Throttle Spring

On my '80 R100RT, the throttle does not return even with cruise screw loose. Where is the spring located to return throttle to idle if no hand pressure?

Down on the carbs.

Here's one picture:

http://www2.buoy.com/gallery/carb_rebuild/IMG_0103

Part #35 here:

http://bingcarburetor.com/pdf/MOTORCYCLE CV EXPLODED VIEW.pdf

Might want to check those throttle CABLES as well...

If I recall ... there is a "primary" cable from the bars that runs down to a "splitter" under the tank. One, or both, cables might be starting to unwind... causing drag on the inner cable(s)

Lmo1131 said:

... there is a "primary" cable from the bars that runs down to a "splitter" under the tank.

Click to expand...

And, if the splitter is anything like the one on for the choke on my 88 R100 RT, then you definitely want to take a look at the splitter. I think the design makes it prone for sticking if it's not in good clean working order.

I think the design makes it prone for sticking if it's not in good clean working order.

Click to expand...

Ya gotta ax yoursef*... you have to synch the two cables that run from the splitter down to the carbs anyway, so what was the point of adding a "splitter"? To save 18" of throttle cable, and add the cost of the splitter hardware?

My vote; two cables, all the way.

* it's a free country, you don't gotta ax yoursef anything!

That might be why there were 2 new throttle cables given to me with the bike. Also got a oil pan gasket that may fix the leak. Must be the cables somewhere. Thanks

If the two cables given to you are the same length, it's an even bet that they are the two that run from the splitter to the carbs. I'd spend an hour or two with the tank off and familiarize yourself with the real estate down there. Disassemble the splitter and clean it up. I'd replace the "primary" cable if you replace the other two.

But remember that you will soon have to learn how to synchronize the carbs, because anytime you disconnecting them it's a necessary step for smooth engine performance. Synching has been discussed many times here, so a "search" of the Airheads forum will turn up several methods and links to many more.

As far as the oil pan leak goes... pressure wash the under side at a car wash and then get down under the bike and wipe the area down with paper towels. Some would suggest that you apply a light coating of talcum powder as a "tracer"... go ride it for 20 (?) miles and then take a look at the underside again.

Those 6mm bolts don't require a lot of torque, and in the worst case scenario it is fairly easy to strip the block if your are too aggressive with your wrenching. I use an inch-pound torque wrench ... I think it's more important that they be evenly tightened.

Frayed cables at carb end can also prevent throttle return.