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Piston compatibility

Posted: Tue Jul 17, 2018 7:31 am
by daxman
Will earlier (Ramair)pistons fit a GT250A Ok ? The later models I believe have ring locating pegs in a a different place (to avoid snagging on the additional transfer ports?)

Cheers

Re: Piston compatibility

Posted: Tue Jul 17, 2018 8:04 am
by dollydog
yes, as long as they are 14mm gudge pins. so will x7 and rg250 :D
cheers, dd.

Re: Piston compatibility

Posted: Tue Jul 17, 2018 9:22 am
by daxman
Ok cool - thanks.

Re: Piston compatibility

Posted: Wed Aug 08, 2018 7:32 pm
by Vintageman
No, As you said they relocated the ring's locating pins so the rings won't snag on the extra ports.

The X7 piston has a shorter skirt and will change intake timing. The GT250A is hot enough as is and no power under 4K RPM due to raised EX port etc. Don't think I would increase intake timing that much unless you are making a road racer with broad sweeping corners.


The GT250A is a rocket stock. say that twice. A set of chamber tuned for RD350 will (Same stroke and ex port timing or very close) wake it up. Stock air box works well set up like this too, stock jetting worked for me.. i tired pods and earlier air box (what a mess I made). Crank BE won't survive high rpms long. Refresh the crank here and if you can find silver cage Big End bearing would help. If you hammer constantly a extra oil in tank. Had one went through two cranks and a few top ends until I figured out what worked well for me. But, I just could not drive it slow. seriously. Still Have nice engine again, but bike is running a t350 or t305... forget which now. Same power, but got bottom end back. Future Kart engine.

https://www.youtube.com/watch?v=90TLzYEkecA" onclick="window.open(this.href);return false;

Re: Piston compatibility

Posted: Thu Aug 09, 2018 2:58 am
by daxman
Hi - thanks for the information. So no-no to K,L,or M pistons but a possible for X7 but be prepared for performance issues, best stick to A,B,C pistons and goe easy on teh revs..
RD350 pipes eh (aircooled I'm guessing..)

Ta

Re: Piston compatibility

Posted: Thu Aug 09, 2018 7:16 am
by dollydog
here you go. 2 genuine suzuki pistons. the one on the left is an x7. the one on the right is a gt250m. spot the difference, because i can't :D nock pins in exactly the same place and same distance apart. note the black lines, that's where the nock pins are behind the rings. the skirts are exactly the same as you can see.
cheers, dd.
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Re: Piston compatibility

Posted: Thu Aug 09, 2018 8:52 am
by markush
Hello :)
the one on the left is an x7.
IMO: No.
X7-pistons look like the following: Note the area around the gudgeon pin eyes.
Image

Image

GT250ABC-Piston can be used for M-Models
Late M-Model Piston with wider knok-pin angel can be used for the later Models.

see the table at my SITE:

Re: Piston compatibility

Posted: Thu Aug 09, 2018 2:20 pm
by dollydog
ok then, work this one out :D
the outside two pistons are the ones i photo'ed earlier. the one in the middle is also a genuine sgp x7 piston. as you can see, the skirts are much SHORTER. both x7 pistons are 0.25mm oversize and both genuine suzuki :D wtf?
cheers, dd.
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