Beta Riders Club Discussion Forum

Cross posting a bit from Thumpertalk,

I had my first real ride on my bike the other day. I have a few carburetor related questions.

I noticed this problem before I rejetted, the bike seemed to drip fuel out of the overflow at times. Usually noticed when I leaned it on it's kickstand. I always shut the fuel off when I'm done so I never had any leaking in my shop that I noticed. But yesterday while out on my ride, I stopped to setup the camera for some video and while the bike was idling I noticed fuel dripping out of the overflow. I noticed it too on a failed attempt over a tractor tire. Is it carb overflow hose routing? Float? Or is this normal?

The other thing that happened was as I rode on throughout the day, my idle seemed to pick up. So I backed down the idle adjustment screw. I just don't understand why it wasn't an issue early on. I made sure my throttle wasn't sticking. All was good there.

Currently the carb has the stock pilot, an NECJ needle and a 162 main jet. The air screw is turned out about 2.5 to 2.75 turns. I'm right around sea level give our take a few 100 feet. Temps were around 80F and fairly dry.

Any help would be greatly appreciated!

Is this a 300RR? Many, if not most of these bikes need the float level adjusted to stop the overflow issue. It's not a big deal, do a search and you'll find lots of results. Usually an increase in idle is due to a lean condition which could be caused by an air leak somewhere in the system. Check your fittings for a loose bolt and try spraying ether around the carb boots and manifold and listen for a change in idle speed to identify where the problem is. Worst case it could be a leaking crank seal, that usually is very noticeable causing very high idle speed.

Thank you. This is a 300RR. I'll try what you suggested.

Float is probably high yes but thats not the cause of your hanging idle. Your a touch lean on the bottom, adjust the air screw and go to the 38 pilot if needed. The NECJ is great, I run it too, but some bikes @ sea level need the 38 over the 35.

Set the float level and the higher idle can be sorted with turning the air-screw in by half turn at a time. I run necj #3, 162 & 35 at sea level to 500m. I need to swing between between 1.5 turns to 2.5 turns depending on temps. and humidity.

All engines run more efficiently when fully warmed up. The rise in idle speed could simply be the engine reaching a more efficient temp. If you set the idle speed after starting after dechoking you will notice this.

Know it's an old thread, but just bought a new 18 XTrainer. Dealer told me to expect idle to be crap for the first tank of fuel, then to rise and be ok once I refuel. He said, in addition to the oil injection, they add oil to the first tank of fuel as well to help with the break-in. This causes the idle to drop off. Once that tank is gone, he told me to expect the idle to rise. Told me also to expect a higher level of spooge out of the exhaust right up front. Will see what happens.

its always possible there could be a little debris in, on, around the float valve needle. Worth a look at least.