Author Topic: Carb questions (Read 825 times)

LarsBloodbeard · « **on:** October 19, 2012, 02:34:34 PM »

Does anyone have any experience with jetting/tuning the BS29? Could you possibly point me in the direction of some good reference material?

I regularly fluctuate my altitude from 0k to 10k, so I'm thinking this carb might be good for me. Or perhaps someone could suggest an even better option. I have a 2002 500 Bullet, which I've upgraded to 535 & free-flowing exhaust. I understand the BS29 is standard on the Electra, and it is a CV carb, unlike my Mikcarb vm28.

dampking · « **Reply #1 on:** October 20, 2012, 08:46:02 AM »

For higher altitude my friends used smaller mains and needle on the first notch. They did push their 500s till 18000 feet with that set up. For city rides in India we use 125 to 130 mainjet and stock pilot and needle on the 3rd notch. I think the stock mainjet should be good for 10,000 ft alt.

LarsBloodbeard · « **Reply #2 on:** October 20, 2012, 12:27:15 PM »

So you stop on the side of the road and change jets?

dampking · « **Reply #3 on:** October 21, 2012, 12:30:44 PM »

Usually when we do such big rides we take breaks. So yea jet change takes 5 to 10mins at maxx, that's something which gets included in our first smoke break (if we are going for such high altitudes). Otherwise.. most of our touring is done with bigger jets. But I think you should try out all possible options, atleast when it comes to jetting. Because I had a very hard time getting the jetting right in my BS29 and also the VM34.

-Sanket

LarsBloodbeard · « **Reply #4 on:** October 22, 2012, 12:18:22 AM »

You guys are hardcore. I like it. I know I'd be tempted to bring a second carb rather than change jets out on a mountain somewhere.

dampking · « **Reply #5 on:** October 22, 2012, 12:58:18 AM »

The parts are dam cheap out here. So we take a lot of risk at times

LarsBloodbeard · « **Reply #6 on:** October 22, 2012, 10:35:08 AM »

Quote from: dampking on October 22, 2012, 12:58:18 AM

The parts are dam cheap out here. So we take a lot of risk at times

Yeah, labor too. I remember reading on an Indian forum about engine rebuilds. I was in shock after converting rupees to USD.

AgentX · « **Reply #7 on:** October 22, 2012, 12:20:55 PM »

Alas, you generally get what you pay for.

dampking · « **Reply #8 on:** October 22, 2012, 12:42:09 PM »

Quote from: LarsBloodbeard on October 22, 2012, 10:35:08 AM

Yeah, labor too. I remember reading on an Indian forum about engine rebuilds. I was in shock after converting rupees to USD.

Yep! And that is applicable on every mech and tuner. I know a friend who got his AVL head tuned by the RnD head of Royal Enfield. He's a racer too and the job was done @ a very cheap price. That AVL 350 now eats AVL 500s for lunch and dinner.. no way mine can even go against that bike in a quarter mile drag. The "Value for money" is the thing here

-Sanket

Ice · « **Reply #9 on:** October 22, 2012, 09:52:02 PM »

I'll just leave this here.

http://www.indiancarsbikes.in/automotive-technology/crisp-punch-ported-throttle-slide-cv-carb-9399/

LarsBloodbeard · « **Reply #10 on:** October 22, 2012, 10:29:44 PM »

Quote from: Ice on October 22, 2012, 09:52:02 PM

I'll just leave this here.

http://www.indiancarsbikes.in/automotive-technology/crisp-punch-ported-throttle-slide-cv-carb-9399/

VERY interesting. Thank you.

Ice · « **Reply #11 on:** October 27, 2012, 01:02:15 AM »

I like the CV Carbs. The continuously variable venturi provides good inlet velocity and cylinder fill at all throttle openings and very good fuel atomization.

They are much less affected by changes of season or changes in altitude tha regular fixed jet/ fixed venturi carbs.

DanB · « **Reply #12 on:** October 27, 2012, 10:25:36 AM »

Interesting article on porting the slide. Has anyone tried drilling themselves or ordering a slide already done? What was the resulting performance like?

Think I'll try it but need an extra slide before doing so..

GreenMachine · « **Reply #13 on:** October 27, 2012, 10:36:20 AM »

Ice: Sometimes its nice to just jump on the bike and ride vs having to adjust the carb settings..Seems like every spring and late Fall its time to play with mine..Wife's GV-250 has a CV carb and it works great....I pretty much stay at the same elevation but see the advantage of the CV carb...Funny how just atmospherics affect the standard carb..It does make each ride a bit different and you do get days when it seems to perform perfect...I would think the CV gives more of those than the latter..GM

dampking · « **Reply #14 on:** October 27, 2012, 11:31:43 AM »

Quote from: DanB on October 27, 2012, 10:25:36 AM

Interesting article on porting the slide. Has anyone tried drilling themselves or ordering a slide already done? What was the resulting performance like?

