My 3 valve twin story so far...

So how did I come to like the 3-valve twins so much?

Let’s see…

It all started back in early 1996 when I was attending school in Gravesend (UK). Our A-level technology teacher, Mr A. Byrom, announced that he was willing to help a couple of teams enter that year’s Youthbike competition in Lincolnshire. There were eventually three teams. The objective was to find a very cheap motorcycle and then customize it. The other teams managed to source a Honda CB125 twin and a sweet Honda CB160 twin.

After scouring the local small ads and the FreeAds paper to no avail, my mum remembered seeing an old bike parked down the side of a house further down the street. It belonged to a guy with an eye-patch, long hair and a freezer full of dead chicks (ha, the yellow fluffy kind) to feed to his owl. Contact was eventually made (he seemed to spend most of his time somewhere in East London, and a price was agreed, 100 quid. Well it turns out the bike was a 1980 Honda CB250N Super Dream. It was hand painted white, very dirty and more than a little rusty.
I pushed it the ¼ mile or so back home and set about trying to get it running. This was my first ever motorcycle and I was so excited. It wouldn’t start, but it had sparks.
Off came the carbs, they were stripped, cleaned and reassembled on the dining room table (start as you mean to continue). Buying the bike cleaned me out so I couldn’t afford a carburetor rebuild kit. I must have got something half-way right, as the bike would now start, albeit with the aid of starting fluid spray. It would rev in neutral but would die when trying to move in gear, and it would always spit back every 10 seconds or so.

The bike was stripped down and transported to school so the team and I could customize it. We hard-tailed it with struts made of steel tube, inverted the handlebars, ditched the fenders (mudguards) and cut the dual seat and mounted only the passenger section. I cut up an old leather jacket and stuck a patch to cover the foam where the seat was cut. The steel pan was screwed to the frame at the front (who needs a pivot?) and the original shocks were bolted to the back of the shortened seat. At the time it all seemed so original. We used chrome BSA mufflers.
The tank was painted black with orange piping and I made a Norton style Honda logo. The filler cap was an attempt at an aircraft style cap. An aluminum disk was mounted on some body filler with flathead screws around it, more for aesthetics than function. The removable part of the cap was another disk if aluminum with a very old brass cupboard knob screwed through it. It looked pretty good with the brass polished up.

Well, we didn’t win any prizes. But we did get this photo in now defunct British bike magazine AWOL.

We got the bike running at the competition, but it stopped very abruptly and wouldn’t turn over, I put it down to a piston seizure. The CB125 team who did nothing to their bike other than paint it assorted bright colors won a prize though. One of their dads worked for K’Nex (toy manufacturer) and talked them into sponsoring it. As the saying goes “we was robbed”.
I ended up keeping the bike as it was my money used to buy it and I did most of the work on it and it was my mum who got stuck with transporting it back and forth in her car, bless her.

Upon stripping it down, I found the camshaft sprocket bolts had come loose and the sprocket had fallen off and wedged in the camchain tunnel. By that time I was on the road with my first learner legal bike, a rather fast 1990 TZR125; the Super Dream languished in my back yard. I tried my hand at airbrushing a picture on the tank. I had a small airbrush for doing design artwork for A-levels, I had it hooked to an old Ford Granada spare wheel as a source of air. Seriously, they sell an adapter kit to do that.

The picture I attempted to replicate was the cover art from the 1977 printing of Sven Hassel novel, “Monte Cassino”. A rather grim picture of a shouting German soldier in a stahlhelm. I got halfway through and realized I actually kind of sucked at airbrushing.

The CB250 languished in the back yard while I went off to university with my cool Z650.

I was obviously smitten with the 3-valve twins though, as halfway through my first year at university I acquired a CB400N with a blown bottom end. It wasn’t in bad condition, and I remembered there was a CB400N engine minus cylinders and head in a small bike shop in Dartford. It had been sitting on their floor next to the counter for a long time. This was an old school bike shop. Wooden trays lined the shelves, filled with assorted used bits of BSAs, Triumphs and some Japanese stuff. The carpet was at least 40 years old and so trodden down with dirt and oil you couldn’t make out the pattern any more. The guys who worked there reminded me of Ronnie Barker in “Open All Hours”. Very old school, wearing brown aprons. It was this shop that bought my mum’s BSA Bantam from her when I wanted the Gobots base for my seventh birthday. I feel like a horrible little shit. Anyway, they wanted 150GBP for the bottom end (as much as I had paid for the whole bike), but I bought it. This project took a back-seat when my Z650 blew a hole in a piston and wrecked a big end.

