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I've been abroad for work the last week, so no progress has been made. The easy part with projects like this is spending the money, now the modifications needed to make the parts work need to happen. I've been considering different options in regards to the upper shock mount.
I think the best way is to alter the frame mounts to have them both parallel. This ensures that the load on the top bushing is spread over the largest surface area as mentioned by Bearuno.
I think the easiest way is to have the top mounts milled out to 22 mm. and a spherical bearing installed. HOWEVER, as the housing width is only 10mm, this does raise some concern. On the other hand Husqvarnas have been using this method since the late 70'es to my knowlegde. If going down this route, I'd also like to have a groove milled, to install circlips on either side, so the bearing stays in the middle.
The most common Spherical bearing sizes for a 10mm ID ( I've been assuming all along that is the bolt size, so I could be quite wrong with that ??) is a 22mm OD, with the outer 'race' having a 10.5mm width. You can get 10mm ID Spherical Bearings with a 19mm OD, with a outer 'race' width of 6mm. They could give you the option of machining the eyelets to 19mm, while leaving a lip to 'stop' the bearing, and having a circlip groove machined in the other side.
But, to repeat, contact BZS - And shock specialists. There may (well, almost certainly will be) be spherical bearings and spacers / pressed pin spacers that have been made to suit the smaller confines of Motorcycle shock eyes.
Hope you don't take this all as my haranguing you - I just wish I could get to my mates C&J BZS replica, and his horde of shocks, to do some checking and measuring for you.
As an aside, we fitted both WP 50s to it, And 97(???) Showa conventional forks. These almost certainly won't fit the bill for many Vet / Vintage / Twin Shock racing rules - though I see Many of those relatively modern front ends on older bikes, say at the VMXdN . But, besides the better performance they can deliver, a Big thing is Not having the Bar Mounts so far back, 'in your lap', like the front end (? - CRs of the 80s era - ?) in your pictures. Having the bars more forward, really does make a lot of the older bikes feel far, far better.
I've ordered a new connecting rod, as the next part of the project will be finishing off the bottom-end.
At the same time I will have the splines on the outputshaft welded up, to remove slack.
Struggling to find a front wheel. So if anyone knows anyone, Im in the market for a CR125/250 front hub.
The Shop
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Luxon 4-Post Bar Mounts
$189.95 - $239.95
Hope this isn’t a deal breaker for you, I’ve been watching this thread and digging the whole project! Those custom race thumpers are just cool scooters!
Lasse ; There can be a sh*tload of distortion. Every bloody where. So much depends on Jigging, Tight, Non Gap Joints, and Weld Patterning. And, even then, you'll have 'corrections' to be made.
But, those corrections, Should be done by the manufacturer. Not the Customer. I found only a few details that I had to correct on my mates BZS, but even they left me, shall I say, a bit surprised. With my frame building, to make sure of no / minimal distortion, I use deep, light press fit brass or stainless inserts, with a hefty through post, all 'locked' in to the head tube. And, perfect mitering, a lot of tacks, and staged welds, with as much of the welding whilst in the frame jig(s) as possible, and that can mean real gymnastics to get to weld points. Yet still, I'll have some 'clean up' to do, be it de-ovalizing a tube, or facing / reaming. With a lot of my frames - well, all - I make the head tubes longer than they are meant to be, to accommodate 'corrections'.
Check the 'length' of the head tube, front to back, side to side. I'd not be surprised after you've found those ID variations, to find the 'length' of the headtube to vary. Check the 'lengths', not only at the end faces, But, at the bearing landings, as They are the real arbiters of parallel bearings. And if They are out, it can be a bastard of a job, if you don't have the correct tooling and machining.
Good luck, it looks like you have a bit of a sh*t fight on yours hands.
BTW - if you ever decide to run Fox Factory Forks on your bike, I have two sets of custom made billet triple clamps from PDE which were made specifically to run the FFF on these Hondas.
I notice there are no mounts on the frame for chain rollers - you might want to fab something up prior to painting the frame.
Anxious to see how your build progresses.
Got the frame issues sorted?
Good to see a company sort things out. Every now and then, things do 'escape' from the workshop that aren't quite what they should have been.
I guess you've got the shock / shock mount situation sorted?
It will be quite the bike, when finished.
Hey, I recently bought some 40mm Husky fork cable guides from HVA, to use on Fox 40 DH forks. Now, they cost me a motza when freight was included, but I want better front brake line control on my DH bikes I make, when they go out my door than just the fork arch clamp. I'd just tried to check out their full Husky 4 stroke builds, and somehow doing that had put one of the bikes in my "cart". I nearly had a 'hearty' at the price of over 26,000 Brit pounds, ( might have been Euros) before I realised what the second line of the invoice was for......
I’ve had the front forks and wheel hubs vapor blasted.
For the forks, I’ve changed the oil seals. Currently running double oil seals instead of a dust seal on top. This is suggested by Elderfield Honda and only the oil seals where available, so I gave that a go. Unfortunately the cartridges are per RaceTech non-rebuildable, so in the future I might need other forks.
Also I’ve been building the wheels. Here I had ordered an incorrect rear rim and spokes, those have been returned and the correct pair ordered. This time I will be going with a 19” inch rim, for more tire options.
As of now I’m just waiting on getting back my crankshaft from a rebuild, so engine assembly can start. In that regard, since the balancing system has been removed I will also be plugging the oil feed going to the balancing shaft bearings, to the bottom end and camshaft instead.
Little by little, piece by piece
I say it is about time for another update!
Picked this close cousin.
HPF XR 500 monoshock
Will start a thread as I am going to make it mine
Here is an update!
Since last the exhaust has been welded up and a bracket for the muffler produced.
Wheels have been laced and tires added. BUT the front and rear sprocket do not line up, so I might have to order a new rear setup. I have sent the bike over to a good friend of mine who will correct my mistake and line it up perfectly. If that means new rim and spoke, then so be it.
Next up would be to get an HPI ignition and do the final test assembly.
Did this ever get finished? Thanks
Pit Row
Hello Aidan,
The bike is currently stored at friends place who has to machine the rear hub as the spokes/rim setup I ordered doesn't align the sprockets.
Hopefully this spring it will be running
Great work!
Love old four strokes twinshock!!
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