylinder on using the old ring in the top grove. The ring groves are scrapped clean down to bare metal. What am I doing wrong.

In some parts fiche it shows 12140-33012 as standard bore rings.

[Craig380]

Is yours a J or a K model? It sounds like the top ring is jamming in the groove.

The J models ONLY used different piston rings that are square section, all the later models used keystone type rings. H2Rick's piston guide details this: http://www.ozebook.com/compendium/suzi/ ... istons.pdf

If you're fitting rings with the part number 33010, they SHOULD be square section (assuming they've been stored in the right box )

Even if the bike is a J model, maybe the bike has been rebuilt previously using later pistons - which is possible, the later pistons which take keystone rings can be used in all 380 model cylinders.

Do you still have the old rings you removed? If so, it could be worth carefully checking them to see what type they are.

[husky99]

Thanks Craig 380. Its really hard to tell which is which with my 60 year old eyes. Put calipers on them and figured out I had keystone rings not the square rings I bought.