Hello,
I have some good news for you guys out there that are running the 76/77 srx's. I think I finally figured a lot of stuff out that's been driving a lot of people nuts. Last night UPS delivered a new set of Wiesco pistons for my 77 srx. That's right new set. I'll need to go to My engine builders shop to pick up my other set of pistons so I can take some pictures of four different wiesco pistons that are being used in the 76/77 srx's. That's right I said four. The only one I do not have is the original Yamaha piston. But we are only going to talk about the Wiesco's. Later to day I'll post the pictures.
1st piston is the 2280 that was a replacement made for .020 GPX. They are in the older wiesco boxes and was made from the 2222 mold. After the 76/77 srx's came out Wiesco had everyone use these pistons and it gave Wiesco a bad name, because it changed the intake porting because of the longer skirts and the L ring that Wiesco is still telling me that they never made a L ring for the srx's is truely there which changes the very important exshaust port timing.that's because the top of the ring is now the top edge of the piston instead of the piston it self, like the org Yamaha piston was. That's why you lost 2-3 hp.
2nd piston is the 2222 that was a replacement just for the 76/77 srx which matched the org Yamaha piston and rings (flat) Shorter skirts then the 2280 and had a flat ring. That worked...
3rd piston is the 2282 which was a replacement just for the 78/79/80 srx's and Leon Koch is making sleeves for the smaller wrist pins so you can use them in the 76/77srx's.
4th piston is the VY2-6850 which is a replacement for 76/77 srx's with re Nickled cylinders and for the 433 GPX .020 over with steel bore. You can't buy them from Weisco but only from aaen Performance. Weisco makes them for Aaen. They retail for $153.43 each. They are light weight like the 2282 is and looks alittle different on the sides where it's cut out for less weight and has a coating on top of the crown. I'm impressed what wiesco has done here. They only make 10 at a time for Aaen and Wiesco just got 10 in Thursday. I hope this helps everyone out there and I know there is no replacing the orginal Yamaha pistons but atleast the guys out there that are still running these sleds in the ovals and drags like me can keep them running and spanking everything else out there in the vintage classes. Amen. Dean-o
I have some good news for you guys out there that are running the 76/77 srx's. I think I finally figured a lot of stuff out that's been driving a lot of people nuts. Last night UPS delivered a new set of Wiesco pistons for my 77 srx. That's right new set. I'll need to go to My engine builders shop to pick up my other set of pistons so I can take some pictures of four different wiesco pistons that are being used in the 76/77 srx's. That's right I said four. The only one I do not have is the original Yamaha piston. But we are only going to talk about the Wiesco's. Later to day I'll post the pictures.
1st piston is the 2280 that was a replacement made for .020 GPX. They are in the older wiesco boxes and was made from the 2222 mold. After the 76/77 srx's came out Wiesco had everyone use these pistons and it gave Wiesco a bad name, because it changed the intake porting because of the longer skirts and the L ring that Wiesco is still telling me that they never made a L ring for the srx's is truely there which changes the very important exshaust port timing.that's because the top of the ring is now the top edge of the piston instead of the piston it self, like the org Yamaha piston was. That's why you lost 2-3 hp.
2nd piston is the 2222 that was a replacement just for the 76/77 srx which matched the org Yamaha piston and rings (flat) Shorter skirts then the 2280 and had a flat ring. That worked...
3rd piston is the 2282 which was a replacement just for the 78/79/80 srx's and Leon Koch is making sleeves for the smaller wrist pins so you can use them in the 76/77srx's.
4th piston is the VY2-6850 which is a replacement for 76/77 srx's with re Nickled cylinders and for the 433 GPX .020 over with steel bore. You can't buy them from Weisco but only from aaen Performance. Weisco makes them for Aaen. They retail for $153.43 each. They are light weight like the 2282 is and looks alittle different on the sides where it's cut out for less weight and has a coating on top of the crown. I'm impressed what wiesco has done here. They only make 10 at a time for Aaen and Wiesco just got 10 in Thursday. I hope this helps everyone out there and I know there is no replacing the orginal Yamaha pistons but atleast the guys out there that are still running these sleds in the ovals and drags like me can keep them running and spanking everything else out there in the vintage classes. Amen. Dean-o