Mini Dirt Bikes, Pit Bikes Forum
Home UserCP Members Register Calendar FAQ

Go Back   Miniriders.com.au : Aussie Mini Bike Forum > Mini Forums > Tech Talk


MIKUNI 25mm CARBIE MANUAL.

Tech Talk


Reply
 
LinkBack Thread Tools Display Modes
  #41 (permalink)  
Old 22-08-2007, 09:22 AM
Junior Member
 

Join Date: Jul 2007
Posts: 29
I was just thinking, are 25mm mikuni carbs even a genuine product? Im pretty sure the Mikuni VM series only comes in vm20, vm22, vm24, vm26... u get the point. I have a "Mikuni 25mm carb" and it doesn't even have normal mikuni jets, my main jet is a big long sucker that rungs all the way through.

Bloody Chinese, i tell you.
Reply With Quote
  #42 (permalink)  
Old 13-09-2007, 10:56 AM
Junior Member
 

Join Date: Sep 2007
Posts: 1
hi guys im having a bit of a problem with my bm racing 110, when i get it started up it splutters and has loss of power and backfires,when i get the biting point it slowly tuggs away and when i release the clutch fully it cuts out (not stalling it) i seem to have a decent enough spark i really dont have a clue what it could be and the exhaust gets really hat very quick.

i would apriate it if you could get back to me on this, cheers p.s i bought this 2nd hand and think that it has a stock carbby on it. :S
Reply With Quote
  #43 (permalink)  
Old 17-09-2007, 03:35 AM
Junior Member
 

Join Date: Jul 2007
Posts: 29
First thing, replace your spark plug. I would recomend a NGK plug. There is a converter on there website, just type in the code on yours, and it will tell you which one to buy.

Now with one of the main ingreadients out of the way, you will want to clean out your carby. Its easy. unscrew the the fitting on your air filter so you can slide it off. theres 2 screws the hold it onto the manifold, just grab an 8mm spanner or socket and take em out. Then unscrew the cab on the top and take out the slide. Then when you have it apart, theres 2-4 screws on the bottem you can take out to take it apart. There a big float and 2 jets, which a ong skinny cylinder things. Unscrew them and give them a blow out, make sure therenot blocked up. And pour some fuel around the carby to wash it out, just try not to get it on the rubber gasget. *You need this place dirt free*. Put it all back together the way you found it. You mightwant to try and wash out your air filter to, just make sure its 100 dry before it goes back on. If theres any dirt oil or water inside the bowl, it will black the jets from suck up fuel, therefor make your bike choke and stutter.

Theres 2 screws on the side, one is the revs and one is the air/fuel ratio. The rev screw is the one clossest to the sentre of the cylinder that ones fine. Screw the other one in untill its firm, but dont tighten it. Then unscrew it 360 degrees, then a ferther 90 degrees. This will be around the right mixture you want to run, but u can change it within the 90 degree mark in most cases to make it run better.

You also may want to pull the tap off your fuel tank and flush it out, just dont reck the threads on any holes. And if you have a fuel filter, you should replace it if its old.

Check the condition of your coil, which is the plug the goes onto the sparkplug, all the way up to the big cylinder part with 2 wires attached to it. Make sure its in good condition and not melted or split.

Its also worth checking your Valve clearence. They may have hammered them selfs in. Any motorbike mechanic can do this easily, and you can do it your self if you know how, although the internet lacks good guide about it for mini 4 stroke engines.
Reply With Quote
  #44 (permalink)  
Old 12-10-2007, 08:20 AM
Junior Member
 

Join Date: Oct 2007
Posts: 1
Quote:
Originally Posted by SIKSPAC View Post
does anyone know whats wrong with my mates bike????
It runs all good but then the bowl will fill up and keep filling causing him to lose alot of fuel????
Its got us stumped whats wrong with it ay....
Oh its on a AGB-29......

this happened to me it turned out to be the overflow control it was caused by a grain of sand stopping the needle in the float from closing hence the fuel from the tank kept on flowing into the carb till it filled up to the overflow and just leaked out.
to fix this you take out the four screws and get the float out by taking the float pin out and then pull the needle out and clean it aswell as the seat that it sits in
Reply With Quote
  #45 (permalink)  
Old 14-11-2007, 06:11 AM
SSR70cc's Avatar
Junior Member
 

Join Date: Nov 2007
Location: Newcastle NSW
Posts: 3
I just bought a 25mm Mikuni before I found this forum. It don't work on a
72cc Ducar motor. Going to put my original carb back on and see how it goes.