Think I'll try it but need an extra slide before doing so..

Yep, I did it on BS29 and BS32 but again.. as mentioned by Anant in that article. Anything more than 1/8th of an inch will cause issues. It's a very good mod and adds a lot of crispy response to the bike.

AgentX · « **Reply #15 on:** October 27, 2012, 02:14:51 PM »

Quote from: Ice on October 22, 2012, 09:52:02 PM

I'll just leave this here.

http://www.indiancarsbikes.in/automotive-technology/crisp-punch-ported-throttle-slide-cv-carb-9399/

I gotta say I'm skeptical. Why wouldn't the factory have spec'd this magic bullet answer to CV carb performance?? You gotta give something to get something in most things in life and mechanics...what is the porting changing besides creating at least a perception of better throttle response at average Indian road speeds?

Ice · « **Reply #16 on:** October 27, 2012, 03:19:07 PM »

The ports are sized for maintaining the highest practical manifold vacume and therefore the best fuel atomization, economy and combustion efficiency.

In the early to mid 90's this same mod was popular with Harley EVO motors. Over use of the right wrist to make use of the mod had more of an effect on fuel consumption.

AgentX · « **Reply #17 on:** October 27, 2012, 08:15:06 PM »

Quote from: Ice on October 27, 2012, 03:19:07 PM

The ports are sized for maintaining the highest practical manifold vacume and therefore the best fuel atomization, economy and combustion efficiency.

In the early to mid 90's this same mod was popular with Harley EVO motors. Over use of the right wrist to make use of the mod had more of an effect on fuel consumption.

Then color me shocked...the first question any Indian asks about any vehicle is "what's the mileage?!"

There was a commercial here featuring a rich guy shopping for Bond-villain class mega-yachts, who after much wordless scrutiny asks, "What kind of miles does it get?"

DanB · « **Reply #18 on:** October 28, 2012, 10:28:37 AM »

@Dampking. A BS 32? On a RE by chance?

Does anyone know of a supplier for throttle slides for the BS29? I don't trust my 'steady hand'.

dampking · « **Reply #19 on:** October 28, 2012, 11:58:51 AM »

Yea. Most of our 500s here run on BS32 with 25, 27.5 pilot and 150~175 mainjet (depending on the altitude). The throttle slides for BS29 is priced at 600 rupees INR. These CV carbs are dirt cheap here so we can experiment a lot with them.

dampking · « **Reply #20 on:** October 29, 2012, 03:15:59 PM »

By the way a new Jap bike just came out in Indian Market and that bike is using a CV carb named UCD33, going to try that out and will post results soon! Can be very good for 500cc enfields! Also heard that the needle has 5 notches unlike the BS32 which comes with 1 notch

DanB · « **Reply #21 on:** March 23, 2013, 07:15:23 PM »

Im bumping this as I got out today and tested my ported BS29 carb slide.

Basically, purchased a new throttle slide / piston valve for the CV carb from India and then increased the 2 vacuum ports from 1/16 to 1/8 inch. The Electra is very punchy and responsive! Im liking it. I could only go through the first 3 gears (riding in 38 degrees), and so far I like. I just followed the instructions on the web site and i contacted the author for the slide. Cost about 11 US dollars + shipping.

Should also say, im using a K&N + free flow exhaust system, w/ 17.5 pilot and 115 main. Needle in the middle clip with 1 shim. May change the needle once it gets warmer.

dampking · « **Reply #22 on:** March 24, 2013, 02:53:37 AM »

Thats great! Who got it done for you? The guy who posted that on that site?

-Sanket

DanB · « **Reply #23 on:** March 24, 2013, 10:19:00 AM »

Got it from:
Chinmay Dangre <macasp@gmail.com>. I just followed the link in the article.

Very friendly guy and very helpful! I caught him in the middle of his Goa ride. One of the things I need to add to my 'punch list', ride to Goa.

dampking · « **Reply #24 on:** March 24, 2013, 02:47:48 PM »

Chinmay is awesome! One of the best Bullet Doctors in India!

I heard that he makes jets of all kinds for RE Specific bikes. Also, a friend tried his custom made exhausts, they were pretty good!

-Sanket

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Author Topic: Carb questions (Read 825 times)