Brad_69
New member
I just looked up the part #s on both the 433 & 338 GPX engine F/A crankshafts. and they show the same part #s. Also the crankcases. Does anyone know that to be true? I am looking for a complete running 433 engine for my GPX SNO-PRO project. I currently have a running 338 F/A GPX engine that runs good and was looking to trake for the 433 F/A. If the bottom ends are the same. I will just look for a set of cylinder, pistons and some gaskets. If anyone can clear this up, that would be great. Brad
thunderjet440
New member
- Joined
- Oct 30, 2005
- Messages
- 114
I thought the top half of the crankcase was different,maybe i'm wrong.You have to take the yamaha web site with a grain of salt.i'm still looking for that 1975 yamaha sr 643
Also watch the timing if mix matching parts,the 338 has different timing specs than the 433.
Also watch the timing if mix matching parts,the 338 has different timing specs than the 433.
Snojet Steve
New member
The top of the case is different. The 338 case 1/2 allows for the closer together bolt pattern of the 338 engine. You can run the same crankshaft though as far as I can tell from my parts, they are exactly the same.
thunderjet440
New member
- Joined
- Oct 30, 2005
- Messages
- 114
i think they have different piston pins too now that i think about it.
YAMMIEGOD3:16
Active member
BRAD, YOU WILL FIND THERE IS ALOT OF SIMILARTIES TOO THE 76 SRX ALSO ! 3:16 (tony)
Brad_69
New member
I didn't know some of the GPX engine parts were the same. I looked up just a few. I am currently looking for a 75 GPX 433 engine. I might have found one. I think I am done with my SRX searching. I will just stick with my 78 and be happy. I think I will be bringing it out for our show on 4 Feb. Hope to see everyone. I need some Yamaha support. Last years event I was the only one who had a Yamaha sled on display. Brad