1970 Honda CD175 "Red"
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Red's Maintenance log since I took it home July 16, 2001.

Log of Honda CD175 K3 "Red"

Frame CD175 2005347  Engine CD175E 200561(4?)       Built in 1969

Red's registration number KNE 652 is from its original country, Kenya (North East Province). It is now registered for Ontario Canada.  I was not able to contact the original owner, but if you know anything about it, please post a comment on my blog (click on email at the top of the page to go there) I would love to know the history of this bike.


This is a picture with the buddy seat taken off.  


July 16, 2001.   4113.1 MILES

I bought the red 1970 Honda CD175 on the eBay auction website.  I drove to Kingston Ontario with a trailer to get it. As it was supposed to be in running condition, I had a short test drive.  The CD175 did not start easily and I had to keep the choke partly on to run it. But we bump started it and I kept it going long enough to drive up and down the street and change a gear or two.  The battery is dead and needs recharging at least.

July 17, 2001

I had to buy a 6 volt battery charger, and charged battery at 6amp/6volt for about 4 hours.  This is way too high, but my new 6 volt charger has only the 6 amp setting at 6 volts.  (Note the battery later died, partly as a result of this high charging rate, and I think took the rectifier with it) The dial on the charger showed about half a  charge when I stopped.  I put it in the bike, and it fired up with the electric start.  

July 18, 2001

It still won't idle properly. I dismantled the carburetor.  Thinking there may be an air leak between the carburetor and head, I put in a new o-ring made by cutting out a section of a bigger o-ring and and gluing it back together with Loctite 495 glue (like crazy glue).  I also got some Wynn’s Carb cleaner in a can for $3.00.  The hole for the idle jet (The one in the carb body, not the precision hole in the jet itself)  was almost closed with varnish buildup.  I used an artists paintbrush to clean it and soaked the jets in carb cleaner.  The idle jet hole is so small you can hardly see through it.

I started it up this afternoon, fiddled  with the carb screws, and now it idles properly . I took two runs around the block. It won’t idle easily until it is warmed up for about a minute.

July 19,2001 Miles 4114.1

The muffler seems pretty loud to me at full throttle, even with my earplugs. I rerouted and oiled clutch and brake levers on handlebar.  

July 21, 2001 Miles 4183

Got a new tire on the front, and its got the safety certificate now.  I am using contact cement to keep the footpeg rubbers on.  I tried to apply Ford Candy Apple Red touch up stick from Canadian Tire Store.  There are a lot more of scratches and chips than I saw at first glance.  Too bad, because the rest of the paint is well preserved original, except for the left side cover.  The touch up does not look good, but at least it helps prevent further rusting until I get around to it.  

July 23, 2001

Red is now “on the road” officially.  I am missing a screw for the taillight lens.  I took a chance and put a self tapping screw to hold it.   M But the self tapping screw broke the glue that was holding the lens together.  I also needed to tighten the license plate bracket bolts and put on two rubber bands to hold the lens on.

July 26, 2001 Miles 4262.1

Used a total of  9.7 liters of gas till now.  I was very lucky to get a tail light lens from salvage yard and 2 screws for $11.95 and a Haynes shop manual for $20.00. I adjusted the chain for the first time, and put some "Big Red Chain Lube" on it.

August 10, 2001 Miles 4444.8

The timing was set so the points separated after the T mark, so I adjusted it to the F mark. Spark plug gap was OK. Point gap was OK.  Now I can get it to 71 MPH I think.  It also seems to idle and warm up faster.  I was getting close to 75 MPG (*UK Gallons) even with retarded timing.  

The horn has stopped working.  

The valves are adjusted now.  The exhausts were too tight, so maybe the valve seats are too soft. Apparently using leaded fuel protects the valve seats, but I'm using unleaded so I'll wait and see if the valves continue to tighten each time. The oil is supposed to be 10w-40.  My car takes 10w-30, the BMW takes 20w-50, so I changed the oil for a mix of 10W-30 and 20W-50. Got some new metric screws from Canadian Tire Store for the points cover and the right hand side cover.  Can't find a replacement for the rotor cover, those screws are very long. I found out there is a 4 inch split in the left hand muffler near the kick stand rest.   The mufflers have so many welds and patches they are almost home made!

