Hey guys, newbie to this forum. But not badass-ery. I purchased a GTR somewhat recently and had no idea what I was getting into. 100% a love/hate relationship. Hate that its no longer around and parts/options are limited,,,but thats also why I love it! Anyway, I have had some issues with my motor (Shout out to the community for help) and wanted to create this as to not Hijack Evil's!! Do to the issues, which I will get into, I figured now would be the time to discuss options of upgrades to the GTR. Such as long travel?? Motor upgrades?? Turbos?? I know that other forums have touched this topic so I will try not to ask repetitive questions. So let me get to it...

My buggy ran great until I noticed a oil like substance would come squirting out of my carb. Eventually, it would bog out and stop running. After talking it over with some of the guys, we determined it may be failed piston rings. I tore her down expecting everything to look like a grenade went off, but things SEEM fine....this makes me realize my lack of experience. SO....as I am trying to solve this problem. I am wondering if I should/can bore out the cylinder to fit a more common and readily available piston and rings?? Then theres the topic of port and polish...a bigger carb...I may even heard of a different top end all together?? Im not trying to drag race this thing lol but are these our best options or is it better and/or cheaper to do a motor swap??

below are pics of the tear down

More angles

I'm not sure how far you can bore the cylinder out safely on these. Or which piston will fit it afterwards. I do know that the cylinder is ceramic lined.
Turbo? Have never tried one on these buggies, but I remember 1 member here installed one on a CN250 buggy.
My suggestion is a bigger carb with a ported or larger intake manifold. Head porting and polishing works great, I also had mine milled(recommend Tom Syc). And a good exhaust adds to all of the above. These 3 options are probably the best mods I've done to mine thus far, besides the little things like HP coil with 8mm Taylor wire, K&N filter, CDI, Dr. Pulley sliders, etc. I couldn't find a aftermarket cam, or I would have bought and installed this too.
If the ring gaps were that close in the last pic when you removed the cylinder, than that would cause a lot of oil bypassing the rings. I think the gap on the top 2 rings looks to be too large too. I would go ahead and install new piston rings and then clock them as well since you're this deep into it. I don't think you can hone that ceramic cylinder, but you can clean it up with some Scotch Brite pads and oil or WD-40.

Yes, as I searched more and more I found that boring a ceramic cylinder is not ideal because of the plating is so thin. I could look more into it but I feel like a motor swap would be a better option than this. That being said, I prefer original. So neither is a option at the moment....

I have read your entire thread and made note of all the upgrades you have made. I think these are great seeing that they're are relatively cheap and easy to come by.

Good news is I have been in talks with a couple of gentlemen from SYM and affiliates. They work in the parts/service departments and have already provided me with a complete manufacturer blueprint of my motor. It was built on sept. 4th, 2007. I have provided them with a list of parts with part numbers I require and now just waiting as they are checking their inventory.

Once my motor is up and running 100% I get to look into upgrading the rest. Now I just need to practice patience lol

You can have the cylinder bored and replated and get a piston made by wiseco if they dont already have one that would fit. You can also still get all engine parts off the shelf. I have a tom syc ported/polished and shaved head for sale if your interested along with a couple other parts.

The GTR's biggest bottleneck is the carb. Throw a larger carb on there and you will see the best bang for your buck of any of the mods.

Anyone know of a engine I can swap easy in the gtr 250 or if I could purchase a new engine. I'm just tired of 5rying to figure the problem out I have spark compression battery life new cdi new starting coil plugs gas flow cranks but just won't turn over thank u

Can Am DS250 and the E-Ton Vector 250 all use the same engine. Have you checked the compression? If it is a spark issue, check the wires leading to the CDI plug on the buggy. This has been a common issue with some of our GTR's. The wires in the CDI plug have been too loose and giving erratic or no spark. Also make sure the coil wire has a good connection in the spark plug boot.

I will check the wiring. I have spark compression just won't turn over I'm thinking the cdi it ran fine until it backfired now won't start that's why I figured just put new engine