Airhead Bing tuning

[zekedog]

I live in Seattle and have spent way too much money on my Bings to have the bike still with poor mileage and constant backfire. R80st now R100st.
Looking for suggestions for a mechanic that's great with the old Airheads and will tune them appropriately. I am willing to travel a bit if needed.
Thanks
B

[SOLO LOBO]

Hi ZD,

Can you check and post the jet numbers. as well as the carb body numbers or as you over this engh you are done mucking about with your mixers?

I'm sure I could swing by the station sometime with my timing light and twinmax to do some initial checks.

Also, you do still have the Supertrapp on the bike? If so, I bet that is the source of some of the ill running.

[blaine.hale]

1. Airhead forum
2. Have you checked your ignition? Backfiring might be more a symptom of the ignition misfiring.

[Airhead Wrangler]

If you're up to 1000cc with the original final drive, you'll probably never achieve good gas mileage regardless of how well dialed in your carbs are. Just curious, what kind of mileage are you getting?

[caponerd]

Originally Posted by Airhead Wrangler

If you're up to 1000cc with the original final drive, you'll probably never achieve good gas mileage regardless of how well dialed in your carbs are. Just curious, what kind of mileage are you getting?

A lot of people report really unrealistic milage numbers for R100's. Mine has never gotten better than 40 mpg, no matter how I run it, and often a lot worse than that, a lot worse.
Plus with the ethanol contaminated fuel we're forced to use these days, fuel consumption has taken another hit.

Try this guy. Just South of Portland, but one of the best in the business, assuming you're willing to pay for quality work.

[supershaft]

Originally Posted by caponerd

a lot of people report really unrealistic milage numbers for r100's. Mine has never gotten better than 40 mpg, no matter how i run it, and often a lot worse than that, a lot worse.
Plus with the ethanol contaminated fuel we're forced to use these days, fuel consumption has taken another hit.

try this guy. just south of portland, but one of the best in the business, assuming you're willing to pay for quality work.

+1

[Mista Vern]

Seriously, it shouldn't be that difficult. First make sure everything else is spot on - valve lash, timing, no vacuum leaks at carbs, clean air filter, etc. then order the cheap tools and instructions for setting the carbs via shorting method from here: http://www.northwoodsairheads.com/

JT posts here often and is a good guy and his tools are superb. The instructions are very clearly written, and if after this you still have problems something more serious is going on.

To start with I think either your valves aren't adjusted properly, you have a bad plug wire/coil, or you have a vacuum leak if you have a backfiring issue. Wish I were closer to take a look at it and give you a hand.

[squish]

The ST had crappy MPG, I can only imagine that a R100ST would be worse.

And I also agree with what others have suggested.

Before you toss in the towel, make sure everything else is as good as it's going to get.

Also look for airleaks around the carbs. Make sure the boots and other intake bits are all sealing up how they should be

And don't overlook the ignition system, check your plugs, HT leads, coils, trigger (Bean can) and all the connections between them.

[zekedog]

Thanks all for responding so quickly. Very cool. To all realize please that I am no motorcycle mechanic.

Gage.....thanks brother, I may take you up on it and no, I replaced the Supertrapp with stock.

Airhead, howdy. Hope all is well south of the border. The bike actually does run pretty well but for the backfire with any throttle let-up. I do come off the bike smelling of exhaust though. Not as bad as with the Supercrapp. My mileage is around 30mpg. I don't have too unrealistic dreams but 35-40 seems realistic doesn't it?

Thanks Mista and Caponerd for the leads.

Cheers all
Brian

[Wirespokes]

Originally Posted by caponerd

Try this guy. Just South of Portland, but one of the best in the business, assuming you're willing to pay for quality work

True! and he aint cheap!

My R80G/S (now a liter) isn't that different from yours and it gets low to mid 40s. On the hwy I think it's about 46mpg.

[SOLO LOBO]

Originally Posted by Wirespokes

True! and he aint cheap!

My R80G/S (now a liter) isn't that different from yours and it gets low to mid 40s. On the hwy I think it's about 46mpg.

Terry,

What carbs and jet sizes are you running in your liter G/S?

[amschnellsten]

I fixed my Bing problems on my r100 with Mikunis.

[mykill]

Popping on decel is usually associated with a lean idle. Either too lean due to an air leak, leaner than stock idle jet or, most likely, too lean mixture setting.
If everything else is as it should be, then with the bike nice and warm, slowly turn the mixture screws in or out seeking the smoothest and fastest idle. Sometimes they do run best when they pop on decel. Too rich an idle mixture makes the transition muddy and flat, too lean can make it rough or notchy.

[supershaft]

What carbs and jet sizes? The real question is what speed? Mid 40's on the highway would have to be what I call damn slow and steady. My all time record with my R100 is 42mpg and I run 130 mains in my 38mm Dell's with no pumps. 42mpg is better than I ever got with Bings but I don't think I had ever ridden that slow before. I was riding almost the speed limit that day after getting two speeding tickets on one trip. I normally get mid thirties on road trips, upper twenties around home and lower twenties if I top off after a hard ride in the twisties. It all depends.

Bings are good carbs and very easy to tune. IMO they are way easier to tune than Mikuni's or Dellorto's mainly for fewer options. Mikuni flat slides? Most I have seen have independent floats and, just like Bing's "alcohol proof" independent floats, they are very problematic. I think anybody that fixed Bings by getting Mikuni's or Dell's were really fixing their own problems, not Bings. Bing's do not have inherent problems. Sure, Bings don't perform as well pretty much over the entire rev range or get quite as good mileage as well set up Mikuni's or Dellorto's but other than that they are great carbs.

[SOLO LOBO]

Originally Posted by mykill

Popping on decel is usually associated with a lean idle. Either too lean due to an air leak, leaner than stock idle jet or, most likely, too lean mixture setting.
If everything else is as it should be, then with the bike nice and warm, slowly turn the mixture screws in or out seeking the smoothest and fastest idle. Sometimes they do run best when they pop on decel. Too rich an idle mixture makes the transition muddy and flat, too lean can make it rough or notchy.

True, assuming the jets are the correct sizes... still need to verify that for this R80G/S within 100 slugs.... don't know about the carbs, heads and air filter yet...