TOPIC:

My 1979 A1 is up and running again. I want to adjust the idle speed but the adjuster seems to be missing - ie it's not there as a knurled knob as per the manual.

I've looked hard at the mechanism to see where the adjustment is made on the throttle pull but can't see anything obvious. Any tips as to how I can manually adjust idle without the knob being there ?

I also have a lazy revcounter which is only picking up at around 1200-1500 revs and then moves real slow, again any clues as to why this would be welcome.

The "knurled knob" is the important fine idle adjustment, try and find another to replace the one that is lost, the other ways to adjust the idle would be to adjust the stopper screw shown in the photo or to adjust the length of the pull cable, both are rough adjustments and once done can't be adjusted "on the fly" as in once the motor warms up if it's too high you can't get at them easily. I have a '79, and I've had the same problem with the tacho, once it was a broken cable, the cable would mesh with the broken ends and work sometimes but it gave up and had to be replaced, other time the problem was in the dash itself, dry and sticky bushes on the cup, just cleaned it and put a very small amount of lube on the bushes and the needle has worked well ever since, image below shows a spare one I have just so you can see the "insides" of the tacho, cheers

I beg to differ with KZA 13 about the use of the fast idle cam screw for adjusting the idle setting. I wouldn't go this route. It will mess up the fast idle when the choke is on.

the question to ask here is if the bracket that the idle adjustment screw threads into is still on the carbs, If it is, then you could simply replace the fast idle screw with a standard screw and a spring to hold the screw in the set position.

Have a look at page 51 in the service manual for the exploded view of the carburetor parts. Item 106 is the piece I'm asking if it is still there in the carbs. If so, then you could replace the idle adjustment screw item 109 with a standard screw and you also need to install a spring item 110.

There is an idle screw adjuster on ebay at the moment $25 nos if thats the route you want to go down
Paul b

Fraserc wrote: Any tips as to how I can manually adjust idle without the knob being there ?

kza13 wrote: The "knurled knob" is the important fine idle adjustment, try and find another to replace the one that is lost, the other ways to adjust the idle would be to....

Kawboy wrote: I beg to differ with KZA 13 about the use of the fast idle cam screw for adjusting the idle setting. I wouldn't go this route. It will mess up the fast idle when the choke is on.

Sorry for any misunderstanding in my posted reply, as you can see I just answered his question, and I did say that the "knurled knob" is the most important piece he needs, but he asked how to adjust without it, I answered, I also do not recommend this way of adjusting the idle, and anyone should be able to make a new knob, just get someone to weld an extension shaft onto a suitable screw and weld a big nut on the end, please don't take this reply the wrong way, I was just trying to answer a question asked, cheers.

Kawboy wrote: I beg to differ with KZA 13 about the use of the fast idle cam screw for adjusting the idle setting. I wouldn't go this route. It will mess up the fast idle when the choke is on.

Sorry for any misunderstanding in my posted reply, as you can see I just answered his question, and I did say that the "knurled knob" is the most important piece he needs, but he asked how to adjust without it, I answered, I also do not recommend this way of adjusting the idle, and anyone should be able to make a new knob, just get someone to weld an extension shaft onto a suitable screw and weld a big nut on the end, please don't take this reply the wrong way, I was just trying to answer a question asked, cheers.[/quote]

I understand where you're coming from and not taken the wrong way. One could bastardize the set up and get the bike to idle with the fast idle cam screw but then everything goes for a shit. Totally agree that if one could not buy a replacement knurled knob then fabricate one.

No harm no foul.