Topic: Steering vibration

[lash]

Bought a 76 750 that had sat for about 10 years and needed a lot of work. On the road now and runs amazingly well considering my mechanical experience level.
I have a vibration that feels like you are riding on very light washboard that is intermittent but more there than not. I don't think it is the front wheel, both tires are brand new and balanced. It does not vibrate the handlebars side to side, just up and down. I have not taken the forks apart so I am thinking it might be springs or fork oil? No leaks in the forks. Maybe steering head bearings? I am going to replace the springs and bearings this winter but would like to have an idea if I am on the right track in my reasoning..

[strynboen]

think the tires had not full seated.

..take all air aut of the tire...give it some "tire soap"..and senter it on the rim..and add pressure at some stagdes
..and help/press it to be total lined up tire /rim..vhen it all sits perfekt,,,, fill to full presure.... thek..and ride..and dont teight the valve steam ..before all is perfekt...to erly ,, teight it...it can hold the tube..so it not find the korrekr seating..

dont thange parts ,,just for thange them...find the error..and safe a lot of time and money

[calj737]

If its sat for 10 years, I would expect that the fork oil is, um, shall we say, #$%*e! You can drain a bit out of the forks from the outside, lower leg. If it smells like a Seafood Restaurants trash container, fully service the fluid.

Then commence checking the steering bearings for proper grease, the rear swing arm for proper greasing, and make sure the forks tubes themselves are properly snugged.

[lash]

If its sat for 10 years, I would expect that the fork oil is, um, shall we say, #$%*e! You can drain a bit out of the forks from the outside, lower leg. If it smells like a Seafood Restaurants trash container, fully service the fluid.

Then commence checking the steering bearings for proper grease, the rear swing arm for proper greasing, and make sure the forks tubes themselves are properly snugged.

Just the thought of what that smell is like is enough to get me to change the oil without smelling it !!

[Deltarider]

Wasn't the 'seafood smell' only the original fork oil that was put in at the factory? I've changed mine recently and although it had been in there for at least 10 years, it didn't smell and it was clean too.

[strynboen]

its only if vater leakes dovn in the oil..it get real smelly..

but still old gear oil in 4wd syncros/gear can also go bad ..think kondens vater and mikroskobic bakteries can make the oil bad..

[lash]

Update, I noticed some loose spokes in the rear wheel so decided to redo it. Respoked with a new rim and the vibration is gone. I am still going to do the forks with progressive springs, new oil  etc. but that can wait for a bit.

[calj737]

Determine if there's oil in the forks now, before you wait. It's very easy to change (and probably really needs it) and doing so could save your life.

Changing while installed on the bike is very doable. So it's not a big job. Still a very important one though.

[beemerbum]

What is the appropriate fork oil for  1977 K?  I have the same up and down bouncing in my forks even with a well seated brand new tire.

[lash]

Did the fork oil this morning. It didnt look too bad colorwise but I 'm sure PO didnt put in the correct amount by half. There are no leaks,seals are good, so I put in the recommended amount and went for a ride. Much better.. Book says 6-6.5 oz.

[lash]

What is the appropriate fork oil for  1977 K?  I have the same up and down bouncing in my forks even with a well seated brand new tire.

Book says for cb750k3 and later 6-6.5oz.