TOPIC:

im very lucky. a week ago I was in coming out of a Mall on my 1978 KZ650. A elderly lady driving a old station wagon, turned in front of me and I went down on the bike. no injuries.

The bike has engine guards and I think that saved me. I wear full gear when I ride so that helped too.

The bike started right up after the hit. While riding a mile after the accident, the bike shut off when I was on the highway giving it throttle. A friend came in his pickup and towed me home. I let the bike sit overnight and noticed the  next morning that the brake lever is squishy, when it used to be tight. The master cylinder level was also very low. I dont know how this happened.

The next day it started up fine. Took it about a tenth of a mile and it died on a hill, it died. I rolled it back home.

Knowing a little about bikes, I took the tank off and had a look at the petcock. Cleaned it out and made sure its free flowing. Im thinking maybe the carbs got knocked? But even if that was so and it caused fuel starvation, wouldnt the other carbs get enough fuel to keep it going?

Ive been at this for 3 days now and cant figure it out. battery is good, charging system is good - but i havent tested the coils. do I need to? but the bike dies while running, especially on a hill.

Carry a can of starting fluid.
When the bike dies spray some in the airbox to see if the bike starts.
That will tell you if it's fuel related.

Good your ok. I’d be looking at fuel. It’s possible that debris got loosened up with the drastic change in tank orientation. It might be overnight is long enough to slowly fill the carb bowls but the low fuel volume will not keep up the a running bike. Do you have a fuel filter?

Hi.

Yes there is a fuel filter in it. Looked at it. Currently arguing with my friend and neighbors who insist its electrical. The bike slowly dies out like its choking under demand. one of my looney neighbors even said the voltage regulator is the problem. I gave him beer so his lips could keep busy with something else.

It really could be anything.
Best to start with the simple things first and keep an open mind about it.
It could also be your fuel tank vent.

As far as electrical.
fire the bike up and put a volt meter on the battery terminals.
note voltage

raise rpm to 3000
note voltage

raise rpm to 5000
note voltage

voltage should stay from 13-14.6

F64 wrote:

It really could be anything.
Best to start with the simple things first and keep an open mind about it.
It could also be your fuel tank vent.

As far as electrical.
fire the bike up and put a volt meter on the battery terminals.
note voltage

raise rpm to 3000
note voltage

raise rpm to 5000
note voltage

voltage should stay from 13-14.6



 

There was a petcock on it that looks like the photo below.
Im not sure if it got damaged in the accident, but it doesnt seem to flow well after the accident and the carb bowls arent filling.

When I put on an auxillary tank, the bike runs fine, but of course I cant take it out on the road with a drip external tank.
My neighbor says pingel are the best petcocks, so I looked it up and ordered one and the adapter.
At this point, it looks like the petcock is the culprit, but like I said, it was fine before the accident.
This is the one on there now.

edit: looks like the site wont let me post a photo.

 

The old petcock can be opened and cleaned. It is quite possible that debris in the tank got knocked loose and has clogged the petcock. Pingle  makes excellent petcocks, though it will be manual, so you have to remember to turn it off and on.

Thanks.

I cleaned the petcock but the flow still seems staggered. Could it have somehow otherwise been damaged in the accident?

Pingels are pretty nice. I've had one on for 3 years.
Others have had theirs for much longer.
They can be rebuilt easily as well.

Check the vacuum hose to the petcock.
Make sure the hose isn't damaged.
Does the petcock flow better on reserve?

The petcock on the bike now is aftermarket. It doesnt have a vaccum port. I wish this site would let me post the damn photo, but it wont. I keep getting a message that says "you do not have permissions to view this page."

 

F64 wrote:

It really could be anything.
Best to start with the simple things first and keep an open mind about it.
It could also be your fuel tank vent.

As far as electrical.
fire the bike up and put a volt meter on the battery terminals.
note voltage

raise rpm to 3000
note voltage

raise rpm to 5000
note voltage

voltage should stay from 13-14.6
 

I took the fuel tank cap apart, unscrewed the three screws, made sure the vent area was clean, and put it back together. In terms of checking the "fuel tank vent" is there anything else I need to check anywhere else?

I would think that after checking the vent there is not much else left to check.
Running the petcock with the fuel tank cap off is another way of verifying the cap vent.

You've pretty much narrowed the culprit down to the petcock.
As TexasKZ mentioned there may be something stuck inside.