S3 Race 250 Port Matched Cylinder and Head

[shawbagga]

Originally Posted by Jakobi

Just another update on the sexy beast!

As most are aware my TTX shock had a 'failure' and has been repaired and revalved by Ohlins USA. I will have it back early next week/late this week and will post an update in its respective thread once getting a ride on it.

The engine is still running strong with loads of compression under foot. The jetting specs of 40 N3CW#3 178 have been running fine with very snappy power and good grunt down low. I feel it might still be a bit lean in the middle as it kind of buzzes up sound wise without as much pull just before it comes on song and then hits super hard. I like it but I have gone a half a clip richer on the needle and dropped a size on the main to see if I can get a bit more torque in the middle where theres a little hole. I've switched between a 175/178 main several times now and both respond well. The 175 feels a bit crisper and I can get a bit more overev out of it so will stick with it for a while.

I need to check the hour meter to be certain but I believe I've got around 60hours on the top end now and moving towards 250hrs total on the bottom end. I have a new piston kit and gaskets ready to roll but not sure if I should try and stretch another top end out of her or pull it down for a complete rebuild. Thats new terriroty for me and I'll need some of the advice of others here to get through that job for sure. Any opinions?

The TTX forks are also due for a service and I'll likely do that when the top end comes down. I'll regrease the headstem at the same time.

I've only attached one pic today. Hard to believe I could put any power to the ground with the old tyre! Sure think the new one will make a small difference this weekend!

mate you need to hang the rear end out a bit more to even up ya tyre wear!

[Jakobi]

Originally Posted by GMP

I think you should be OK if you kept a clean filter in it, just check the rod big end side clearance. Actually 60 hrs isn't a lot for a top end, I've been going 85 - 100 hrs and things are still fine.

I'm going to build my '07 into my first ever GG300. Head mod and I'll play with the Suzuki needles as I wan't smooth on this one. KYB forks will eventually go on too. This will be my hell trail bike, my '12 250R my race bike.

Thanks Glenn. I always went around 85hrs on the 300 top end and the pistons always came out well within spec. Air filter is always clean.

Originally Posted by shawbagga

mate you need to hang the rear end out a bit more to even up ya tyre wear!

You know I haven't got any mad drift master skills.

[nambo-trev]

I've just ordered the same S3 conversion, going to turn the nambo into a 250!

[GMP]

I thought you were a die hard 300 guy Trevor?

I picked up a 300 top end to try on my '07, but that is not my race bike now and will be used for hell trail duty.

Its funny, but my '12 cylinder is marked with an "S3" in ink on the gasket surface, nothing in the casting. The ports are very smooth though and the bike has very good top end. I wonder if there is anything too this?

[nambo-trev]

You know Glenn I've had a lot of seat time on the 2 strokes over the last 3 years and what initially brought me over was riding my buddy's 250. Last year I had to ride a buddies new 250 up a few hills for him and was like "wow" this is so easy to climb with even with my 300. I also find as I've become a Better rider and am riding with expert and pro level riders I'm understanding that its not all about power. The 250s I've rode lug just fine and climb great but the BIG difference to me is the fitness part. These guys ride on a totally different level and a 4-5 hour ride chasing them I need to keep as much of my energy as I can I feel like the 250 helps me with that. The 300 gets very exhausting on big hills and tight single track from all that power pulling on me. I tried to fight it thinking the 300 was the weapon of choice but for me in order to reach that next level I feel a different weapon is required. I guess time will tell and hey if it doesn't work out the way I wanted someone here will get a great deal on a s3 cylinder kit!

[GMP]

Now you get the point of less is more, welcome to the club.

[Jakobi]

I don't think you'll be disappointed Trev. The only time I ever miss the 300s grunt is when I'm being lazy and running too many gears high into a hill and then get out of shape. Nothing that changing back down to the right gear can't fix.

With the 250 engine, and TTX suspension I honestly can't see things getting any better than this.

Glenn, I'm almost certain some of the newer bikes are using the same S3 cylinders. Next time I have mine off I'll check if its also stamped on the underside. The finish on the ports between the S3 and my stock cylinder were worlds apart.

I think I'll be having a go at doing my first bottom end some time this year so no doubt will just continue to add to this thread.

[alta redneck]

Hey Trevor where are you ordering your s3 kit from? I've been thinking of getting a s3 head for my bike.

[nambo-trev]

I ordered mine from gofasters, you'll need the cylinder kit and the head with inserts though. I already have the head and jakobi off the forum sent me a spare 250 red insert

[alta redneck]

I wasn't thinking of doing the 250 conversion, just a 300 s3 high comp head.