Thought I'd share my recent experience with repairing the best running engine I've ever had, a .91 Saito Golden Knight that I bought about 7 years ago.

I noticed a louder than normal "clicking" in the top end & discovered the exhaust rocker arm shaft had loosened and damaged the threads to where it would not tighten up which made it impossible to adjust the tappet clearance . I was bummed and especially in these economic times I was looking for the least expensive way to fix it. My alternative was to purchase a new cylinder & probably at least a new piston ring for $115-120 plus shipping & tax not to mention I'd probably have to do some "break-in" on the new parts.

After talking to a number of folks, creatively brainstorming on different repair options & looking through some forums I had come to the conclusion I was going to have to break down & spend the money but then I realized the threads were 3mm X 0.50, pretty standard stuff so I located a heli-coil kit with no difficulty at all and for about $46 I seem to have satisfactorily fixed it.

The first step of drilling out the damaged threads and making sure it was square was a little nerve-racking but the next step seemed to be more crital and a little easier as I carefully lined up the special thread tap and cut the new threads making sure as I went that everything looked good and straight. I then ran the insert from in between the rocker arm supports outwards so I could more easily remove the excess material, which also allowed me to confirm proper fit and depth on the rocker pin and I actually ground the excess insert material with the pin in place and tight which probably kept the Dremel bit from spinning it right out of place.

In addition the heli-coil kit came with another 19 inserts and the same threads are used in mufflers and a handfull uf other applications so it might save me more in the future.

BTW, in my research I discovered that on the larger, 120 & up Saito's the rocker housing by itself is available.

I hope this will help someone in the future and I might consider selling the heli-coil kit for half price if anyone is interested.

Forgot to add photos to the previous post.

That is a really nice repair job you did there. It is looking really good.

You might have gotten a cheaper price from B.J.'s or Mr Clarence Lee. However, your fix looks great and now you have spares for future applications.

Nice job on the repair Bob! That Saito runs like a Swiss clock, glad you were able to save it!

Originally Posted by Chip01

You might have gotten a cheaper price from B.J.'s or Mr Clarence Lee. However, your fix looks great and now you have spares for future applications.

Granger wanted almost twice that price so I thought I was doing OK with what I did spend, the one I got came from Zoro Tools in IL whom I found on line and I received it within days of ordering so their service was great. I'll keep the others in mind for any future needs, thanks!

Nice repair.


Had the same thing happen. I found next size up SAE bolt/screw. Tapped the hole with the threads messed up to the correct size. Cut the head off the bolt/screw and slotted it with my dremel. Screwed it in with a little blue loctite. Didn't even have to re-size the rocker arm. $6 including the tap I had to buy.