My plan is that is going to be a long term project, keep me out of mischief for a few months, so exhaust is on the back burner at the moment.
In an ideal world, an SL175 system would go on. However, these are rare and expensive, and I doubt that it would fit the CB frame without extensive mods, so it'll probably simpler to build ( or get built ) a custom system. Also, for an off road bike, it seems mad to run the pipes under the frame. Despite the stock bash plates, used pipes I've seen on line are often well dented.
I don't want to go for a high level CL type system. Pipes will be in matt black heatproof paint on mild steel, not chromed or stainless tube. So, bend some 38mm tube to make a 2:1 system similar to the SL, with an silencer can in the SL position is one possibility.
Or, perhaps simpler but heavier, something like the SL350 system, with individual exhaust pipes and a can on either side. That could be achieved using the stock CB down pipes, extended with 38mm tube with a 30 degree mandrel bend to flip the end of the pipes up, into silencers mounted in the SL350 style.
For silencer(s), I'm looking at Triumph Street Triple 675 cans. These are available very cheaply on Ebay, many owners ditching them in favour of noisy straight through 'race' exhausts. No catalytic converter in them, I won't get caught like that again.
( I fitted a Triumph Scrambler can to my CL175, couldn't work out why it was getting too hot to touch, until it dawned on me that the internal catalyst was struggling to cope with rich carburetted exhaust gases ! ) The Street and Speed Triples have the catalyst in pipework closer to the engine.
They came apart really easily, didn't need the electric impact wrench, fork bottom allen bolts came out without a problem. Similarly, no internal circlip retaining the fork seals, just a simple wire ring, easily fished out using a small screwdriver.
Nothing prepared me for the mess though. I just assumed that ancient leaking forks would be almost empty, instead of which floods of filthy black oil poured out. And after the oil came out, fork internals were still filthy. No real signs of wear, so this muck must get past the seals over the years.
Fork top bolts had been butchered, apparently by a chimp using a pipe wrench. Luckily, I found some marginally better ones in my box of bits. Same ones used on CB200, CB400/4 etc.
Fork bottoms cleaned and painted, using Metal Protekt aluminium coloured direct to metal paint. I'd intended to use this on the frame parts, but I think it is a bit too bright, Hammerite silver may be more suitable.
Ready to reassemble now, got the fork seals, just need to get some fork oil, 150ml each side, probably go for 10w.
I got the forks reassembled with new seals today, after a further wash with solvent to get the dregs of the black mess out of them. Remembered to put some sealant on the threads of the allen bolt at the bottom of the fork leg, to back up the existing copper washer.
I made up a fork seal driver from a length of 35mm OD stainless steel tube, and a section of 35mm PVC waste pipe, opened up with a lengthwise saw cut, so that it could be slipped over the outside of the steel tube, to make the OD big enough to bear on the outer edge of the lubricated fork seal. Worked a treat, used like a slide hammer.
Primed tanks now painted Honda Milano red, curing nicely in todays sunshine.
Some more parts of the jigsaw arrived today, an aftermarked Honda CRF front fender, and a secondhand rear fender from an SL175.
Front fender looks like it will fit nicely, fits neatly under the bottom yoke, just need to make up a bracket like the original SL part. Rear fender fits snuggly between the rear frame rails, I will just have to fabricate a small matching section to fill the gap under the seat, between the integral fender in the frame, and the new part. I can also now get an idea of how a rear hoop can be fitted, to emulate the SL frame. I'll do a mockup build in the next few days, post a pic then.
I was going to fit an aftermarket 'brat' seat, but it looked crap and the build quality was appalling. So I've decided to use the original CB175 K4 seat, which I think works quite well with the SL tank and rear fender. Two holes with captive nuts in the SL fender line up with the two rearmost holes in the CB frame, accident or design ?
I've made up a small mild steel section to fill the gap between the SL fender and the CB frame, and tack welded this to the SL fender. Will weld this up a bit better then clean and paint the whole assembly. I've also finalised the position of the tank on the frame, need to sort out the mounts now. Also make up a mount for the front fender. Get the fuel tank masked up ready for the white paint and stripe.
Not without drama, tried to cut my left thumb off with a hacksaw this morning, blood everywhere, would not stop. Ended up wrapping it in adhesive tape from my car first aid kit. Didn't hurt at the time, but is throbbing like a ( insert rude word here ) at this moment.
