• Don't overlook our Welcome Package, it contains many links to important and helpful information about functions at VHT like posting pictures and sending PMs (private messages), as well as finding the parts you need.

    AD

CD175 engine

Richard Pitman said:
Advert said it came from a CL72
Click to expand...
Correct size but should have had linkage choke then. Probably came from a C/CA77 or 72 single carb.

I think it may work well for your 175. I don't see the 'power jet' features so #38-42 slow and #90-125 main, is the range, according to Bill Silver's guide.
#35 and #90 are available and might be a good target for you.
 
Last edited:
Thanks, that's good to know. I wondered about the lack of a linkage for the choke mechanism, was thinking that those earlier Hondas must have had separate chokes for each carb. But that would have been silly, bit like expecting to find float bowl ticklers like on an Amal carb ...

My Haynes 'Book of Lies' suggests that the CD175 carb used a 38 pilot and 98 main, same as one carb off a CB175 K6.
 
Richard Pitman said:
Thanks, that's good to know. I wondered about the lack of a linkage for the choke mechanism, was thinking that those earlier Hondas must have had separate chokes for each carb. But that would have been silly, bit like expecting to find float bowl ticklers like on an Amal carb ...

My Haynes 'Book of Lies' suggests that the CD175 carb used a 38 pilot and 98 main, same as one carb off a CB175 K6.
Click to expand...
Lol !
I like what you say about Haynes manuals ;I was curious how you feel about Clymers shop manuals?
I've had some specs in Clymers that were off also.
 
So far as I can remember, the Haynes manuals were christened thus by the late Neil Murray, who used to post on a Usenet dial up uk.motorcycle forum under the handle 'The Older Gentleman'. It has stuck with me ever since.

This carb works, video to follow. It has a 35 pilot and 120 main, but started and ran straight away, no leaks from the float bowl gasket or float bowl overflow, which was nice. I naively assumed that my CB/CL 175 carb jets would fit. They don't, even though to my naked eye the threads on the main jets look the same. Pilot is completely different to the 175 part, so this will be my next bit of searching.

To recap, the engine this attached to is my rebuilt ( new std pistons and later type 5 part rings in honed std size bores, new cam chain and all oil seals, Capellini tensioner idler wheel ) SL175 engine, modified to take electric start, CD 175 head with CD cam, new exhaust valves. Ignition is via a Chinese knockoff Dyna coil, with home brewed copper plug leads. Points fitted at the moment, but I will be trying my Dyna ( modified Goldwing) ignition later on.

41iP3ZC.jpg
 
Here's a video of it running. CL175 pipes with a 2:1 piece ending in a Triumph Speed Triple (1050) left hand silencer. No cat in these silencers, cat is in the pipework closer to the engine.

 
Windmill John said:
Love the pickup, it sounds a lot more responsive on the throttle than mine.
Click to expand...
That might simply be due to the twist grip - I have a quick action pit bike throttle on that rig, whereas I think ( from memory of a friends back in the day ) that the stock CD throttle turns a long way to fully open.
 
Yes, there is quite a lag before the throttle kicks in. Very strange design inside the twist grip. I’ve had too many bikes, but never had one with such a weird design like this.
 
Selection of CA72 jets ordered from CMNSL, just hope that they fit .....

Logged in as a Guest, turns out that my email address was already on their system, seems that I've ordered stuff from them in the past. Senior times, no recollection of this, unless it was a kickstart pinion for my CL175, when I first started this malarky.
 
Richard Pitman said:
Selection of CA72 jets ordered from CMNSL, just hope that they fit .....

Logged in as a Guest, turns out that my email address was already on their system, seems that I've ordered stuff from them in the past. Senior times, no recollection of this, unless it was a kickstart pinion for my CL175, when I first started this malarky.
Click to expand...
I like CMSNL as they have Many parts and shipping is excellent.
 
Windmill John said:
Yes, there is quite a lag before the throttle kicks in. Very strange design inside the twist grip. I’ve had too many bikes, but never had one with such a weird design like this.
Click to expand...
The slidy thing inside called ,"the Hinge" makes a big difference if it's worn very much. Not too expensive to replace but makes the normal sloppiness of those throttles better.
 
Latest developments. I bought a very cheap all in one rev counter, speedo etc etc unit from Ebay. Turned out to be an almost exact copy of a Koso RX2N. I was fully prepared to be disappointed, but so far all seems quite positive.

I've bought a genuine Koso in the past, and that came with all manner of brackets, replacement temperature senders, mounting hardware for Hall sensor speedo pickup etc. This unit came with a rough looking Hall sensor and a couple of magnets and an A4 instruction sheet, nothing else.

