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Old 04-03-2013, 08:55 AM   #1
band-aid OP
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1974 R60/6 fouling plugs-not running well

Hi all,

This time I'm inquiring about a friend's bike that I am helping to work on. He recently acquired another 1974 R60/6 (just like mine) but with about 35,000 miles on it.

When he got it it needed an electrical overhaul at the clutch perch and in the front headlight bucket for a number of shorted out wires including the light switches, horn etc. We sorted that out fairly easily and have since had the bike running.

In the few hundred miles that have been ridden it has been revealed to us that the bike is fouling plugs at an astounding rate.

After opening up the airbox we found an air filter that was soaked in oil. We replaced a reusable K&N filter with the Mahle filter. We also inspected the breather valve for damage but found none and reassembled the unit after cleaning it. As a sidenote, we weren't sure exactly what to look for in terms of damage on this part but basically the fiber disc was in good condition and seemed to seal snugly over the vent and the spring and post were fine and operated without binding.

So, with the new air filter and a new set of sparks, my buddy rode maybe 20 miles and found the plugs completely black and soaked in oil around the threads of the plugs.


We just ordered a complete carb kit from Bing and intend to rebuild those next but what else are we looking at?

Incidentally the bike has been adjusted at the carbs to allow for as much airflow as possible which I reduced after changing the air filter with the hope that the bike had been choking for air based on the clogged filter.

So, does it sound like we just need a top end overhaul? Piston rings? Valves?

No leakdown test but compression was fairly high at the heads- 150+ but I can reconfirm that number easily because it was last year when I checked and haven't looked since.

I hadn't initially suspected top end work (at least when comparing it with my r60) because it doesn't seem to burn much oil- at least the level has been stable over the few hundred miles ridden and there's no visible smoke when riding behind it except maybe at startup.

Thanks in advance for all your advice.

Also, I'm still soliciting advice for NorthEast US convenient shops to do head work as Randy Long has not returned my calls regarding other heads.

Thanks!
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Old 04-03-2013, 09:13 AM   #2
Plaka
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Quote:
Originally Posted by band-aid View Post
Hi all,

This time I'm inquiring about a friend's bike that I am helping to work on. He recently acquired another 1974 R60/6 (just like mine) but with about 35,000 miles on it.

When he got it it needed an electrical overhaul at the clutch perch and in the front headlight bucket for a number of shorted out wires including the light switches, horn etc. We sorted that out fairly easily and have since had the bike running.

In the few hundred miles that have been ridden it has been revealed to us that the bike is fouling plugs at an astounding rate.

After opening up the airbox we found an air filter that was soaked in oil. We replaced a reusable K&N filter with the Mahle filter. We also inspected the breather valve for damage but found none and reassembled the unit after cleaning it. As a sidenote, we weren't sure exactly what to look for in terms of damage on this part but basically the fiber disc was in good condition and seemed to seal snugly over the vent and the spring and post were fine and operated without binding.

So, with the new air filter and a new set of sparks, my buddy rode maybe 20 miles and found the plugs completely black and soaked in oil around the threads of the plugs.


We just ordered a complete carb kit from Bing and intend to rebuild those next but what else are we looking at?

Incidentally the bike has been adjusted at the carbs to allow for as much airflow as possible which I reduced after changing the air filter with the hope that the bike had been choking for air based on the clogged filter.

So, does it sound like we just need a top end overhaul? Piston rings? Valves?

No leakdown test but compression was fairly high at the heads- 150+ but I can reconfirm that number easily because it was last year when I checked and haven't looked since.

I hadn't initially suspected top end work (at least when comparing it with my r60) because it doesn't seem to burn much oil- at least the level has been stable over the few hundred miles ridden and there's no visible smoke when riding behind it except maybe at startup.

Thanks in advance for all your advice.

Also, I'm still soliciting advice for NorthEast US convenient shops to do head work as Randy Long has not returned my calls regarding other heads.

Thanks!
Redo the compression check, wet and dry, check the amount of carbon on the piston crown and valve lips, check the plug heat range, check the amount of brown discoloration inside the rocker cover on the exhaust side.

At 35K it isn't broken in. But that K&N, and mis-oiled to boot, does not speak of a savvy owner. if it was used in dusty conditions there could be more engine wear than the mileage would indicate.

The leak down will tell you something about what's sealing, but not so much about what's leaking. The simple visual on the valves will tell you much. Look through the sparkplug hole with a Streamlight Reach or similar.
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Old 04-28-2013, 05:07 PM   #3
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Throttle lag and stalling

Hi all,

So my friend and I got around to rebuilding the carbs and found a couple of odd things. I noticed that the idle jet was screwed out about 2 1/2 turns on both carbs. I also found the needle set at the wrong clip setting for an R60. We changed both of these conditions. We then had the carbs synced professionally (I just never feel that competent at it) and our work was checked over and ok'ed. Now the bike is set to idle fairly low- About 700rpm when warm but we are having other trouble.

