Team-BHP - Enfield: Upgrade from BS26 to BS29 carburetor?

Quote:

Originally Posted by Sutripta (Post 3792518)

^^^
A) Would look at the float level.
But considering it is a homebrew, would look at two other things: Is the carb level? And in normal idling, is the butterfly position controlled by the idling screw, or by the throttle cable , which is shifting position when using the front brake lever.

Talking about the two things you have mentioned, can you please elaborate what "Is the carb level?" means? Couldn't figure it out exactly.
For the 2nd thing, the butterfly position is controlled by the idling screw and the throttle cable is entirely free and it is not shifting position rigidly while I use my front brake or even if I turn my handle bar left or right at extreme. However the problem which I am facing does not only happens when I pull the front brake and shake my bike but it also happens when I am just sitting and just bounce my self a bit while sitting, or say when I keep the rear wheel of the bike at a higher level on a step or something. Also, when I decelerate the bike just by using the rear brakes or both the brakes. In short it is happening when the front portion of the bike is leaned downwards.

Quote:

Originally Posted by pathik810 (Post 3810575)

Sutripta means that you need to check whether the carb is horizontal. If the carb is tilted, the jet may be only partially submerged in the float bowl. When the fuel sloshes around because of braking, tilting, acceleration, etc., the jet may no longer be submerged in fuel causing fuel starvation. Two things to do are to first ensure that the carb is mounted horizontally and then to check the float height.

Hello Everyone,

Kindly excuse since I have been away from this project. Basically I could not succeed in installing the BS33 carburettor because it proved to be over sized for my 350 CC AVL. Faced a lot of minor issues like uneven idle, jamming of un burnt fuel in the intake manifold, black smoke from exhaust and really low fuel efficiency, lower than I expected. I tried different combinations of the pilot and main jets as well but it did not work.

Finally I ended up fixing the BS 29 carburettor with stock jets. Dint had to change any thing after that. It is running perfectly till date with increased gear shifting range with low vibrations and increased acceleration. Also, it did not make any great impact on the milage as well.

And yes, with the increased shifting range, I have to take care for not revving it too high because as a side effect, oil seals start leaking.

Thank you!

Hi pathik810,
Thanks you for the info on carburettor.
I have an Machismo A350, which comes with an AVL engine. My carburettor stopped working and could not find an alternate. I did try MiKi carburettor, but ended up with incorrect fuel mixture.
Just to confirm, BS29 will be the only option? And is your engine similar to Machismo A350?
Venky

Hi GrayBerry,
You are most welcome. Sorry for being soo late to reply. Not been active over here since long.

Hope that your problem is solved by now. If not, following is some information for you!

The BS26 is basically the stock carburettor, if you want your bike to be stock then you can fetch the same from market. If you are unable to find it in the market, and also want to upgrade, then BS29 is the only option. It will work smooth on your AVL.

And yes, TB350 AVL and Machismo 350AVL both are same.

You could also try the VM28 (RD350) or one of it's licensed copy made by Mikarb in India.

The VM series of round-slide carburetors work well on a bullet and are slightly more responsive than the standard CV carburetor only issue being, you might have to re-jet it.

You can find bigger sized VM30s as well online. Also sudco.com makes some carburetors and jets. For jets, try http://www.jetsrus.com/

Most REs with carburetors came with very lean jets which made the engine run lean and hot. So you can start with up-jetting it till you find the sweet spot.

Pulsar carburetors will have to be re-jetted as well and might not work perfectly as a plug and play option.

Quote:

Originally Posted by Crankpin (Post 4541478)

You could also try the VM28 (RD350) or one of it's licensed copy made by Mikarb in India.

The CI 500 came with a VM28 optimized for 4 Strokes.

Cost me 1,350/-(Ex. Shipping) when bought from Delhi Motorcycles back in 2012.

Since an OEM spare they can be sourced from RE spares outlets provided they have it in stock.

Quote:

Pulsar carburetors will have to be re-jetted as well and might not work perfectly as a plug and play option.

Know a fellow enthusiast who rides a AVL 500 with a Pulsar 150 carburetor, leaves mud flying every time he starts rolling from a standstill.

He didn't have much info about the jetting though as it was done by his mechanic.

Quote:

Originally Posted by pathik810 (Post 4404228)

Finally I ended up fixing the BS 29 carburettor with stock jets. Dint had to change any thing after that. It is running perfectly till date with increased gear shifting range with low vibrations and increased acceleration. Also, it did not make any great impact on the milage as well.

Thank you!

You can get the vacuum port slightly enlarged for a more peppy mid-range. I had gotten such a slide from Chinmay Dangre, Pune. But this has to be precise and better not done by FNG folks!

Quote:

Originally Posted by katoom (Post 4541543)

You can get the vacuum port slightly enlarged for a more peppy mid-range. I had gotten such a slide from Chinmay Dangre, Pune. But this has to be precise and better not done by FNG folks!

Just to add, if increasing port diameter or drilling secondary hole, make sure to re-tune idle circuit as with a modified slide quick throttle actions tend to significantly lean out the fueling causing the motorcycle to bog down and die or knock under load.

Chinmay is a wonderful person to get in touch with, back in the day when aftermarket jets were hard to source, I'd get it from him, pricing was steep at 650/- per drilled jet IIRC, but nonetheless ensured the motorcycle ran well.

Once while transitioning to the VM's from the CV I was absolutely clueless on installing the carburetor end of the cable in the slide, Chinmay was kind enough to come on Skype and show me how it was done, and this in spite of me not having purchased any of the said parts from him.

One of the better folks in the business without a doubt. :)

Hi all. I have a classic 350. I want to increase the pick up. I am planning to replace the carburettor with the bs29 mikuni. I had some doubts.
Is it a direct fit ?
Which stock jet size come with the bs29? Any need to change the jets ?
What should be the air fuel mixture screw position for tuning ?
Will it cause any problems like sputtering , engine shutting off or misfiring etc ?
Do I have to change the stock air filter ?
Thanks

Quote:

Originally Posted by urban legend (Post 4880484)

A few days ago installed a BS29 from the Pulsar 180 in a Gen 1 Fazer/FZ16;

Enfield: Upgrade from BS26 to BS29 carburetor?-img20200903190038.jpg

It is cheaper as its a licensed copy from Mikuni manufactured by UCAL.

Enfield: Upgrade from BS26 to BS29 carburetor?-price.jpg

The carb comes with 17.5 Pilot and 112.5 Mains.

I'm wondering why you're contemplating changing the carb as the UCE350 comes with a BS29 from factory if I'm not wrong.

Cheers,
A.P.

Re-starting this discussion! I'm not a RE/ bullet guy but I've been asked to look after a Std 350 which has been neglected for a while. I got it serviced from RE in Chembur. Thing is, it has a big flat spot and tends to starve when throttled hard. It has a Ucal CV carburettor which could be choked or mal-functioning (vacuum circuit).
I would be interested in up-jetting it (slightly, perhaps one size up) and would like to know what are the stock Std.350 CV carburettor jet sizes. I'd also appreciate if anyone wants to sell me up-size jets!