Glayne

Does the sound go away when the clutch is pulled? If it does, seems normal to me.

I am far from an expert, I would have to see a picture and still not be an expert, but I'm not sure the bush would be removable, or serviceable?

I'm a sucker for Yamahas, I would have bought it too!

...and be very careful at 80PSI, air can be very scary...

Lefty Loosey

As Lineaway mentioned you are probably thinking base gasket. I would hate to dumb down my GG 280 that much as I like the snappy power, but I would be interested in the results and what jetting changes it would need to do both. Probably best to try one first, then if looking for even more tame try the next. Sorry to all those that this offends, the black throttle tube is just too much wrist movement to get a hand full, I feel like a Harley rider pulling out of the gas station trying to use one!

Sounds like a standard security torx here in Canada, not sure where you are?

Guess a head insert or flywheel weight may help, of the two I would choose a bit of flywheel weight? I just wouldn't want to lose its snappy power when you need it. I agree with fourex, the map switch can certainly help dull but I find most of the dull to be in the high RPM's. I find the clutch slip to be the best for smoothening the power pulses.

Nope, wanted one when I first got my 280 Raga, ended up just getting used to it and I'm glad I did. What benefits would you want from one?

I don't know if you have had a pro gasser motor before, as mentioned above I have set my pilot circuit a touch rich (mine is Keihin) I cursed mine when I first upgraded to it but quickly learned. It rarely takes more than 2 kicks to start hot or cold. You need to get the kickstart to a point that you know it will engage and not slip, then it is a very fast sharp kick, *fast sharp kick* Not a hop up and weight transfer to the kicker. I was ready to change to a different head, and a different carb, then I learned the technique, up sized the pilot 2 #s and I'm happy!

I would start with a carb clean, or at least dump and clean the bowl. With warmer weather I would expect to be unscrewing the air screw for more air if anything, not the other way around. Last month I had an idling issue, promptly fond some slimy stuff in the Keihin float bowl. I'm a little unsure of fuel quality these days...ethanol, additives... A different pilot jet would be the equivalent of a different air screw.

Well, that sounds like a good excuse for a trip to the tool store!

Good find, I would start getting the chain guide straight or replaced. I would imagine just about any spring gets fatigued over time, I have not had to replace mine...yet...

As feetupfun said, lots of your situation seems normal, your clutch probably needs some new clutch fluid and bleed? some new transmission oil? and some adjustment? Is there a sticking throttle cable? a sticking carb? or a routing issue with your throttle cable?

From that short clip the rattle seems a touch intermittent? Is the master link catching on something? As advised above it certainly sounds chain related, could the wheel be installed any straighter? 9 second video of that is making me want to figure it out!

Any updates?

I wish I could remember what it was with mine? motor magnets need to be 180° from the brushes?

If I was to guess, something needs to spin 180°

This also happened to me on my WR450, I also thought I had it back together the same way it came apart but I had spun the insides 180°. Also as faussy said, wires backwards could certainly do this as well. Definitely messed with my head when it freewheeled backwards!

...And don't rule out the 280! I liked my 250, it was smoother than my 280, and I like my neighbors 300. I can certainly feel the extra 20cc from the 280 to the 300.

New boots are usually the worst, especially MX or ski boots. I had a good experience with new Wulf trials boots. They broke in fast and easy. I definitely prefer used boots for the kids, when they get them they are ready to use!

I could certainly get the itch to ride one of those!

I have always been a Yamaha fan, mixed feelings here for sure! Looks shiny...

Well said turbofurball, Gasgas Pacific in B.C. Canada seems to have any old stock for my EC300 (also known as mototrialswest). It's a few hours north but in my experience great parts, and great to deal with!

I'm not sure what your experience is with trials bikes but they sure don't sound quite like other motorcycles, my 280 2 stroke has quite a pop sound as well and is completely normal. Otherwise I'd be possibly changing out a pilot jet? With a rich pilot circuit I have had very erratic backfiring (on a 4 stroke)