The bike takes 20-25 minutes to truly warm up without stuttering. There is an intermittent blip in the throttle from about 1000-1500 rpm and worst of all it has stalled downshifting at low speed from 2 to neutral or from neutral to 1 even when it seems warmed up. It seems to have a gap in throttle response with a bogging condition when taking off.

I haven't checked the timing/points yet but does that seems like a possible culprit? Any thoughts? I will report back after checking on these things but I want to see if I'm barking up the right tree or not. I think the carbs are good at this point (they've been gone over by three sets of eyes) but please tell me if you suspect we missed something there.

Logic leads me to suspect the carbs because that's the only area that's recently been worked on besides a new air filter but I think perhaps because they were so out of whack and the idle was set so high it might have been masking a different (timing) problem all along.


Thanks as always.
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Old 04-28-2013, 05:26 PM   #4
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Turn up the idle to ~1000K .. At 700 you're not getting enough oil pressure.

If your timing was off, or intermittent, you'd get some preignition (stuttering) or backfiring. Of course a set of points are cheap, and I've seen very weird engine behavior on worn points. So that is a possibility.
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Old 04-28-2013, 05:35 PM   #5
Plaka
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Quote:
Originally Posted by band-aid View Post
Hi all,

So my friend and I got around to rebuilding the carbs and found a couple of odd things. I noticed that the idle jet was screwed out about 2 1/2 turns on both carbs. I also found the needle set at the wrong clip setting for an R60. We changed both of these conditions. We then had the carbs synced professionally (I just never feel that competent at it) and our work was checked over and ok'ed. Now the bike is set to idle fairly low- About 700rpm when warm but we are having other trouble.

The bike takes 20-25 minutes to truly warm up without stuttering. There is an intermittent blip in the throttle from about 1000-1500 rpm and worst of all it has stalled downshifting at low speed from 2 to neutral or from neutral to 1 even when it seems warmed up. It seems to have a gap in throttle response with a bogging condition when taking off.

I haven't checked the timing/points yet but does that seems like a possible culprit? Any thoughts? I will report back after checking on these things but I want to see if I'm barking up the right tree or not. I think the carbs are good at this point (they've been gone over by three sets of eyes) but please tell me if you suspect we missed something there.

Logic leads me to suspect the carbs because that's the only area that's recently been worked on besides a new air filter but I think perhaps because they were so out of whack and the idle was set so high it might have been masking a different (timing) problem all along.


Thanks as always.
Methinks the "profeswional" that set up the carbs wasn't very good at it either.

It's a pretty simple procedure. if you don't want to learn it then perhaps airheads are not for you. Get a thumper or something fuel injected. Not a put down, just realistic. If you don't wanna mess with t, really don't mess with it. Having to trot of to some so-called pro and throw money at them for routine tuneups are not what airheads are about. You can get more performance and comfort out of just about anything else (newer), but you can't get something easier to work on.
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Old 04-28-2013, 08:35 PM   #6
band-aid OP
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Quote:
Originally Posted by Plaka View Post
Methinks the "profeswional" that set up the carbs wasn't very good at it either.

It's a pretty simple procedure. if you don't want to learn it then perhaps airheads are not for you. Get a thumper or something fuel injected. Not a put down, just realistic. If you don't wanna mess with t, really don't mess with it. Having to trot of to some so-called pro and throw money at them for routine tuneups are not what airheads are about. You can get more performance and comfort out of just about anything else (newer), but you can't get something easier to work on.

Plaka, while I have appreciated your advice in the past on other issues I think your comment is unproductive and rude.

I have in the past year alone (successfully) replaced my clutch, torn down my friend's 84' R80RT and replaced all engine and transmission seals, replaced a timing chain, replaced an alternator and a significant chunk of other electricals, rebuilt two sets of carbs, wired up an acewell speedo to my R60 and done all routine maintenance myself on my bike as well as two other airheads. I have tools, I'm not a dummy and I do nearly everything myself. I also am not too proud to admit that despite my competence I feel that there are others with more experience who can be valuable to consult in a troubleshooting scenario. That's why I post on this site. Carb syncing in particular is a bit of an art and I don't think I am beyond improvement in the area when gauges are not an option as with the slide carbs on an R60.

While I realize now that mentioning the carbs being synced "professionally" was low hanging fruit for those inclined to make a snarky comment, I brought it up only to underscore that I no longer suspect the carbs as culprit. I DID sync them myself at first but experienced the same issues that I am now asking for advice on. The bike was then taken to get it's mandatory annual safety inspection done at my local mechanic who has specialized in airheads for the past 35 years. He synced them (or rather tweaked them based on our preliminary work) and he too agreed that they were okay.

