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Beta Evo 250 4T Carb Settings


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32 minutes ago, klonheadd said:

I didn't need to undo the shock, cdi or regulator -  but it's tricky. A lot of observation and some turning/wigling and it will come out.

Well done! It was too tricky for me. But one bolt for shock, one for the CDI and two for the regulator just seemed easier than even more knuckle-skinning wiggling. And an opportunity to clean behind/under/around the said parts too.

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2 minutes ago, trapezeartist said:

Well done! It was too tricky for me. But one bolt for shock, one for the CDI and two for the regulator just seemed easier than even more knuckle-skinning wiggling. And an opportunity to clean behind/under/around the said parts too.

First time removing it was disaster but after couple of times it's not a bother at all.  

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2 hours ago, trapezeartist said:

Some people have suggested to me that I should use 127.5 main jet but 120 seems to be working fine for me.

Hey, you might be missing on some top end kick. The adjustment on Air/Fuel screw will help to richen the mixture but will not affect top end/full throttle that much.

I haven't tested it with stock silencer, but with my current setup which is Arrow pipe ,changing main jet from 120 to 127.5 made BIG impact to the top end power. 

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Edited by klonheadd
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10 hours ago, trapezeartist said:

Some people have suggested to me that I should use 127.5 main jet but 120 seems to be working fine for me.

There's nothing tricky about the spring. The difficult bit is removing and refitting the carb on the engine. I wouldn't suggest this is definitive, but it goes something like this:
Remove rear mudguard.
Remove airbox (The jubilee clip may be difficult to access and there are two hidden rubber pipes under the main part.)
Disconnect the top of the rear shock and lean it back.
Remove CDI unit on right hand side.
Remove the finned aluminium ignition box that lies on top of the gearbox.
Remove the rubber connector to the carb. (Another tricky jubilee clip).
Disconnect the fuel pipe and throttle cable.
Undo the jubilee clip fixing the carb to the engine stub (this one may be easier).
Twist, fiddle, wiggle and turn the carb until it comes out, probably on the left side.

When you come to refit the carb, take care to make sure none of the breather pipes are going to touch the exhaust and try to point the jubilee clips in the direction that is easiest for access. I found it was easiest to leave all the jubilee clips loose until everything was together, then tighten them all. It helps with the alignment.

Awesome.  Thanks for the details - just what I need!  I've ordered new front and rear springs, so will be pulling the shock.  Will plan to do it all at once.  May post some pics of the whole thing to post in this thread (1. in case I screw it up and need help, 2. to help the next rider wanting to do this).

Edited by markbxr400
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22 hours ago, klonheadd said:

Hey, you might be missing on some top end kick. The adjustment on Air/Fuel screw will help to richen the mixture but will not affect top end/full throttle that much.

With my riding skills, top end power is of negligible interest. My main concern is "driveability". I would like to think that my riding is getting better, so it can be easy to confuse improvements to the bike and improvements to the rider. Nevertheless a slow throttle, adjusting the slow-running mixture, adjusting the idle speed and (possibly) sorting out the breather pipes have been the things that have brought the improvements.

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1 hour ago, trapezeartist said:

With my riding skills, top end power is of negligible interest. My main concern is "driveability". I would like to think that my riding is getting better, so it can be easy to confuse improvements to the bike and improvements to the rider. Nevertheless a slow throttle, adjusting the slow-running mixture, adjusting the idle speed and (possibly) sorting out the breather pipes have been the things that have brought the improvements.

Fair enough. Although in my case the changes equaled better "driveability", and more fun. I really like the this engine and it only shines more when it's "un-corked". You always have the throttle to control it :)  but....  I have to say I managed to break 2 fenders on first 2 practices after jet changes haha. 

Edited by klonheadd
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