Hi All,

So, I've just finished doing Kreiger manual CCTs and cleaning my carbs. The bike will start, but it'll only keep running for a second and then it dies. If I keep trying to re-start it, it'll quit starting after a 2 or 3 starts. If I let it sit for a few minutes, it'll start again, and then die.. and then quit starting again after 2 or 3 starts. That first always runs longer than the subsequent ones. The longer I let it sit in between attempts, the longer it runs (most I've gotten so far was maybe 2-3 seconds).

I've checked and re-checked the small vacuum line on the petcock and it's on the back, not the bottom, so it's not the infamous "PIVLR".

It honestly sounds absolutely great for that second or two that it runs..

Any ideas?

This is basically my first attempt at servicing carbs, but I'm very experienced mechanically, just never owned anything before this bike that was carbureted. It really seemed like a simple job though.

I'm left wondering how the carb bowls fill initially though, the petcock is vacuum controlled, so how are the carbs supposed to fill the bowls initially? Do they need to be primed somehow? Am I barking up the wrong tree?

Any help is greatly appreciated!

 

Oh, almost forgot! I set the TPS to 500ohm while I was in there.

 

Gas in the tank?
Gas tank fuel tap on?
You could discretely apply vacuum to the petcock to fill the float bowls.

 

Thanks for the ideas!

Gas in the tank. Not a ton, but enough that the light isn't even on.

Petcock is on.

Applied vacuum to petcock with mityvac, didn't seem to make any difference....

I did manage to catch it just right with the throttle on one of the better starts and keep it running for a while. It sounded really anemic though and it wouldn't rev past about 2k rpm And it died as soon as I released the throttle.

I haven't been able to catch it again, but the battery is pretty dead now so it's on the charger...

 

valve diaphragms seated / sealed at carb top?

 

Yep. both slides slide/sound/feel perfect. Just like the ones in the video on this thread www.vtr1000.org ? View topic - Carb Strip Jetting Pictures

So, update on what I've tried:

I popped open both bleed screws on the float bowls, so there's fuel in there.

I pulled the top off of the air box and checked just to make sure I didn't make the noob mistake of leaving rags in the carbs.

I've tried adjusting the TPS while trying to start it, just to see if it really doesn't like being at 500ohm...

and I've gotten one pretty intense fireball backfire..

Otherwise, just a lot of cranking and stumble-start-die...

What did I do??

 

Ok, another update. This might mean something!

I pulled the carbs back off and the front port is full of fuel. The front carb is clearly just pouring fuel into the cylinder.

Now, what this means, I have no idea.. other than something isn't working properly.

What could cause this??

 

1)Float valve is partially obstructed open by debris so it no longer controls fuel flow correctly .

2)Or you somehow damaged the float itself in the reassembly.

 

Ok. That's what I was thinking... Thanks for verifying!

I pulled the float bowl and cleaned the float valve and it's seat. Then held the valve in the seat and blew down the fule feed line to ensure it's closing up tight.

I put the float in a bowl of water and it floated. Then I held it under and no bubbles.

Anything else to check before I put it back together?

Also, if it weren't for the fact that I read a few threads last night describing stuck floats causing puddles under the bike and in the air box but the bike still running, I would have been convinced this was what was preventing my bike from running. but after reading those threads, I'm not so sure.. Could it really run like this?

 

If you have had fuel poring down the intake port....... it would be good to check your engine oil and make sure it has not been diluted. Check the level and see if it has increased. Give the oil a sniff test to see if you can smell gas.

You may want to compare the height of the float in both carbs as the rear is not flooding. With the float bowl off invert the carbs and look at the height of the floats the should be the same.

If different bend the small metal tang that pushes on the inlet needle so that front and rear floats match.

 

I checked my oil, and there was definitely fuel in it, so I changed oil and filter. Thanks for the heads up!

I compared the heights of the floats, and they're the same.

I don't see any metal tangs.. the float is completely plastic, there's no metal parts at all. Am I missing something?

I blew down the feed line and then lightly pushed the float up and the valve definitely closed.

I put the carbs back together and put them on the bike. Tried cranking it with the air box off and the front carb is shooting fuel out of the three little brass tubes just below the throttle opening. Since I'm a total carb newbie, I have no idea what those are for, but I'd doubt fuel is supposed to come out of them... especially not squirting out.

What does this mean? loosing my mind here! The weather's been beautiful for the whole week the bike's been down!

 

Hmmmm I still suspect something with the float or float needle.

I you have carbs off again I would put both floats in gas and compare the buoyancy. They should both at float the same height.

I have never had these particular carbs apart but on any other card I have ever worked on there is always some way to adjust the float height / level in the bowl. Maybe someone else can enlighten on that point.

If you see no difference in the floats you could try swapping the needle seat, needle, and float from front to back carb to see if problem moves to rear carb.

 

If you can rig up another fuel supply to the carb you can check to see if the carb floods before you put it back on the engine. Save some aggravation.

 

You might try sending a PM to 8541Hawk and ask him to have a look at this thread. He knows a lot about VTR carburettors.

 

Is the enrichener needle fully seated and sealed on the front carb?

 

Sorry, total newbie.. what is that?

 

"Choke" needle.

 

Sorry still don't know what that is. Where is it? What does it look like?

 

Well if you had the carbs out of the bike and apart to clean them you must have noticed the Y shaped cable attached to both carbs with a **** that pulls out to enable easier cold starting. People call it a "choke" since it effectively does the same thing, but it's really an enrichener control.

 

Gotcha. After reading the service manual some more, I figured it out. I was aware of the choke, I just don't know how it works and had no idea there was a needle in there. Sorry for my ignorance.

I also realized something else while looking over the service manual: My bike is a CA model and I removed the evap canister while I had it apart, but I capped the ports on the carbs that the lines to the purge valve attached to. According to the manual, those ports have "air vent lines" on them for the 49 state model.. I'm thinking capping something that's supposed to be a vent is probably not the best thing to have done.

Really sorry I forgot to mention having removed the evap system in my initial post, it just slipped my mind with all the problems I've been having.

So, I'll pull those caps when I get home and see how it goes

 

Well, so... I'm dumb. But the bike runs great now

I did, in fact, cap the vents when removing the CA emissions stuff. Amazingly enough, capping something that's supposed to be a vent makes it not work right. Duh.

At least stupidity only cost me a few days of missed riding and some internet embarrassment.

Thanks guys! I really appreciate the help!