No start

[Firehawk]

It has gas. It has spark. Yet, it won't start.

Carbs have been looked over by mechanics, and it was discovered that plugs were missing from the pilot circuits. They said the carbs were in good working order.

I crank, yet nothing happens. Both coils are firing. And if I pull a spark plug out, it smells of gasoline.

What might be causing this?

[skids]

Re: No start

Make sure that your oil is not contaninated with gasoline (leaking petcocks and/or fuel valve into the carbies). Pull the air filter and see if it is gasoline soaked. Take the spark plugs out and clean them with a propane torch and replace them. Try starting with the "choke" pushed all the way in.

Originally posted by Firehawk
It has gas. It has spark. Yet, it won't start.

Carbs have been looked over by mechanics, and it was discovered that plugs were missing from the pilot circuits. They said the carbs were in good working order.

I crank, yet nothing happens. Both coils are firing. And if I pull a spark plug out, it smells of gasoline.

What might be causing this?

[Firehawk]

Oil does have gas in it. From it flooding due to previous problems with the carbs. That would cause it to not start? I guess I'll change the oil tomorrow and try again.

[skids]

Well, I wouldn't contaminate another 4 qts of oil. Find out why the gasoline is going into the crankcase and fix that first. If the air filter is soaked, that could cause fuel fouling of the plugs.

Originally posted by Firehawk
Oil does have gas in it. From it flooding due to previous problems with the carbs. That would cause it to not start? I guess I'll change the oil tomorrow and try again.

[Firehawk]

Gasoline was going into the crankcase from the carbs flooding the cylinders while it was running, and from flooding it at start. That's taken care of.

There is no more flooding. Petcocks and fuel lines are good. The carbs aren't letting any excess fuel go into the crankcase.

I guess I'll check compression tomorrow. I can't think of any other reason why it would fire, if it has fuel and spark. Low compression may make me a very, very unhappy person.

[Firehawk]

I can't quite edit, but I should say that the spark plug I pulled after cranking was dry but did faintly smell of gasoline.

This is with full choke too.

[LoserShoes]

Give it a shot of starter fuid down the carbs and see if it fires. Sounds like you have the opposite problem now, not enough gas. Check to see if gas flows out the fuel line with the petcocks in prime.

Steve

[Brian_D]

Firehawk,

I'm probably waay off base here but the carbs for an 1981 XS1100H should not have plugs in the pilot circuits!

[Brian_D]

Edit: At least the BS34 carbs from my '81 LH do not use the plugs in the pilot circuits - although Yamaha's on-line microfiche shows the plugs for my model.

[skids]

My 81H standard didn't have them either.

Originally posted by Brian_D
Edit: At least the BS34 carbs from my '81 LH do not use the plugs in the pilot circuits - although Yamaha's on-line microfiche shows the plugs for my model.

[Ridinhi]

you may check the timing also

[mason79]

i know how you feel , i got low compression, my engine that is

really puts a damper on enthusiasm for my new toy, what the heck it's got 48,000 miles, but i heard they go to 200,000

maybe i'm just a lousy mechanic, but no way am i parting the bike
maybe needs a stronger spark.

[Firehawk]

Yeah, when I rebuilt them, I didn't notice any plugs in there. That's just what they said. They put the plugs in and now it doesn't flood anymore (and they said that's all they did).

I'm gonna spray some starter fluid in there and see if I can get it to start that way. Maybe mess with the pilot screws until it idles nicely.

Compression checking will commence shortly!

[John]

Those plugs are blocking the supply of fuel to the pilot jets. I have both types of carbs (78-79 & 80-81) on my bikes, and the 80-81 carbs should not have the passageway plugged. It should never idle like that. That circuit supplies all of the fuel to the engine until around 3k rpm, then the main jet circuit comes in, but the pilot circuit is still suppyling fuel to the engine also.

[TopCatGr58]

Firehawk,

Pull the carbs and the pilot plugs, and look inside that pilot jet tower, IF you see a little hole going to the Main Jet Tower, then, yes, you need the pilot plugs. But IF you don't see a little tunnel, then PULL THE PILOT PLUGS OUT!!! IT's not getting any fuel thru the pilot circuit, and even though it may get some fuel thru the choke circuit, it won't get any thru the pilot/idle circuit!
T.C.