She puzzles me !

[georgesgiralt]

Hello !
The context :
'82 R65 highly overhauled last spring. (new piston rings, valves checked, carbs completely rebuild, new sparks wires with NGK 5k Ohm caps, ignition checked, new coil....etc  etc etc...)
In France, 95 "plain" gasoline is phased out in favour of SP95-E10 which is "the same" but with 10 % ethanol in it.
So I decide to tune my carbs to get a decent riding with such mixture.
I began by using the settings for after 1983 bikes and try to get something from here. Nothing works well. She is complaining either for too rich a mixture or to lean, lacks power, a total mess.
A I use the bike to go to work, I decide to put back the standard settings and all seems fine. (she barely heat up during the commuting and there is a lot of traffic jam so speed is at best 90 km/h for a very short period.)
Last Sunday, I decide to go for a ride and she refuses to run well. Same as it was when I had my modified carb settings. I can't go above, either 4000 RPM or 100 km/h. Se seems to run fine if the engine is at low rpm but lack power.
Back at home I check the ignition and I discover that I've a bad cable. I put an old cable I keep for this and everything is fine. She runs perfect at idle and the carbs are perfectly synced. The settings into the carbs are correct (145 main jet, 2.64 needle jet, needle position 4 and diaphragms fine, so as it should be for 64/32/307~308 carbs)
This morning, I've to use the bike longer, take the motorway, and use her for far more that the 5~8 km a day...
What a mess ! She can't get above 90 km/h, refuses to go above 3500 RPM and if I can go above 500 she runs badly. Like she was deprived of fuel. I check the bowls but the level is fine and no water/debris of any sort.
What's wrong ? What should I check ?
Helps PLEASE ! I'm desperate ....  

[Bob_Roller]

Just a wild guess here, but like you said, it seems to be a lack of fuel issue .

If I remember correctly, you have an '81 model year bike .

Do you have a Germa fuel tap ?

It has the fuel outlet at the 6 o'clock position .

If you do, remove the nut from the bottom of the fuel tap and check the small mesh screen that's in there,for clogging .

Only other thing I can think of, is a possible kink in one of the fuel lines restricting fuel flow .

If you have a Karcoma fuel tap, the fuel line comes out at the 3 o'clock position, it doesn't have the small screen in the fuel tap, but it does have a fine mesh screen over both intake tubes inside the fuel tank .

Another remote possibility, is the fuel cap not venting properly, try loosening the fuel cap and see if it makes any difference or not .

[georgesgiralt]

Funny enough when you typed this, I was looking at the tap filter...
It is quite clean. there was a little paint particle just bigger than a needle top. So I've to exclude this lead. The fuel lines are new, cloth covered and changed last September.
Tomorrow, I'll try to run her with the fuel cap partially open.
I'll check the fuel filter often as I fear the alcohol in the fuel may rip the tank liner off...  So far, so good.... (as I was told that there is around 5 to 7% alcohol in "normal" fuel.... I check the inside of the tank often...)

[georgesgiralt]

Hello !
So this morning I had to buy gas.
I feed her with expensive 98/88 gasoline.
Yesterday, I had put a new NGK cap to replace the bad one I had, the filter is clean and the fuel lines are not worn out/damaged/kinked.
The bike does run a little bit smoother but it is not that significant.
If I'm at 80~90 km/H and I open the throttle in full she won't accelerate, looks like she is starved of fuel and refuse to increase RPM. If I do the same, but open the throttle lightly, she accept to accelerate... and I'm able to go above the speed limit...
Arriving at work, I took a look at the main jets and they are correct and not clogged.
Any clues ?

[MR.E]

Sounds like you might need to look at the breather on the tank.
there is a point the bike will get to where it 'bogs down' feeling like it is running out of fuel, making you feel the need to shut off the throttle.

one of my tanks has a breather on the underside (i think on the right in the recess), it may be worth cleaning it out to make sure its working as normal.

Hope it helps

[Bob_Roller]

I know you have rebuilt and gone through the carbs, but the condition you describe is about the same as a  carb diaphragm problem, cracked/torn, etc. .

By chance is one or both of the metal plugs at the top of the upper part of the carb, loose

There is a port in the slide that allows manifold pressure to the top chamber on top of the diaphragm, are both of them clear ??

Again, just thinking out loud !!!!

I've owned my '81 R65, since January, 1981, resided in the Chicago metro area until June, 1993, 5% ethanol was in the fuel supply in Chicago, since the mid '70's, 10% ethanol has been in the fuel supply here in the Phoenix area since '02 and I have not seen any deterioration of the OEM liner in the fuel tank .

