1975 R75/6 Barn Find Resurrection - Finally back on the road. First 50 miles were smooth, good power, nice idle. Recently though, it coughs and sputters at low speed, but once I gas it, everything is better. When I get home after a 7 minute ride, the idle is not bad, but the clicking from the front of the engine is LOUD. It doesn’t click when cold. Only once warmed up. Any thoughts?
I can offer a few thoughts on the topic.
1) First off, I have never experienced an issue like that myself, so this would be an exercise in guess work.
2) Two things happen when a motor gets warmed up. Parts expand ever so slightly, and motor oil thins to its normal consistency when circulating in the motor. Assuming the oil pressure light (which is amber) is functioning correctly, lit up when you turn the key on before starting the motor, does it ever flicker when the motor is at idle when warmed up?
3) You might try using a long screw driver as a stethoscope (unless you have an actual stethoscope) to pinpoint the the location of the clicking sound.
former Airmarshal, IL.
I can offer a few thoughts on the topic.
1) First off, I have never experienced an issue like that myself, so this would be an exercise in guess work.
2) Two things happen when a motor gets warmed up. Parts expand ever so slightly, and motor oil thins to its normal consistency when circulating in the motor. Assuming the oil pressure light (which is amber) is functioning correctly, -illuminated when you turn the key on before starting the motor,- does it ever flicker when the motor is at idle when warmed up?
3) You might try using a long screw driver as a stethoscope (unless you have an actual stethoscope) to pinpoint the the location of the clicking sound.
former Airmarshal, IL.
Jim gave you some good ideas.
I'd suggest removing the front engine cover (after you disconnect the battery) for a closer look and listen. The best I can come up with is the cam chain, which is directly behind the alternator. Worn chains can flap around. There is a "chain follower", that takes up slack, but they can also get worn and even break. There is also a later model spring that helps tension the chain. (I also believe the tensioner is oil pressure assisted. So back to Jim's remark on oil pressure.)
There is also the odd chance that the ball bearing has gone bad from years of sitting. The bearings can develop a small rust spot when oil isn't circulated, and the balls "chatter" when they hit that part of the bearing race. The bearing is not going to explode or do anything crazy, they simply sit there and make lots of noise. There will be slightly more metal in the oil filter and the noise will simply get worse as the balls are slowly destroyed.
If you decide to remove the inner cover, then you'll want to do the whole job: chain, tensioner, spring, bearing, seals and o-ring. The work is straight forward. You will also need the Alternator Puller Tool. Allow maybe 3 hours.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Oil pressure light is working normally. Stethoscope is my next move. The ticking does not appear to be coming from either side, more from the front. Thanks for the thoughts. I will post more as I figure it out.
Thanks Wobbly,
I do intend to dive into the timing chain in the future, but I think this noise is too "mechanical and regular" to be something flopping around. It is as if someone is tapping on the cased in a very regular pattern that speeds up and slows down with the engine.
Going to try listening with a stethoscope to see if I can isolate the noise. DOES seem to be more in the middle than from either side. Thanks!
Within the last 60 days there has been a similar complaint, and the problem turned put to be the bearing.
https://www.airheads.org/forum/my-airhead-needs-help/1204-83-r100rt-updated-alternator-noise#5777
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Jim and Wobbly!
My daughter-in-law brought me a real stethoscope. Wow, does that help! The noise is definitely not coming from either head and actually consists of a couple noises. One is the crankcase valve, which is on my list of things to do. The other is definitely from behind the front cover, so your thoughts about the timing chain, etc are on-point!
Should I not ride the bike until fixed? I can't dive into that for a few weeks, but I will be studying up on how to do that work. Thanks for your thoughts. It is great to have a place to go for help!
I think Wobbly has it nailed, particularly when referencing the link to the other thread. If it were my bike, I would not ride it. Then again, I have a second rig to putt around on.
You can run the motor with the front cover off if you want to get a little closer to the noise with your new stethoscope. Just be sure to pull the negative battery cable first. This is something we should do every time we remove the front cover. Then, just hook it back up to start and run the motor.
former Airmarshal, IL.
Jim and Wobbly!
My daughter-in-law brought me a real stethoscope. Wow, does that help!
A REAL friend would have gotten all of us a stethoscope.
I guess Jim and I are finding out just exactly who our real "pals" are. 👿
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Shamed again...:unsure: Gotta learn to keep my big mouth shut.
I should get a stethoscope,..I'm still using a long screwdriver.
former Airmarshal, IL.
Jim and Wobbly!
It’s timing chain day!
Look again at my photo and you'll see I use 2 cable ties as tools. A red one holds back the plunger with new spring, and a black one pulls the 2 ends of the chain together so a person can slide the master link in from the rear. Getting at the rear of the chain to install the master link is best done at that 1 o'clock position. A pal swears that a common bread twist tie is the best way to hold that master link !!
The cover gasket consists of 1 big gasket and 2 little ones. You really need all 3 to keep from warping the cover.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Update!
Long day, but got it all ready to fill with oil and check things out. Why oil, you ask. Well my bike has a double row chain and the master link must go in from the front, making mr. fumble fingers nervous, and for good reason. Lost the master link backing plate in the engine and had to pull off the sump to find it. No problem really, just made for a long day.
The timing chain was really slack, so I’m optimistic that this will help my strange ticking noise. Also changed out the breather, so that will change the way things sound in the am.
I’ll report more tomorrow.
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