Welding new nibs on the starter clutch or not?

Some weeks ago my bike underwent massive repair and renewal of several parts. The thing I want to talk about now is a change that was done to the starter clutch-flywheel system of my old V45 Magna 1988 model.

It turned out that the starter clutch was totally shot and needed to be replaced. The mechanic told me that it was beyond his means to get a replacement part starter clutch BUT he offered me to do this: to put in a starter clutch from the earlier 1987 700 cc Magna. This, he told me, would fit in, but at the cost of some misfiring and rougher idle. I said yes but I did not know what I was in for.

The two starter clutches, 1987 and 1988, are totally similar except in one important detail. The 1987 one has one long "ridge" which, when the wheel is turning, gets detected by the sensors and sends signals or pulses to the two CDI's. The conversion of the 1988 to the 1987 model system also meant I had to put in two CDI boxes instead of the one I had.

On the 1988 model, which is my bike model, the starter clutch - flywheel has seven small "nibs" or "notches" instead of the one long ridge on the 1987 system.

When everything was ready, I found that this conversion had only been partially successful.

1. The bike starts perfectly now, every time, on first try. The starter clutch is in prime condition.

2. Running the bike at lower rpm's is a pain in the ass. All "finesse" is gone out of it. The engine revs a bit up and down on its own, irregular idle. At higher rpm's things are better and I would say normal power normal running at higher than 4000 rpm's.

I still have the old starter clutch - flywheel and the old CDI.

I approached a man with 30 years of experience in these and similar bikes. He knew the problem and told me what I could do, unless I wanted to buy a new starter clutch from Japan:

You remove the present starter clutch unit and take it a machine tool shop. You have them file down the long ridge on your flywheel, and then weld seven new metal "nibs" onto the flywheel, using the original as a model, taking exact measurements and etc. Then, you will be able to put your original CDI box in place and the bike will run normally.

Now, my question is, what do you think, should I have this welded on (which is easy and has been done before, my sources tell me) or, should I get a new part from Japan?

One consideration is, I have already spend a pile, and more than one pile, on this bike, and feel that buying a new starter clutch - flywheel system at 1/6 cost of of the whole bike is a bit excessive, if it is not strictly necessary and you have other options.

(It is little use to buy a second hand starter clutch since the 1988 model was notorious for starter clutch problems. In normal running, the unit would not last more than five years, and then would have to be replaced. But there is a company in Japan that still produces these things, I have been told.)

 

Go for the repair.

 

What is very critical is the air gap between the reluctor and the pulse coils, I had a troubling misfire on my CB recently and I found that by filing the coil plates so that I could close the gaps to 10 thou, it cured the miss, worth a try

 

Yes, I will and today.

 

True, the gap is very important and must be exact. Going for the repair today.