I just see an occasional chip of red liner at the bottom of the fuel tap, when I drain the fuel tank and let it dry out in the summer sun, to get any residual water that may have accumulated in the tank .

That's probably from the fuel nozzle contacting the tank while refueling .

[montmil]

<snip> one of my tanks has a breather on the underside (i think on the right in the recess), it may be worth cleaning it out to make sure its working as normal.

That sounds like the fuel drain for the recessed area under the fuel cap. When I first purchased my R65, I thought it was a breather but when I ran a long pipe cleaner thru it, it popped up in the fuel filler ring.

Point in fact, there should be a small hose attached to that stub and run to exit below and aft of the engine. It prevents fuel overflowing onto a hot engine and igniting. I have a distant memory of a member hereabouts that experienced such a fire.

R65ers... Check for that fuel drain hose. They often go missing via different POs.  It is rather important

[montmil]

... By chance is one or both of the metal plugs at the top of the upper part of the carb, loose?

Another job for JB Weld.

My '81 R65 had loosey-goosey metal caps on the Bing domes. Saw one Airhead that had silver Mercury Dimes epoxied in place. Clever monkey.

[georgesgiralt]

One of the cap is new because that ring came loose (and was lost).
The other one is supposed to be OK. I'll check when going back home.
I wonder if I've not torn one of the diaphragms during one of the dismantling to change the needle position...
I've one new  diaphragm as a spare at home... So ....

[MR.E]

<snip> one of my tanks has a breather on the underside (i think on the right in the recess), it may be worth cleaning it out to make sure its working as normal.

That sounds like the fuel drain for the recessed area under the fuel cap. When I first purchased my R65, I thought it was a breather but when I ran a long pipe cleaner thru it, it popped up in the fuel filler ring.

Point in fact, there should be a small hose attached to that stub and run to exit below and aft of the engine. It prevents fuel overflowing onto a hot engine and igniting. I have a distant memory of a member hereabouts that experienced such a fire.

R65ers... Check for that fuel drain hose. They often go missing via different POs.  It is rather important

Cheers for the info, i assumed it was a breather!
It got chopped out a while back, and i assumed it was why the bike bogged the other day whilst speed testing it . . . . . i think i got it to 105/7mph on full throttle when it started, i thought i was out of fuel!!

All the best

[georgesgiralt]

Hello !
So the two "dime" are in place and sound.
Today, I had a meeting outside the office and it took less time than we sought. So I was out early.... I decided to go for a ride. It took me more than 60 km to get home  
When hot, she runs fine up to the red line in low gears (still that bad spot when opening full around 3500 RPM but nothing new here).
In fifth it's a different story .... She refuses to go above 4000 RPM so can't go above 110 km/h.
So when in the garage, as the engine was hot, I decided to measure the compression. The spark plugs are fine, with a nice colour.
The test proved not as good as I thought.
Right cylinder is at 10.5 bars (155 psi) and left is at 10.0 bar (145 psi)... So in the low figures. I checked my notes and the values are lower than they where before the new rings where fitted... I doubt that the Sikes-Pickavant tester is the culprit as it served before the ring job...
I'm a bit worried...  :-?

[Bob_Roller]

Have you checked the valve clearances on the low pressure cylinder ?

Do a retorque on the cylinder/cylinder head retaining nuts, check/adjust valve clearance and then do a compression test .

[georgesgiralt]

No I did not check the valve clearance nor did I squirt a little oil in the cylinder to find what part is wrong...
The ring job was done about 2500 ~ 3000 km ago. And the head were torqued at 1000 km after the valve job. As the valves are noisy, I think the clearance are set properly. But, you're right a check is in order...
By the way do you know a Christian name of a famous German female dancer ? Because it could serve to baptise the bike...
My wife tells me that it's my dancer... when she saw the time and the money I put on it..... There is always something...  

[Bob_Roller]

I don't know how many kilometers you have on your bike, at 78,000 miles (126,000 km), my '81 R65 went through a major maintenance period and I think I put more money into the bike than it is worth !!!!!

[georgesgiralt]

She is going to pass around 178 000 km soon.
I do not know exactly because the previous odometer broke at 78 000 and I did not have the money, then, to buy a new one. So I used the bike for some time with the broken one. The new one has seen 96 400 k...
But as I used them for day to day use, the maintenance has been constant. Valves at 120 000 and springs piston rings, main rod bearings, gearbox bearings.... Last spring she was reviewed from front to rear... using my wife's patience and all my energy.