Bike is a 1979 R100 RT which is a pre-EPA "Pulse Air System" model.
1979 was at the start of the EPA leaner burn requirements era. The Hanes manual states the carb needles were one notch leaner for the USA than the same bike in the UK. Are there other changes to the fixed jet sizes that are also recommended to get some color back on the plugs ?? I looked in the archives and didn't see anything.
Thanks.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
The Bing Agency catalog contains a table of carb jetting for not only USA but Euro models as well.
Scott -
Is the "catalog" you refer to the "Bing Manual" they sell for $11 on their web site ? That seems to be the only instructions or tables Bing has to offer on their entire web site.
Corn-fused in Cornelia
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Asked Bing CS about UK or German model BMW jetting for the RT. Got a message back today...
Hi,
I don’t have specific “European jetting”.Our Manual list jetting by carb numbers, yours is jetted a little leaner than the other 94/40 carbs. You have 2.64 needle jets the others are 2.66 or 2.68. The Main Jets have a range of 150 to 170.
The manual takes you through each circuit of the carburetor with trouble shooting, jetting tips, altitude compensation charts and more.
Best Regards,
Fay R. Laughridge, VP
This is all the "manual" they have now, but it doesn't sound like what you're describing. Any ideas ?
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
In the continuing saga....
A selection of larger jets will be here next week. Meanwhile I've replaced both original intake rubber hoses and replaced the air filter to make sure neither has an undue effect on the plug readings.
Replacing the air filter knocked the oil consumption down to zero. So good things are coming of this.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Scott -
Many thanks for your help. That's pretty much what I had arrived at myself by scanning the parts books online. Still a work in progress. Bike is running much better, and not nearly as hesitant below 3K.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
So here are my final settings in case anyone cares...
Neddle Jet was: 2.64 changed to: 2.68 (as per earlier models)
Main Jet was: 160 changed to: 165
Needle Position: Third notch (45.6mm exposed)
Float Level: Stock
On my carbs the needle settings cannot be set external to the slide, like on a Mic or Amal carb. The clip is made into the slide, and so measurements must be used to determine which notch the clip is sitting in. Each change in notch position changes the exposed length approx 1.5mm, which makes needle position the major adjustment. Therefore, changing needle jets is mandatory for the fine adjustment.
I'm using NGK BP7ES plugs and getting excellent readings and throttle response.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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