Attention all boaters...we need your help...well your lateral thinking actually. Nobody seems to have any answers for us.....'Stacey' , my son's beloved motovespa 125 1971 scooter restoration has come to a standstill because of a problem. Boaters, we hope that ingenuity and problem solving capability shown by all self builders and small boat sailors will come to the fore......'help us all you obi-wans'!
The problem can be seen in the photograph below. We have stripped the forks; replaced all the lower and upper steering rings and bearings - exactly like for like and we have reinstalled it. It is tightened up as it should be and the front steering is not rocking forwards or sideways. It is perfectly correct but cannot be slackened off, for to do so is to introduce looseness into the front fork.
So explain this.......the gap between the rear mudguard and the legshield has reduced and is now too close; a bump on the road and the two will meet! Originally the gap was 2 cm between legshield and mudguard before dis-assembly. We have triple checked everything. Nothing is wrong; everything in the correct sizes and in the correct order at bottom and top of steering fork.......we have no idea what's happened; and we have no idea how to make that gap back to 2 cm.
Now come on people - we know how adaptable, flexible and creative we are........suggestions please...how do we
a) increase that gap without
b) loosening the steering nuts so that the front fork and wheel rattle or have sideways/forwards movement
We are baffled and no one on the scooter forums seems to have the answer.........so will someone creative please save us - any suggestions gratefully received because we are out of ideas!
Steve and number one son!
The problem can be seen in the photograph below. We have stripped the forks; replaced all the lower and upper steering rings and bearings - exactly like for like and we have reinstalled it. It is tightened up as it should be and the front steering is not rocking forwards or sideways. It is perfectly correct but cannot be slackened off, for to do so is to introduce looseness into the front fork.
So explain this.......the gap between the rear mudguard and the legshield has reduced and is now too close; a bump on the road and the two will meet! Originally the gap was 2 cm between legshield and mudguard before dis-assembly. We have triple checked everything. Nothing is wrong; everything in the correct sizes and in the correct order at bottom and top of steering fork.......we have no idea what's happened; and we have no idea how to make that gap back to 2 cm.
Now come on people - we know how adaptable, flexible and creative we are........suggestions please...how do we
a) increase that gap without
b) loosening the steering nuts so that the front fork and wheel rattle or have sideways/forwards movement
We are baffled and no one on the scooter forums seems to have the answer.........so will someone creative please save us - any suggestions gratefully received because we are out of ideas!
Steve and number one son!
Obviously, if you simply loosen the nuts at the top of the fork it will wobble badly. Is there a possibility that a shim was mislaid while the assembly was apart? You would be looking for something that fits closely over the shaft at the top of the fork. If you replaced any of the bearing races, they might also be of slightly different thickness.
ReplyDeleteI seem to recall you mentioned that you were previously running out of threads while tightening things up the first time you assembled the fork to the frame. That could also be indicative of a missing shim.
Best of luck!
Wayne
Hi Steve, Phil here again In common with many sailors I used to be a biker. The 1st thing I would do is check that those forks haven't been in a front end shunt and are the correct shape.If you can compare them directly to a known good set. If they are ok then you could try making up a spacer to go under the bottom headset race (bearings). But be careful not to push the race of it's seat completely. It's the diameter that's important, not the base.
ReplyDeleteHi Steve,
ReplyDeleteAssuming you are not missing a shim that would give you the clearance needed without making assembly impossible, I would next look at if the parts are in the correct order. The wheel fender looks high to me. Could there be a shim that should be above the fender instead of below it?
That's my best guess. Love the blog!
Wayne, Phil, jim - thank you. funny how sailors are often bikers - before or after!! this is the kind of advice we need. we will go through it all again and take it apart to check all the pieces one more time. we don't think any shims are missing and the bearings are exactly same size as some of the originals which we kept and re-inserted. we'll check the fender position one more time as well. we dont think the forks were damaged ebcause the original gap was larger before disassembly. the idea of putting in a shim between the lower bearing set and the bottom support is a good idea because that will make the gap a little bigger - that is a possibility. we will take it apart friday night and see what we come up with - thanks guys - really appreciated - we'll up date you asap. good to hear from you all again - thanks
ReplyDeletesteve
ps if anyone else has anything to add to the great tips from the guys - all thoughts welcome - we are desperate people
Steve, my first reaction is that 2cm. is a significant (big) difference, and I think that packing-out by adding shims etc. to try and correct the problem is to miss the root cause. Have either of the mudguard or leg-shield been modified at all since the time when the clearance was correct? Especially anything that would alter bearing mount locations. Not much help I know. Cheers, Alan H.
ReplyDeletehi Alan - no - absolutely nothing - it really is baffling isn't it! we have been over it now four times and will do so again tomorrow night.
ReplyDeletewhat do you think - can we get away with that gap as it is - we dont understand enough about the mechanics - will the front shock absorb impact of bumps or potholes sufficiently that mudguard and legshield won't meet?
or would inserting bigger ball bearings - say 9 or 10 mm dia ones help push it down a couple more millimetres and that will make the difference?
baffled and frustrated does not describe where we are at the moment!!
and thanks for replying - really appreciated
steve
You do NOT want to try to adjust this gap by changing the size of the bearings. Bearing races are designed for a specific bearing diameter. The wrong size balls will probably not turn as smoothly and may also cause premature failure or pitting of bearing races.
ReplyDeleteWayne
Thanks wayne - we sort of figured that might be an issue but not knowing enogh about these things we are trying to look at all possible options - Son and I are nothing if not creative in thinking - just not having enough knowledge to then assess how daft the idea is...thanks for helping out again - really appreciate it. like the blog by the way and love the family photos - what fantastic young people youhave
ReplyDeletetake care
steve