lineaway

Thanks for that, but I have a full supertrapp exhaust.

Go to page 3-8 in your manual and turn the idle adjustment screw 1 full turn counterclockwise. You have to remove the seat to get to it.

Did you ever adjust the idle?

The Beta was imported to America by Cosmopoliton Motors starting in 1985. From '85 to '89 they were quite a popular bike in the trials community. We probably had a dozen or more in our club. You sill not find many around as they were rode to death. If rode hard the frame would break around were the coil mounts. Mine was rewelded 3 or four spots. At the time the bike made quick power, but the rear disc was quite a poor design and the rubber kit had to be replaced often. I spent two decades riding Beta's after my first tr34.

Sorry its the keihin thats easy to loose the needle jet!

You need a bigger pilot jet. Try a 38. P.s check a carb diagram. You could be missing the needle jet.

Put a one way valve on it. Also heat can cause it too.

https://www.revzilla.com/motorcycle/bridgestone-tw9-trail-wing-front-tires?gclid=Cj0KCQjw0JiXBhCFARIsAOSAKqDsWjyUNICPfmSm2LVxBAL9wn3R5fFQgy2-qkWmIjlqQP5hhh8bAyoaAhmFEALw_wcB&sku_id=1000079

Easiest solution would have been to buy the correct tire. https://www.rockymountainatvmc.com/tires-and-wheels/irc-tr-11-trials-tire-(tube-type)-p You will always be fighting the issue with a tubeless on a DID tube type rim. On the ty 80`s I drilled 8 holes in each side of the rim and screwed the tires to the rim. I always use a bead sealer. https://www.amazon.com/Steelman-G10106-Tire-Bead-Sealer/dp/B00NBTGCF4/ref=sr_1_59?crid=OVD6WK9CN290&keywords=tire+mounting+lube+and+sealer&qid=1659102586&sprefix=tire+mounting+lube+and+sealer%2Caps%2C138&sr=8-59

Quick fix would be to drop the needle. You are running rich with the heat

Carl was spot on. You need a Lanyard type tether, not the crap magnet switch. We are the only moto sports that use the magnet for a reason.

Before you waste a lot if time and energy. Open up the air screw a full turn counter clockwise Let idle for a full minute and go ride it for at least 20 minutes and see how it feels. Its almost always low idle is the problem. As mentioned, a new plug and make sure your tank is venting properly.

You need to check all grounds. Did you paint anything? It is possible to have a spark and no spark with the plug in the head.

After riding the TRS for a year, I did something I swore I would never do. Having ridden the Expert line since 1974 I figured it was time to ride an easy line I have 3 generations of my family riding and soon will have 4. I hope to still be competing well into my 80's. So I bought a 301 Montesa 75th anniversary edition.And dropped down a class. It is heavy, but I am having a blast!

You do have the center nut to remove. I just use a rattle gun.

Pull the mag cover off and turn the flywheel backwards with a socket and ratchet. If it`s mains it will probably free up. Happened to me during an event and pushed it back to the pits, spun it loose made it back to section 3 and it stuck again. Pushed it almost 5 miles that day! Of course you have to do new mains, seals and gaskets.

Yes , I found a solution. I have only stalled once in 15 months now.

You have to weigh the whole bike.

So did you buy shocks. I bought another TL250 last weekend. Was supposed to had the front end pulled in, but not. Interestling it had a rear shock mod done. Stockers were 14 inch long, this has 13.5 inch shocks. Thinking of a set of 15 inch shocks.

It's worn out, take it to a Sherco dealer.

Remember you have to loosen the rear engine mount bolts to get the shaft out.

I show 22201-376-000 are the correct plates.

The chrome tubes should be straight forward replacements as the guts have all the parts on them. I have no idea on quantity the Zokes on a Ossa use. The rest of it should be similar to a Gasser with the same type. Should be a video out there somewhere. Not hard if you have an air gun, otherwise try loosening the lower bolt in the fork with it compressed before you take anything apart. Minimum is all you need is new fork seals and dust seals.

I once put a Beta under the Christmas tree and swore to her I had nothing to do with it. It was all Santa`s fault. That was in 1989. Then last year I took her to the Yamaha shop to put a deposit on her new Waverunner, we immediately stopped and I put a deposit on my 75th Anniversary Edition Montesa 301. Fair is fair.