August 16, 2001 Miles 4576.0

I don't have any welding equipment, so I got my friend Barry to braze up the split, and now the exhaust sounds quieter.  But I thought I detected an intake honk wide open at 40 Mph in 4th.  So I took apart the air filter.  The plastic air filter case is duct-taped together, but should not be a problem for dust leaks. (but it may contribute to the honking,)  However, the 4.3 inch by 1.5 inch Inside diameter rubber hose connecting the carburetor to the air cleaner is cracked next to the carburetor, and could be leaking dirt into the engine. It may also be contributing to the intake noise, especially if the hose collapses where it is split.  I swapped ends (carb end goes to air cleaner now) and duct-taped it up.  I also used LocTite crazy glue in the crack to try to prevent it from collapsing under suction.  

The air cleaner itself looks new.  The air cleaner plastic box is a  K3 model, and the filter itself is a K3. Because Honda changed the location of the air snorkel between the K3 and the K4,  no air will get into the engine unless you cut a snorkel in one part or the other.

Did a high speed run last night, got it to 70 mph but as I went past a couple of cop cars and the traffic around me slowed down, I had to back off.

August 18, 2001 Miles 4734.9 

The spokes are all present and have a good ring when I tap them.  The speedometer needle dances around a lot.  I oiled the chain with two drops per link of Big Red Chain Oil, and adjusted it one third turn.  My new Ontario license plate has cracked the top left corner completely off. I fixed it with oversize washers and rubber grommets.

August 23, 2001 Miles 4917.5  

I oiled the chain again.  Also took off the rear shocks and put some vaseline on the rubber spacers. Last two fill ups got 80 MPG UK.

August 27, 2001 Miles 5125

I started noticing a rattling sound. at 40 mph.

The engine cut out once at a stop sign.  I thought it was a dead battery because the instrument lights were dim.  But after I shut off the lights, it got me home. 

The last gas mileage calculation has me at 91.5 mpg (UK) for one tank.  Cumulative average is now 78 mpg (UK)

August 28, 2001 Miles 5132

The gears are getting stickier and the clutch cable or mechanism stickiness is getting more noticeable.  I poured oil down the clutch cable with duct tape around, and I attempted to rotate the cable sheath and I took of the sprocket cover and put oil on some of the clutch pivots.  It didn’t really help.

The battery is run down!  The headlight could barely light up our driveway. M Accidentally hooked it up to the charger on 12 volt switch.  It BUZZED and the needle vibrated at the end of the dial.  Now I’m charging it at 6 volts starting at about 9:00 PM

August 29, 2001 Miles 5137

I charged the battery again today.  Vapor is coming out of it.  The floating balls tester says left (+ side) cell is 5/5, (overcharged) Middle is 4/5 (OK) and right (- side) is 3/5.  The charger dial indicates 50%.  So I stopped charging. 

August 30, 2001 Miles 5142

I lubricated throttle grip mechanism.  It was not returning fast enough.

September 5 Miles 5146

CAM CHAIN ADJUSTMENT: This is not explained in the Haynes manual, but I perform the operation on a warm, idling engine. I loosen the cam chain tensioner locknut and bolt.  Then tighten the adjuster bolt then tighten the lock nut.  (NOTE: a year from now a cam chain will snap on another CD175 that I have adjusted, so maybe I have not understood this procedure properly yet.  One problem maybe was that I did not tighten the adjuster bolt enough.  I have to be careful not to strip it though.)

Adjusted the clutch at the engine case.  Back off the handlebar adjustment, then turn the adjuster on the case until about a quarter inch of slack is felt in the lever, then tighten.  Went from about 12 oclock to about 12:30.

