I've had my Yamaha RD400E for nearly ten years. The first owner was my neighbour - an obnoxious yob whose only moment of good taste in his whole life was buying this bike. I used to see him starting off for work every day with a hundred yard wheelie, revving the balls off the cold engine. Running in had consisted of putting a full tank of petrol in and doing a hundred miles of full bore work. When he had tired of the bike he offered it to me. I approached it with caution, knowing its history, and went as far as having a friendly dealer give it a full check over. A1 he said, so I bought it.
Two strokes are the not the same as four strokes and a quite effective way of getting the pistons bedded in is to thrash the engine. My first ride on the bike was a little disappointing. Keeping the revs below 5000rpm, the engine pinged and vibrated and the reed valve motor seemed to have as much urge as the CB250G5 I had in the garage awaiting a new cylinder head.
Sod this, thought I, and whacked open the throttle at 30mph in second gear. Good grief, I screamed, as I tried to hurl my body forward to stop the bike going completely vertical. Unfortunately, the rapidity of my reaction meant the front wheel hit the ground whilst the forks were turned slightly away from the straight ahead position. The result, when the tyre hit the ground the bars were wrenched from my hands as the wheel turned inwards and the bike fell over. A group of school kids gathered but did not help me wrench the bike off my leg. Embarrassed and bruised, I started the bike again only relieved that no real damage had been done.
The suddenness of the power delivery was not helped by the fitment of noisy expansion chambers. My neighbour told me that these were originally off a racer; judging by the way he used to wake up everyone in the street at 8am when he set off for work this was quite true. I put some wire wool in the expansion chambers which dimmed the row a little, but it was still a head turner.
It took me a month to adapt my riding style to the Yamaha's power characteristics. Doing vicious wheelie start offs from the traffic lights became the norm because it was the only way to clear off rapidly. Even opening the throttle in fourth would get the front wheel off the ground. I decided that this kind of juvenile delinquency was extreme fun and grin inducing.
Not so funny was the fact that such behaviour wore out the chain and sprockets in 4000 miles. The chain behaved more like knicker elastic than high tensile steel and required daily adjustment and monthly removal of links. Front tyre wear was predictably minimal because it was rarely on the tarmac and the rear lasted a mere 5000 miles, or less after I discovered that as well as wheelies I could induce wicked wheelspin from a standing start. Phantom tyres suited the bike best. Metzs were okay but made it a little twitchy in the wet. Roadrunners didn't seem to wear but allowed a high speed weave that made me feel a little seasick.
The frame was a basically strong tubular design that provided good support for the forks and swinging arm. Its only problem was that it seemed to rust from the inside out and needed blasting and stove enamelling every three years. The rear shocks were soon thrown away, replaced with Girling and then Konis, the latter offering an excellent blend of suppleness and control. The front forks are still on the original springs and seals, and they still work well.
Swinging arm bearings last about 15000 miles; I eventually fitted a trick alloy swinging arm with eccentric adjusters and taper roller bearings. To be truthful, it did not make much difference to the handling, but it made chain adjustment a cinch and looked the business.
Wheels are very heavy cast items carrying discs that even with sintered pads only just work in the wet. Caliper rot is endemic, they need stripping and greasing once a year. The wheels have to be cleaned up at the same time as they corrode at the first hint of rain. I solved that problem with a clear, protective coat of lacquer. Braking in the dry is good, though, and I have lifted the back wheel off the ground under heavy braking. Engine braking is minimal.
The E model differs from earlier models in that it has electronic ignition. In theory this is fine as it removes one more maintenance chore, but I find the black box only lasts for about 20,000 miles. It's impossible to buy them secondhand so you have to shell out for a new 'un. Ouch!
Slightly more moderate power delivery was achieved by fitting Allspeed exhausts - they offered more low end power and a lovely whine once beyond 5000rpm. Sales of ear plugs in our area thereafter plunged, although the bike was still not as quiet as a standard RD. The exhausts last for about two years before rust spoils the chrome.
When I first had the bike, the gearbox was easy to use, even slick. With 62000 miles up, sixth has disappeared, fourth only engages on a good day and a certain degree of mechanical art is required to effect clean changes. The bike is on its fourth set of clutch plates and there is a chattering noise from the clutch area, the clutch action becoming very jerky. Attempting clutchless changes is not recommended as it makes mechanical noises indicative of stripped gears and wrecked bearings.
It's on its third set of pistons, although, surprisingly, it has not required a rebore, the pistons wearing rather than the bore. Carb balancing, a tedious business, is needed every 4000 miles. The first set of carbs were badly worn out by 23500 miles and a used set was bunged on, although these have showed no signs of wear. Ignore carb balance, power drops off and vibes increase. The twin cylinder engine is never completely smooth, vibration affecting the footrests and bars. Pillions report that their pegs thrum badly at high revs.
Top speed is 120mph on the clock, which is probably 110mph in real life. It's quite feasible to run along at 100mph if you can stick the stock riding position. I haven't bothered to change it because most of my riding is done in town where it's very comfortable. Fuel consumption varies between 25 and 55mpg. I only did the latter once when I ran down to reserve in the early hours of the morning and there was no chance of filling up again. I usually get around 40mpg with spirited riding. 25mpg is the result of flat out riding - you can almost smell the petrol being bunged out through the exhaust.
