Starting issues...all comments welcome!

[Steve]

Are you applying any throttle while cranking and using the "choke"?

The throttle should not be used AT ALL while starting the bike. The "choke" circuit requires the high vacuum of a CLOSED throttle to draw the extra fuel and air through the enrichener circuit. Opening the throttle AT ALL will eliminate that high vacuum and you will be trying to start the bike with the normal (lean) jets.

Using the throttle while starting a warm engine is a matter of personal choice, but it really bugs me to hear an engine that is started and immediately raced to several thousand RPM before the oil has a chance to flow.

.

[kwest187]

All passages are clear. When I had the choke system disassembled, I was able to spray clean through both ways. on the starter circuit I could do the same-I am not using the throttle at all.

[kwest187]

I just read through the BS-CV rebuild guide I found on someone's post on the "thumper talk" thread...
Wow what a great piece of literature. It does seem I've done all the correct carb rebuilding processes...ONE thing though...my vacuum line to petcock is capped-should I uncap this?
If so do I reroute...I do NOT have a place on my current petcock to attach this line-

[TheCafeKid]

So your petcock is not stock then? Cause they all had vacuum operated taps from the factory. If it's not stock, then you need to leave that capped as otherwise it will draw air freely. Might check to make sure the cap is still good and tight too. What are your mixture adjustment screws set at? Need to be about 2.5-3 turns out. Have you checked your plugs to see if they're wet or dry after cranking?

[kwest187]

The petcock and tank are not stock and are not vacuum. Question-I've never had a vacuum petcock...does it draw any fuel?
I'd assume no or maybe on prime.
I'm thinking of pulling the needles and adjusting them to the richest position. BUT, the needle has little to do with starting. Also if I manually prime the carbs I can get the bike to run on choke, If I release the choke the bike will die, if I touch the throttle...the bike will die?
Also to add insult to injury, I burned up my starter relay with all the starting attempts...
thanks for watching this thread and all the help guys, I know I'll get it sooner or later...keep the tips coming and ask away for what I've tried and so on-

[koolaid_kid]

In a vacuum petcock there is a diaphram. When the vacuum line draws a vacuum, it allows fuel to flow to the carb(s). No vacuum, no fuel. Extremely safe, no fuel on the floor in the morning, just the best of the best.
The needles have nothing to do with starting, don't bother.
You need to be concentrating on your pilot screws and their passages. Are the pilot air screws 2-3 turns out?

[TheCafeKid]

In a vacuum petcock there is a diaphram. When the vacuum line draws a vacuum, it allows fuel to flow to the carb(s). No vacuum, no fuel. Extremely safe, no fuel on the floor in the morning, just the best of the best.
The needles have nothing to do with starting, don't bother.
You need to be concentrating on your pilot screws and their passages. Are the pilot air screws 2-3 turns out?

Just to clarify a couple of things: a vacuum operated petcock requires vacuum to open the diaphragm to allow fuel flow, the vacuum is created by the engine spinning over (an engine is essentially an air pump..) which is why your bikes stock petcock would have had a second line connected to the now capped port on your carburetor (carb number two, second from the left hand sitting on the bike). That now capped port is the vacuum port. It's free to suck air into the motor to create the vacuum to open the diaphragm on the petcock. A properly working vacuum petcock would NOT flow fuel into that tube. A failing one would. It would also likely flow fuel in any setting, which is bad. The only position that fuel should freely flow without the engine turning over is the prime position. Which, if your bike has sat a long time, you need to fill the float bowls with.

But since you say you don't have a vacuum petcock anymore, you likely have a manual petcock which usually only has an "OFF", "ON" and sometimes "REServe" position. If the bike is off, that petcock should be off. If you don't turn it off, you'll end up with a crank case full of gas and thats very bad.
If the bike is low on fuel, and your petcock has one, it should be set to the "RES" position. This position has a shorter pickup tube that allows that last gallon or so of fuel to reach the carbs.

Lastly, again to clarify, your carbs have pilot mixture adjustment screws, not pilot air screws like earlier model mechanical slide carbs did. The screws on your carbs control the amount of a pre-mixed air and fuel mixture into the pilot/starter circuit. these need to be opened to 2.5-3 turns out as a starting point or you'll not get enough to fire the bike. Just so you don't confuse them with separate air and fuel screws the earlier carbs used if you search around for more info.

Oh..and no, the needle position has nothing to do with startup. The bike will actually start and idle without slides in the bores if the carbs are working/set correctly. The needle doesn't come into play until 1/4 throttle or so.

And you really should pull those plugs and see what they look like. That's an easy and quick way of helping you figure out what's going on. If they're wet, you know they're getting fuel, possibly too much. If they're dry you're not getting enough. If they're black you're too rich, or have been running on choke a lot....etc. No short cuts.

[kwest187]

Plugs are dry, pilot mix adj. screws are 2.5 turns out...guess I'll crank them out 4 times, if still no start, I'll get bigger pilots-
And the starter relay...still got to pick one of those up today-

[tom203]

Understand that throttle plates will appear completely closed in idle position-you might think no air could get thru-but it does. If idle stop screw or throttle cable holds the plates too open, you're defeating the purpose of the enrichment and idle circuits which is to draw mixture thru those little holes. Dry plugs ( when you know the little carb passages are clear) might mean too much air is whizzing by throttle plates ,i.e.,you're not sucking on those holes.

[kwest187]

Thanks Tom203-I'll double check the throttle plates...I eye-balled them and at the top I see 3 very small holes-I adjusted the plates so the hole closest to the engine appears to be about half covered by the plate/valve-does that seem right-or should I open or close the plate more. ie the sync adjusters-

[tom203]

Thanks Tom203-I'll double check the throttle plates...I eye-balled them and at the top I see 3 very small holes-I adjusted the plates so the hole closest to the engine appears to be about half covered by the plate/valve-does that seem right-or should I open or close the plate more. ie the sync adjusters-

Good question! In your case, I'd use a straightened paper clip as a gauge between throttle plate and carb bore to get me in ballpark. First do #3 carb ( the one that idle stop screw hits), adjust by the stop screw; then do the others to match the paper clip clearance by moving their own adjusters. Hopefully, this will be close.