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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: DRxBMW on July 08, 2012, 10:01:40 PM
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My K 75 whip started to backfire recently. Happens around 2500 to 3000 K on the tach after I shut the throttle down. Gentle poof sometimes, bang, if if you hammer on the throttle and let off or on a hill.
I've always had some minor back-snapping/gurgle going down a steep incline but this situation is new.
Missing the mica gasket between the header pipe and muffler after I sold the Supertrapp and went back to stock exhaust.
Cut up a coke can in an attempt to save money instead of pricey one time use gasket ___ First test run,NO change, insert swear words here.
Loosened the TPS, I hear a soft click rotating it back and forth. The loud click was the idle adjustment screw hitting the stop, which I thought was the TPS sound WRONG.
Anyway during the second test run, things are improved. I set the TPS semi in the middle, bike idles fine but the TPS click is almost inaudible.
Long road test on the slate for Monday, stay tuned. Saying a prayer to the motObrick Gods that the snafu is fixed.
TPS was anchored on tight, confused why rotating the damn thing would make much difference.
Assuming that the throttle cable is part of the equation ? I did tinker with the idle advance aka "false choke" tension slightly two weeks ago. But the butterfly's were closing correctly.
FWIW,Paul Glaves from IBMWR claims that rotating the TPS usually cures the backfire condition also. How is a mystery, can you enlighten me Drake ?
Does a TPS go bad from age ? Anything else I should be aware of ?
Wicked T storm locally last night, baking around a turn, I encountered a HUGE pile of downed tree limbs. What a trip, forced to run over the debris and hope for the best.
thanks ___ bricKheads.
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Loosened the TPS, I hear a soft click rotating it back and forth. The loud click was the idle adjustment screw hitting the stop, which I thought was the TPS sound WRONG.
Anyway during the second test run, things are improved. I set the TPS semi in the middle, bike idles fine but the TPS click is almost inaudible.
Long road test on the slate for Monday, stay tuned. Saying a prayer to the motObrick Gods that the snafu is fixed.
Backfire issue is now WAY better, only a random pop descending a steep hill is present,I'm satisfied with the outcome.
I still do NOT understand how rotating the TPS did anything, since it seems to be almost in the same position as before BUT it did work !
Accessing the inboard TPS anchoring screw is a mechanical challenge. Ended up removing the fuel return hose to make things easier, damn tight space.
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Accessing the inboard TPS anchoring screw is a mechanical challenge.
I keep meaning to replace those Phillips screws with hex-head screws for that very reason.
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It seems like you got your TPS correct adjusted,.....when the switch is closed, the Jetronic cuts the fuel when above 2000 rpm with closed throttle.
Inge K.
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It seems like you got your TPS correct adjusted,.....when the switch is closed, the Jetronic cuts the fuel when above 2000 rpm with closed throttle.
Inge K.
Ya, it is much better.
My K 75 has always gurgled slightly on a steep downhill since new.
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I keep meaning to replace those Phillips screws with hex-head screws for that very reason.
Done :yes