Dual Pull Throttle Body Adjustments

[julienm94]

Hi all,

I am on the verge of finishing my 650 project but can't for the life of me find any information or manuals on how to adjust a dual pull throttle on the earlier bikes. I just ordered new cables to run to stock carbs, but I have no clue how to get it fit right to the throttle housing. Is there a manual somewhere? I have the cables through the entry holes and sitting correctly on the throttle sleeve grooves. The throttle pulls but doesn't snap back at all. There are a couple of screws on the housing that are for "adjustments", but I don't see how they even work. Is there a manual that also shows the correct cable routing?

Any help is appreciated.

 

[Dom]

If the throttle isn't returning I'd say either the cable routing needs looking at or the throttle grip needs checking. Are they new cables, so no fraying?

 

[willis]

Do the carbs snap closed when the cables are not attached? I’ve had friction issues in the past with the little rubber sleeve that goes into the throttle housing before. If it’s not seated just right it creates drag.

 

[julienm94]

Do the carbs snap closed when the cables are not attached? I’ve had friction issues in the past with the little rubber sleeve that goes into the throttle housing before. If it’s not seated just right it creates drag.

Yes they snap closed when not attached to the throttle housing. The rubber grommets don't seem to fit the AMAL dual pull housing cleanly.

 

[julienm94]

If the throttle isn't returning I'd say either the cable routing needs looking at or the throttle grip needs checking. Are they new cables, so no fraying?

It seems routed OK (how I got the bike, and it worked before) but not sure about the housing.

 

[willis]

Are you not using the factory throttle housing? Have any pics?

 

[jpdevol]

Not sure - pics from earlier posts....
Says Amal on it? (old british manuf.)

 

[jpdevol]

Look like this?

 

[jpdevol]

I just ordered new cables to run to stock carbs, but I have no clue how to get it fit right to the throttle housing

What brand and application are the cables? Did you oil the cables? Is the throttle tube (metal or plastic) extended beyond the bar-end a bit? Is the grip rubbing against the cable housing?

Sorry for all the questions; trying to eliminate common generic causes and narrow it to possible mismatch of cables and throttle housing.

 

[Dom]

They should be routed below the brake lever, leaving the throttle housing facing down to the ground if that makes sense. As they are they are fouling the brake lever.

 

[julienm94]

Not sure - pics from earlier posts....
Says Amal on it? (old british manuf.)
View attachment 227183View attachment 227184

Yes, this is how I bought the bike of the original owner. I know that the housing should be downward and cables run down the left and right respectively. I purchased another housing like the one you sent below because it seemed this old one was pieced together. Not sure what the screws are that stick out of the throttle casing. It should be relatively close to OEM Yamaha from what I've researched.

 

[julienm94]

They should be routed below the brake lever, leaving the throttle housing facing down to the ground if that makes sense. As they are they are fouling the brake lever.

Thank you. I just realized this yesterday doing more research.

 

[julienm94]

What brand and application are the cables? Did you oil the cables? Is the throttle tube (metal or plastic) extended beyond the bar-end a bit? Is the grip rubbing against the cable housing?

Sorry for all the questions; trying to eliminate common generic causes and narrow it to possible mismatch of cables and throttle housing.

The cables are genuine OEM from Japan. Cables are lubed. Metal tube. It does extend beyond the bar just a smidge. grip is not rubbing.

 

[julienm94]

Correct! Do you know how to use the screws on the housing? Not sure of the use.

Look like this?
View attachment 227185

 

[jpdevol]

Well, I think I do (pending memory); one is a stop screw that limits total amount of throttle and the other is a tension adjuster that can hold throttle in a set position (crude cruise control). The throttle should work fine with both backed completely off, temporarily, to diagnose issue.

 

[julienm94]

Well, I think I do (pending memory); one is a stop screw that limits total amount of throttle and the other is a tension adjuster that can hold throttle in a set position (crude cruise control). The throttle should work fine with both backed completely off, temporarily, to diagnose issue.
View attachment 227245

Thank you for the tips. I just ordered brand new, OEM cables and a new throttle housing. Will do all the steps over again with new parts and see how it goes. Coming to the final stages.

 

[julienm94]

@jpdevol wired the throttle with new housing, downward, through the left side, and using a couple of zip ties at the throttle case connection. Snaps back and works like a charm. 95% complete. Thank you for the help along the way!