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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Freelancer on June 21, 2015, 03:45:18 AM
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Trying to help a friend here.
The issue:
He has an 86 k100rt, that starts and runs fine then 30 minutes into the ride, he says the bike acts fuel starved and then dies.
If he lets it cool for a bit, it will restart fine and run for a bit then the same thing.
The setting:
-He replaced the fuel filter just two months ago.
-He's cleaned and inspected all wiring in the fuel tank and the 4 prong connector running out of fuel tank.
-He has checked and cleaned his chassis grounds.
-He just went up to Colorado and installed the High altitude jumper/loop.
List of suspects:
-He is thinking fuel pump.
(I have a spare that I'm mailing him, just in case.)
- Personally, I am suspecting something in the ignition timing or fuel injection electrical other than the pump.
What ideas do you guys have?
Could it be the Hall Effect sensor?
Something in the Jetronic?
Any help will be much appreciated,
Freelancer
P.S.
Will post more details after he and I talk tomorrow
Again,
Thanks
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Could it be the Hall Effect sensor?
Yes.............to test: remove the T-shaped cover in front of the engine (be careful with the gasket).
With a cold engine, heat up both HES with a hair drier....start, then the engine should stop much
earlier...if it's one of the HES that is the problem.
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This probably has no bearing on it, but I had a similar situation with my late model ford explorer when towing a trailer with 2 bikes. 200 miles after each fill, it would sputter and die. 5 minutes of sitting later, it was fine.
Turns out there's something funky with the venting, because all I had to do was loosen the gas cap to let air into the tank. Seems vacuum was building inside the tank as the fuel was consumed and the pump couldn't compensate. Burn rate was much higher than normal due to the extra tow load...
So maybe it's as simple as a clogged vent? Is that possible?
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Thanks guys, have let him know your ideas and how to test.
Also, read a thread where a cheap rebuild of the HES was mentioned but no detalis on the how to and whether the wires match up.
If anyone has, or knows of, a good detailed write up of the HES rebuild please post it up. I'm looking for one where you rivet new sensors onto the old plate.
Your assistance is much appreciated,
Freelancer
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Oilhead Hall Sensor Diagnosis and Rebuild (http://users.rcn.com/dehager/service/oilhead_hall_sensors.pdf). This applies equally to the classic K-bikes.
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Thank you rbm,
Will forward this to my friend.
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Well, he did the heat test and the Hall Effect Sensor passed with flying colors. Dave has gone through and cleaned every plug and ground contact that might be involved.
He will try a long ride on his bike in the next day or so. He is waiting on a spare Fuel Pump I sent him. Dave is in a remote area of the West slope and is trying to avoid another all day limp home situation.
We'll keep ya'll posted as to whether its fixed or still cuttin' out.
Later,
Freelancer
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Sorry its been so long. Friend fixed his problem then went out and hit a deer.
He is ok and the bike is fine, just cosmetic damage(to the bike, not him :2thumbup:)
Turns out that the problem was a dirty/weak connection where the harness plugs into the jetronic module. After cleaning it and all the other connectors twice the problem stopped.
Thanks for the input, you guys/motobrick community are aces.
Later,
Freelancer
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Sorry its been so long. Friend fixed his problem then went out and hit a deer.
He is ok and the bike is fine, just cosmetic damage(to the bike, not him :2thumbup:)
Turns out that the problem was a dirty/weak connection where the harness plugs into the jetronic module. After cleaning it and all the other connectors twice the problem stopped.
Thanks for the input, you guys/motobrick community are aces.
Later,
Freelancer
[/quote
Can anyone tell me where this connection would be located on the bike? I have a similar problem. thanks
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update: found the connector under the fuel tank. fixed problem.