jareth

If it was a car, I'd check the crank position sensor. That is almost always the reason when it's running great but then won't start. I don't know if bikes even have them, but there must be something that tells the computer the crankshaft position.

I figured out my problem. I'm an idiot! Ran 2 tanks of fresh racing fuel through it and now it runs great. I guess the fuel from last year didn't hold up as well as I thought!

A helpful trick I do for cleaning carbs. I use a can of brake cleaner, or WD40, with a straw attached to the spray nozzle, and put the straw tightly into each hole of the carb and watch the spray come out the other end of the hole. This way there is no chance of thinking it's cleared when there is still something stuck in the hole. Watch out you don't get it in your eyes!!

Some food for thought on the topic of fans. I switched from pump gas to VP Racing fuel, years ago, in my '96 Gas Gas, and the fan didn't come on all day, no other problems, but I thought there was something wrong. At the end of the day I was racing some kids in the pit with motocross bikes, that was fun, and bewildered them, and the fan came on, and I burned all the carbon out of the exhaust! I have since learned that the racing fuel runs much cooler and the fan runs much less often. Have a great day, feet up!

Thanks, will do today, and report back.

I wonder if you can describe the CDI malfunction symptoms more specifically? I have a 2018 TRRS 300 and a couple months ago it started misfiring at high RPMs under load. Most noticeably in 5th gear and then roll on the throttle, then it starts to skip and act like it has a fouled plug and loaded up with fuel at the same time. It clears up when I slow down and keep throttle at about half. I suspect the CDI issue may be the problem too. Runs great all day, hot or cold, as long as I don't open up the throttle. It has gotten a little worse now, so I can't do any big hits.

I replaced the center case gasket in my 2012 Beta 300 with no special tools. You should be fine. Be patient. It's all about balance.

http://www.betamotor.com/system/attachments/0000/0749/REV3_inglese.pdf

http://www.betamotor.com/en/support/manuals