Found out that the Honda dealer's microfiche for CD175 says it has a 6 volt sealed beam headlight.  Mine has a separate bulb. But I think the dealer has the fiche for the US K3 model.

September 7 Miles 5151.9

I read on the internet that if the oil spinner/filter gets filled with crud, and the relief valve fails, then the engine will be starved for oil and break. One day I hope to get that spinner cleaned out.

September 8 Miles 5151.9

Checked the wiring harness white tag under the gas tank for the date of manufacture.  It was almost faded out, but I could barely make out a number 6961, which I thought might be Jun 1 ’69, but then I looked at it upside down and it said 1969. I can’t make out the top row of numbers, but the 1969 is in the middle of the bottom row.  The wiring harness appears to be original, and is a little cracked.  There is reddish dust on the coil, too.  My serial number is the CD175 2xxxxx series, meaning it is the CD175 K3 model.

September 9 Miles 5192

I changed Oil to Pennzoil 10w-40. I was not able to look at the inside of the oil filter  because the screw is too tight and inaccessible. But at least the relief valve is working.  The shifting seems a little better after the oil change. 

Also changed fork oil to the blue stuff I’ve had on the shelf for about 10 years. (Hydra Spec 2 Medium weight suspension fluid 7W-10W, 150cc each.)  The old oil looked black and watery and kind of metallic.  The front suspension seems stiffer now.

I had a misfire when I tried to accelerate at full throttle at high RPM.  This is caused by the battery being run down again.  I don’t see bright indicator lights even when the engine is running.  All cells needed water and all balls sink after water is added, maybe because its not mixed well. 

September 10 Miles 5192

I bought new battery at Canadian Tire, exactly the same as the other one but not labelled  BikeMaster.  They found it by the reference number 6N12A-2D, apparently that is a universally understood reference number.  It read about 5 volts or 5.5 on leaving the shop.  The store clerk said  ”It’ll be 6 volts by the time you get home.” When I tested it immediately at home, all balls were sinking, and the battery was warm.  I did not install battery yet.

Testing the rectifier: Positive direction:  the red/white is 500 Ohms all rest are 0

Negative direction: Red/White is 70K Yellow is 50K, rest are 0

I decided I need a new battery charger.  I got a genuine and expensive  “Battery Tender Junior” (6 volts 750 milliamps) and started charging new battery.

September 11 Miles 5192

The tender's light went green at 7-8 AM today (About 18 hours of charging, which is normal for a new battery.)  3 Balls float in all cells.  I put battery in the bike. The new battery vent hose was coiled up and would not hang down straight from the battery vent, so I boiled it to straighten it out.  

The right winker does not light, but all four signal bulbs are OK. The horn still does not work.  Looks like everything else works, I tried the starter too. I hooked up the Battery Tender, with battery in the bike.

5205 Miles

Lights and turnsignals are working now (Just reconnected terminals for orange and light blue.)  The battery seems fully charged after the run.  No more misfiring at high speed.  Seems like the green light on the Battery Tender will come on after a few minutes if the battery is fully charged already.

September 12 Miles 5232

I checked with digital voltmeter after a trip. 6.05 Volts across the terminals.  6.01 when running.  5.9 when running with lights on.  Seems like the charger/rectifier is minimal, maybe slightly discharging all the time.  Better with the lights off, though.  (Prediction: Something is indeed still wrong, I will find out soon.)

The Ontario traffic rules require any motorcycle manufactured after January 1, 1970 to have headlight on at all times. (A conspicuous white light at the front, and red light at the back.) Because mine was manufactured in 1969, I guess technically I am OK.  

To keep the headlight from discharging the battery, I am going to see if I can find a lower wattage bulb.  Permanent magnet alternators lose power with time heat and shock.?!?! If there were any I might want to clean off  the alternator brushes, but I can’t find them.    

