Cam timing GS750 '77

[Anonymous]

Hello friends,

After rebuilding my GS750 from 77, it's up and running again.

But the engine is making a lot of not synchronised exploding sounds (as the gas is exploding in the exhaust, farting) Next to this, sometimes I can also hear a blowing sound through the carbs.

Can someone give me some help which things I can check to find the cause of this prob. I also would like to know how I can check if the cam timing is perfectly adjusted (for a GS750 '77).

Thanks in advance for your reply.
It will certainly help me to know my bike better!!

[robinjo]

Hi there, I would suggest you get a manual for your specific bike, it will come in handy a lot of times when working on your bike. I don't have one for the 750, sorry.

[Anonymous]

Kobe,

Get a manual and check the following, in this order:

1. Valve timing (camshafts).
2. Valve clearance.
3. Compression.
4. Ignition timing.
5. Carb synchronization.
6. Idle mixture.

If you methodically follow the above steps and verify proper operation in each category, your engine withh purrr like a kitten.

On a GS1000, when at TDC on cylinders 1 and 4, the notches in the camshaft ends should point towards each other and line up. You'll see what I mean when you take the valve cover off.

[Anonymous]

Dear thx for the info,

I checked compression, and all the cylinders are around the 5 (Low).
Can this cause the too loud nooises, are is this low compression caused by something else.

I ordered a manual for my GS on e-bay.

Can't wait untill it arrives.
Please inform.

Thx!
Kobe

[Anonymous]

Check your valve timing. You will need to remove the valve cover.

[Anonymous]

Dear James,

I did remove the valve cover and checked the valve timing. This seems to be ok. I've checked it with a manual i borrowed from a motor shop. (My manual hasn't arrived yet).

One thing I can tell is that the cam chain is becoming depleted. Could this cause this low compression and the extra noise. :roll:

Thanks!
Kobe

[Anonymous]

Now, carefully check your valve clearances.

A worn cam chain would not cause this but, it may need to be replaced.
This is a big job, you will have to remove the crankshaft to replace that chain.