*by the way the MIXTURE screw is under the carby you need to take it off to adjust it*
Reply With Quote
  #46 (permalink)  
Old 27-11-2007, 05:08 PM
Junior Member
 

Join Date: Oct 2007
Posts: 1
The screw you want is directly under the venturi (big opening, or throat) screw in is leaner, out is richer.
Reply With Quote
  #47 (permalink)  
Old 13-02-2008, 04:58 PM
Junior Member
 

Join Date: Jan 2008
Posts: 5
what is the screw on the right side
Reply With Quote
  #48 (permalink)  
Old 13-02-2008, 05:00 PM
Junior Member
 

Join Date: Jan 2008
Posts: 5
the only way I can get my 70cc ducar to run is put the small throat manifold back on but it defeats the purpose. It wont run with big diameter mnifold that matches mikuni
Reply With Quote
  #49 (permalink)  
Old 15-02-2008, 01:39 AM
Gecko's Avatar
Member
 

Join Date: Feb 2008
Location: Cooloola, Sunshine Coast
Posts: 38
Sounds like, you may have a sticky needle in the float bowl.
Take the bowl off, turn your fuel tap on.
Lift the float gently with your finger till the needle is just closed.
Fuel should stop running before you have to squash the little spring in the needle.
If not, new needle and seat.
__________________
Linux - It is now safe to turn on your computer.
Reply With Quote
  #50 (permalink)  
Old 15-02-2008, 03:56 PM
M@rkay's Avatar
Senior Member
 

Join Date: Dec 2007
Location: Hills area,sydney NSW
Posts: 334
Send a message via AIM to M@rkay
hey guys. i think i got a 25mm or 26mm mikuni carby and when i start my bike when its cold it never wants to idle. my dad has adjusted it but it just doesnt want to idle. i have to rev it to keep it going. once the engine is warm though it idles fine, probably a little bit to high. would anyone know what the problem is. Also how to fix it. help would be very appreciated.
__________________
2005 Motovert pro 125cc.
Pro taper bars and grips.
uni air filter.
Full makita sticker kit.
yellow plastic kit for when im riding in mud or heavy dirt.

Reply With Quote
Reply



Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Need a Bike Manual JEST_Thumpstar Mini Chat 4 19-01-2007 08:13 PM
25mm Mikuni swap for 18mm Mikuni sid Mini Classifieds 2 10-11-2006 06:24 PM
WTB: Intake manifold to suit 25mm mikuni mjc85 Mini Classifieds 4 30-09-2006 11:42 PM
anyone want a 25mm Mikuni Carb vertially brand new cra38l Mini Classifieds 11 30-09-2006 11:36 PM
25mm Mikuni on 110cc ? mjc85 Tech Talk 25 30-09-2006 09:49 AM

» Site Navigation
» MiniRiders Links
Subscribe to MiniRiders
Join Our Facebook
» Our Sponsors

Advertise Here

» Current Poll
Vote for fifty of the month!!!!
crazzy#1 - 3.92%
2 Votes
motoxxx - 0%
0 Votes
wogtaz ryder - 23.53%
12 Votes
redbaron199 - 23.53%
12 Votes
gavgav - 11.76%
6 Votes
pitst3r x4 - 3.92%
2 Votes
mitch 250 - 1.96%
1 Vote
roost666 - 5.88%
3 Votes
trent yeo - 1.96%
1 Vote
creature - 7.84%
4 Votes
ryan2282 - 5.88%
3 Votes
dirtrider - 9.80%
5 Votes
Total Votes: 51
You may not vote on this poll.
» Online Users: 99
14 members and 85 guests
)(_COZA_)(, barnsey, drewmini, drop_a_set101, FMXCR250R, FMX_boy, motocross_mouawad_6, motoXXX, Muksy, nick125, Peter1230, Shaun__19, SnItChY, SPM 16v benz
Most users ever online was 263, 27-06-2007 at 03:04 AM.

Powered by vBadvanced CMPS v2.2.0

All times are GMT +11. The time now is 05:17 PM.
Powered by vBulletin Version 3.6.0
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.1.0