Dirtrider
Well-Known Member
Will do... I'm going to order it today.
Mikuni 30 mm or Keihin replica Oko Flatside 26mm
- Thread starter Faturk
- Start date
Help Support Mini Dirt Bikes & Pit Bikes Forum:
dylanatomik70
Member
- Joined
- Jan 28, 2008
- Messages
- 5
- Reaction score
- 0
can someone please give me some tevhnical info on how to tune a 26mm mikuni. I have recently put this mod on my 70cc after it had a standard chinese carb on it and now I cant get the bike to run good. I can only find one screw on right side and beleive it to be mixure screw. What is a rough setting for mixure I beleive years ago on old mowers the trick was to screw all the way in and then 1 1/4 turns out. Also I need to know which and where are my idle and mixture screws.
Cactus Jack
Master Spanner Spinner
- Joined
- Jan 18, 2007
- Messages
- 2,742
- Reaction score
- 53
The mixture screw (fuel screw) is right underneath at the carb flange to manifold end ......... OKO's , KF's , Keihins and genuine VM-Mikunis have an easy to get at AIR screw up on the side of the carb on the air filter side .......
Here's a link here which refers to carbs with fuel screws .......
ThumperFaq: MXA Fuel Screw
I've explained in detail how I tune idle air mixture in quite a few threads and my method works spot on very quickly ........
I always correct carb to manifold / manifold to port and gasket mismatch problems first ...... plus get the exhaust side set right as well ....... I actually go a step further and remove all sharp edges (detonation points) from the combustion chamber , valves etc and smooth and blend the ports ...
IF you have fitted that "26" mm Mikuni to a 70 with a smaller intake port with mismatches and it has a pipe less than 26 mm I/D ....... then good luck living in bog and stumble city when you open the throttle .......
To dial a carb in you have to first get it to idle steadily and smoothly ...... THEN with the needle set in the middle position ...... you do a full throttle thru top gear test and change main jets until the engine peak revs crisp and clean ....... then if it has a hesitation or bog off idle or when the throttle is opened up quickly you need to change pilot first then possibly mess around with the needle taper and slide cutaway until you get it working to suit you ....
My engines usually crank hard and clean after the first two steps with a #38 Keihin or the Mikuni equivalent pilot jets and a #100 to #105 Keihin size main jet ....
Here's a link here which refers to carbs with fuel screws .......
ThumperFaq: MXA Fuel Screw
I've explained in detail how I tune idle air mixture in quite a few threads and my method works spot on very quickly ........
I always correct carb to manifold / manifold to port and gasket mismatch problems first ...... plus get the exhaust side set right as well ....... I actually go a step further and remove all sharp edges (detonation points) from the combustion chamber , valves etc and smooth and blend the ports ...
IF you have fitted that "26" mm Mikuni to a 70 with a smaller intake port with mismatches and it has a pipe less than 26 mm I/D ....... then good luck living in bog and stumble city when you open the throttle .......
To dial a carb in you have to first get it to idle steadily and smoothly ...... THEN with the needle set in the middle position ...... you do a full throttle thru top gear test and change main jets until the engine peak revs crisp and clean ....... then if it has a hesitation or bog off idle or when the throttle is opened up quickly you need to change pilot first then possibly mess around with the needle taper and slide cutaway until you get it working to suit you ....
My engines usually crank hard and clean after the first two steps with a #38 Keihin or the Mikuni equivalent pilot jets and a #100 to #105 Keihin size main jet ....
On the topic of the OKO26:
Anyone tried the clear float bowl. Click on this link and scroll down: OKO Carbie Products Image See the calibration marks. Cool.
Where do I buy rubber spare parts for an OKO26? Specifically a new rubber float bowl gasket (mine is expanded and does not fit), and a spare inlet manifold mount/join piece? I've emailed OKO already. I'll reply here if I get an answer and no one else has an idea on where to buy OKO spares.
Anyone tried the clear float bowl. Click on this link and scroll down: OKO Carbie Products Image See the calibration marks. Cool.
Where do I buy rubber spare parts for an OKO26? Specifically a new rubber float bowl gasket (mine is expanded and does not fit), and a spare inlet manifold mount/join piece? I've emailed OKO already. I'll reply here if I get an answer and no one else has an idea on where to buy OKO spares.
Last edited:
Cactus Jack
Master Spanner Spinner
- Joined
- Jan 18, 2007
- Messages
- 2,742
- Reaction score
- 53
DHZ sells spare mount rubbers plus the round slide 26 mm OKO's :
NEW MANIFOLD RUBBER ADAPTOR, SUITS OKO MIKUNI KEIHIN - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 16-Mar-08 15:33:10 AEDST)
NEW VM26MM REPLICA PERFORMANCE CARBY KIT 140CC 150CC - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 14-Mar-08 10:42:18 AEDST)
NEW MANIFOLD RUBBER ADAPTOR, SUITS OKO MIKUNI KEIHIN - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 16-Mar-08 15:33:10 AEDST)
NEW VM26MM REPLICA PERFORMANCE CARBY KIT 140CC 150CC - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 14-Mar-08 10:42:18 AEDST)
durt girl
Member
They look like they may actually work. We got our carb to fit the bike bike by making a new inlet out of stainless..worked out awsome after my man spent a few hours profile cutting it and getting it right. Can you PM me how it fits and wether or not it actually does the job? Still trying to piece together how everything slides and fits together.
Cheers
