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1984 R65 jetting

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Lawrence Ayotte
(@8244)
Posts: 49
Eminent Member
Topic starter
 

Has anyone done a really deep dive into jetting an R65 to run properly on today’s fuels? I find that they run too lean stock and I want to cure that. After a complete rebuild with stock setup it was obviously running very lean, so I took a shot by raising the needle a notch. That made the first 3/4 of throttle run perfectly, but above that it flattens out dramatically. I installed mains two sizes bigger and that didn’t help much. I’ll get there eventually, but if someone has it figured out I’m all ears!

 
Posted : 08/23/2019 08:36
Richard W
(@wobbly)
Posts: 2530
Member
 

Hi and welcome.

Common question. Let me reply by copying another response....

• Adjustment of the carbs is unlike other aspects of tuning in that there are VERY FEW static settings you can check with a gauge. Most important adjustments are made dynamically, and these settings are a direct result of subtle changes in spark, compression, timing, and 100 other aspects of tuning. Thus all carb adjustments must be made when ALL other aspects of tuning are perfect. So the questions need to be asked... Is the compression good? Is the compression matched on both cylinders ? Are the sparkplugs new ? Are the spark plugs correct ? Are the plug wires new ? Are the plug caps new ? Is the fuel high octane and less than 4 weeks old ? Are the valve adjustments correct ? Has the ignition timing been set with a strobe at Full Advance ? Have both intake hoses been replaced ? Are the blocking screws for the carb balancing holes in place ? Is the air filter new ?

So while I agree with your question, I'm afraid to give you the answer until you tell me all the background steps you've made to tune the bike in preparation for said carb adjustments.

2. Then replace the float, float needle, carb needle, needle jet, intake manifold hose, and check your diaphragms on both sides.

3. Lastly, I'd like to see you run though a bottle of Star-Tron carb cleaning solution, just to make sure everything is as clean as it's supposed to be.

Then we can start.

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 08/23/2019 16:20
Lawrence Ayotte
(@8244)
Posts: 49
Eminent Member
Topic starter
 

I know where you are coming from. The rest of the bike is spot on. I rebuilt the bike from the frame up for my personal ride. I’m going to replace the needle, needle jet and main jet, but I’m not convinced that I should go by the book.

 
Posted : 08/23/2019 19:50
Richard W
(@wobbly)
Posts: 2530
Member
 

Building a bike from the "ground up" doesn't mean replacing every part. So while it sounds great, you haven't really told us very much. You're in a hurry to build the building. I want to check the foundation first.

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 08/24/2019 11:18
Lawrence Ayotte
(@8244)
Posts: 49
Eminent Member
Topic starter
 

Ok, now I know what the problem is and I learned that I should have listened to Snowbum’s recommendations about getting parts from Bing! Both 1 year old diaphragms from Bing have split! Lesson learned!!!!

 
Posted : 08/24/2019 15:39
Robert Whigham
(@1872)
Posts: 126
Estimable Member
 

I bought "O" rings from Bing and broke three while trying to install. Ordered from Bob's and the rings went on without problem. I have installed O rings before.

Bob

 
Posted : 08/26/2019 11:11

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