R1100RS Choke

[JamesW]

I recently noticed that when I apply choke on my '94RS that the engine begins running very rough as though the throttle bodies go out of sync very badly. So, today I decided to check and or adjust throttle bodies. Using a Twin Max set to maximum sensitivity both idle and throttle sync is spot on. I began by adjusting all slack out of the TB cross over cable and setting .5mm of slack in the throttle cable and 1mm of slack in the choke cable both measured at the left TB. I had to only very slightly loosen the cross over cable to attain perfect sync. Idle sync was perfect to start with. Now, it seems to me that the TBs should stay in sync when choke is applied but they don't although they are somewhat better than when I began. How is it that if throttle sync is spot on the same is not the case when applying choke or throttle position with the choke control?

[dirtrider]

Morning James

 

What you are seeing seems to be normal on the older single cable (no Bowden box) bikes with some miles on them.

 

When you advance the choke (fast idle) lever it pulls ONLY on the L/H TB cam so the L/H cam starts turning first & allows the crossover cable to slightly slip at the cable barrel hole due to the main cable slackening.

 

When you use the twist grip- that pulls on the main throttle cable & keeps it tightly wrapped on the L/H cam so it then also keeps the crossover cable in place on the L/H cam.

 

If you want to try sometime to get a more even choke cable pull you might try a spot of Gorilla Snot (Fast Tack) on the L/H side where the main cable barrel sits in the cam hole. (something to keep the cable from slipping slightly on the L/H cam) - OR about anything to tighten the cable barrel in the L/H cam hole.

 

I would imagine either your cable barrel has a little wear or the cam hole is slightly worn (or both).

 

[JamesW]

Hi DR,

That sounds reasonable only my '94 only has 2.8K original miles. That's one good thing about the Bowden box.

[dirtrider]

Afternoon James

 

One other thing you might try-- Is to first open the throttle with the twist grip then while still holding it slightly open advance the choke lever to choke position.

 

That should keep the main cable tightly wrapped on the L/H cam as the choke cable holds it there.

 

[JamesW]

Hello DR,

I just went out and gave that idea a try and it worked!

 

Thanks,

Jim

[cris nitro]

Afternoon James

 

One other thing you might try-- Is to first open the throttle with the twist grip then while still holding it slightly open advance the choke lever to choke position.

 

That should keep the main cable tightly wrapped on the L/H cam as the choke cable holds it there.

Brilliant! I love reading stuff like this.

 

Thanks for all your contributions, dr.

[JamesW]

I certainly do second that. DR is a valuable resource.