Bonanza steering issue
MB's models don't have bushings...steel on steel.
Somebody probably tightened up the bolt to try and take out some of the slop...that's why it's binding.
Take it apart and see if the tube is worn or the fork plates....most likely the fork plates. It's not going to be an "E-Z fix" unless you have some fabrication / welding skills.
Somebody probably tightened up the bolt to try and take out some of the slop...that's why it's binding.
Take it apart and see if the tube is worn or the fork plates....most likely the fork plates. It's not going to be an "E-Z fix" unless you have some fabrication / welding skills.
if the nut isn't welded to the bottom fork plate then you can change out the bolt and nut with a metric bolt and nut that is slightly larger then the standard one that is in it.
Unfortunately you wouldn't be able to go a size up with a standard bolt because it would be to big but a metric one may work since they would be slightly smaller.
Unfortunately you wouldn't be able to go a size up with a standard bolt because it would be to big but a metric one may work since they would be slightly smaller.
The closest metric bolt would be 16 mm which would only be .005 larger in diameter. I would bet it's worn more than .005. So next up is 17mm...about .045 bigger. This is going to require drilling and reaming the entire length of the neck tube as well as the fork plate. A 17 mm chucking reamer is about $80 unless you can borrow one from somebody. Making it worse is the holes are no longer round ..they're likely worn egg-shaped from front to back. Trying to pull this off with a hand drill would be an adventure. Setting up the frame and the forks in a drill press or milling machine would also present some challenges.
Even that may not work as you are looking at a "size on size" scenario. The bolt may or may not be exactly 17mm.. a lot of times the bolt will measure slightly undersize...sometimes right on size...sometimes slightly oversize by a few thou..might need a 43/64" ream...or adjustable ream..that won't be cheap either. You'd have to measure the bolt first before trying anything if you don't end up with a precision fit than it was a waste of time.
I own one of these bikes..(actually a cousin to it an MB 1110) and it has the same issue so I have given it some thought. It's a 5/8" bolt in a 7/8" neck tube...probably .120 wall tubing which leaves about .010 clearance . There's really not enough wall thickness to put in a standard bushing and no "E-Z" fix that I know of .
If it's only the fork plates that are worn there are a few tricks you can try....
Even that may not work as you are looking at a "size on size" scenario. The bolt may or may not be exactly 17mm.. a lot of times the bolt will measure slightly undersize...sometimes right on size...sometimes slightly oversize by a few thou..might need a 43/64" ream...or adjustable ream..that won't be cheap either. You'd have to measure the bolt first before trying anything if you don't end up with a precision fit than it was a waste of time.
I own one of these bikes..(actually a cousin to it an MB 1110) and it has the same issue so I have given it some thought. It's a 5/8" bolt in a 7/8" neck tube...probably .120 wall tubing which leaves about .010 clearance . There's really not enough wall thickness to put in a standard bushing and no "E-Z" fix that I know of .
If it's only the fork plates that are worn there are a few tricks you can try....
I posted this in the OldMiniBikes Shop Notes a couple months ago...
http://www.oldminibikes.com/forum/t...niBikes-shop-notes-post903371.html#post903371
Not real proud of it...but it did take most all of the slop out for now, didn't hurt the orignal paint, and it's invisible.
http://www.oldminibikes.com/forum/t...niBikes-shop-notes-post903371.html#post903371
Not real proud of it...but it did take most all of the slop out for now, didn't hurt the orignal paint, and it's invisible.
If only the fork plate was worn I think I would try this next time:
Using a step drill (because it self-pilots and won't "grab" like a regular twist drill) I would open the fork plate holes to 3/4". Then I would machine a set of 3/4" x 5/8" bronze or Oilite bushings without flanges that would press in and be invisible when assembled. You could also trim down the bushings from OldMiniBikes if you don't mind seeing the flange.
Using a step drill (because it self-pilots and won't "grab" like a regular twist drill) I would open the fork plate holes to 3/4". Then I would machine a set of 3/4" x 5/8" bronze or Oilite bushings without flanges that would press in and be invisible when assembled. You could also trim down the bushings from OldMiniBikes if you don't mind seeing the flange.
On my mb250 I welded the perimeter of the holes in the top and bottom trees as I do on most rebuilds then grind it flat and use a step drill to open the holes back up to 5/8"....it's nice and tight now.... Use a new good quality bolt, the cheap bulk bolts at most hardware and big box stores can vary in diameter from end to end.
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Something I have found on these old mini bikes and go kart is that the king pin bolt they used a bolt just long enough to go threw the strap and put a nut on and you end up with the threads in the lower strap and in the spindle this gave you a lot of slop what is needed is a longer bolt that the threads end out side of the strap and then cut them down to the length needed I found this was the same on my Bonanza fork bolt the bushing in the head tube had some nice threads in the lower bushing what I found is the front axle bolt is just right but needs about 1 1/2" cut off the threads and its just right ken