Topic: Clunky sounding gears 77 cb750

[walnut777]

i noticed theres alot of noise coming from the left side of engine. im assuming the gearbox.
It seems to get worse as my bike warms up.
I read on this forum somewhere that the cb750's were just that way and the hard selection noise wasnt for the faint of heart but if i remember correctly they were saying that was normal when the bikes were cold. mine is the opposite. mine makes little noise when cold but more noise when warm

it only happens when bike is rolling of course.
the teeth on the sprockets look good. the bike sat for 7 years. i sprayed wd40 on the chain and that didnt stop the noise as I thought maybe it was frozen chain from age.
i sprayed some white lithium grease on the chain today but havent had time to ride the bike cuz i have the front caliper off. any ideas where to start or is it a common thing>?

[MCRider]

The most common noise that is "just that way" is the clutch rattle. Right side of engine, at idle, goes away when clutch lever pulled in.

Any other noise is not common, or at least not "just that way".

You are right to suspect the chain. Regardles of what the sprocket teeth look like, if its left side of engine, its almost got to be chain and/or sprocket. The only way to really lube an old chain is to remove it and soak it in a solvent bath and bring it back to life 1 link at a time. Better to just buy a new chain. Both age and mileage will puke a chain. Sprockets, mostly mileage.

Transmissions themselves rarely make any noise. Shifting is clunky but that's the nature of a constant mesh transmission (all motorcycles) and only occurs at the shift, not ongoing. a transmission problem usually manifests itself as jumping out of gear into a false neutral.

Buy a cheap chain and I suspect  a quieter ride. If your ready buy new sprockets and a good chain and prepare for silence.

PS: The rollers on a chain can get real rattly and louder as the chain warms up. You did say you only hear it when the bike is rolling.

[walnut777]

thanks for the reply.
I had read a thread on here about how if the 750's carbs arent synced just right then it can cause alot of noise. i  I need to find that post.  come to think of it im gonna search for it now.

[walnut777]

Too many post came up when I typed in a few keywords I could remember.

Anyway. Other than the chain issue I have I noticed that my bike cranks an runs very smooth at idle.
It doesnt run very smooth while driving under 3000 rpm. Its not rough but seems to hit n miss a little.
If you get it over 3000 rpms and and red lineit while driving it doesnt miss a lick. I mean this thing runs perfect when you get on it, but just cruising it seems a little off.

Im gonna download some manuals and learn about the points and carbs.
I just got this thing from the shop and the mechanic there put for 4 carb kits, and set the points. The guy had been a honda mechanic before my bike was ever made. so i assume he synced the carbs right.

[the technological J]

do the 300 mile tune up and check the score marks on both side of the axle and make sure your wheel is straight... what weight oil are u running?

[dave500]

if your chain sat for 7 years?how old was it before that?i would replace that chain incase it snaps and takes your left ankle into the gearbox and makes a noise.

[walnut777]

do the 300 mile tune up and check the score marks on both side of the axle and make sure your wheel is straight... what weight oil are u running?

i called the shop yesterday and asked them what they put in the bike. they said they use castrol synthetic 10w-40