So far, I've made up a mounting bracket that will fit the handlebar clamp, dropping this unit into the space left by removing the original clocks. (All this, so that I can get a rev counter onto a CD175 engine.) I've also rearranged the connectors, poked them out of the original 9 way connectors into some more useable 4 way connectors. So far, just wired up switched and permanent ( for the time clock ) live feeds, ground, neutral switch and tacho connection. The tacho connection ( yellow/black wire) is tee'd into the negative (points) side of the coil - this was my best guess, instructions not given for this, and luckily it seems to work.

It also has separate right and left indicator repeaters, and a host of stuff that I can't / won't use, such as fuel, oil and water temp, gear position, EFI malfunction etc.

I've made a quick video of it running. My phone camera doesn't seem to like the display on the unit, it is actually much sharper and clearer than on the video. Rev counter also appears to lag on the video. Video coming later.

ZrLnahh.jpg


BvC9eOs.jpg


QK459bT.jpg


0BWX6GB.jpg
 
Here's the video. Bear in mind comments made above, my phone camera doesn't do the rev counter display justice, I've seen similar effects on other Youtube videos when folks have filmed under fluorescent lighting.

I haven't set the parameters for the rev counter ie number of cylinders etc, but at first glance it seems to be reading correctly, not multiplying rpm X 2 as I'd feared, wasted spark and all that. Haven't set the real time clock yet either.

Noticed the battery warning light flash briefly when I activated the starter, so looks as though that is working as expected.

I now want to work out how to stop the low fuel light illuminating. Instructions state that it connects to a variable resistance to get fuel level from sender. I'd assumed that grounding it would turn out the light but that didn't work ( need to try this again to confirm )

Now wondering how to mount the speedo sensor - front or rear wheel, where to stick the magnets etc. On my Hornet I mounted sensor on the rear brake caliper, magnets in the heads of the rear disk mounting bolts. No such option on the 175.

 
Some thoughts about how and where to mount the speedo pickup.

I'm not happy about using the rear sprocket, too messy for one thing. So it looks like it'll be the front wheel. Where to mount the magnets. I have eight little neomidium magnets left over from when I installed a genuine Koso unit on my Hornet. I'm thinking about gluing them equidistantly around a suitable sized tin lid, hole saw cut in the centre of clear the fron wheel axle, tin lid then glued to front hub like so.

QPiyOAF.jpg


Then mount the Hall effect sender on a bracket attached to the spare fender mount on the bottom of the fork leg. I've tested this sender by waving a magnet in front of it, and I get a reading on the speedo head, so looks like it works Ok'

1714849183429.png
This was the rather more elegant mount that I came up with for my Hornet, magnets sitting neatly in the tops of the disk mounting bolts, sender sitting in a carefully drilled hole in the caliper bracket.

1tgykit.jpg
 
LongDistanceRider said:
The system only uses 1 magnet, using 8 is going to mess up the speedo
Click to expand...
No, it can use up to 12 magnets, you set the number of pulses per wheel revolution. Apparently, using more magnets smooths out the speed reading, one magnet per wheel revolution causes jerks in the speed display when accelerating. My Hornet is using four magnets on the rear wheel, mounted on the disk bolts, and this works fine, so I may just go with four magnets on the 175, especially as it doesn't increase speed quite as quickly as the 600 :devilish:
 
Richard Pitman said:
No, it can use up to 12 magnets, you set the number of pulses per wheel revolution. Apparently, using more magnets smooths out the speed reading, one magnet per wheel revolution causes jerks in the speed display when accelerating. My Hornet is using four magnets on the rear wheel, mounted on the disk bolts, and this works fine, so I may just go with four magnets on the 175, especially as it doesn't increase speed quite as quickly as the 600 :devilish:
Click to expand...
Oh, that's different. Lets you do cosmetically pleasant installation like you showed. (y)
 
Here's my first prototype magnet mount. I bought a 75mm diameter disk of 3mm aluminium. First problem was finding the centre - I did this by cutting out a paper template and folding this in four, which gave me both the centre and the equidistant spacing for the four neomydium magnets. Drilled the four M6 holes for those first, used these holes to screw the disk down onto a long piece of 4 x 2 timber. Then used a hole saw to cut the centre hole.

I'm not entirely happy with the result, don't think that my central hole is concentric, or large enough ( my 57mm hole saw was a cheap one, wouldn't cut metal, so I went with a quality 46mm saw, which went through easily. I think though that I really need a 55mm hole for this disk to sit neatly on the wheel hub.)

I will try this first, but if it doesn't work out I think that I will buy a 100mm square of aluminium. Working with a square should make it easy to accurately mark out the centre and magnet positions, doesn't really matter if the outer diameter is a touch wavy, although I could always splash out on a larger hole saw, say 85mm, to cut a tidy outer rim.

All this effort, Millyard would knock this out in 5 minutes on his lathe ...

oZLb2fa.jpg


Magnets drop into holes, to be fixed flush with the surface using JB weld on reverse.

