83 GS550L No/Hard Start. A few questions.

[Guest]

I have an 83 GS550L that can be very hard to start. Here is what I know.

Battery voltage 12.6v static, about 11v while cranking.

Compression numbers, cold and WOT are between 110 and 125 after 4 seconds cranking. With a shot of oil they all go to 150+. Obviously low but it was my understanding that this is not so low as to not start. Is this true?

Spark has been verified on all cylinders but is seems thin and weak on all four.

Removed carbs and cleaned them out. Ran wire through the pilot and main jets, observed that they were clearly unclogged.

Shooting some starter fluid will result in a stronger attempt to fire and will eventually get it fired up but you still have to work to get it to fire up.

Once running it seems to run fine.

I am beginning to wonder about the thin weak spark. Check coils etc?
Will a present but weak spark prevent starting? But allow proper operation after starting? That does not seem right.
Or perhaps is it really the low compression that I am fighting?

I have and will continue to use the search option but any helpful hints would be appreciated.

[tom203]

bjones said..."Removed carbs and cleaned them out. Ran wire through the pilot and main jets, observed that they were clearly unclogged."

Maybe, but all these carbs ( dual throat units ???) have seperate enrichment circuits to aid cold starts- they likely need thorough cleaning to make sure extra fuel is delivered during "choke" use. Since you said it runs fine after warmup, I'd suspect your enrichment circuits are clogged.

Edit; avoid the starter fluid- it's already told you all it can!

[bjones]

Maybe, but all these carbs ( dual throat units ???) have seperate enrichment circuits to aid cold starts- they likely need thorough cleaning to make sure extra fuel is delivered during "choke" use. Since you said it runs fine after warmup, I'd suspect your enrichment circuits are clogged.

Edit; avoid the starter fluid- it's already told you all it can!

OK, I'll recheck the carbs.
On thing I failed to mention is that it is not always hard to start. Generally (though not always), once warmed up it is easier to start. This would appear to be consistent with the enrichment circuit issue correct?

[Toasty]

The voltage seems quite low, I would check the battery.

[JEEPRUSTY]

You need to check your valves immediately
I should think they are tight.

Having run an engine like this for several years I can say the last one I ran with these symptoms burned valves and became useless.

I should have been on the valve specs but hey its a newbie mistake.
67k kms on it but it would still be running sadly the adjustment spec was gone on the threaded adjusters and upon tear down there was palpable wobble when checking the valve guide wear.

[bjones]

Thanks to all

Ok, I think I have this one wrapped up. Wanted to thank everyone for their help.

I pulled the carbs again and gave them a thorough cleaning this time pulling the pilot screws and jets which I had foolishly not done last time.

However, I think the real trick may have been replacing the cylinder head/intake o-rings or perhaps a combination of the two.

I had also noted a hanging idle so I replaced the o-rings and now all is well. Fires right up from stone cold which it never would before.

Thanks again!
Bruce