Hi there. I’m pretty new to trials so this might be a silly question. After transporting the bike, at startup the bike revs uncontrollably for about 15 seconds and then sorts itself out. I make sure the fuel tap is OFF before transporting. What could be causing this? 
Thanks 

Drain the tank before transporting it, then fuel it to identify if this is the problem.

Are you using the choke? That can sometimes make it rev pretty high. Have you tried starting without choke?

 

12 minutes ago, pindie said:

Are you using the choke? That can sometimes make it rev pretty high. Have you tried starting without choke?

 

Interesting you mentioned the choke. The two times it’s happened up to now, the choke has been on. I’ll try starting it with the choke next time without transporting it anywhere to see if it revs higher than with the choke off, if it does infact rev higher with it on, it might be a combination of the choke and aerated fuel (due to transportation) in the carb that’s causing it to rev so high?

31 minutes ago, b40rt said:

Drain the tank before transporting it, then fuel it to identify if this is the problem.

I’ll try that next time. Thanks. I’ve transported it a couple of miles before without an issue. The problem has only started as I’ve transported it a lot further recently, ironically, to get it serviced. So now I’m confused as to whether the problem has occurred as a result of something that’s happened at the garage or if it’s due to it being in the van for much longer.

It can't be "aerated fuel" - how much shaking about is it getting in the van compared to being ridden at a trial? Good advice above but I would also check your throttle cable for smooth operation and correct slack.

9 hours ago, splatered stu said:

my bike lived in the van for years...went everywhere..never a problem.sounds like a carb issue.is the secondary jet free? sometimes that will make it rev out and come down after 10-15 sec.or possibly the fuel cock is leaking and loading up the bottom end? if the main valve is leaking or the floats are too high...maybe then bumps in transportation might be an issue...putting a bike in a van and transporting it is not the issue it just may be pointing to it though.

As above, try starting without the choke, if it will start, you have a carb problem.

Have you checked that you hear the noise of a float hitting the bottom of the carb or the idle screw if you (while the engine is out)
suddenly let go a half open throttle?

Sometimes the routing of the gas cable is a bit too thight and the outer cable has got disconnected from the seat at the carb,
there should be a 2mm gap at least in the throttle too.

My bet would be that something has been done to upset the run or seating of the throttle cable while the bike was being worked on. Check the cable is not snagged anywhere along its length and that it's seated properly at the twistgrip  and carburettor. Also check the top of the carburettor has been fitted correctly (can't remember if the Beta uses a threaded, screw-on top or the type attached with two screws. If the latter the top should be attached with the cable slightly forward of centre - it's possible to fit it back to front in error) and that the twistgrip is not binding on the end of the handlebar. As mentioned above, when you let the throttle snap shut it should do so instantly, not gradually, and you should hear the "clack" of the slide bottoming in the carburettor. Check these last two points with the handlebars on both left and right lock.

Edited February 28, 20206 yr by cleanorbust

35 minutes ago, cleanorbust said:

My bet would be that something has been done to upset the run or seating of the throttle cable while the bike was being worked on. Check the cable is not snagged anywhere along its length and that it's seated properly at the twistgrip  and carburettor. Also check the top of the carburettor has been fitted correctly and that the twistgrip is not binding on the end of the handlebar. As mentioned above, when you let the throttle snap shut it should do so instantly, not gradually, and you should hear the "clack" of the slide bottoming in the carburettor. Check these last two points with the handlebars on both left and right lock.

Thank you. I’ll check this tomorrow! 

1 hour ago, pschrauber said:

Have you checked that you hear the noise of a float hitting the bottom of the carb or the idle screw if you (while the engine is out)
suddenly let go a half open throttle?

Sometimes the routing of the gas cable is a bit too thight and the outer cable has got disconnected from the seat at the carb,
there should be a 2mm gap at least in the throttle too.

Going to check the entire throttle cable etc tomorrow to rule out anything to do with the throttle. Thank you

10 hours ago, b40rt said:

As above, try starting without the choke, if it will start, you have a carb problem.

Started first kick tonight without the choke on. What does this indicate?

19 hours ago, splatered stu said:

my bike lived in the van for years...went everywhere..never a problem.sounds like a carb issue.is the secondary jet free? sometimes that will make it rev out and come down after 10-15 sec.or possibly the fuel cock is leaking and loading up the bottom end? if the main valve is leaking or the floats are too high...maybe then bumps in transportation might be an issue...putting a bike in a van and transporting it is not the issue it just may be pointing to it though.

I’ll check the fuel cock but that’s about as far as I could go at the moment. I’ll check the cock and the throttle body/cable and if it’s nothing to do with them I’ll take it to someone else. Thank you

3 minutes ago, StP said:

Started first kick tonight without the choke on. What does this indicate?

Running rich. Check how many turns out the mixture screw is.

Edited February 28, 20206 yr by cleanorbust

I agree. Rich on the pilot/air screw setting. Not necessarily a bad thing. It’ll be smooth and torquey. Once started without choke does it run ok? Mine is rich. I start with no choke then if need be lift the choke plunger a bit but without it clicking fully on. As soon as it seems happy I release choke fully and ride. 
 

Thinking about it I can’t remember the last bike I had that needed the choke every time to start it?

If it’s starting and then runs sweet once warm I’d not worry.