Piston compatibility

General discussion about Street two-stroke Suzuki motorcycles.

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daxman
To the on ramp
Posts: 348
Joined: Thu Nov 07, 2013 1:59 pm
Country: United Kingdom
Suzuki 2-Strokes: A100 GT250 & 4t Yams!
Location: Brussel County, England

Piston compatibility

Post 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
dollydog
Yeah Man, the Interstate
Posts: 630
Joined: Fri Aug 11, 2017 7:09 am
Country: england
Suzuki 2-Strokes: several gt250 ramairs

Re: Piston compatibility

Post by dollydog »

yes, as long as they are 14mm gudge pins. so will x7 and rg250 :D
cheers, dd.
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
daxman
To the on ramp
Posts: 348
Joined: Thu Nov 07, 2013 1:59 pm
Country: United Kingdom
Suzuki 2-Strokes: A100 GT250 & 4t Yams!
Location: Brussel County, England

Re: Piston compatibility

Post by daxman »

Ok cool - thanks.
Vintageman
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Suzuki 2-Strokes: Suz, Yam, Honda, Kaw.
Location: New Hampshire

Re: Piston compatibility

Post 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;
Current Bikes
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
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77 Yamaha RD400 (Daytona Cyls),
daxman
To the on ramp
Posts: 348
Joined: Thu Nov 07, 2013 1:59 pm
Country: United Kingdom
Suzuki 2-Strokes: A100 GT250 & 4t Yams!
Location: Brussel County, England

Re: Piston compatibility

Post 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
dollydog
Yeah Man, the Interstate
Posts: 630
Joined: Fri Aug 11, 2017 7:09 am
Country: england
Suzuki 2-Strokes: several gt250 ramairs

Re: Piston compatibility

Post 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.
Image
Image
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
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markush
On the main road
Posts: 187
Joined: Thu Oct 03, 2013 4:39 am
Country: Germany
Suzuki 2-Strokes: GT250/380
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Re: Piston compatibility

Post 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:
dollydog
Yeah Man, the Interstate
Posts: 630
Joined: Fri Aug 11, 2017 7:09 am
Country: england
Suzuki 2-Strokes: several gt250 ramairs

Re: Piston compatibility

Post 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.
Image
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
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