NOTE FROM THE FUTURE:  I will find out things about  the CD175 charging system that I wish I knew today.  First, the rectifier heats up and can burn out if the generator is running full blast and nothing is there to absorb the current. Second, by switching on the headlight, you also switch on another generating coil to produce more electricity.  Knowing this, you would want to avoid running at high speed with the headlight switch ON with a burned out (or even a low wattage) headlight!!!!!  Especially if the battery is fully charged already or will not take a charge.  The rectifier will last for long distances at high speed if you have a good battery in the bike, and the headlight switched OFF or switched on with a good working 25-35 watt bulb.

I got a 6v35/35 w headlight, a 12v60/60 w headlight, a 6v taillight, and could not find 6v10w turnsignal, so I took same pattern 12v20w (It’s a little dimmer but not much.)  I have the 12v headlight in now, and am putting aside all the originals.  12v headlight is really dim, but will try it anyway. (Prediction.  THIS IS GOING TO HELP FRY THE RECTIFIER)

I oiled the chain with Big Red, every plate, both sides and link. No adjustment needed.

Battery is flat after a 2 hour ride. I started charging at 4:00.  I was looking at my rectifier results and found that Pink – Ground should be the same as Yellow – Ground, but P-G is actually 0 while Y-G is 50K.  I think it indicates a partial failure of the rectifier (New one lists at $80?).  The CB175 12 volt selenium rectifiers have a different part number from the CD175's.

September 12 Miles 5272

The Battery Tender light was green this morning.  I took  out the rectifier, (had to pull the carb).  The red white wire insulation was melted on its entire length.  And the yellow wire now has no resistance either (like the pink wire last time.)  I got a replacement at salvage shop for $40.  It looked the same, but had a different plug. They switched end plugs plugs for me, and now the lead wires are a bit shorter.  I started it, it works and I see the neutral light brighten a little when I rev it.  I tested it with a digital tester, and I see 6.7 volts across the terminals when I rev the engine.

The needle wobbles on my speedometer at almost all speeds. I took out the entire speedometer cable and tried to straighten and rotate the outer casing. The needle still dances around. It must be a problem inside the casing.

September 19 Miles 5453

The clutch mechanism looks OK (no stickiness in the mechanism), but I am out of grease for the grease gun.  However, I removed the cable and oiled it full length from the bottom up.  The cable feels better now, but still a little sticky, and is dripping oil out the bottom.  

September 23 Miles 5469

I thoroughly lubed chain again with Big Red. There is a rattle at about 7000 rpm, I think it’s the muffler.

September 24 Miles 5469

Got one new footpeg rubber, 3 * 17 inner tube and a mix and match Honda toolkit from Zdeno's Salvage Yard.  I took a 22 mm box wrench for the kit, as listed in the K4 parts manual. But then I realized the K3 has some different tools in the tool kit.  The K4 toolkit has a 22mm wrench, but nothing to fit the 19 mm axle nuts on my K3. I am also still missing the 18mm spark plug, the 17mm spanner and the big Phillips screwdriver. And the T handle for screwdriver. I accidentally got a 0.7 feeler gauge in the vinyl pouch (I think for the CBR900RR disk caliper), and an extra (useless) 22mm spark plug socket.

 September 28 Miles 5469

It’s been rainy and cold, so I was not riding. I charged battery again, light went green in under 2 hours.  I thought the neutral bulb was dim, but it was because I was wearing my sunglasses.  I bought 2 new spark plugs DR8HS and a key blank at the Honda dealer.

October 1 Miles 5492

I think oil is coming out of the crankcase vent tube.  Also, oil on the dipstick still looks clean. I did a compression check on a warm engine, with throttle closed and kick over not electric start.  110 lb/in right, 119 lb/in left. It should be higher with open throttle and electric starter. The right plug had a few deposits that I knocked off.  Both were dark tan color.  I got a few missing tools for the tool kit. (19mm axle and 18mm spark plug socket, 17 mm spanner and T for screw driver (and an 8 mm wrench) Now I’m just missing a number 3 Phillips.

I squirted WD-40 into the ignition key switch, because it was sticking. 

