K75 throttle return problem

[pc759]

Hi everyone am really struggling with a k75 and its throttle cable not returning .
I’m Paul and I bought a hacked to pieces 1986 k75 about 18 months ago from eBay . It did run but it was in bad shape and the seller had hacked the upper loom into the speedometer to pieces so he could connect up the typical iztoss speedo from amazon . I thought I woukd just clean it up go through it mechanically then fit a tenet. Adapter for said speedo … but no! I have it working and running and am getting there with the wiring to the tenet but after having the frame off and then reassembling I can’t seem to get the throttle cable to snap back or even return slowly. I’ve lubed the handle area under the front master cylinder and routed the cable several ways, to no success. The cable length is 112 cm for the non standard bars I have sorry no idea what make. Wider than normal ones . When the cable is disconnected the throttle body springs seem to work well and take the bike back to its stops so I can’t seem the throttle body springs being weak or any thing . The cable itself seems to move freely to me although it is old so wondered if this was likely the culprit any advice on cable routing gratefully received

[pc759]

Here is pic of the handle bar are under the master cylinder

[Laitch]

Remove that throttle gear wheel from its axle, inspect it and the throttle tube gear to which it mates for broken teeth. Broken teeth can interfere with rotation. If both gears are okay, thoroughly clean the housing with solvent the lube the works with white lithium, silicone grease, or silicone spray because it looks like a mess in there, unless the gummy appearance is a photo artifact. If the throttle cable was a BMW cable and the previous owner tried lubing the cable channel with oil, it's likely the cable's teflon lining turned into goo and is obstructing smooth operation.

Verify that the tic marks of the cable gear and the throttle gear align on reassembly and verify there is no rubbing of the throttle tube assembly on the switch housing.

[pc759]

Thank you I will try that I think throttle tube might be culprit it seems sticky in one area.
 The cable when up there but not in snaps back just fine  so throttle body springs work well enough to pull the old cable back in to idle position . I’ve got the correct greases but will reapply and clean thanks again .
Paul

[daveson]

Another possibility is that there's an adjustment screw on the opposite side that works a little bit like cruise control. If you turn it anti clockwise, say a quarter turn, it might then retract normally. After a while, you might prefer to set it back where it is now.

[pc759]

Heard of that but don’t think I can see it thanks

[Laitch]

Heard of that but don’t think I can see it thanks

This is one and its location on a Brick. Some owners indicate that theirs didn't come with one originally.

[The Mighty Gryphon]

Loosen the clamp for the right hand grip assembly and slide it out about a centimeter.  Sometimes the end of the grip rubber can rub on the end of the handlebar.

Carefully check the throttle cable along it's length for sharp bends pinches and kinks.

Does the grip rub against the throttle housing? 

[Chaos]

Have you pulled the grip entirely off the handlebar and cleaned off all the gunk that accumulates on the rotating surfaces?  That was the issue with mine, made a world of difference.

[Motorhobo]

Loosen the clamp for the right hand grip assembly and slide it out about a centimeter.  Sometimes the end of the grip rubber can rub on the end of the handlebar.

Carefully check the throttle cable along it's length for sharp bends pinches and kinks.

Does the grip rub against the throttle housing?

Happened to me, too. Easy fix. When I had the sidecar rig attached, I think I was even using this as a poor man's cruise control.