hi all , my sons 2010 evo 125 is having some issues 

can be a bugger to start , would rev tick over then just die  then kick and kick no joy tilt bike to side with fuel out overflow would help get started again but same issues 

I've  checked plug which was new last outing 2 weeks back as same issues  and is sparking , stripped carb and a jet was a little blocked  all cleared with an airline  started back up and same issues wouldn't idle off choke  but once bike warmed up by keep revving /blipping to intervene  or riding it down lane it ticks over nice and only get a dip in engine note every 30 seconds or so at idle don't hear or feel a dip when riding it around 

coolant was a little low so topped up thinking couldn't it  be getting hot but still same 

any help out there please driving us nuts now 

thanks 

Andrew 

 

To me it sounds like you have a problem with dirt in idling system. Not easy to clean. Must take everything out from carb and carefully blow and clean. Remember to blow and clean all drillings and passages in carb body. After only use a good, clean and oiled airfilter and change often. As I see it, dirt in idling system is one of the most common problem in a dirt bike. If problem is only at certain throttle openings I would say it isn´t the ignition. Ignition problems is most often at all throttle settings.

thanks for the response 👍 

I've taken carb apart twice  , cleaned out with airline every jet blown through etc   , 2nd time a piece came out of the jet which opened up quite a bit 2nd time 

 

I was adamant that that cleared out and topping up of the coolant would have been the cause   but its still the same 

 

only thing I've yet to check is the breather pipes for any blockages ,

It might be residues from air filter spray that follows the airstream into idle system and get stuck. It is not dissolved in clean petrol. Some people use Carb-Cleaner to dissolve. Have no experience of that liquid. When blowing, should use well filtrated HP-air. The passages are very small in the idling system so it can be difficult to clean.  It happens it is a nightmare. Perhaps you should concentrate on cleaning the carb body and buy a new jet.

As jets can be dirty from factory it is best to have it ultrasonic cleaned before assembly. For safety´s sake, HP-blow the jet after the Ultrasonic cleaning.

Is it a Dellorto VHST or Kehin PWK?

My last carb-cleaning-nightmare was approx  8-10 years ago with a Mikuni (original) on a Beta evo 4t. Eventually a man (not me) fixed it.

Also check you don´t have an air leak.

thanks I will gave another look later and can then check what carb is on it 

 

any ideas on what jets should be in there  tried looking on the beta online manual but no mentions of jet sizes 

cheers

Andrew 

Edited January 20, 20224 yr by awh1

checked carb it's a keihin pwk 

there appears to be some numbers ground off but can make out last bits it's ground away before the 9 

9   OW18 

 

 

not stripped back down yet to see what size jets are in there etc 

As far as I know, usually no major problem with PWK. Splatshop are good at carbs and have spares,,jets etc

https://www.splatshop.co.uk/performance-parts/keihin-pwk-spares.html

On 1/13/2022 at 4:03 PM, carl ekblom said:

As far as I know, usually no major problem with PWK. Splatshop are good at carbs and have spares,,jets etc

https://www.splatshop.co.uk/performance-parts/keihin-pwk-spares.html

thanks will take a look 

Well took bike back out  same thing got it warmed up drove it up the road  then died  kicked for ages no chance , popped a new plug in and all fine 

 

tonight I've stripped carb again let the jets soak in some carb cleaner for a bit then airline blew it all out they did look blocked again ,  I noticed a breather pipe was missing so not sure if that could draw dirt in ?

 

also took not of jets 

52 pilot 

130 main 

didn't really want to mess with jets as about 2 years back when it was in use no problems at all and just been sat around unused til last few weeks again 

cheers 

keihin has a problem with the jet tower. The piece with the security torx. Thats the only way to clean the carb. Oh yeah , the o ring gasket should be replaced.

19 hours ago, lineaway said:

keihin has a problem with the jet tower. The piece with the security torx. Thats the only way to clean the carb. Oh yeah , the o ring gasket should be replaced.

can you advise where the o ring gasket is or where to buy from  

 

tbh didn't really notice  a torx bit in there lol 

 Once you remove the jet tower, the gasket is really obvious. It takes a security torx to take it apart. It used to be you could not get the gasket. You tube Keihin jet tower. I never would of touched it until it left me no choice. But that is where the real problems exist.