R65 bing carburator standard idle jet

[Adamastor]

Hi there!

I am having some trouble with fouled plugs. I am currently cleaning my carbs once again and just figured out the idle jet is a 45. Isnt this supposed to be a 40?
This would explain my overly rich situation...

My carb is a 64/32/347...

Sergio

[Bob_Roller]

Here's what the 64-32-347/348 carbs had from the factory .

Main jet : 138, Needle jet : 2.64, Jet needle : 251, Atomizer : 591, Idle jet : 45 .

The needle clip position is 3, that's third from the top .

I would check the enrichening circuit of the carbs, that's part that has the other cable going to it .

There are four small diameter holes in the rotary disc, make sure they are open .

Also make sure the cables are correctly adjusted for the 'choke' or enrichment, and that the springs bring the arm up against the cast in stop of the cover plate .

[Lucky_Lou]

According to Real Oem its a 45 on my 1980 the 40 will be for the R45 presumably.
Lou

[Bob_Roller]

The carbs on my '81 R65 (64-32-325/326) have #40 idle jets .

I wonder why the different combinations of jets and needles, for the same engine .

[Adamastor]

Yes, everything is like it should with the "choke" component...

Before I changed my R65 cylinder the left side always had been fouling plugs, the right side is a bit on the rich side, but ok i guess.
I assumed this would happen because of the lower compression on that cylinder. Now that I have switched both cylinder and piston and have new rings I thought that this thing would end. Wrong, it didnt..

The mixture screw is all the way in, (higher revs there) and still it is overly rich at idle.. what else should I look for? A new carb? I cleaned this carb so many times you wouldn't believe.. I even bought a new mixture screw because I though the top could be too round because of too much use...

I can get the bike on a very healthy and steady idle and she drives really good (although it pops a bit on overrun (decelerating with throttle all backed up)).

I switched idle jet from one carb to the other, and the problem remained on the left side.

I used carb cleaner on all holes, but... at idle can anyone tell me what is going on? Where does the air come from? If I spray carb cleaner throught the idle jet hole I can see it appear on the center of the carb, but turning th idle mixture screw in or out doesn't seem to affect. Is it supposed to affect this? Or does the mixture screw command another way to let some more fuel go in? I am a bit lost... :|

Sergio

[Bengt_Phorqs]

Can you tell us the type of plug you are using?  Possibly you have a plug with a cooler heat range.  Also note that on the "chokes" the rotary discs are left and right handed.  Sounds like you are confident these didn't get mixed, but just a thought.

Also, can we assume the timing is spot on?

[Adamastor]

The carbs on my '81 R65 (64-32-325/326) have #40 idle jets .

I wonder why the different combinations of jets and needles, for the same engine .

So some of them use #40 jets? Can you tell me what do the numbers on the carb say? (64 - 32 - 325) I guess 32 is 32mm, but the others I have no clue...

[Adamastor]

Can you tell us the type of plug you are using?  Possibly you have a plug with a cooler heat range.  Also note that on the "chokes" the rotary discs are left and right handed.  Sounds like you are confident these didn't get mixed, but just a thought.

Also, can we assume the timing is spot on?

I should receive this week a strobe light to check out timing, so that is still an unknown subject, I used NGK BP7ES since I bought it, today I switched to BP6ES to see if it would behave better, but after only 35 km it is already getting dark... BP5ES might be asking for trouble?

I just rechecked the choke rotary disc, and on the off position the holes on one side don't align with the the holes on the other side, so it really is off, right?

Sergio

[Adamastor]

Some other details I remembered:

- rings are new, so maybe some more oil might be coming to the combustion chamber, right? This doesnt however justify that I have to put the mixture screw all the way in for higher revs at idle..

- I can start her at cold with no choke, just a bit of throttle (like we all do with a hot engine)

- Floats are ok, and float needles too and they shut/open when floats are parallel to the carb side

[Bengt_Phorqs]

Sergio, let's ask the Illuminati if someone has a photo of the rotary disc in situ as they should be installed.  That could be a contributing factor.  I'd stay away from the B5ES plug.  And really you need to confirm the timing is correct before making wholesale carb adjustments.  Not to say adjustments aren't needed, but it all begins with the correct timing.

[Adamastor]

the correct timing.

Yep, that's correct, but assuming the right side is more or less ok and that the mixture screw is where it should be, even without checking timing I would guess there's some other problem.. :|

A bad choke disc position would be really good (easy to fix). But if choke was off would the engine still run well (of idle)?

[Barry]

According to Real Oem its a 45 on my 1980 the 40 will be for the R45 presumably.
Lou

Suprisingly the R45 uses a a 45 pilot also although the pilot mixture screw maybe is turned further in than on an R65.

Sergio

The fact that you can turn the idle mixture screw all the way in would suggest there is a leak somewhere as this would normally stall the engine.  Are the O rings on the idle jet and idle mixture screw sealing properly.

The dot on the enricher shaft should point towards the operating arm and there is an L for left carb or an R for right carb stamped on the inside of the shaft.

[Lucky_Lou]

Some good images here
http://www.gunsmoke.com/motorcycling/r100gs/carb_rebuild/index.html
Lou

[Barry]

I used carb cleaner on all holes, but... at idle can anyone tell me what is going on? Where does the air come from? If I spray carb cleaner throught the idle jet hole I can see it appear on the center of the carb, but turning th idle mixture screw in or out doesn't seem to affect. Is it supposed to affect this? Or does the mixture screw command another way to let some more fuel go in?  

You should expect this even with the idle mixture screw all the way in because there is a another transfer port not controlled by the idle mixture screw. The idle port and transfer port  are tiny holes almost directly under the butterfly.  Is it possible they have been enlarged.

[Adamastor]

According to Real Oem its a 45 on my 1980 the 40 will be for the R45 presumably.
Lou

The fact that you can turn the idle mixture screw all the way in would suggest there is a leak somewhere as this would normally stall the engine.  Are the O rings on the idle jet and idle mixture screw sealing properly.

The O-rings are new and were bought from motobins, they do seem to fit a bit loose, but they are the same on both sides. Should i try to put grease in there to see if anything changes?

Sergio