Leaky base gasket

[Guest]

I am discovering a leak around the base gasket area. My mechanic friend and myself do the maintenance on the bike but we have not re-tourqued the head. Do you Suzi guys think that's the issue? I'm not learned enough yet with the metrics so please direct me. Thanks

[Nessism]

Retorquing the head is on the Suzuki maintenance schedule, but few people ever do it. I'm not sure how many head and base gasket leaks are related to that, but I suspect a good many.

[520eek]

what are the intervals for re torque of head?

[2BRacing]

According to the OEM service manual for the 850, the cylinder head nuts should be retightened every 5 000 km (3 000 miles).

I have to admit that I never did this in the 34 years that I have owned my bike since new! There has been a weep from the left front side of head gasket for the last 10 000 km. Never serious enough to worry me, until it recently started to get worse.

I just used a ring spanner to "feel" the front outermost cylinder head acorn nut for tightness. Guess what? It was actually loose enough to move just using the spanner without a lot of force! So I tend to agree that oil weeps could result from loose cylinder head nuts.

But now here is the thing: It is impossible to get at the 4 innermost cylinder head nuts without removing the valve cover, so this job should be done at the same time as valve adjustment. Furthermore, I will most likely not be able to get my relatively large 1/2 " drive torque wrench under the central frame tubes to torque the 4 innermost nuts. Next time I adjust the valve clearances, I will investigate further.

EDIT: Should add that you also need a relatively slim socket to fit into the machined "well" around the inner 8 nuts. Perhaps a 3/8" drive socket of 14 mm or a deep 1/2" drive socket of 14 mm? (the "standard" 1/2" drive 14 mm socket cannot fit down into the "well").

[520eek]

Now that is interesting....and on that same thought, would one just check to see if torque value is there or would one loosen just a little and re torque on these intervals that you mention?

[2BRacing]

It is standard practice to loosen the nut a little first, and then tighten to the correct torque.

[Grimly]

But now here is the thing: It is impossible to get at the 4 innermost cylinder head nuts without removing the valve cover, so this job should be done at the same time as valve adjustment. Furthermore, I will most likely not be able to get my relatively large 1/2 " drive torque wrench under the central frame tubes to torque the 4 innermost nuts. Next time I adjust the valve clearances, I will investigate further.

EDIT: Should add that you also need a relatively slim socket to fit into the machined "well" around the inner 8 nuts. Perhaps a 3/8" drive socket of 14 mm or a deep 1/2" drive socket of 14 mm? (the "standard" 1/2" drive 14 mm socket cannot fit down into the "well").

I re-torqued mine recently. The middle four were awkward but certainly not impossible, and that with a 1/2" drive torque wrench.
I used a 1/2" -> 3/8" reducer, short extension and slim socket (deep one). Just so happens the wall thickness of the 3/8" sockets are just right for this.

[2BRacing]

I re-torqued mine recently. The middle four were awkward but certainly not impossible, and that with a 1/2" drive torque wrench.
I used a 1/2" -> 3/8" reducer, short extension and slim socket (deep one). Just so happens the wall thickness of the 3/8" sockets are just right for this.

Thanks, good to have this confirmed!

[Scout]

Thanks everyone, will be retorquing this weekend

[cyclepat650]

I'm a motorcycle newby , can you explain why a head would need to be tightened up? Never have done it on a car. Does my gs650 head need retorqued?

[JTGS850GL]

Let us know if it stops the weeping. GS850's are notorious for base gasket leaks. Mine is doing it now so I'll be interested in how retorquing the head bolts worked for you.

[chef1366]

Won't stop your leak
Sorry

[JTGS850GL]

Thanks for the encouragement Bill. Guess I'll just have to swap in the spare 1000G motor.

[cyclepat650]

Won't stop your leak
Sorry

Sorry to reask but what does the head torqueing do? Is this vital for performance of my bike becuase I did not do it yet

[eil]

retorquing the head is loosening the head nuts and torquing them back down to the proper torque value one by one. I believe it's supposed to be a regular maintenance item or at least something you do after the first x miles after a rebuild.

It does not affect performance.