Have my crank seals gone? GT380

[grumps]

Symptoms. Engine starts fine on choke but the r/h cylinder cuts after choke removed. Also, some oil/petrol liquid blows out of the exhaust drains. The cylinders do all cut in on hard acceleration but it will stall on tickover as the third cylinder cuts out.

Does that all sound familiar to anyone?

New plugs made no difference as I hoped maybe one was breaking down.

Speaking to a local restorer he points at the crank seals. Last night I met a GT550 owner ar a rally and he pointed the finger at the seals too. He did say they were not really a difficult to change.

Many thanks for any advice

Cheers

[jabcb]

The pilot circuit for the right carb could be cruded up. The pilot jet orifice is quite small & it doesn’t take much.

Was the bike running fine last year?

[GTandcbr]

Hi
Can you give a little history, how long have you had the bike? Was it running okay until you got this problem?
Changing the crank seals is a major and expensive job that has to be done by a specialist. As said by Jabcb its more likely to be carb issues. The petrol/oil coming out the exhaust drains is normal if you have carb problems. Unburnt fuel going into the exhausts. A good run when you are sorted will blow all that out!

[grumps]

Hi. REALLY appreciate the replies

History

Bought it last autumn and ran it in the garage of the guy selling it. It ticked over aok but no option of a test run as SORN etc. Bought as seen!

Brought it home in a van and very occassional ride but only less than about 10 miles. Ran OK for a while but began to cause the issues I mention. Sparked it up a few times in the winter but only in the garage and the issue has been getting worse which made me think (hope) that it is only carb muck.

I hope it is! Maybe that's my next task, get the carbs fully cleaned and if it really is the seals then at least I know the carbs are good to go after a rebuild.

It was run regularly by the PO - that's why I chanced buying it.

Thanks for coming back to me

David

[GTandcbr]

David,
It does sound like this bike needs fettling and then given a good run. It is now very likely that the black mixture coming from the exhaust drains is fuel/water. This is caused by frequent startups in the garage causing moisture to condense on the inside of the exhausts. I would remove the carbs and clean all the jets spraying through with carb cleaner and if you have access to an ir line, blown through with compressed air. Given the nature of your current problem pay particular attention to the slow jets as they are very important to the tickover and low throttle movements.
I would also remove and clean the exhaust baffles as they affect engine running too.
Here is a copy of the carb manual to aid you. Happy reading!
http://www.3cyl.com/mraxl/gt/manuals/su ... /cover.htm" onclick="window.open(this.href);return false;

[grumps]

Lads

Advice like that cannot be bought.

Absolutely appreciative to those who know more!

Thanks

David

[sportston]

The pilot circuit for the right carb could be cruded up. The pilot jet orifice is quite small & it doesn’t take much.

Was the bike running fine last year?

+1 on that! Check and sort carbs before writing off crank seals.

[grumps]

I have sent the carbs off to someone who knows a lot more than me about them.

I'll update you when I get them back.

Thanks again

[Craig380]

The right-hand side crank seal very rarely fails on 380s unless something really serious happens like a little-end bearing failure that puts metal debris in the crankcase. That seal is lubed by the gearbox oil so it doesn't dry out as long as there's oil in the gearbox.

If it starts OK from cold, generally speaking the crank seals will be fine.

I would echo the comments above - a problem with the pilot jet or circuit in the carb. Hope your mate can sort the carbs.

Where do you live out of interest? I'm in Macclesfield, Cheshire if you need a hand.

[grumps]

Droitwich in Worcestershire, so not too far away.

Thanks for your kind offer