October 10 Miles 5500

I just got back from Pro-Formance Cycle with the custom 2-into-1 header (black) and chrome trumpet muffler.  He did a really nice job. It sounds much louder than stock, but it weighs a lot less.   I cannot detect any real change in engine performance, so rejetting should  not be needed.  The big disappointment is that the rattle at high revs is still there.  So it was not a muffler rattle after all.

October 13 Miles 5513

But I used premium gas with new muffler starting at 5514.1 km.

Because the muffler on the left is gone, I had to make a tab for the foot peg bracket to stop the center stand from hitting the chain case.  

My trumpet muffler sounded too loud riding without earplugs, so I tried to cap it with a j-bolt and plate to restrict the outlet.  I can run at 65mph on the freeway, and I got it over 70 mph on the downhill run. (The freeway in Kitchener has a 90 kph limit, so I actually passed a couple of cars!)

The rattle is present at a narrow range of rpm, at about 20 –22 mph in first gear, 30 – 33  in second, 40 - 43 in third and 47 - 50 in fourth.  If I pull in the clutch, it goes away, but it does not matter if I am accelerating or not.  Can’t tell where it’s coming from.

October 22 Miles 5657

Changed oil to Amsoil 100% Synthetic 10w-40.   I will probably not use Amsoil again because of the price, and the shifting does not feel any better.  It's almost double Mobil 1's price. Also, I don't think it is tested and certified according to what I see on the container.  I would have to run it for 10,000 miles without an oil change to make up the difference in price to mineral oil. 

Adjusted cam chain, also with no effect on rattle.

October 25 Miles 5657

Greased the lever end of the clutch cable, to try to give it a smoother feel. The lever pivot hole is worn, and I think this may be the cause of the stickiness. There should be a bushing in there instead of plain aluminum.

October 29 Miles 5682

How to cure rattles:  Hit the bike all over with a stick, and listen for something that rattles. Assuming only one thing is rattling, you will find it.  This was how I discovered that the front fender stay bolt was loose. (And partly stripped, so I replaced it.)  This cured the rattle I was hearing at at 50 mph in top gear, and 40 in fourth etc.

October 30 Miles 5719

It was 8c today and sunny. Went for a ride and I wore just regular stuff – motorcycle boots and socks.  Jeans over track pants. T-shirt, Sweat shirt, Icelandic sweater, winter jacket, winter gloves, and I was warm enough for a 2 hour ride. (Mostly in and around town).

October 31 Miles 5719

Got some CD175 parts from Matt:  Air filter, air box, and intake tube.  Clutch and throttle cable.  Condenser, left mirror without the glass, and driver’s foot peg assembly with both foot peg rubbers (the one on the left is worn).

November 1 Miles 5794

I replaced the foot peg bracket with the one I bought last night, and put on the new left foot peg rubber I got last month. I greased the clutch with my new pistol grease gun – no noticeable effect.  Replaced the air box and intake hose. There was a noticeable reduction in noise when I took it for the first test ride.  The intake noise is like a honk that is dependent on throttle opening.  Slight reduction in power?  Hard to say because I got it up to 75 mph but that was on a downhill with a strong wind behind me.  I eased off before over-revving it  The new intake box has a different design.  It has a baffled air intake.  This is correct for the K4, and I suppose an improvement over the K3.

November 2, 2001  Miles 5794

Took off the front wheel.  Oiled front brake cable, put a dab of grease on the brake shoe cam surfaces.  The axle was covered with oil, and not corroded.  Drive chain still seems tight enough and not visibly dry.

November 2 Miles 5794

Went for a ride in 5-6c cloudy morning. About 80 miles. Leather pants with knee padding, sweater, gray coat, winter gloves.  My hands got cold.  Chin and feet a bit cold.  The front brake is much better, probably by oiling the cable.  I checked battery water and the level has not dropped since new. (it’s a bit over the top line.) I found a hairline fracture on the plastic red headlight shell, just in front of the left mounting bolt.

