Can and how to fix throttle cable to carb without taking off tank??

Can you fix throttle cable to the carb without taking off tank?? And if so how...???

Just bought nice xs400 had to do a few things to get the rwc. Brake lights not working etc etc same with front lights. The throttle grip was rotten thru and the cable itself was problematic. The small screw end was off the cable. I found it lying on the engine. No ability for throttle to work.

How does one properly fix the throttle cable to the carb?

Do you do it with the screw end already tied off?

Do you thread the cable first thru the top guide slot then into bottom lever without the screw end then thru the screw end with the lever pushed up??

It looks real easy to figure out if you have the tank off, but I have never had the tank off... and I dont want to dig deeper and open a can of worms just yet if possible.

Am I missing something here? Why the reluctance to taking the tank off?

One little bolt at the back, then remove the vacuum line from the right carb mount and the fuel line to the petcock and lift it off sliding it towards the back a bit. Might want to watch how that vacuum line is run to avoid pinching it when putting tank back on.

I have not seen how the cable fits into the lever. Which way does the end of the cable fit in??.... I will take the tank of tomorrow morning and I expect it will be much clearer once I can see it all properly.... I am still at the stage of everything is breaking... this bike has sat in the hot Queensland tin shed for years and all the rubbers are cooked and cracked...I sat on the seat and a line of stitching popped.... so I am trying to avoid moving anything around to much.... my local yamaha shop has no spares for the 1978 model....

Once the tank was off it all made sense kind of... now throttle cable is sticking...at the half way point.....

need a photo of the correctly set up cable to make sure I am doing it right...

thanks for encouragement...

ps taking off tank embarrassingly easy...

Now's the time to get into it.check everything.if something breaks better now.before you ride.

Once I got the tank off it was easy to get the throttle cable into the allocated slot and place (does it goes screw facing left or right though??).... but now the throttle sticks at least half way..causing high revs constantly, with no spring back function. I have ordered a replacement cable as the end of this one were frayed and the cable is as old as the bike. When the cable is not in place the spring works well and it goes back to no revs position, with cable in sticks half way no matter how I adjust the cable need the throttle itself.,,... in the mine time Help???

butterbeats said:

Once I got the tank off it was easy to get the throttle cable into the allocated slot and place (does it goes screw facing left or right though??).... but now the throttle sticks at least half way..causing high revs constantly, with no spring back function. I have ordered a replacement cable as the end of this one were frayed and the cable is as old as the bike. When the cable is not in place the spring works well and it goes back to no revs position, with cable in sticks half way no matter how I adjust the cable need the throttle itself.,,... in the mine time Help???

Click to expand...

Sounds like you found the problem. I'm guessing that with new cable installed you will find it works just fine. Be sure and clean everything in the throttle control while you have it apart.

Still waiting for new cable to turn up. This cable had a screw on ending at the carb end. Rather than a fixed end. Is this normal?

Here is a picture of the problematic throttle cable... it had a screw attachment as pictured. No wonder I could not get it to fit. 98% sure its not factory standard I replaced it with a second hand cable I picked up from dealer out of the Gold Coast. Once I got the secondhand but original, it slipped straight into place in both the slot fixed to carbie and the sprung throttle lever .

Problem 1 - Sticky throttle.
Unfortunately the throttle is still sticky. If the throttle cable is slotted into the holder on the carb, and you twist the throttle grip, the throttle stays up. When it is not in the slotted/ grooved holder the springs operate well and the throttle and grip springs back to zero/no throttle position.

Problem 2 - sounds like starter has sh.t itself.
Even worse now the bike wont kick over.... there is a weird slow tick tick coming from the back of the bike....half sounds like dead battery and half sounds like starter problems...I have new fuses in place... new spark plugs.... fresh brand new battery.... ??

Throttle cable with screw attachment pictured.

An rough idea of where I think I might go with the bike.....

Got a new Brake Light switch for the Rear from Yambits in the UK. Professional service with well packaged parts and good simple communication/ invoice/ returns policy.

Pictured here is the old rear brake switch which had the loop at bottom broken. The Yambits replacement spring (pictured next to old switch) was too short by 2 inches however. I simply swapped the old spring with the new and the switch activates. Someone modified the existing wiring so I am slowly working thru that unfolding scenario...

That end with a screw is NOT factory. It is a emergency replacement to get you home so you can get a new cable.
Stick throttle can be a poorly lubed cable. I lube cables by taking the cable out of the throttle housing and loose from the carbs. Same with the clutch cable. Taking them completely off the bike is good too, hang up with a string, lubing before install is good.
Make a funnel around the upper end with kitchen foil. Fill the funnel with engine oil. Let it set, as the oil flows down the cable keep oil in the funnel. Moving the inner cable in/out helps speed the process.
This works much better than one of those clamp on things that you use with a spray can lube. To spray the lube has to be very thin. This won't lube well or very long.
Leo

Replaced the throttle cable with another cable and had to shortened it to make it fit. It worked but unfortunately the throttle would not zip back into the 0 throttle position. Would not rev out but would not return to zero revs position.

Finally the brand new replacement cable turned up from Yambits in the UK. Well packaged and well boxed. Set it up but I am still in process of tuning the cable so to speak. Took it for a ride yesterday to work and some issues. It fit no problem. ... but the throttle now zips back to the 0 position but it sometimes can continue revving. Building up to around up to 3000 RPM at the lights... I have tried adjusting the adjuster nuts on the cable. Will try lubricating the brand new cable today as well as playing around with adjuster nuts some more and I might also try a different route for the cable thru the body into the carb throttle holder.

One good thing was I also got a new rear brake light mechanism and replaced that as well. I found out half the problem was someone had added a brown wire into the yellow wire rear brake. The brown wire ran to nowhere. It seems that when the braking mechanism attached to the foot pedal failed and they had tried to rewire the rear brake light system but gave up. So yellow back into yellow wire, new mechanism and now working rear brake lights.

I also have to fix the broken brake connector in the front. The Yambits part did not fit.

Also the nut that attaches the tacho cable to the tacho shit itself and snapped in half.

Two steps forward ... one back.

Your problem with the rpm's might not have anything to do with the cable, sounds like a carb issue.

Replaced throttle cable with Yambits replacement and was still a little sticky. Took cable out and spray lubed the cable from either end with home made tube made out of electrical tape, slide cable back and forwards for a while to make sure lubricant was working. Spray can had long skinny pipe attachment which helped direct a smaller more precise flow into black tubing. Then I sprayed some suitable lubricant on springs that are attached to throttle mechanism carb attachment. I also adjusted the path the throttle cable took and made sure that the throttle cable was not moving too much. Replaced throttle cable and now working great.

Just took off one exhaust tonight and I am giving the chrome a polish and hit the main section of the exhaust pipe with some pot belly stove black. Did a test run on a section before riding to work this morning and then went for it on side behind before dark and dinner hit.

Worked on cleaning up the chrome on the back half of the tail pipe, after dinner.