Why Won't You Start!!!

[Guest]

Alright... I need ideas.

I have soaked my carbs, changed all the o-rings.
I have four nice blue sparks.
Compression measured at 100 for each cylinder (measured cold).
The bike will start for about 2 seconds on starter fluid.

Why wont it run?!?

I want to say carbs still because of the starter fluid... But I cleaned them pretty darn thoroughly!

Ideas?

[Larry D]

Airbox sealed ? Any mods or are you running it stock ? Valves adjusted ? Battery fully charged ? Have you synced the carbs ?

[chuck hahn]

Is float height correct? This regulates the gas into the carbs and subsequent flow once the bike starts..How about removing the drain plugs and see if there is a strong flow from each carb. Did you also replace the intact boot orings..vacuum leak there maybe..try to start it with petcock on prime and once it starts ( and will stay running ) then switch to on and see if the bike dies..that will be an indication of a toasted petcock... just a few things i can think of right now..

[Adler]

Airbox sealed ? Any mods or are you running it stock ? Valves adjusted ? Battery fully charged ? Have you synced the carbs ?

Airbox is sealed (i think?).
No mods, bone stock.
Battery is charged.
Carbs have been bench synched.

[Adler]

Is float height correct? This regulates the gas into the carbs and subsequent flow once the bike starts..How about removing the drain plugs and see if there is a strong flow from each carb. Did you also replace the intact boot orings..vacuum leak there maybe..try to start it with petcock on prime and once it starts ( and will stay running ) then switch to on and see if the bike dies..that will be an indication of a toasted petcock... just a few things i can think of right now..

I checked the float height.
There is fuel in all the carbs.
I replaced two of the intake o-rings and found that the PO had likely changed them already.
I am running on a temp tank, no petcock.

Thanks for the responses.

[chuck hahn]

well if its a free flow gravity fed tank there should be no problems as far as delivery except maybe the temp tank needs vented a bit.. what they call vacuum lock..seems it should start just fine otherwise from what you are saying..HMM!!

[Adler]

OH forgot to answer one of Larry's questions...

Valves have not been adjusted... But could that really cause it not to start? Especially considering how it starts on starter fluid?! And has compression...

The temp tank is more a funnel attached to the fuel line... So it couldnt really be a vacuum lock there.

I really dont want to have to tear down my carbs AGAIN!!!

[Larry D]

Yes. Valves to far out of adjustment makes it difficult to start.

[Adler]

Yes. Valves to far out of adjustment makes it difficult to start.

Wouldn't it then catch and stay on after using the starter fluid?

[chuck hahn]

do you have the vacuum port on the carbs that usually goes to the petcock plugged off??

[hampshirehog]

Wouldn't it then catch and stay on after using the starter fluid?

Not if they're much too tight it won't. Valve clearance checks are a must on these old girls.

[Larry D]

Not if they're much too tight it won't. Valve clearance checks are a must on these old girls.

Correct. These bikes like well adjusted valves like a kid loves candy. It's my opinion that it's the reason why alot of bikes got parked "back in the day". They got harder and harder to start and eventually got put in the back of the shed to rot away. When actually an hour spent adjusting the valves would've woke them right back up.

[Adler]

do you have the vacuum port on the carbs that usually goes to the petcock plugged off??

OOOOOH! No I did not!!! I had it plugged but I had unplugged it! (Because I needed that screwdriver ).

Unfortunately, having plugged it... Still no go.

Not if they're much too tight it won't. Valve clearance checks are a must on these old girls.

It has started recently (pretty easily), so while I fully intend to do a valve adjustment very soon, I don't want to wait till I have just to find I have the same issue still...

[Larry D]

If it started recently and fairly easily....what has changed between now and then ?

To answer you're question as to why it won't start....I'd say because you need to adjust the valves. You're going to do it anyway to ride the bike daily, so, what can it hurt ?

[Adler]

If it started recently and fairly easily....what has changed between now and then ?

To answer you're question as to why it won't start....I'd say because you need to adjust the valves. You're going to do it anyway to ride the bike daily, so, what can it hurt ?

I know! I need to do the valves... I've been procrastinating, I'm terrified I'll break something.

Anyhow, story of the bike.
After I got it from the OP, Changed the air-filter and did an oil-change and I cleaned the carbs... badly.
Didnt work, so I started learning on here.
Cleaned the carbs better, still no soak (couldnt find).
Now it worked but rather badly (high and not very reliable idle).
Bought some carb cleaner and soaked the carbs and changed the o-rings, also polished the exhaust. Now it wont even think of starting.