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Elevated Engine Idle RPM

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Lawrence Ayotte
(@8244)
Posts: 49
Eminent Member
 

Sounds like sticky advance weights to me.

 
Posted : 08/23/2019 07:42
Bradley Barrus
(@895)
Posts: 34
Eminent Member
Topic starter
 

That''s my opinion as well. A Motorrad Elektrik Alpha electronic ignition system is on order to replace the bean can. I'd still love to open up the bean can to inspect the centrifugal advance to find sacked springs and hardened grease.

One of the front brake discs on the R65's dual-disc Brembo front brakes is warped (lateral run-out). When the front wheel is spinning on a NoMar tire balancing jig, we observe the disc moves in and out ever so slightly. We didn't have a magnetic base dial indicator to measure and quantify the run-out value and we're unable to find acceptance criteria for lateral run-out, therefore, a new disc was ordered from EME.

Wouldn't you know that EME shipped the wrong disc?

Sounds like sticky advance weights to me.

 
Posted : 08/23/2019 09:51
Lawrence Ayotte
(@8244)
Posts: 49
Eminent Member
 

Sticking weights caused that same condition (high idle) on my son’s 82 RS. That’s electronic isn’t it?

 
Posted : 08/23/2019 12:15
Bradley Barrus
(@895)
Posts: 34
Eminent Member
Topic starter
 

The 1982 R100RS and the 1982 R65 would have an electronically-triggered ignition system. The electronic trigger (Hall-Effect sensor) resides within the bean can. The ignition spark timing advance consists of centrifugal flyweights (mechanical) spinning inside the bean can. They're normally inaccessible for servicing (grease replacement and springs replacement).

How did your son resolve the high idle problem?

Sticking weights caused that same condition (high idle) on my son’s 82 RS. That’s electronic isn’t it?

 
Posted : 08/23/2019 12:24
Lawrence Ayotte
(@8244)
Posts: 49
Eminent Member
 

There is a little window in the side of the ‘bean can’ with a metal cover. Pry that cover off and you are looking right at the weights. Lubed with light oil and worked the weights back and forth gently. Been fine all summer.

 
Posted : 08/23/2019 15:10
Richard W
(@wobbly)
Posts: 2530
Member
 

I greatly prefer a really good roller chain lubricant, such as Motul or Bel-Ray. These go on light, soak in and then thicken to stay in place despite high temps, water, high speeds, etc. Your regular "thin oil" will be gone in 3-5 days.

Boyer makes a modern EI that fits in that space which does away with the AAU and holds the advance curve in software. Such a design is highly preferable since the advance curves have changed radically due to degradation of the fuel supply and octane levels.

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

 
Posted : 08/23/2019 16:06
Lawrence Ayotte
(@8244)
Posts: 49
Eminent Member
 

Well, when it acts up again, I will try one of those choices. More a matter of what I had on hand at the time than anything else. It’s been around 4K miles and still ok though.
Thanks

 
Posted : 08/23/2019 20:00
Bradley Barrus
(@895)
Posts: 34
Eminent Member
Topic starter
 

An Emerald Island Alpha ignition was installed and this corrected the engine idle RPM. We're now working on the engine vibration problem. At ~4200 RPM, the footpegs and handlebars start vibrating badly.

 
Posted : 09/03/2019 00:17
Lawrence Ayotte
(@8244)
Posts: 49
Eminent Member
 

If you can make that vibration go away on an R65, be sure to let us know how! Seems most of them have it.

 
Posted : 09/04/2019 06:52
Bradley Barrus
(@895)
Posts: 34
Eminent Member
Topic starter
 

The short-term fix is to install rubber bushings on the front motor mount. The rubber replaces the 5mm spacers located on either side of the engine block.
The tightening torque is lowered to 12 ft-lbs. The rubber bushing is sourced from motor mount off 57 Chevy. Alternately, use BMW /2 rubber motor mount bushings.

 
Posted : 09/04/2019 07:57
Bradley Barrus
(@895)
Posts: 34
Eminent Member
Topic starter
 

We completed a 2100-mile, 6-day trip from Cape Cod to West Virginia. The Maryland Airhead's Last Days of Summer rally is so good that we're willing to travel 550 miles (one way) to attend this event. The R65 and my R75/5 LWB performed very well except the R65 battery began to fail on the second day. My R75 battery is apparently weak also because the starter "cricket" noise was present during engine-cold-start when it was unusually cold that morning. We found a best-fit replacement battery for the R65 in Cumberland, Maryland. The R65 engine was still difficult to start in the morning. It would fire on one cylinder repeatedly when cranked by the electric starter.

My R75 starter "cricket" went away when the morning temperature was above ~55 degrees. I used a voltmeter on battery terminals with engine running.
The R75 electro-mechanical voltage regulator would cut off charging voltage increase at ~13.2 volts. I increased the voltage regulator's spring pre-load tension a bit such that charging voltage would rise to ~14.2 volts before voltage regulator cut-off occurred.

The R65 would fire on only one cylinder engine-cold-start. We tried cleaning out the starting jet in the bottom of the float bowls. The engine has resistor spark plugs installed which is wrong. I advised my riding buddy to get non-resistor spark plugs installed ASAP. I also think the spark plug lead's resistance should be verified correct 5000 ohms. He thinks the ignition timing is not set properly.

 
Posted : 10/11/2019 14:46
Richard W
(@wobbly)
Posts: 2530
Member
 

Replacing everything in the sparkplug circuit (wires, caps and plugs) will cost less than $20 per bike. It's the least expensive repair insurance you can buy for an Airhead. And all those parts, even the correct ones, eventually die from old age. So theories, conjecture, measurement and testing are really a complete waste of time, considering the low cost and ease of installation.

NGK 5K Ohm caps

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

 
Posted : 10/12/2019 22:51
Bradley Barrus
(@895)
Posts: 34
Eminent Member
Topic starter
 

Thanks. What do you use for replacement spark plug lead wire?

 
Posted : 10/13/2019 00:11
Richard W
(@wobbly)
Posts: 2530
Member
 

It's called your local auto parts store. You walk in and say to the guy, "I need metal core spark plug wire by the foot. And while you're back there could you bring out 2 NGK BP7ES spark plugs, too ?"

He'll say, "How many feet."

Then you say, "3 feet, please."

It's really that simple.

If you don't like leaving your chair, then you can get pre-made wire sets from Motorrad Elektrik.

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

 
Posted : 10/13/2019 08:33
Bradley Barrus
(@895)
Posts: 34
Eminent Member
Topic starter
 

After spending the weekend rebuilding the R65 carburetors (new O-rings, diaphragms), engine still exhibits poor cold-start capability. We've already tried cleaning out the starting jet in the bottom of the float bowls. Carbs are balanced at 5000 RPM and engine runs pretty smooth now.

 
Posted : 10/14/2019 13:04
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