Being bikeless and resorting to borrowing a friend’s GS125, I bought a CB250N from a guy near Nottingham. He was an AA Patrolman and vouched that it was a great bike, even if the red paint had faded to pink in the sun and the side panels had a horrible curvy script. He even threw in a leather jacket which (almost) fitted me to sweeten the deal (250 quid). I rode it back to Loughborough, but wasn’t impressed with the starting. It needed to be push started every time once I got it home so I wasn’t too happy. It was the end of the academic year though, and I had to go back home to Kent. The bike didn’t make it under its own power. I got as far as the M25/A12 junction and it died. No sparks but plenty of charge. While waiting to be recovered by the AA I laid down and took a nap, only to be woken by a very nice Motorway Patrol Policeman who explained that if I wanted to lay down I should do so way up the embankment; apparently people driving past had thought I was a dead body and been calling the police.

The starting problem turned out to be a bad stator. Again I found bike breakers in the UK to be the biggest rip-off merchants, being charged 65 pounds for a well used stator. At least I was running again, and with a pair of ace bars fitted I felt like Geoff Duke whizzing around the back lanes near Brands Hatch.

I had 3 months off for summer from university and landed a night shift position at a Co-op warehouse in Swanley. After the third shift I thoroughly hated it, and so when I heard what sounded like a big-end failing on my way up “Death Hill” (original local name for the A20 from Farningham up to West Kingsdown) on the way home I just thought “fuck it” and continued to ride the 8 or so miles home, knowing I had the 400 engine nearly complete back in Loughborough. The little 250 finally gave out a mile from home. It had become slower and noisier until by the time I got close to home it didn’t have enough power to idle without a lot of throttle. And damn the engine was hot.
I pushed it the rest of the way home, called in to work and said I wasn’t going back. I ended up getting a much better warehouse temp job with better hours and pay. Everything happens for a reason.
I did strip the 250 engine down but it was all totally fucked. The big-end bearings had indeed failed, and where I had run it into the ground all the bearing shells had magically transformed into what looked like weird feeler gauges protruding around the rods. And so a 3-valve twin engine died and was no more.

After a couple of weeks I got the train up to Loughborough to collect the bottom end and the rest of the top-end parts to build it up. I somehow managed to wedge it all into a very large rucksack. It was however a brutally heavy rucksack with which to walk back to the train station, get across London on the Underground and then walk from the train station at the other end. I managed it, leaked a bit of oil out of the rucksack into the luggage rack on one of the trains and looked like Quasimodo the whole time, being nearly bent double by the awkward weight and shape.

The bottom end was nice, the top end from the blown 400 was really nice, hone marks still visible in cylinders. It went together quickly, I bolted it into the frame and started it up. What a difference. While still not a very vibratory engine, the power pulses on the 400 are that much more obvious. It felt right. With the ace bars and a gloss black paint job (with union jack) and a Dunstall looking 2:1 it looked rather good. I had a lot of fun riding around the back lanes of north-west Kent. The twin front discs made a world of difference in the braking. I wouldn’t say the handling was as good as the Z650 but it was certainly acceptable.
Back in Loughborough the next year a car turned through a junction right across my path. My front wheel hit the side of the lady’s car (Ford Granada Mk3), catapulting me over the car and sending me spinning down the road on my back. I was wearing a rucksack with a plastic case socket set and that hard case acted something like a turtle shell and I think it prevented me getting hurt.
I pushed the bike home (a recurring theme). The front end was twisted, my thumb was broken and I was bruised up.
It occurred to me then that the bike was still insured as a 250 and the assessor was coming out to inspect the bike to see if it was a write-off. I had to make a quick run in the Capri back to Kent, where I pulled the engine from the original CB250 Youthbike project. I got the engine swapped over, the bike was a write-off and they said it wasn’t worth anything so I could keep it and fix it if I wanted to. He didn’t even look at the engine, all that work for nothing. And I learned my lesson.

Before I put the 400 lump back in I pulled it apart to check the crank bearings. Everything was ok so it went back together, this time with black engine paint and the edges of the cooling fins exposed. It looked quite smart and lasted a year until one day I was on the M3 southbound when my tacho stopped working. I didn’t think it was anything other than a broken cable until I started losing power. I pulled over onto the hard shoulder, checked the engine oil and found it be full of very fine metal filings. Luckily the bike and I were given a lift in to Basingstoke by a bike courier in a transit van. He wouldn’t accept payment, just encouraged me to do something to help a biker in need in the future if I had the chance.
I renewed my AA membership, had the bike picked up and taken home. Stripping the engine down I found the problem. In one of my previous forays into the engine I had neglected to loctite the bolt securing the oil pump drive sprocket. The bolt had backed out and the sprocket fallen off. The tacho is also driven from this area. I had done about 2 minutes of riding at 80mph before stopping the bike and I found the damage was extensive. All plain bearings trashed, pistons scored, camshaft bearings scored. That was the end of that engine, it would have been uneconomical to revive it.