So, if I look beyond your condescending tone to the meat of your comment I take it you still think it's the carbs. Noted. Thanks for that, I haven't ruled it out myself and I will give it a third look if other hypotheses prove incorrect.

Just as airheads are not about "trotting off to a so-called pro for routine maintenance", forums are not about being a smug, self satisfied individual who doles out life advice rather than addressing the question. If you have nothing to say then... say nothing.
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Old 04-28-2013, 08:50 PM   #7
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I had a 76 R75/6. Despite rebuilding the carbs with new float needles and having a BMW mech check the float valve seat,it would dump gallons of gas into the bottom end of the engine when left sitting with the petcock turned on.
I learned to turn the gas off.

But if this may have happened to your buddy's bike it makes the bike run bad/foul plugs/eventually blow smoke once its running on half gas and half oil for lubricant.
Also of course destroys bearings and probably the whole engine at some point.

Just another airhead oddity. In the Bing Carb book this is acceptable and it says to turn the petcock off.
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Old 04-28-2013, 08:56 PM   #8
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Quote:
Originally Posted by Plaka View Post
Redo the compression check, wet and dry, check the amount of carbon on the piston crown and valve lips, check the plug heat range, check the amount of brown discoloration inside the rocker cover on the exhaust side.

At 35K it isn't broken in. But that K&N, and mis-oiled to boot, does not speak of a savvy owner. if it was used in dusty conditions there could be more engine wear than the mileage would indicate.

The leak down will tell you something about what's sealing, but not so much about what's leaking. The simple visual on the valves will tell you much. Look through the sparkplug hole with a Streamlight Reach or similar.
At 35K it isnt broken in............. Who told you that?
I took an R75/6 apart at 60,000 miles and it was beyond being on it's last legs,the entire bike was worn out not just the engine.
But they ARE easy to work on . For a reason.
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Old 04-28-2013, 09:34 PM   #9
Plaka
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Quote:
Originally Posted by Foot dragger View Post
At 35K it isnt broken in............. Who told you that?
I took an R75/6 apart at 60,000 miles and it was beyond being on it's last legs,the entire bike was worn out not just the engine.
But they ARE easy to work on . For a reason.
It's possible to wear a top end out in 60K. A K&N will help. (and I used to run them before I wised up). Not changing oil will really help. 120K is more usual. Maybe valves a little sooner but piston work at 120.

Not a matter of "someone telling me" but a matter of running compression checks on the bike I'm riding. Some conversations with very experienced airhead mechanics about what mileages represent the major wear intervals were worth something. Rings at 120K and pistons around 160k or something IIRC.

I tore into my 75/5 at 75k (to dual plug it). No wear on pistons or jugs. I mean the cross hatching looked like new. No taper, no oval. Ring grooves on spec. Spooky.

Some heads had valves incompatible with modern gas. These needed service sooner but once upgraded lasted as long as anything.

Aggressive riding and shifting at high rpm is good for more wear of course. Usually shows up in needing a new alternator rotor first. And rear drive spline wear. Common on "cafe racers" that get the stoplight to stoplight Eddie Lawson treatment. Ain't I fast? No.

Plenty of oil and filter changes are completely worth it. Costs less than it would seem if you do the numbers (operating cost/mile). But many owner seem to balk at simple arithmetic. Dunno why--- far from my strong suite. Lengthy threads about the magic juice are more popular. Run crap, but change it a lot.

I think engine oil additives (like LubriMoly) are going to be worth it (Or use LubriMoly oil). No data yet.

Proper warm-up time is worth it. Turning off the chokes after you are riding = bad. Should be warm enough to come off the choke before applying any sort of load.

Correct oil viscosity is critical. This is all about what happens in the first 10 seconds or so of operation. I'm still working on data here.

Plaka screwed with this post 04-28-2013 at 09:41 PM
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Old 04-28-2013, 09:58 PM   #10
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How about this? It has 135,000 miles on it?

Setting up and balancing carbs on an Airhead are a pain in the butt. Half the time the problem is not the carbs tho.

Good Luck.
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Old 04-28-2013, 10:07 PM   #11
Plaka
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How about this? It has 135,000 miles on it?

Setting up and balancing carbs on an Airhead are a pain in the butt. Half the time the problem is not the carbs tho.

Good Luck.
At 135K miles I'd check the top end.

Setting up and balancing carbs is a snap. some seem to struggle. I don't know why. On a long trip with worn rocker shafts I had to do valves and check the carb balance every morning, on the road. Maybe I got quicker at it. But the carbs have 3 adjustments and one is a no brainer with the other two close behind. Manufacturer documentation is through. I can't compare with other carbs (I've only dealt with dual SUs before, the other engines were single carb) but I can't imagine anything simpler. Set the idle mix, set the idle throttle opening, set the high end throttle opening, touch up the idle throttle if needed. Go ride. It's a 15 minute operation.
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Old 04-28-2013, 10:37 PM   #12
Plaka
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Originally Posted by Foot dragger View Post
I had a 76 R75/6. Despite rebuilding the carbs with new float needles and having a BMW mech check the float valve seat,it would dump gallons of gas into the bottom end of the engine when left sitting with the petcock turned on.
I learned to turn the gas off.

