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monkeybikegirl
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VBMWMO #9267
Joined: 05/15/2017
Posts: 46

Hi everyone
I have 1972 R75 that does not want to rev down once it is hot. I checked all carb connections and it seems tight. A friend suggested AT springs in the advance mechanism. What else should I check?
Thanks

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6423
Usually this is a result of a

Usually this is a result of a couple of things. Once the engine is warm and the idle creeps up, try releasing the clutch to create enough drag to slow the engine back down. Does the idle stay at the normal RPM or does it creep up again? If it stays at the normal RPM, then it could be the advance unit springs or it could be that the advance unit is dirty and needs to be cleaned. If the RPM creeps up again, that suggests that the carbs were synched when the engine was cold or not fully warmed. The carbs should be adjusted after a 30 minute ride or so...then the adjustments you make are for the same situation as when you're riding.

Be sure that all carb connections are tight, the clamps that connect the carb to the head. Spray some brake fluid around these connections with the engine running...if the RPM changes, then the connections are loose.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

monkeybikegirl
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VBMWMO #9267
Joined: 05/15/2017
Posts: 46
Advance springs

Thanks Kurt
The idle stays down once I drag it down with the clutch.
I ordered new springs and will try to lube the unit also. I think I will check the diaphragms also tonight. Will follow your advise and sync carbs hot after that.

mark_weiss
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Arizona
Joined: 11/17/2013
Posts: 171
Every once in a while, the

Every once in a while, the carburetor mount spigots are loose in the heads. The spigots are best tightened when the heads are hot.

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Mark
qualitycycleservice.com

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