November 5 Miles 5924

The horn was not working for the last couple of months. I took apart the horn button and now it works. Sanded the contact areas.  It’s kind of tricky to get back together, but at least the spring is not preloaded.   It’s much easier to reassemble the button if you remove the mirror first, because the wires are short and it is too heavy to hold while reassembling the switch.  Also took off the fuel tap, and reinstalled it.  The critical part is that 4 hole rubber gasket inside.  Mine looked a bit beat up between two of the holes on one side.  But other than that, it does seem to work at holding back the fuel.

I took off the chain guard to check if any links are seized.  A few seemed tight, so I oil soaked them .  The center part was shiny. Adjustment still OK.  It’s about 500 miles since the last thorough chain lube.

November 8 Miles 5924

Big project today, I decided to look at the rear swing arm pivot bushings.  I managed to get the swing arm off after removing wheel, shocks, chain, and front sprocket cover, and the frame side plate that holds the passenger foot peg. And the chain guard.  If I had the factory muffler, that too.  The Haynes manual had an idea how to do it, - lift up on the left side then wiggle it out.  I found out I also had to disassemble the dirty chain guard inner piece (the middle piece of the chain drive case, between upper and lower.)  I had to hammer out the swing arm shaft, but it was not corroded.  The swing arm bushings are like the ones on the lower shock mount.  I had to think for a while to figure out how the bushing works. At first I thought the sliding was between the shaft and the inner surface of the bushing.  But I noticed that if you tighten the nut on the swing arm shaft, the motion of the swing arm is stopped – it tightens against the inner metal of the bushing so that the swing arm can’t move easily.  So actually I think the rubber sandwich type bushing is intended to twist the rubber with no sliding metal to metal friction at all.  There is only about 1 or 2 degrees of twisting on the swing arm.  I could not remove the bushings, but they look to be in good shape, so they can stay.  The lower shock mount has the same type of bushing.

On the K4 there is a castellated nut and cotter pin on the end of the swing arm shaft, but not on the K3.    The CB175 has a split bushing with dust seals that looks like it may be an improvement on the CD175 combined rubber/metal bushing.

The chain has quite a bit of side play (lateral bend).  But it pulls only about 4 mm off the sprocket.

I also put a dab of grease on the rear brake cam.

November 9 Miles 5993

I bought a new chain.  I had to knock 14 links off the 126 link new ‘made in Japan’ chain, as I think the Honda takes 112 links.  I used a grinder on the end of the rivet and drove the pin out with a mallet and punch.  The chain is a 428H (heavy duty), and it does not have O-rings.  There were no O ring chains back in 1970, but 428 chains are now available in O-ring sizes if you want them.  The Honda CT110 trail bike is one model that uses 428 O-ring chains, but I'm not sure if they are heavy duty or if they will actually fit the CD175.

Took the bike out for a test drive, and the rear suspension is stiffer. (I think)  Maybe I tightened it too much.  Or maybe I should have tightened it while I was sitting on it, to put the bushing in the middle of its travel.

Jerry at Zdeno Cycle says they do sell replacement baffles.  But the baffles are usually held in place by spot welding in addition to the end rivet, so to get it out you have to knock it hard.  But she says a 175 engine should not need too much baffling to make it quiet.  If I need to I may be able to go there and get the guys to pull it out and fit a new one or the same one with packing material.

I gave it another try and got the baffle out finally.  Part of it had cocked and was jamming inside.  I flattened the middle passage tube opening with a hammer to make it quieter.  Of course that will also reduce top end power, but hopefully not too much.  Then I put a package of fiberglass muffler packing material in and reinserted the baffle.  

My test drive went well.  Did one hard stop for a red light.  Got up to 70 mph on the freeway.  It's hard to tell if the top speed is reduced because of hills and wind effects, but it feels a little more reluctant to get over 60 mph.

November 10, 2001  Miles 6015

Winter has set in.  On December 10th I bought a parts bike, which I will call "Blue Lite".  To follow what I am doing during the winter, click  Blue Lite to see the web log.

Click here to skip to where Blue Lite blows up and I continue Red's log.