2007 125 Atomik

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jimbo jones

jimbo jones

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2007 125 Atomik can someone0 come tune the carbi?

Yesterday I bought a 125 Atomik, the brake master cyl,s were both seazed and the motor wont rev right out but I got it at the right price and I have pulled the rear master cyl apart and cleaned it and now the rear brakes work I did the same with the front but had no luck it wont bleed up so Ill have to replace the front system.

Now with it not reving. it looks to have the wrong carbi on it the choke is on the right and is hard to get to couse I have another 125 atomik and the carbi is different have a look at the pic and seen what you guys reckon
also my mate said you can adjust the slide in the carbi he said it might not be getting full throttle



 
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i would try adjusting the mixture screw first


start the bike up and let it run for a minute or so,

turn the idle speed screw inwards to raise the idle speed a bit,(the screw with the spring on it, centre line of carby) up to somewhere 1800 rpm, not too high

now the smaller, brass mixture screw can be adjusted.
turn the screw out a quarter of a turn.
listen to the engine carefully,
if the rpms drop, then the mixture screw needs to be turned in a 1/4 of a turn.
the rpms should increase to what they were,
now try tuning the mixture screw another 1/4 of a turn in
if the rpms increase again, then try another 1/4 of a turn in.
if at any stage the rpms drop, or it starts running funny, then turn the mixture screw back out a 1/4 of a turn

adjust the mixture screw, until the engine is revving at it's highest/smoothest point
when you are happy it is close to perfect, then you can unscrew the idle speed screw (with the big spring) until the rpms drop back down to a decent idle speed.



see how it runs like that, and post up your results



if you cant get it running nice in the upper rpms, then the chinese Mikuni copys 22/26mm are cheap off ebay
 
the carby you have now are easier to work on than the Mikuni copys.
and are pretty well suited to the 125 engines when they are set up nice.


the Mikuni can give you a slightly better top end being a slightly bigger bore
but are a bit harder to adjust/set up, as the mixture screw is underneath, at the front.

here are a few Mikuni copys, you may need a bigger i/d manifold , insulator and air filter to go with them too.
http://www.ebay.com.au/sch/Motorcyc..._from=R40&_nkw=MIKUNI+26MM&rt=nc&LH_PrefLoc=2
 
with your front brakes, do you mean the brake calipers were seized ?


have you tried taking the top off the brake master cylinder next to the throttle,
then put a clear hose onto the bleeder nipple on the caliper,
now open the bleeder nipple, and wait until fluid comes out into the hose.
if it doesn't then you may need to slowly pump the brake lever to get it moving.
as the level drops in the master, refill the brake fluid with new stuff, and when the new fluid comes out the clear hose (different colour usually?)
tighten the bleed nipple.

don't let the master cylinder empty, otherwise you will need to bleed the system from scratch again.

then try out the brakes again when you are done
 
thanks for the info I think my carbi is stuffed it wouldnt idle and I had to screw the idle screw all the way in just to get it to idle I thin I might just by the one in the link you posted
 
it sounds like your Pilot jet is blocked up,
or the Pilot jet port where the fuel goes into the bore (between the slide and intake manifold)

see the hole to the left of the main jet, (the Pilot jet has been removed in the pic)
but either your jet will be blocked, or that tiny hole at the bottom of the thread where it screws into.





if you end up buying a Mikuni from DHZ, buy a bigger Pilot/Slow jet for it too, a #20
they are $5 extra, and will make your bike run a lot better too
http://www.dhz.com.au/buy/mikuni-carburetor-slow-main-jets/CARB-012-MIKUNI
 
rarely is the carby "stuffed", not much to break or wear out (easily), the most likely cause is that there is crap blocking the jets.

Did it rev out for the previous owner, has it been sitting for a extended period of time, this commonly causes fuel to dry and block jets.

It looks easy enough to pull off and clean, give that a go before buying a new carb, at the worst you might need new jets for your current carby, which are cheap enough. A new carb will usually require new jets anyway as there not tuned to specific engines.
 
I have a bike im working on with a carby like that
i found when the bikes cold you must run it on choke and after it warms up then turn the choke off and tune it (take the airfilter off and look) with the choke off and it should rev out and run like a dream after that
 
Thanks for the advice I'll give it a go next week and post up my results
 
I couldn't be stuffed playing with the old carbi so I orded a new 26mm Mikuni of eBay I would rather have the origanal type one on it anyway hopefully the new one is easy to tune it was only $46 posted
 
did you order an new air filter to fit the Mikuni?
and the #20 Pilot jet too ?
it makes the carby a lot easier to start, rev better etc
most people can't believe the difference
 
yep, my67xr is exactly right. i recently put a #20 pilot jet in, replacing the #15 that most of those 22/26mm chinese mikuni copy use. i seriously coulndt beleive the difference :)
 
yeh, but i would just e-mail DHZ and just ask if they have a #20 pilot jet for the mikuni 26mm copy carbs in stock. it would probably only be around 5 bucks anyhow :)
 
to late if it insist I just odder it
How long dose it take to come normally?
 
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yeah that is them,
you posted the same link i gave you for the Pilot jet at the bottom of post #8, it was $5 extra
 
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