1980 Build for Dad

You’re doing terrific work and making good progress! A little polishing always makes you feel good too.

The starter gear fix is something a lot of us have done and it really needs to be done on most of these bikes. On both of my bikes, I installed new wishbone springs because the old ones were pretty weak and the new ones were also beefier. Here’s a page shot from one I did a couple years ago. You’ll need a fish scale or some such thing, I bought an inexpensive one on eBay.
It's your lucky day... I still have the Christmas special. :D
Have a look here.

Rhy: there is only one place to go for a new alternator rotor and this is Jim. His work is impeccable and he always delivers.

On the #4 starter gear issue - there is TONS of information on the forum. In fact, it is one of the very few aspects of XS650 ownership that might be termed a problem - and the issues can be solved.

Basically, the spring-hairclip-wishbone thingy (I always call it a hairclip - but I have three daughters) must grip the starter gear very tightly (basically, the tighter the better) and if that is the case, the condition of the actual gear teeth is rather secondary (within limits).

The problem is that in older worn units, the grip loosens over time and even in some new starter gears and hairclips are not made to quite the right tolerances and the grip is too loose.

That is why people talk about doing "the squeeze" on the hairclip - simply to tighten the grip on the starter gear. If you search around, you will find all kinds of information on fixing this problem - and most of it is good. NOTE: there is a YouTube video on fixing the hairclip - but it shows the installation of the hairclip in the incorrect position inside the engine case. You can spot it right away because there is some very lame country music playing and the guys wife comes and tells him that she loves him - at least once or twice - during the video. :shrug:

One caution: when you disassemble the clutch to get access to the #4 gear, keep careful track of the multitude of spacers, washers and little gubbins that is in there and the order in which it goes. If you reassemble it incorrectly, the clutch will not function properly. The problem isn't fatal, but you'll have to do it all over again to make things right.

Hello Rhy,
I, too extend a welcome to this Forum. Rest assured, the answer to all things XS is here.
I have just completed the 4th gear repair. I used a new gear, wishbone, (hairclip Pete!?? I have three sons!) and spring from Mikes. You still have to compress the spring in a vice to achieve a solid grip on the gear - apparently, you can't overdo it unless you visibly deform the clip. Job went by the numbers and as several have already mentioned, there is a host of information on the topic. This guy has done a neat little video although he too places the clip back in the cup which is no longer recommended.
Rhy: there is only one place to go for a new alternator rotor and this is Jim. His work is impeccable and he always delivers.

Have to agree with MaxPete. I've purchased a few rotors off Jim over the years. None better.

Edit: all for different bikes just in case anyone is wondering.:laugh:
On the tach drive, you may want to break the edge on the hole in the case. If there's a sharp edge, it'll grab the o-ring. Doesn't take much, just a light touch with a deburring tool or a piece of emery cloth.

Good idea, I will give this a go. I might also try a smaller O-ring, as I fear I have stretched this one out with my failed attempts.

It's your lucky day... I still have the Christmas special.

Nice! I have given Mikes enough money as of late. Can you PM me the details, address, etc..?

This guy has done a neat little video although he too places the clip back in the cup which is no longer recommended.

Great video! It does seem like a system that is destined to fail, relatively smooth metal surfaces trying to grab each other in a lake of oil... I wonder if anyone ever tried to create some texture on the inside of the spring? Wouldn't want to create any metal shavings, but it might help to get a few more pounds of pull when the spring starts to go. I plan to get a fish scale and see where I stand with this before installing the clutch.

And thank to everyone for the feedback, much appreciated! Will keep you posted.
Yes, that drag clip on the #4 starter gear is a known and common issue on these. Every 4 or 5 years, you may need to go back in there and squeeze it tight again. I've done mine twice (in about 12 years) since I've had it. Best thing you can do is reduce the stress and strain on it by keeping the bike in a good state of tune so it starts quickly and easily.
Weekly Update

I did not get the time I was hoping for over the holiday weekend, but still have managed to get a couple of things knocked out.

I did get the jugs back from the machine shop. They were nice enough to run my freshly-enameled piece through an industrial parts washer… The enamel lost the fight, big time. Spent a good deal of time getting this piece stripped and repainted. In hindsight, I should have waited to paint until they were machined... Oh well, they are good to go now.

Per your last set of comments I got a fish scale and squeezed my #4 starter gear to about 8 pounds of pull. I finished the clutch assembly replacing the lock tab and springs. The clutch plates were surprisingly in good shape and as flat as could be. It is finally starting to look like an engine!


I installed the broken rotor and an old stator temporarily so I could set the timing. I think I will reuse the stator that is currently on the bike, as none of the ones lying around Dad’s shop are in very good shape and I know that one works.

I did run into an issue with the clutch pushrod. When I tried to install the left case, I found that the pushrod was protruding too far out and making contact with the worm gear before the cover made contact with the case. I backed the adjustment screw all the way out, but that didn’t help. Any ideas? Could it have something to do with the one-piece pushrod I used? I am fairly sure that I have the worm gear together correctly. The gap is about an eighth of an inch…


Next step is to start on the top end assembly. This is getting a little tricky, as I have never disassembled this part of the engine. This extra engine came with the bike, but the top end was already totally disassembled. It also turns out that a couple of pieces were missing, such as the rear cam chain tensioner and the front cam chain guide. I ended up finding a rear tensioner in good shape around the shop and purchased a new front guide as they sound like they are the weak link in the system. This guide by @5twins was very helpful in matching together my hodgepodge of pieces.

This guide by @Jim has proved to be invaluable for the top end so far. When I work on this project I have four texts in front of me; Haynes, Clymer, Pahl, and the service manual. Most of the time they are more or less in agreement, but when it comes to the top end they are all over the place. Each has a different approach and none of them address using an endless cam chain. I beat my head against a wall for 10 minutes trying to figure out how it went through the rear cam chain tensioner mount, only to discover that the mount has to be ground down and temporarily separated if you are using an endless chain!

I am optimistic that the rest of the assembly will go quickly once I get the jugs installed. Will keep you all posted!
On the push rod, one end is necked down a bit, this end faces out. Another possibility would be an extra ball bearing at one end or the other. Some of MikesXS worm assemblies had the ball bearing retaining stakes protrude too much and wouldn't let the push rod insert all the way to the ball.
Some things you can check for that left cover not seating fully - the pushrod, if properly installed and in far enough, will protrude from the case about 48 to 50mm. Also, the stepped end of the pushrod should face out .....