Hi guys ... has anyone tried changing from an Amal ... or similar carb ... to the OKO ? I'm running a 24 year old Amal carb on my Armstrong and can't get the carb. just right ... old age probably ... the carb ... not me...! I'm led to believe some of the better twinshock riders are using OKO on Honda and Fantic. Any info. would be gratefull.

!!!! Contact Chris at Classic trial in the UK . http://www.classictrial.co.uk/index.html He can sort out whatever you need . And speaking from experience with a OKO on my Fantic , Most likely the best improvement to my bike . And there have been alot of improvements ...

Glenn

And keep in mind , He WILL NOT just sell you a carb in a box and say have fun ... He will only sell a carb for a specific bike after he has spent the time to make sure it will be a properly jetted pure bolt on setup . Intake/airbox adapters and all where needed . the extra effort shows when you bolt on the carb and it works great from the first startup ! Just for the lack of frustration and possable engine damage , his Carb tweaking knowledge is priceless !

Edited May 27, 200917 yr by axulsuv

Spoke to him on the phone but ... as he hadn't done an Armstrong he couldn't help. He suggested I buy one off e bay and set it up myself ... Can't get to see him as I'm in the Far north of Bonnie Scotland. The carbs and the main and pilot jets are available on e bay but do the slides, needles etc need changing as well? I may give it a go as I feel I can set up a carb as long as I have a base to start with

Hi cmt320

I'm going to change from an Amal to a Mikuni 28 mm flat slide carb VM28-418 or a Keihin PE 28 mm round slide carb. Have to try which one of these two works better with Montesa Cota 348.

I've bought these carbs as new on eBay with standard jetting. I'll lathe an adapter from carb to airbox. I'll start with standard jetting and then I have to try and try with different jets etc. so that at last the jetting is as good as possible.

All kind of tuning info, jets and parts are available, from example:

http://justkdx.dirtrider.net/printcarbtuning.html

http://keihincarbs.com/home.html

http://www.allensperformance.co.uk/index.html

http://www.keihin-us.com/list.htm

http://www.sudco.com/mikuni.html

http://www.dellorto.co.uk/

http://www.showandgo.com.au/jet/jet.htm?je....html~mainFrame

http://www.mikuni-topham.de/

http://www.mikuni.com/pdf/vmmanual.pdf

Well Jaan... I thought I knew what I was doing till I went through the web sites you suggested.... mmmmmmmm ... Maybe I'll just buy a new Amal ... I've just rebuilt the engine and tonight I had it running pretty good ... but at the back of my mind I'll always be thinking ... can I get it better ... in your opinion is there anything wrong with the Amal in general? Let me know how you get on ... I don't know what way to go yet .... Cheers Iain

... in your opinion is there anything wrong with the Amal in general?

Only the same poor zinc alloy material of both body and slide.

I replaced the slide but the carb body too is a little bit worn and soon perhaps the new slide too.

I want to check if this is true too for my 348, Mikuni flat slide and me:

"Fitting an OKO to any Spanish bike that still has the very poor and often badly worn OE carburetion fitted, does make a tremendous difference to these machines, and results in a bike that is smoother, more powerful, and much easier to ride in serious competition."

(http://www.classictrial.co.uk/okokitsspanish.html)

If Montesa Cota 348 + Mikuni flat slide doesn't work, then I'll try Keihin 28 mm round slide carb.

Hi Iain interested to read this thread, I am some way down this process as I have already have an Armstrong which uses a 26mm Dellorto and have also used a Mikuni VM26. If your Armstrong still uses the standard middle box on the exhaust the Dellorto will not fit between the frame rails and the exhaust easily and the choke is difficult to operate. I made a shorter inlet pipe to move the carb forward but then aquired a bike with a custom middle box and used the Dellorto on that one. Then I started to look at the Mikuni for the sandard bike. There is no doubt in my mind that the Mikuni transforms the running of the bike but there is a snag, the air screw is on the right hand side of the bike and is very difficult to get to to set up. I've also been playing about with pilot jet sizes so I'm not there yet with the Mikuni! I'm planning to try the OKO next but what choke size would you go for (26mm or 28mm) and will it fit in the frame or will it foul like the Dellorto? My final thought is I doubt you'll get a new 27mm Amal, when I priced them (26mm) they were very expensive and any of the carbs I've listed above give as good if not better performance than the Amal.

The plot thickens Bostit ... I'm on a 27mm Amal and can get a new Amal for