single carb conversion

sivuvaunu · Oct 13, 2012

Hi there,
What would be the best working single carb conversion for 850 Commando MK3?
I have seen SU, mikuni, keihin and amal, are there any others.
Do these work also with 920 cylinder, or should the jetting be altered.

sivuvaunu(sidecar)
Finland

MrNorton · Oct 13, 2012

Hej sivuvaunu.I have on my MK3 Mikuni VM36,but very difficult jetting(PW3 cam,ported cylinderhead and big exhaust elbows).I think now Keihin and Mikuni are both very popular,but seems that every engine has own "personally"jettings.
(på finska:Mikuni taitaa olla halvin ja helpoin konversaatio).

Rene

Brooking 850 · Oct 13, 2012

Hi there finnish member, I am looking at putting these carbs on a 850 projetc I have on the go.
Email Kevin Gilham at Lectron, here is the website link.
Made in the States, non Japanese or Taiwanese copies.
Regards Mike
http://www.lectronfuelsystems.com/technical.html

Hobot · Oct 13, 2012

i asked here about my Combat's 34 Miki single set up for break in use on Ms Peel's 920 and was told may only need to increase pilot to #43 then diddle the needle as indicated. Ain't tired it yet but the 34 might be a bit easier to get away with than a 36mm.

cjandme · Oct 15, 2012

JS motorsports has them set up for our bikes, I haven't visited his site lately but I believe he offers a 36mm one with manifold. If I remember right, the price was right too.

Cj

christulin · Oct 16, 2012

SUCO sells kits in the U.S.
I use a 2 into 1 manifold with an Amal Mk II carb for later triumphs, jetted for 1-cylinder Triumph Tiger 750. Works better than the Mikuni. I also used a new "stay up" float. I have lots of Amal spares, plus it keeps the Norton more British.

Torontonian · Oct 16, 2012

If I had to do it all again ,it would be a flatslide.

Snorton74 · Oct 16, 2012

I wanted to get the flat slides but ran out of money funding CNW's expansion. Ha

mikegray660 · Oct 16, 2012

Ive ran the Mikuni VM's and TM's and I'd say that for a stock bike there is very little difference between the two (comparing as a single to a single and and a dual to a dual carb setup) - yes the TM flatslides are a little better (and little more expensive), but not enough to make me scrap a VM setup if i had it on the bike and they were working properly -

on a bike with headwork and a cam i'm sure there would be a larger difference with the TM's over the VMs but to what degree again would be another discussion

one thing i do prefer about the VM's is they have a bit more spring tension than the TMs, so the return after releasing the throttle is more positive

tpeever · Oct 16, 2012

I have been running a Mikuni VM36 on my '74 Commando for several years and am very happy with it. Ran perfectly right out of the box.

pete.v · Oct 16, 2012

I think that the most consistant and proven application for the 850 is a vm36 setup. No muss, no fuss. You will love it, I did.

I have tried many many setups. My 750 is somewhat modified and needs even more then a 36mm carb to get the full effect of a single carb setup.

When I ran the vm36 it was great. Once tuned, I could play with the main jets, practically on the fly, to adjust for performance or economy. 240 for economy and all the way up to 330 for top end boost without effecting the low and mid range attributes.

Bernhard · Oct 17, 2012

sivuvaunu said:
Hi there,
What would be the best working single carb conversion for 850 Commando MK3?
I have seen SU, mikuni, keihin and amal, are there any others.
Do these work also with 920 cylinder, or should the jetting be altered. sivuvaunu(sidecar) Finland

You really have to sit down and consider exactly what you want as regard performance from your engine.
Do you want more low range grunt :?:
Or better fuel economy :?:
There are variations out there to achieve these but are different setups, no two are exactly alike.

OldBalz · Oct 17, 2012

pvisseriii said:
I think that the most consistant and proven application for the 850 is a vm36 setup. No muss, no fuss. You will love it, I did.

I have tried many many setups. My 750 is somewhat modified and needs even more then a 36mm carb to get the full effect of a single carb setup.

When I ran the vm36 it was great. Once tuned, I could play with the main jets, practically on the fly, to adjust for performance or economy. 240 for economy and all the way up to 330 for top end boost without effecting the low and mid range attributes.

I also have a VM36 and once I got it dialed in it has proven to be a great setup and pvisseriii speaks the truth.

boz · Oct 17, 2012

I have a single Mikuni on my 750. Worked great out of the box. Starts easy and idles smooth like a Jap bike. As for the throttle return spring take one of the springs out of your old Amals and put it in the Mikuni. It will fit in the center of the Mikuni spring like a double valve spring. With this setup take your hand off the throttle and she will snap shut right now.

mikegray660 · Oct 17, 2012

yes that works on the VM since its a large round slide (like i said the VM has better spring tension) , not the TM since its a slender flat slide

boz said:
As for the throttle return spring take one of the springs out of your old Amals and put it in the Mikuni. It will fit in the center of the Mikuni spring like a double valve spring. With this setup take your hand off the throttle and she will snap shut right now.

single carb conversion

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