Fast forward another year and I scored another CB250N (a deluxe model from 81) from another friend for another paltry sum (I think it was 50 quid). I stripped it down to transport it home in my car. By this time I had sold my Z650 and had gone through an Enfield 350, RG400, a CBR1000 and a CBX250RS but still wanted a working Superdream. That summer I café’d the latest CB250. I fitted new tires, bullet indicators, resprayed black again, and rather than ace bars I bought some proper clip-ons. It sat, waiting to be completed in my parents back yard in Kent for a number of years once I had started work after university. I was busy with my other cool vehicles, a lifted Hilux, a BMW 320 coupe with M3 bodykit, a Moto Guzzi V1000 (turned into a really sweet café racer), a Triumph Trophy 1200, KLR650, XT600 project, CX500 aborted projected and Moto Guzzi 1100 Sport. There never seemed to be enough time for the CB250, and when I finally turned my attention to it the new tires had gone flat and cracked, everything was rusted and the carb rubbers had disintegrated.
When I moved to the USA the last Super Dream stayed in my parents’ back yard until they disposed of it a couple of years ago. Rest In Peace little Super Dream…and all the other Super Dreams I broke over the years. An unforseen side-effect of my mechanical adventures with Super Dreams is that my dear old dad who gave me so much advice with bikes in general now has a strong dislike of Super Dreams which I'm not sure is wholly deserved.
Now I have a 1969 Harley-Davidson XLH900 chopper project and it’s going great. But I still have a fondness for the Honda 3-valve twins and the chopper is more for cruising than general riding.
How I came by my latest acquisition is interesting. I hadn’t actually planned to get another bike just yet even though I’ve wanted to get a bike on the road since I moved here.
After watching the excellent motion picture “The World’s Fastest Indian”, with Anthony Hopkins’ great portrayal of Bert Munroe and his quest for speed at Bonneville, I got to looking at the current land speed records for the different motorcycle frame and engine types and capacities. I noticed that there are many classes not listed, meaning there is no current record. There are literally hundreds of classes though, so a cursory glance doesn’t indicate just how many records aren’t filled. A couple of hours with an increasingly large Excel spreadsheet filled in the blanks. And then my wheels started to turn; if I could find a class in which I could enter a bike built using a Honda 3 valve twin engine I could set a land speed record by default. I would, in effect, have the “World’s Fastest Super Dream”!!!

Looking on eBay one afternoon for any interesting pre-1956 Brit twin crankcases (to start building a vintage LSR bike) or 3 valve twin parts, I found a CM400 parts bike, pickup only, starting bid $9.99, no bids yet and with only 3 hrs left to run. After all the times I’ve seen cool stuff on eBay go really cheap but a pickup only and too far away here was a 3 valve twin very close by. I plunked down a bid ($31.02, just in case) and hunkered down, watching the auction every few minutes expecting someone to snipe at the last minute. The snipe never came. I couldn’t believe it.
The next day I went to collect the bike. The seller was immensely helpful and helped me load it into my car. Yeah, still stripping bikes down and transporting them by car rather than truck or van after all these years.

The bike was mostly complete but with the front end removed. It has less than 10000 miles on the clock but has been sitting in rainy western Washington for about 20 years. Extensive rust, aluminum oxidation and perished rubber mask what is actually a very stock bike with no rounded off screws.
Off came the carbs, the rubbers temporarily repaired with RTV silicone, carbs stripped and cleaned properly. With the carbs back on, I kicked it over a couple of times and not only did it start, it idled nicely, no blue oil smoke, revs ok too. The carbs still need a bit of work, and some more rubber components replaced but I’m very happy with the bike. You just can’t complain for $9.99…
The plan had been to build a land speed record bike, but this CM400 is just too complete and stock to butcher just yet. A couple more weeks and I should have it on the road. A nice economical bike for general riding and commuting, it will save me a lot of money in gas.

The land speed project will happen at a later date, but for now I’m happy with the CM400. To make it even better, my brother back in England just bought a CB250N in decent condition so we can compare notes back and forth as we work on our bikes.