Q0Amnoc.jpg
 
I'm going to press ahead and see if this works even with some slight misalignment. I bored out the centre using a 50mm hole saw so that it just fits the hub thus. Magnets now JB welded into place, waiting for that to go off before JB welding the assembly into position. :unsure:

JNlCyGp.jpg


ivGtg4A.jpg
 
It looks fine overall, you're the only person who will know of any minuscule inaccuracies during fabrication. And I'm quite sure it will function as needed regardless.
 
Mounted the wheel and sensor on my wheel building rig, and connected it to the digital speedo. Set the wheel circumference to 1890 mm, measured with a bit of string, and the pulse count set to 4. Seems to work as expected. Shaky video to follow, but here's a couple of stills.

HzDteae.jpg


fTlpgeu.jpg
 
Belated progress. Too much else to do at this time of year, walking dogs, cutting hedges, helping the head gardener etc

Got a bracket for the sensor made up, helped by a bit of CAD. ( Cardboard aided design ). Next job will be to test it, see if it still picks up the speed signal, before biting the bullet and installing it on the CL175, which will involve removing the existing tacho and speedo, cables etc, and revising some of the wiring in the headlight shell.

lvgiR05.jpg


fDXeybO.jpg


rph77aw.jpg
 
I do understand the economy of the knock-off version and I like the unit so far for its affordability and design. If I were to go with aftermarket clocks I'd consider using one, very few aftermarket gauges out there are appealing to me but that one seems decent with a style I can appreciate.
 
From an engineering/stress standpoint, the bracket as-is will flex and result in erratic counts. Further, fracture is likely.
Suggest an additional/second flat bracket (same thickness metal) on the fork lug back side be added. Attach via longer M6 screw to act as a stud, with washer/nut. the sensor itself has enough threads to accommodate. Will be rigid and never fracture.
 
Suggest an additional/second flat bracket (same thickness metal) on the fork lug back side be added
Click to expand...

Thanks, yes, I see what you mean, I'll give that a go. Metal is 1mm stainless steel. Might be an excuse to play with my mig welder again, weld the two pieces together.

Mind you, it'll be a while. Bathroom pop up waste to fix, just started building a new side gate for the garden, then there's hedges which won't stop growing, where does the time go ...
 
Took delivery of a used CD175 head today, started dismantling it this afternoon. Heavily corroded on the outside but all good inside. Tappet covers were very tight but all came off undamaged, using a 6 point 19mm socket on the mains powered impact driver. Similarly, the screws holding the cam journals on yielded to a no.2 JIS bit in the battery impact driver. The advance mechanism was stuck on the end of the cam, but drifted off by gently tapping on a long 8mm socket against the end of the cam. The advance mechanism itself is presently seized solid and has been left to soak, in the faint hope that it will free off.

Main thing is that the cam, bearings and followers look in excellent condition. More than worth the purchase price for those bits alone.

Haven't pulled the rocker shafts out yet, need to label up some jiffy bags to store the four sets in. Only question mark at the moment is the spark plug threads. Both came out but were well stuck in place. One NGK and one Champion, not a good sign. I need a suitable tap, or perhaps notch a spark plug, to chase the threads clear to get a better look. Followed by valve removal and inspection

But for 35 quid I'm well pleased with my purchase. Vendor also chucked in the top cylinder head cover and a stator side cover as well.
 
Finished stripping the head this afternoon. Pads on the cam followers are immaculate, just one tiny spot on one. Cam lobes are similarly perfect. Maybe CD 175 owners don't thrash them as much as us CB maniacs. Combustion chamber, valves and exhaust ports all heavily coked up, but once cleaned the valve seats and valves themselves appear to have good seats, no recession or pitting.

Spark plug threads OK on one side. Other side showed signs that it had been started cross threaded, not all the way in thankfully, and my notched spark plug cleaned the threads up, new plug now screws home nicely.

Despite having a word with myself about this before starting valve removal, I still managed to loose a valve cotter. Hands and knees search failed to find it, despite me hearing it hit the floor. Fortunately, DS had one it stock, order placed along with valve seals and one exhaust stud.

On the plus side, I've managed to unseize both of my CD175 advance mechanisms. Cams were rusted solid on their shafts, and I'd previously given up one some time back, despite soaking it for weeks in various solutions. This time, I held the mechanism base plate in the vice, then heated the cam using my propane butane mix torch, working it back and forth using vice grips, along with some flaming WD40 ! This freed this one off, so I repeated the treatment successfully on the earlier one.

Next boring job will be cleaning the bare head casting, although a quick whizz with some wire brushes in my drill got the easily accessible parts back to bright metal very easily, it's the nooks and crannies that take the time.
 
You must log in or register to reply here.
Back
Top Bottom