Oily carbs

[Guest]

Took the beast for a spin last night ('78 GS750) it farted once on initial start up but nothing unusual as it's been standing for a few weeks while I contemplated adding floats in place of the wheels.

I digress, started well, warmed up nicely ran fine. Got home and there was what looked like 3:1 oil on the overflow from no.1 carb, nothing on the rest. When I had the engine stripped spring last year, measured the piston diameters, all in spec. Bores likewise all in spec, new piston rings had been fitted. I then removed them, cleaned them and the grooves and re-fitted the rings. The oily substance does smell like petrol but that's to be expected as it's dripping out of the carb. I have VM slides on the bike and they have been cleaned, dipped and blown through last spring and generally run very well.
Can't post pictures as the bike is at home and I'm bored to tears in work.

 

[LAB3]

If you're confident in your work on the rings then the best bet is a valve seal failing. Try a compression test to rule out a problems with your cylinder, piston and valve face. If that shows a constant number compared to the other cylinders then the oil seal is the likely culprit.

 

[Guest]

Had the valve seats re-ground last year, found out P/O had installed a valve guide in 'on the *@%^$*@%^$*@%^$*@%^$' and had to have it repaired. Replaced all the valve seals when I reinstalled the head.

huh apparently you can't use swear words on the forum.

 

[Rijko]

Had the valve seats re-ground last year, found out P/O had installed a valve guide in 'on the *@%^$*@%^$*@%^$*@%^$' and had to have it repaired.

don't understand, maybe due to lack of proper sentence-forming supporting swear words ? :xsmilie_mrgreen:

huh apparently you can't use swear words on the forum.

Don't worry, we get your drift anyways

 

[Guest]

So glad. Translation:-

Someone previous to my ownership of the bike replaced a valve guide. Apparently it seemed a good idea to them to put it in at a slight angle ensuring the valve didn't seat properly. Found this out when I sent the head to get the valve seats recut. A very nice engineering customer of mine at work removed the old guide, trued up the guide hole, and installed the new guide.
When I rebuilt the engine after it had sat idle for 15 years it had little / no compression. Bores, pistons measured with a calibrated digital vernier and all within spec.

Managed to get compression up using 2stroke oil in the bores to coat the bores and create a seal between the bore and the rings.

The oil dripping from the overflow tubes is just 1 or 2 drips not a constant flow, more annoying than a big issue at the moment.

 

[LAB3]

The oil dripping from the overflow tubes is just 1 or 2 drips not a constant flow, more annoying than a big issue at the moment.

Do you have the hoses attached to those tubes? The reason I ask is, knowing that I can offer the following. I'm cheap and used the motor oil and baggie method to lube my throttle cable. Noticed oil on my carbs and couldn't figure out where it came from, upon searching it turned out it was coming out of that freshly lubed cable!

 

[Guest]

No hoses on the tubes, throttle cable greased rather than oil lubed.

 

[B17]

If using the stock air filter, when did you last clean and oil it.

I find that my carbs do have an oil mist until the filter clears of the oil.

 

[Guest]

Ohhh no I'm one of those spawn of satan who has a 4:1 exhaust and pods. As soon as we can venture out from home again I will give it a run and see if it still drips.