78 Convert cable question

[jguzzi]

Re: 1978 Convert...Remember no tach on this model, just speedo.  This winter I installed new K&S switches which are nice and also lubed my cables. The switches work great.   I have a Thomaselli daytona throttle.   I also had the tank off for cleaning. 

I put it all back together and my throttle cables now seem to be causing a high idle speed when warm. The speedo reads around 20 to 23 mph.   It used to idle at around 10-12 mph when warm.  The cable ends seem seated in the carbs when the throttle is turned off and I can pull the cable ends at the carbs up and the engine RPMs go up and then when I let go they seem to seat and the idle is around 20-23 mph.  If I put on the foot brake the engine slows to around 10 mph.  It seems to do this only when parked on the center stand with rear wheel spinning.  When riding, it seems ok.  When stopped with the foot brake on, it idles fine.  I need advice how to trouble shoot this (step by step for the novice would be great) and also how to adjust the free play.  There is not much free play in the cables.  Do I loosen the lock nut at the cable end, turn the nut above it and then move the throttle to see if I have a little free play?

Also, is it possible I crimped the cables when putting the tank back on....I could not remember if the cables go down the center channel under the tank from the front and then split to each carb, or enter under the side of the tank on the right side. Perhaps they are crimped or stretched.....they are entering under the right side of the tank now.

I appreciate all advice.

[Scout63]

It sounds as if you have no free play. You need to have a tiny bit of free play before the slide starts to move. Start with the adjusters on the carbs. If you have no room bc of the new throttle you can remove the locknuts on the carbs to pick up more room. If you can’t get any free play you could trim back the cable sheath a little, or so I’ve heard. Smarter minds please weigh in.

[jguzzi]

Thank you....when I adjust the ends of the cables to get a little free play, do I first loosen the lock nut and then twist the adjuster nut so there is more space between the two nuts or less before I again tighten the lock nuts....I tried the carb ends and loosened them (more space between the two?) but that did not help....I will also try the throttle ends as they look pretty tight.....I have not done this before.

[jguzzi]

I adjusted the cable ends now on both cables.  I had to screw them down about to their limit to get 1/8" to 1/4 inch of freeplay.  But, this made no difference.  It still idles on the center stand at about 20-23 mph with tire spinning.  Is this normal?  I have had this bike since 1987 and never adjusted them with seemingly no problems....so I must have done something when lubing them and putting them back together.  The cables have some slack under the tank so they do not seem crimped.  Are there other things I should check?

[jguzzi]

OK...took the tank off and the left hand cable was crimped under the tank.  Happy to find this as a possible problem/solution.  Before I put the tank back on is there a recommended routing for the two cables under the tank....down through the center channel from the front to back for example or some other way so I do not crimp it again?  Thanks again for any advice.

[chuck peterson]

When it’s back together...cables should slide easily forward/back...with additional slack of 1/4-1/8” at the throttle end. Close it. Slowly slowly roll it open until the sheath seats. Now slowly slowly open it while gently pulling on the sheath, without pulling the cable inside. That little difference is the slack you need before adjusting the...

Idle speed, and gas/air mixture, and syncing the two together

Haynes Manual for tune ups might help for a step by step

Not Amazed, that your bike stayed okay for so long. Guzzi does that..

[Bulldog9]

Cable routing on the convert can be a bit tricky. When I got my convert last year I did a total strip down to clean oil adjust etc. I had a heck of a time getting the throttle cables routed properly. The prior owner had put some type of plastic accordion cable wrap around the outside of the throttle cables which seems to help with pinching and chafing.

[jkguzzi]

Check the choke cables. I struggled with those on my Convert causing a high idle. That choke lever under the tank is convenient but I finally ditched that and bought the flip levers that mount on each carb.

[chuck peterson]

On the centerstand w no brake, yeah it runs up to speed. If you don’t do that often its freaky.

Stomp on the foot brake. Now how’s the idle? Adjust w the brake on. Some use a strap to lock the foot brake lever

Sitting on the bike, I could just hold the bike back w my feet, no brakes. With both feet down, a touch of front brake to keep from moving.

I needed a lot of help w carbs and had to learn to stop fidd-ling after tuned up.

[jguzzi]

Thanks to all.  I think I have it about right and cables are not pinched now.  I have 1/8-1/4 in of free play.  The rear wheel still spins on the center stand a little faster than before but when riding seems ok...maybe the new points, plugs etc have made this difference. At stop I need to use the front brake or it will move forward but i do not think more fiddlin will help....sometimes you need to know when to stop fiddlin.