But if this may have happened to your buddy's bike it makes the bike run bad/foul plugs/eventually blow smoke once its running on half gas and half oil for lubricant.
Also of course destroys bearings and probably the whole engine at some point.

Just another airhead oddity. In the Bing Carb book this is acceptable and it says to turn the petcock off.
The float bowls have vents and overflow tubes. if these are plugged the carbs won't feed any gas when running. Conceivable if they are clogged AND the floats stick down the gas could go through the jets into the intake AND if the intake valve is open it could go from there into the cylinder at which point a certain amount could get past the rings into the bottom end. It's volatile and burns off quickly but washing the oil off the cylinder walls isn't good.

Getting "gallons" of gas into the bottom end sounds very odd indeed. I don't necessarily mean "odd" in a nice way but I'm not a nice person, ask anyone.

You turn the petcocks off to keep gas from going on the exhaust and ground if the float sticks when parked. Even then it can stick while riding and piss on your boot.

If you don't like it, sell the airhead and get a Honda or something.
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Old 04-28-2013, 10:57 PM   #13
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Quote:
Originally Posted by Plaka View Post
Redo the compression check, wet and dry, check the amount of carbon on the piston crown and valve lips, check the plug heat range, check the amount of brown discoloration inside the rocker cover on the exhaust side.

At 35K it isn't broken in. But that K&N, and mis-oiled to boot, does not speak of a savvy owner. if it was used in dusty conditions there could be more engine wear than the mileage would indicate.

The leak down will tell you something about what's sealing, but not so much about what's leaking. The simple visual on the valves will tell you much. Look through the sparkplug hole with a Streamlight Reach or similar.
At 35k it isn't broken in? Oh sure. They're not broke in till 100,000 miles. I thought we had all moved on from that joke since around when the quit making /2's?

I guess you do know that K+N's are suppose to be oiled band aid? We need more info on that situation. Don't fall for the oh so popular internet crap about how K+N's don't filter and that 'savvy' owners don't use them. That's a huge load of crap although they really don't filter hardly at all NOT oiled like you see them in photos so often on so many bikes.

Plaka, how can a leak down test tell you if something is sealing and at the same time not tell you if it is leaking?

supershaft screwed with this post 04-28-2013 at 11:12 PM
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Old 04-28-2013, 11:08 PM   #14
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Quote:
Originally Posted by band-aid View Post
Plaka, while I have appreciated your advice in the past on other issues I think your comment is unproductive and rude.

I have in the past year alone (successfully) replaced my clutch, torn down my friend's 84' R80RT and replaced all engine and transmission seals, replaced a timing chain, replaced an alternator and a significant chunk of other electricals, rebuilt two sets of carbs, wired up an acewell speedo to my R60 and done all routine maintenance myself on my bike as well as two other airheads. I have tools, I'm not a dummy and I do nearly everything myself. I also am not too proud to admit that despite my competence I feel that there are others with more experience who can be valuable to consult in a troubleshooting scenario. That's why I post on this site. Carb syncing in particular is a bit of an art and I don't think I am beyond improvement in the area when gauges are not an option as with the slide carbs on an R60.

While I realize now that mentioning the carbs being synced "professionally" was low hanging fruit for those inclined to make a snarky comment, I brought it up only to underscore that I no longer suspect the carbs as culprit. I DID sync them myself at first but experienced the same issues that I am now asking for advice on. The bike was then taken to get it's mandatory annual safety inspection done at my local mechanic who has specialized in airheads for the past 35 years. He synced them (or rather tweaked them based on our preliminary work) and he too agreed that they were okay.

So, if I look beyond your condescending tone to the meat of your comment I take it you still think it's the carbs. Noted. Thanks for that, I haven't ruled it out myself and I will give it a third look if other hypotheses prove incorrect.

Just as airheads are not about "trotting off to a so-called pro for routine maintenance", forums are not about being a smug, self satisfied individual who doles out life advice rather than addressing the question. If you have nothing to say then... say nothing.
A broken clock is right two times a day but they still aren't much help since you never know when. Plaka just likes throwing Pro's under the bus because there are around four or five of them here that offer better advise most always.
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Old 04-29-2013, 02:54 AM   #15
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Band Aid, rule number one when setting up the carbs, is check the ignition is right first.

New plugs, ( you've probably done that if they keep fouling), new points, set the timing, then play with the carbs. It's meaningless to chase a carburation problem if the ignition is not burning the fuel properly.
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