Possible AVL Carb options.

[Coles89]

Hi all

   Has anyone on here had any experiance in using non standard carburetors on 350 avl engines. The standard CV carb on my bike is ok but it tops out at about 70mph. It would be nice if there was a set up out there that gave the motor a little more gusto at the top end.

Cheers

[dampking]

Hello Cole,

I think AVL 350s had a true speed of 115kph, going by that you are pretty close to it. However, we did get better results when we tried few VM carbs. We tried VM28,30, 32 and also Flat Slide 30's. They offer way more crispiness than the stock BS26 carb.

For now, I think you can play around with the existing carbs jetting. I also think that you can push the mainjet till 110 and pilot till 22.5 (not sure about the pilot). My friend has a similar setup but he's got free flow exhaust and airfilter, which is pretty compatible with bigger jets.

Oh !! and we also got rid of the PAV and catcon - that helped a bit.

-Sanket

[Coles89]

Thanks Sanket, will start looking into those alternative carbs. Ill make a start by removing that emissions rubish first though.

[Coles89]

On the subject of removing the emissions gear, what size bolt should i source to plug the gap left by the pav?

Cheers

Olly

[mattjohnson207]

Got mine from Hitchcocks

[dampking]

Sorry for the late reply Cole. My bike is at my friend's place, I will get the blanking nut specs once I go there. Will update ASAP.

[St1g9203]

I am wondering if i can a plug a BS29 or BS34 in it. they are available in india for around 50$ each. Genuine items, powering Bajaj Pulsar bikes.

[dampking]

Hello St1g9203,

The biggest CV carb that you can buy in Indian market will be BS33, used in Royal Enfield UCE500 (Carbed version) and the Pulsar 200NS by Bajaj. But if your bike's inlet port is around 28mm then why go for such big carb? It won't help anyways. I have seen 350s using 30mm flat slides, they work pretty well, the difference of 1mm or 2 is fine I feel but 6mm difference is just too much for the 350. I am pretty sure that the low end crisp will just die. If you want to experiment with carbs then the next best option for you will be a BS29 with ported throttle slides

-Sanket

[St1g9203]

Hello St1g9203,

The biggest CV carb that you can buy in Indian market will be BS33, used in Royal Enfield UCE500 (Carbed version) and the Pulsar 200NS by Bajaj. But if your bike's inlet port is around 28mm then why go for such big carb? It won't help anyways. I have seen 350s using 30mm flat slides, they work pretty well, the difference of 1mm or 2 is fine I feel but 6mm difference is just too much for the 350. I am pretty sure that the low end crisp will just die. If you want to experiment with carbs then the next best option for you will be a BS29 with ported throttle slides

-Sanket

Thanks for your quick input Sanket. I have zeroed in on the BS29 Carb.

Can some one put the jet sizes of BS29 used in RE (TBTS models)

[Adrian]

Just a thought, but didn't the early AVL 350s use 26mm Dell'Orto carbs? A slight hike up to a 28mm Dell'Orto ought to give you some tuning potential. Likewise. a properly jetted VM28 Mikarb off a 500 cast iron Bullet could be a budget tuning option. Also the stock AVL cams might be limiting your top-end performance, this is certainly the case on the 500 AVL models.

REgards,

A.

[dampking]

Thanks for your quick input Sanket. I have zeroed in on the BS29 Carb.

Can some one put the jet sizes of BS29 used in RE (TBTS models)

I think the BS29 carb has 12.5 pilot and 110 mainjet, either that or 15 pilot and 115 mainjet.

Just a thought, but didn't the early AVL 350s use 26mm Dell'Orto carbs? A slight hike up to a 28mm Dell'Orto ought to give you some tuning potential. Likewise. a properly jetted VM28 Mikarb off a 500 cast iron Bullet could be a budget tuning option. Also the stock AVL cams might be limiting your top-end performance, this is certainly the case on the 500 AVL models.

REgards,

A.

Only the first series of AVL 350 bikes came with Dellorto, PHBH 28 carb, later changed to 26mm one, after few months. That was the Machismo A350, later came Thunderbird and Machismo (Not the A350) which had UCAL Mikuni BS26, not that great as the Dellorto ones

[DanB]

I think the BS29 carb has 12.5pilot and 110 mainjet, either that or 15 pilot and 115 mainjet.

On the 500 AVLs its:

15 pilot
110 main
Needle on middle clip with spacer