GS450 piston rings

[John Park]

While searching around for piston rings for a GSX400 to GS450 top end swap, I ran across the possibility that rings from a Yamaha Timberwolf 250 ATV should fit. All the numbers are the same [1.2X2.8X71mm] and the motor was made during the 90s and maybe past that. There are also very nice looking aftermarket pistons made by Namura [Taiwan] which are useless for our purposes, but the rings are compatible with OEM and are available for $18 - $20 on the net. Plus they are available in .5 and 1mm OS.

The only OEM Suzuki rings I could find on ebay were silly prices. As we never got the 450 here, I don't know what the dealer availability and price is. I'm tempted to try the Namura rings; they seem to be a well regarded product and plentiful, as they made a lot of the ATVs. I'm not the least worried about using rings from something else as I used to use Kawasaki 750 rings in the 250 Aermacchi motor in preference to the OEM; better metallurgy and half the price and no problems.

Any thoughts?

[GregT]

While searching around for piston rings for a GSX400 to GS450 top end swap, I ran across the possibility that rings from a Yamaha Timberwolf 250 ATV should fit. All the numbers are the same [1.2X2.8X71mm] and the motor was made during the 90s and maybe past that. There are also very nice looking aftermarket pistons made by Namura [Taiwan] which are useless for our purposes, but the rings are compatible with OEM and are available for $18 - $20 on the net. Plus they are available in .5 and 1mm OS.

The only OEM Suzuki rings I could find on ebay were silly prices. As we never got the 450 here, I don't know what the dealer availability and price is. I'm tempted to try the Namura rings; they seem to be a well regarded product and plentiful, as they made a lot of the ATVs. I'm not the least worried about using rings from something else as I used to use Kawasaki 750 rings in the 250 Aermacchi motor in preference to the OEM; better metallurgy and half the price and no problems.

Any thoughts?

Depends how much of the swap you've already got. I'd have looked for GS500 pistons and rings as they're a lot more common - and the 450 barrel bores to 74mm easily. Ring groove width is the main bit to look at and while 1.2mm is often the top ring, the second and oil rings can vary quite a bit. Quality wise, I'd doubt if there's a problem.

[John Park]

Depends how much of the swap you've already got. I'd have looked for GS500 pistons and rings as they're a lot more common - and the 450 barrel bores to 74mm easily. Ring groove width is the main bit to look at and while 1.2mm is often the top ring, the second and oil rings can vary quite a bit. Quality wise, I'd doubt if there's a problem.

According to the Yamaha specs, the groove widths and all that are identical. I think I'll give the Namura rings a try. If they work out well, then we know of an inexpensive alternate supply for rings, because they're only bound to get scarcer. People are far less likely to pass over a re-ring if the rings aren't silly expensive and hard to source. The standard pistons I have are like new, but the original rings are a bit pitted; they'd work, but why risk having to take it apart again. Surface irregularities lead to cracks and also land wear, and I plan to run this motor rather 'fully'. A deglaze and rings is all it needs at 10k miles.

[Shaun6691]

So did you ever get the rings? How'd they work out?

[tkent02]

Don't know about the rings, it will probably work, but....

Just so you know, GS 500 cylinders and pistons are a direct bolt on, I found a complete set with rings and the tensioner for less than I could find used pistons alone for the 450. No wear on anything, the rings sealed up great. 10% more displacement for $50 or so? I'll take it.

It's a current production bike, so there are always several sets of 500 cylinders and pistons on Ebay. Make sure you get the cam chain tensioner too, the 450 one won't fit the 500 cylinders.

[Shaun6691]

Don't the gs500 exhaust ports on the cylinder heads interfere with the down tubes on the gs450 frame?

[tkent02]

Yes, don't use the 500 head. Just the 500 pistons, cylinders and tensioner, use the old 450 head. All bolts right on, easy as pie.

[Shaun6691]

Sweet! Any specific years I should be looking at?

[Shaun6691]

Also, wouldn't this screw with carb tuning? Is there a write up on this? Sorry to hijack this thread.

[tkent02]

Yes. slight change in jetting. Probably need to drop a half size on the mains, maybe a size. I'm at 6,000' elevation so your jetting will be different. 115 is stock, I'm using 105s which is pretty close to being right. This with completely stock air box and exhaust.

Write up, nothing about the 500 stuff specifically, but here's my thread:

http://www.thegsresources.com/_forum/showthread.php?222293-I-m-in-the-twin-club%85

The piston stuff started around post #75 I think.

[Shaun6691]

I'll get to looking. Wish I could find a complete deal like you did. My elevation is 604' (dallas, tx). I've got a Sigma six stage 3 jet kit on my carbs. Can't remember the jetting. Pods and a 2-1 exhaust. Still learning about carb tuning. Can you tell a world of difference with the added CC's?

[tkent02]

I never rode it as a 450, but it's 10% more displacement so it's probably something like 10% more power. It runs strong, quicker than my 550 at low speeds unless you scream the heck out of the 550. Has no problems at interstate speeds, although it was a bit weak trying to go up a 12,000 pass at 75 or so mph. Might do it easier now that it's tuned a little better.

Just scan the local Craigslist for a GS500 parts bike, keep an eye on Ebay, something good will turn up.

[John Park]

So did you ever get the rings? How'd they work out?

No. Some almost new rings showed up with some other stuff so I decided to use them instead. The end gaps were on the tight side of spec and the surfaces barely shiny so I'm just going to hope they seat to a deglazed hole. I'll know in a few weeks when I get the engine in and it's warm enough to run it in. It's just a spare engine to run while I do some mods and such to my good motor, so it doesn't have to be perfect.

[tkent02]

It's just a spare engine to run while I do some mods and such to my good motor, so it doesn't have to be perfect.

That's what we like to hear. Just removed the spare to put the good one in. Can't wait.