Anyway, after cutting the extremely poor quality loop to fit, confirming my opinion of after market café racer dross, I welded it to the removeable bracket that holds the K4 rear seat hinge in place, thus avoiding cutting up the frame. I also drilled out the M6 threaded holes in the fender to M8 clearance holes, so that an M8 bolt could pass through the bracket, frame and fender, nyloc nut on the inside. Fitted small spacers between the bracket and frame, to keep everything tight.
I also made up an extension piece from 1.5mm mild steel plate, to fill the gap between the end of the fender and the frame. Lock nutted two M6 bolts through this piece, to form the mounting studs at the rear of the fender. Tack welded this from both sides of the fender. It now all needs cleaning up and painting. Red for the fender, silver for the frame.
Also need to make up the little strap and rubber mount that hangs the fender to the frame loop. It will only be for show, as the fender and rear end are already very firmly mounted. I took care the loop followed the shadow left in the faded paintwork by the original frame. I know it's not quite the same, but the best I could come up with, without sawing the entire rear off the CB frame.
While in the early stages of planning for my 450's rear fender, I actually bought a rear fender strap bracket with the rubber insert for (I believe) either an SL100/125 or 175, can't recall. Obviously I didn't use it, and you'd be welcome to it if you like, Richard.
Having largely sorted out my rear fender, I've turned my attention to the front end. I've had a look at how Honda mounted their high level SL mudguard, and have come up with my own variation, using an after market 'UFO' front fender.
I noticed that the SL bottom yoke differs from the CB/CL part, by having two lugs with drilled and tapped holes at the rear, to take fender mounting bolts. My K4 bottom yoke does have a single tapped hole, possibly to attach a hydraulic steering damper ? ( not as if it needed one ). So I've taken advantage of that hole to provide a mounting point for my home brewed bracket. Which took me all of yesterday afternoon to 'design', then fabricate.
Waiting for some plastic primer, so that I can have a go at spraying the new plastic fender Honda Milano Red, like the rest of the red bits.
EDIT And that lock stop, bodged by a PO, is going to get sorted out properly.
I also masked off and painted the white bits on the fuel tank. Bit annoyed to find that white paint had 'bled' under the masking tape in places, managed to sand most of this off. Whole tank is now flatted back, ready for 2k lacquer, but I'm not going to rush this, will ensure underlying paint has thoroughly cured, because the 2k stuff is impermeable. On my first tank done with this stuff, I ended up with a hard outer shell with soft paint underneath it.
Revised front tank mounts also fitted, by drilling a 10mm hole straight through the frame then tapping a piece of 10mm mild steel bar into place, tack welding it similar to the original mounting points. Debating whether to angle grind these off, it would always be possible to retro fit them by using method just described. As an aside, there is some appalling original welding on the front down tube, puts my attempts into perspective. Now, the originals have lasted 50 years, but I am tempted to try to improve them.
I have a spare headlight assembly, originally intended for a CG125, but converted by me to take a 12v lamp.
However, I don't have any headlamp ears that will fit these forks, so this afternoon I made some. Quite pleased with how they turned out.
I used 35mm OD polished stainless steel tube, which has a 32mm ID, slips neatly over the 31mm fork legs. I will take up the play either with large O rings at either end, or a few turns of rubber tape around the fork leg.
Ears cut from 2.5mm stainless steel plate, drilled M10 to take headlamp bolts. My less than stellar stainless welds are hidden on the inside. Whole assembly could now be polished, if I get around to it.
The Rustoleum plastic primer worked a treat, went on very easily and dried to a matt white finish which then took a couple of coats of Honda Milano red. I did the plastic case of my replica CG125 headlamp while I was at it. They will get 2K clear coat after they have cured for a while.
Here's the parts test fitted to the chassis.
The CB200 yoke stripped back to bare aluminium. I will paint the bottom yoke to match.
I also need to make up an instrument mounting bracket, so that I can use earlier clocks with the CB200 top yoke. I have some 2.5mm stainless steel left over from making the fork ears, so will probably use that.
Now if only you could find an original SL exhaust system, then you could make it like the "limited edition" version found only on two SL175K0s ever in existence - one Candy Red and the other Candy Orange, originally purchased in North Tampa FL at Honda Village. Something my father did one afternoon while looking at the "peashooter" single pipe out of the upswept muffler... I don't have any pictures of his, but after seeing it I asked him to make the modification to mine as well.
My thoughts for an exhaust system. 38mm stainless tube with a 45 degree mandrel bend, sliding fit onto (pattern) header pipes.
Won't be able to finalise this until engine in frame, then probably weld tabs to the pipe to line up with rear footrest mounts. Waiting for a pair of Street Triple cans to arrive, hoping that these can be made to fit.
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