Dies and/or Run poor when hot

[5azzmonkey]

OK I'll start by giving some history first

Bike had been sitting for about 10 years here is the setup it had in it:
82 GS1100E
PODS -- no name brand
Kerker Megaphone
Stock Needles 3rd from top
Diaphragm drilled out
160 air jet (stock is 170)
Pilot jets set to 3 1/4 turns
165 main jet --- Freaking huge
Pilot Jet #45 -- stock
What's been done (engine wise) and the configuration it is in now:

New rings with stock pistons ... professionally honed on a machine
valve job
all valve clearances set to .005"
New K&N PODs
Same Kerker Megaphone exhaust
Carbs dipped and the tutorial followed very closely
Carb plugs new OEM
Gaskets new OEM
Bench sync
Floats set
Pilot Jet #47.5 -- (stock 45)
new carb boots
Dynojet Kit--
Dynojet needles 3rd from top
138 mains
160 air jet (Stock is 170)
Pilot jets set to 3 1/2 turns
New Plugs
New Coil wires
New plug caps
Electrical connections all cleaned with Deoxit D100 and Charging Well
Coil rely installed

I'm not sure if this is a carb issue or an electrical issue:

I finally got the bike on the road today All was good except a stumble from 2.5k to 4k rpm, I'm thinking no biggie I will just need a needle height adjustment. I pulls very hard above 4k and I wound it up to ~8k a few times too. I did not want to push it too much in the high rpm's as the top end was just rebuilt. About 10 miles into my ride the bike started to sound choppy and just not right, losing power and I had to keep the rpm's up to get anywhere then it died. I noticed the oil temp was around 210. I waited about 5 minutes and tried to start it and it did except again it ran and sounded horrible and died again about 1/2 mile up the road. I let let it sit about 20 minutes and then started it, it sounded fine and I drove it home ~1/2 mile. It is now sitting in my garage and here I am typing away hoping someone here will have some advice.

Thanks,
Dave

[hampshirehog]

First thoughts are dodgy petrol tap or vacuum in the petrol tank.

[5azzmonkey]

First thoughts are dodgy petrol tap or vacuum in the petrol tank.

Petcock is new but I guess I could try running it again on prime and see it that cures the issue.


Thanks,
Dave

[azr]

I'm wondering if one of your pickups is failing or one of your coils? when they heat up they will fail, just a thought.

[hikermikem]

Hi Dave,

Are you running a fuel filter? What do your plugs look like? Have you checked the voltage at the battery after it died?

Sorry for your frustration - it will get better...

mike

[koolaid_kid]

That is exactly how my bike ran when the igniter decided to take a dump. It's my understanding there are transistors in there that can heat up and fail. Then when they cool off they can run a bit more. Go to BassCliff's site under Electrical Odds and Ends. There is an igniter test there.

[5azzmonkey]

First thoughts are dodgy petrol tap or vacuum in the petrol tank.

hampshirehog --- you nailed it! I raised the needles to get rid of the stumble then took it for a ride. about 1/4 mile later it started to act up and I switched it to prime, BINGO!. I rode the bike about 50 miles afterword with no issues. It felt great getting back on my GS after ~10years sitting and lots of work this summer on it.

Big thanks to everyone for the suggestions fortunately hampshirehog suggested the easy item to check first and it was it!

Now to figure out if it is the new petcock (one of the few items I didn't buy OEM) or if I have a lack of vacuum or a vacuum leak.

Thanks again,
-Dave

[hikermikem]

Great! Glad you found the problem... just remember to switch it off PRIME when the bike's not running, otherwise it will likely start filling the crankcase with fuel as fuel seeps by the needle valves in the carbs. Running with fuel in the oil is a bad thing.

Perhaps the vacuum line simply is kinked, cracked or became disconnected? Did you use new lines or re-use the old ones?

Disconnect the vacuum line from the petcock and with the bike running there should good vacuum at the hose end.

If that checks out, run separate lines from the petcock: route the fuel line into a container, then suck on the vacuum line while the petcock is positioned in "ON" & then "RES". Fuel should flow nicely in both settings while there's vacuum applied.

[5azzmonkey]

Great! Glad you found the problem... just remember to switch it off PRIME when the bike's not running, otherwise it will likely start filling the crankcase with fuel as fuel seeps by the needle valves in the carbs. Running with fuel in the oil is a bad thing.

Perhaps the vacuum line simply is kinked, cracked or became disconnected? Did you use new lines or re-use the old ones?

Disconnect the vacuum line from the petcock and with the bike running there should good vacuum at the hose end.

If that checks out, run separate lines from the petcock: route the fuel line into a container, then suck on the vacuum line while the petcock is positioned in "ON" & then "RES". Fuel should flow nicely in both settings while there's vacuum applied.

I used new line and even snipped ~ 1/2 inch off each end and it still had issues. I plan on more trouble shooting as you suggested this week as time permits.

Thanks again
-Dave