650 curvy - sticky throttle

Hello,

I've been trying to help a friend fix a sticking throttle with his early 650. I've been hunting through this forum but apart from one guy who had a rad hose that heated up and pinched the cable most problems seem to be cable related.

The bike is ok generally, but when it gets up to temperature the rpm sticks at about 3k. On the way to finding this I've removed and cleaned the choke cable and plungers, checked the air box and generally fiddled around and cleaned. With the idle stop wound right out if you blip the throttle it'll still sit at about 3k.

I did notice one of the plastic slides inside when moved forward and back sounded a bit gritty and sticky so we had the carbs off and gave them a good clean inside (they were fine anyway). One of them still isn't perfect but seems to operate normally.

I don't believe it's the cables as the grip returns to the stop ok. I'm going to run it without the airbox to see if the plastic slide in the front carb is sticking open, and without the cables attached to make sure it's not them.

Pushing on the linkage and forcing it back into position seems to set the idle back to normal until you open the throttle again...

Do you think it's just the carbs need to be off and dismantled and given a really good clean externally particularly around the linkages etc? Or do they sometimes suffer a sticky worn slide? The bike has done 19k.

Thank you muchly

[Biker Biggles]

There should be a little play in the throttle cables.I dont have the manual with me but its in there and how to adjust it correctly.If they are too tight they dont close properly.

Thank you, I'll give that a double check and test it without the cables connected to be sure. If anything they were a bit slack so I suspect it's something else

Cheers