Worn governor shaft bore

Mini Bike & Go-Kart Parts

ELT

Active Member
#1
I have a hs40 with a very worn governor shaft bore. Is there a way to install a bushing in the block to fix this or do I need to find a better block?
 

markus

Well-Known Member
#5
I drill them and press in a sleeve I make out of brass tubing. Its a simple as drilling to appropriate OD of the tubing you are using as the bushing, and pressing it in. I score the tubing on the outside and apply a little locktite when I press them in, cut flush with the block and dress the ends, I did some writeups on here in the past I think. I have to do it every couple of blocks I rebuild. dont forget to have the little washer on the nside of the block installed and the c clip on the outside, to avoid excess travel back and forth on the shaft (would also keep the bushing/sleeve in check and captive should it come loose from the block for some reason it cant go anywhere or cause a bind).
 

ELT

Active Member
#6
I drill them and press in a sleeve I make out of brass tubing. Its a simple as drilling to appropriate OD of the tubing you are using as the bushing, and pressing it in. I score the tubing on the outside and apply a little locktite when I press them in, cut flush with the block and dress the ends, I did some writeups on here in the past I think. I have to do it every couple of blocks I rebuild. dont forget to have the little washer on the nside of the block installed and the c clip on the outside, to avoid excess travel back and forth on the shaft (would also keep the bushing/sleeve in check and captive should it come loose from the block for some reason it cant go anywhere or cause a bind).
Thanks, this is what I thought might be possible. Now to pull the engine back apart. Where did you find brass bushing stock that small?
 

markus

Well-Known Member
#7
Thanks, this is what I thought might be possible. Now to pull the engine back apart. Where did you find brass bushing stock that small?
K&S precision metals. If you have a good hobby shop (for R/C, Trains, scale models, etc...) they usually have a fully stocked rack, a good hardware store sometimes does as well. Or you can just find the stuff online.
 
#8
I did a complete how-to writeup on repairing these back on 10/28/17. It has been my experience that if anything is worn, it will be the bored hole in the (aluminum) block, not the (steel) governor shaft. (Think: The softer aluminum vs. the harder steel= aluminum loses. I di a complete how-to write up on this repair back on 10/28/2017. (see below)
Michael
Oct 28, 2017
#4



UPDATE:
My son and I had some time in the shop together today so we decided to come up with a fix for the shaft wobble in our 1970 HS40. What we came up with is relatively easy and the parts are readily available. After disassembly, we saw that our shaft hole was significantly worn in an oblong shape with much more wear up and down than side to side, very similar to the photo Marcus posted.

We went to our local Orchard Supply Hardware and purchased a section of aluminum tubing ("K & S Precision Metals # 8104 Round Aluminum Tube") that we used as a bushing. The size on the package stated 3/16" X .014". (The latter number is the wall thickness). You need a length cut to a hair less than 5/8". Don't try to use a tubing cutter to cut it to length, as you will crush the ends (we tried!). We used a small metal cut off wheel in a Dremel. Using a good precision caliper we measured the tube ID at 0.154" and the OD at 0.187". Make sure and clean up any burrs on the ID or OD of the tubing.

You will need a good-quality & SHARP 3/16" twist drill to drill out the worn shaft hole in your block for the new bushing, however, I would recommend working up to that size with a couple of smaller drills first. We used a hand-held cordless drill on high speed holding it steady, square and level to the engine block. The 3/16" drill bit we used measured exactly 0.187" (Hint: We noticed that different drill brands measured larger than others by up to .006" even though they are all sold as 3/16"- we selected the largest one we could find (.0187") which was a "Dewalt Industrial Cobalt # DWA1212").

The new bushing was a nice snug fit in the newly bored governor shaft hole, just pressing it in with our fingers. After lubing and reinserting the governor shaft it was a HUGE improvement over the previous slop of the shaft. Also, after running the engine I have no more oil leak there like I had before.
Michael
 

SAT

Well-Known Member
#9
I did a complete how-to writeup on repairing these back on 10/28/17. It has been my experience that if anything is worn, it will be the bored hole in the (aluminum) block, not the (steel) governor shaft. (Think: The softer aluminum vs. the harder steel= aluminum loses. I di a complete how-to write up on this repair back on 10/28/2017. (see below)
Michael
Oct 28, 2017
#4



UPDATE:
My son and I had some time in the shop together today so we decided to come up with a fix for the shaft wobble in our 1970 HS40. What we came up with is relatively easy and the parts are readily available. After disassembly, we saw that our shaft hole was significantly worn in an oblong shape with much more wear up and down than side to side, very similar to the photo Marcus posted.

We went to our local Orchard Supply Hardware and purchased a section of aluminum tubing ("K & S Precision Metals # 8104 Round Aluminum Tube") that we used as a bushing. The size on the package stated 3/16" X .014". (The latter number is the wall thickness). You need a length cut to a hair less than 5/8". Don't try to use a tubing cutter to cut it to length, as you will crush the ends (we tried!). We used a small metal cut off wheel in a Dremel. Using a good precision caliper we measured the tube ID at 0.154" and the OD at 0.187". Make sure and clean up any burrs on the ID or OD of the tubing.

You will need a good-quality & SHARP 3/16" twist drill to drill out the worn shaft hole in your block for the new bushing, however, I would recommend working up to that size with a couple of smaller drills first. We used a hand-held cordless drill on high speed holding it steady, square and level to the engine block. The 3/16" drill bit we used measured exactly 0.187" (Hint: We noticed that different drill brands measured larger than others by up to .006" even though they are all sold as 3/16"- we selected the largest one we could find (.0187") which was a "Dewalt Industrial Cobalt # DWA1212").

The new bushing was a nice snug fit in the newly bored governor shaft hole, just pressing it in with our fingers. After lubing and reinserting the governor shaft it was a HUGE improvement over the previous slop of the shaft. Also, after running the engine I have no more oil leak there like I had before.
Michael
Nice
 

ELT

Active Member
#10
I have acquired brass tubing that is the size described. After drilling the block to proper size I was thinking some lock tite would be a good thing on the outside of the bushing. Now all I need is time to get after this repair.
 

ELT

Active Member
#11
I have acquired brass tubing that is the size described. After drilling the block to proper size I was thinking some lock tite would be a good thing on the outside of the bushing. Now all I need is time to get after this repair.
I had time to install the brass bushing last week. It works perfectly.
 
#12
Thank you for following up and providing the update- it is appreciated. So often individuals post on here asking for help and after members take the time to answer them providing solutions we never hear from them again.
Michael
 

Top