Are GSX250 EX's and GS250 TX's pistons the same?

[Johnny]

I've got a GSX250 EX (1981) and I'm planning to get new pistons etc. for it. There is a piston kit for GS250 TX on Ebay: http://www.ebay.com/itm/Piston-Kit-...torcycle_Parts_13&hash=item5406c72603&vxp=mtr. Are these pistons the same as my GSX250 EX's or not?

Basically, which GS/GSX 250 models engines from that era are identical? This site: http://www.cmsnl.com/ lists and sells several parts for similar models but there isn't the exact bike that I have, so currently I'm just guessing what number of part I may need.

 

[Guest]

The GSX's are 8 valve engines and the GS' are 4 valve engines... but in the US GSX's are called GS'... which is confusing!

However... if you go by the photo on that listing you can see indents for 4 valves so in theory yes they'd be fine, but you would need to contact the seller to find out for sure, I never go by photos on auctions for things like this.

Alpha Sports list a 1981 GSX250TX on their parts fiche which *might* be the same as the eBay listing and it's an 8 valve motor, piston part number is 12111-11401.

 

[Gorminrider]

I'm a GSX400 guy but...
Is your bike like this?
http://www.suzukicycles.org/photos/GSX/GSX250E-adverts/1980_GSX250E_SEad-Bike5_800.jpg
and here is a US model GS250T
http://www.suzukicycles.org/photos/GS/GS250/1980_GS250_ad_USA_800.jpg
Both these have square camcovers and that indicates 4 valve per cylinder engines. "GSX" in other words.
More:
I get the following directly from the Suzuki shop Manual for the GS250T
they have this stamped on the right side of engine .
as in: GS25X-100xxx, (the "xxx" being the actual serial number of the engine) You will have the same serial identification on your GSX250E engine.
Again, this "GS25X" indicates that the GS250T engine is indeed a "GSX" 4 valve per cylinder engine. The manual goes on to a lengthy description of the 4valvepercylinder engine with TSCC and the counterbalance etc.

Per my 81 400s, I have the E (square tank) and the T (teardrop tank).
The Engines are identical. and they have GS40x- 100xxx stamped on the engine Only the frames and body parts differ per E and T.

 

[Gorminrider]

Now, more. I share your fear of Ebay...
From the Suzuki shop manual GS250T manual, Bore is 60mm. This is confirmed in the Haynes Manual.

The Ebay ad has "Outer Diameter 72mm" ...this would make me nervous and require more research.

as a note, the GSX400 has a bore of 67mm. This makes me wonder if this ebay kit is in fact for a single cylinder GN250?

 

[Johnny]

Thank you for your replies!
Gorminrider: Yes, my bike's like the one in the first link you posted, with the square tank.

 

[Johnny]

Now, it's still very confusing. That particular eBay kit aside, I'm trying to figure out the correct piston part number. There are period correct NOS pistons on eBay with part numbers 12111-11401 and 12111-11404, which one is right, I don't know. This page: http://www.suzukicycles.org/1980-1989/1981c.shtml states that in 1981 they made a GSX250 T with an engine of 247cc and 8 valves, AND they made a GS 250 T with a 249cc engine with 4 valves. While GSX250 E is 249cc and 8 valves. If that's true, then the GSX250 T engine is not the same as the GSX250 E, dispite the 8 valves, BUT the 4 valve GS250 T has the same engine capacity as the 8 valve GSX250 E. ???

 

[Gorminrider]

AND they made a GS 250 T with a 249cc engine with 4 valves

but if you click the link offered quote :"Here's even more info"...l here is the link:
http://www.suzukicycles.org/GS-series/GS250T_adverts.shtml
It's an an 8 valve 250. That's the Internet for you. Every so often there are mistakes.
The United States model was called GS250. Not GSX. Even though it is known as a GSX in Europe.
The engine serial number and square cam covers are the best clue as to which is which.

Want more ? Try these and see how REALLY confused you can get
http://www.cmsnl.com/suzuki-motorcycle_model13053/
http://www.cmsnl.com/suzuki-gsx250_model13604/
http://www.cmsnl.com/suzuki-gs250_model13416/