I have a 1975 xs, the engine is bone stock only recent modification is installing Hugh's new pipes. Now here is the issue: when the motor is hot it seems like the throttle holds open at certain rpms, no tach but usually around when I'm shifting. The weird thing is the throttle is fully closed. The engine seems to rev up when I pull in the clutch to shift. If I drop the clutch and lay off the throttle it usually comes back down. It has also happened in neutral when I cracked the throttle, again the throttle is fully closed but the engine continues to rev up as if I'm on the throttle. Any help would be greatly appreciated. Thanks!
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NONclow
Confirmed Laquer Breather
Have the throttle cables been disturbed recently?
Not sure what carbs are on your bike, but there should be 1 cable with linked carbs, or 1 cable to each carb. If the latter, make sure the cables sit completely in the guides. Also check the idle screws.
Have they been sync'd?
Not sure what carbs are on your bike, but there should be 1 cable with linked carbs, or 1 cable to each carb. If the latter, make sure the cables sit completely in the guides. Also check the idle screws.
Have they been sync'd?
Speedthriller
XS650 Enthusiast
Maybe your advance unit doesn't move freely when your engine gets hot.
+2 check your cables, check your sync, check your advance mechanism stem to stern, there are threads.
It case it actually is your throttle sticking, loosen one of the screws on the grip and slide the grip back a hair so that the throttle can't drag on the bar end. Also, you should adjust the cable up at that "L" thing at the top so that there's 1/8" or so of free play; you should be able to twist the grip about that far before all the slack is out of it.
Air leakage around intake manifolds.............................mixture screws not adjusted correctly............................needle jets O-ring worn out and need replacement.....................carb sync needed.
Pull the tank and check the routing of the clutch cable. Manipulate the clutch and see if the clutch cable moves somewhere it shouldn't...
Very strange that you mention that about the clutch cable. When I turn my bars hard to the left, like if I'm parking or moving the bike. The engine revs up, but the throttle is not opening up and the slack is still in the throttle cable. The plot thickens
NONclow
Confirmed Laquer Breather
Throttle cables, new/old?
If old, they could've been previously pinched, or routed wrong.
How are they routed now?
If old, they could've been previously pinched, or routed wrong.
How are they routed now?
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