Bike Gets Hot Then Dies?

Yes Nebr_Rex you are right, those bolts are just the rocker fulcrum on the late 400/440 head

Here are the pics of the early 400 head and plug caps, source www.kz400.com
The valve clearance should be 0,08 - 0,13 mm

Just rode it around for about 20 minutes and it happened again. The initial symptoms were the idle kept going lower and lower. Then it started bogging and I took it straight home. Below are the spark plug pictures taken from just now.

k1z947060 wrote: Just rode it around for about 20 minutes and it happened again. The initial symptoms were the idle kept going lower and lower. Then it started bogging and I took it straight home. Below are the spark plug pictures taken from just now.

How new is the battery? what is the condition?

Is the vent in the cap clear? Strainer on the petcock clear. Does it have a sediment bowl? Plugs look good. Sounds like it's running out of gas.
Steve


www.mikesxs.net/yamaha-xs650-petcock-fue...ters-pk-2-70-77.html

Could be condensers or coils. Run the bike in a very dark room to check for electrical discharges where they shouldn't be. Condensers are cheap enough to replace.

Check the vents on the carb bowls are not plugged and the petrol cap vent is clear as mentioned above.

weeZee wrote: Could be condensers or coils. Run the bike in a very dark room to check for electrical discharges where they shouldn't be. Condensers are cheap enough to replace.

Check the vents on the carb bowls are not plugged and the petrol cap vent is clear as mentioned above.

He wrote, in an earlier post, that he changed the coils. I suspected the coils as well, until he mentioned that he changed them.

weeZee wrote:
Run the bike in a very dark room to check for electrical discharges where they shouldn't be.

A weak condenser generated strong sparks on the points = (new) points wear out fast (pitting) = wrong ignition timing (gap/dwell)




A clogged tank cap vent generate a vacuum inside the tank earlier or later dependent of the filling level and fuel consumption .
Try to ride the bike with unlocked tank cap to prof the theory. Just a thought.

650Dude wrote:

k1z947060 wrote: Just rode it around for about 20 minutes and it happened again. The initial symptoms were the idle kept going lower and lower. Then it started bogging and I took it straight home. Below are the spark plug pictures taken from just now.

How new is the battery? what is the condition?

The battery is not older than 6 months. Its one of the big heavy traditional batteries that has to stand upright. I also have a very cheap small AGM battery. This issue happens with both batteries, and without a battery connected. (Ive started it then disconmected the battery, same issue same time frame)

SWest wrote: Is the vent in the cap clear? Strainer on the petcock clear. Does it have a sediment bowl? Plugs look good. Sounds like it's running out of gas.
Steve

www.mikesxs.net/yamaha-xs650-petcock-fue...ters-pk-2-70-77.html

I went throygh and cleaned the gas cap and fuel petcock. Ive checked the petcock several times. I ended up removing the fuel filters because gas wouldnt flow through them. I have hecked and fuel does run freely out of the hoses now.

I will check the gas cap again. But when this problem has occured in the past I have opened the gas cap and it did not help even after trying for 15 or 20 min.

Im certainly no expert but I thought the plugs looked lean to me. If it was slowly running out of gas, wouldnt it cause a lean and hot condition before dying? (Just asking for understanding)

weeZee wrote: Could be condensers or coils. Run the bike in a very dark room to check for electrical discharges where they shouldn't be. Condensers are cheap enough to replace.

Check the vents on the carb bowls are not plugged and the petrol cap vent is clear as mentioned above.

I am going to remove the breather/vavuum hoses to make sure there werent any pinches and try that. I will also double check the gas cap.

I wanted to replace the condenser a while back but could not find one. If you guys have a link i will probably purchase today.

Look for blue sparks at the points.
Steve

Is it supposed to be blue?

Also - I think I found a fool proof way to determine if its running out of gas or not. Next time it dies lay the bike over and see if any fuel comes out the overflow. Hopefully it won't die again though. I hope it was due to a kinked breather tube on the VM carburetors.