Hi there I am new to the forum and have recently bought a 2003 Beta rev 3 250cc but its running very badly on low revs, I had the carb off and cleaned it in a sonic bath, had a new cut  off jet fitted and had a new set of reeds.

It was running better until my son fell off it and it instantly went back to running badly again, has any one got any ideas what it could be?

Thank you

Phillip

Have you checked the float height and looked at the carb issues that are fixed at the top of the Beta sub forum?  My Rev 3 ran badly after the bike went upside down.  When the carb was removed there was a metal item in it (I think a fragment of a nail) which I can only assume was put in to stop the flooding issue.  The mechanic put a new jet in it and cleaned it up and it is OK, but there has been some flooding.  The Mikuni seems to be problematic - the fix described is a good start point.

I (foolishly) thought on an old bike all this would have been done by at least one of the previous owners.

My missus has now taken over the Beta full time and I have bought myself a TRS.  Riding the Beta I wonder if the bike revs out properly - the TRS is worlds apart.  When she gets to the point that this is an issue I think it is new bike time rather than keep throwing money at a 15 year old bike.  Ironically the Beta runs nicely at low revs and the relative lack of power is just what she needs for the time being so it is doing a good job.  It also has the slow throttle so that is a factor.

i did think about fitting the later Keihin as per the Evo, but it needs a new reed block as well so the overall expense is significant.

Hi there

Thanks for your reply on this subject, I will be stripping the Carb down for the 3rd time at the weekend, surely it must be a fixable job??

 

Thank you

 

Regards

 

Phillip

 

12 hours ago, phillip Richardson said:

..., surely it must be a fixable job??..

 

I hope so mate.  Ours certainly runs a bit "off" after the bike has been wrong way up.  My TRS ran a bit "off" after it got the better of me as well and then settled down after a couple of minutes.  I wondered if that was a carb issue so i will follow your progress with interest.  Hope you get it sorted at the weekend.

Can you swap with another carb? At least you will know that's the problem if it runs ok.

Just to let you know that I have fixed the Carb know by stripping the Carb down again and blowing out the Fuel cut off valve  which had dirt in it causing the bowl to overflow and blowing out the pilot jet and as a result the bike starts and runs perfectly now.

Thanks for your help.

Regards

Phillip