Hi, I'm midway through resealing the heads on my '74 R75/6. Got the right cylinder reassembled and noticed an odd noise while I was rotating the engine to set the valves. Hopefully you can see/hear it in this video. Essentially, it seems there is a click when the intake valve begins to open. My hunch is it is related to the valve spring/assembly. All of the head bolts are torqued, and the rocker arms are adjusted to spec. Gave things a good cleaning before reassembly, so I'm wondering if the valve assembly is just a little dry? Thanks in advance for your help!
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R75/6 valve click (not what you think!)
- Thread starter spencer_p
- Start date
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- Tags
- r75/6 top end valve adjustment
Hmmm... little hard to hear but I guess you're using the kick lever to turn the engine? You could isolate noises by putting the transmission into a higher gear and turning the engine with the rear wheel.
That said, sure doesn't sound right. Probably some interference somewhere. Maybe get someone to turn the rear wheel for you while you put a close eyeball on where the sound is coming from.
That said, sure doesn't sound right. Probably some interference somewhere. Maybe get someone to turn the rear wheel for you while you put a close eyeball on where the sound is coming from.
nrpetersen
Curmudgeon
Might the exhaust valve/rockerarm interface be worn and need resurfacing? The clicking noise I hear (very bad ears tho) is when the exhaust valve first starts to open.
Correction - On relooking at the video, I should have said Intake valve.
Correction - On relooking at the video, I should have said Intake valve.
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beemeruss
Member
Head Gasket
The only thing that comes to mid is whether the gasket is installed in the correct orientation. Because they are not quite symmetrical, an improperly placed one can slightly bind the pushrods through part of their travel. Or so I have been told. FWIW YMMV
Russ
The only thing that comes to mid is whether the gasket is installed in the correct orientation. Because they are not quite symmetrical, an improperly placed one can slightly bind the pushrods through part of their travel. Or so I have been told. FWIW YMMV
Russ
Yup, I made sure the gasket was oriented right. There is a lot of extraneous noise from the kickstarter... I'll try to isolate it better.
When you had the heads off did you check the guides and seats on the valves. It sounds like the valve is moving sideways a bit, just as it seats. Really hard to tell as the kick starter makes a lot of noise we hear on the video. If you have another person with you, have either them or you listen to the valves as they close and open. You can use an automotive stethscope or long handled screw driver to figure out which one is causing the noise. Once you figure out which one it is, you should take the head off and remove the valve spring so you can check sideways play on the guide and the valve seat wear.
As another has commented, could be the gasket rubbing on the push rod.
As another has commented, could be the gasket rubbing on the push rod.
Mystery solved! Somewhere along the way, I rotated the piston 180-degrees, so the intake valve didn't mate properly with the piston's indent, since the exhaust is a slightly different dimension. Fortunately, no damage done, just managed to scrape off a little of the carbon, which was the tell-tale sign. 
manitou_commando
Member
You know removing the pistons and soaking them in straight Simple Green for a day or two will remove all that carbon.
Yes, Simple Green. Awesome cleaner.
Clean as a whistle and zero elbow grease.
Snowbum suggests diluting Simple Green and not soaking all that long...read what he has near the bottom of this page:
https://bmwmotorcycletech.info/chemicalsetc.htm