Reed valves are supposed to expire around 40,000 miles but mine are still original. There are various aftermarket reeds available, which along with some porting can significantly increase the horsepower. A friend of mine went the whole hog and had his engine set up in race tune. It took about half an hour to start, wouldn't rev below 3500rpm and when the power finally punched in the bike was almost uncontrollable with wild wheelies, massive weaves and a terrible banshee wail that rattled windows. After 5000 miles it needed a complete rebuild including the gearbox which featured stripped gears. He gave up in the end and fitted a used, stock engine in his chassis. He still has his bike and we often buzz around together.
After careful adjustment of the oil pump, plug oiling became a thing of the past with use of the latest synthetic oil. Constant, low speed, town work does provide a momentary hesitation when you whack the throttle open, but when it does catch it makes the rush of power all the more horrendous.
Things like mudguards and seat bases rotted after the first three years and were replaced with non standard items. The bike had one complete respray four years ago and still looks good. Engine cases, barrels and head have all been beadblasted and are regularly polished with Solvol. I like the styling of the bike and think it still looks quite modern - I prefer it to things like RGs, although the TZR, I will admit, does look well tasty.
I don't think I will ever sell the bike. It's been a part of my life for so long that it would be like selling a sister or brother. I still take off with mad wheelies and scream around with a wild grin on my face, although I don't do that in my own street - I keep telling the wife that it's a cheap, economical way to get to work and far too old and fragile to do silly things on...
Ian Myatt
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It was one of those incredibly hot summer days when you could really believe in ozone depletion and global warming. So hot that every time I went below 90mph steam started rising out from under my matt black helmet. I’d done about 150 miles on my pristine RD400, rebuilt and refurbished so many times that it made a mockery of its age and mileage (1977 and 83,400 miles), when the bugger started running on one cylinder with loads of fumes coming out of the exhaust. The heat coming up off the motor suggested I was lucky to have avoided seizure.
I knew exactly what had happened. It had burnt a hole in the piston. I liked to set the engine up on the lean side because it gave searing acceleration and a top speed of 120mph; it would actually cruise at 90mph for hours on end. For most of the time. But when the temperature soared and the mileage was extensive there was always a slight chance of burning a hole in the piston. It was my own fault really, as I insisted on fitting dodgy racing pistons rather than the tougher standard items. The RD400 has one of those simple looking engines that cry out for serious tuning attention. RAC time.
One of the nice things about RD motors is the ease with which they can be torn apart. Replacing a piston takes less than 30 minutes (once you’ve been forced to do it a few times), one of the reasons I’m willing to tempt fate with a precarious state of tune. I often carry spare pistons but had somehow forgotten them that time as I hadn’t planned to ride so far, the weather and the buzz had got the better of me.
Electronic ignition at least ensures I have one less thing to worry over, models with points a bit notorious for overheating their motors if not regularly checked. The last failure on the road was a reed valve breaking up, being sucked through the engine, wreaking all kind of havoc on the crankshaft. I suppose I should be grateful that the gearbox has its own completely separate compartment so was insulated from the metal debris. The only time the lubricant intermingles with the engine oil is when the crankshaft seals go, but usually they are as long lasting as the crankshaft bearings.
That rebuild had cost me a lot of my spare components and set back my attempt to assemble a second engine by half a year. I’m always buying RD bits, both racing and stock parts, on the principle that you can pick stuff up dirt cheap when you don’t really need it, but that it’s bound to come in useful somewhere, sometime down the line. Again, the reed valves were non-standard so questionable to begin with.
I’d originally run the bike on a completely standard engine, more than 20,000 miles possible without doing any major engine surgery. The problem was that as my mates got hold of newer, faster machinery the poor old Yam was getting left behind and rather than abandon the wailing stroker I went the tuning route. There are very few entirely stock RD400s on the road, for those very reasons.
Yes, I’m one of those lunatics who run around on screeching spannies and like to turn each GP start from the lights into a test of my ability to wheelie for a few hundred yards. The RD is one of those bikes that feel very edgy once up on the back wheel, rather too easy to fall over into a heap. Er, I’ve lost count of how many clutch plates I’ve been through, but that’s a relatively cheap and simple job.
The one job I really f..ked up was replacing a selector fork and leaving an essential bolt out. The gearbox seized solid, locked the back wheel up and the lovingly restored chassis was wrecked as the bike slid down the road. The gearchange is generally slick but after about 25000 miles the selectors wear to the extent that false neutrals are more likely than engaged gears. Very dodgy on a bike with a very wild power delivery.
The RD has one of those old fashion tubular frames that works rather well with a decent set of bearings, improved suspension and a newish set of Metzelers. The latter when bald set up some very wild weaves and wobbles. Not recommended, especially as they got me an endorsement and massive fine. The whole set-up is so simple and straightforward that only the most foolish of owners would neglect to keep it in first class condition.
The swinging arm bearings are the quickest wear item but dead easy to check (and bloody obvious by the way the back end swings around at 70mph). The front end was eventually replaced by XJ650 components, the twin discs extremely powerful, which is exactly what I need with my somewhat wild cut and thrust style. Squealing the front tyre on dry roads is quite easy, with a lot of control available.
There was nothing really wrong with the stock set-up but by the time I’d tuned the motor for more power they had worn their bushes quite badly and were about due for a rechrome. A friend had blown his XJ650 motor (with 112,300 miles up, so no great shame), was selling off the remains for whatever he could get as the wobble that resulted from the dead motor was so vile he’d sworn never to ride a motorcycle again. It was his loss and my gain, although I have got him to come pillion a couple of times and he’s now missing the game so much that he wants to buy something like the RD. I think it’s the machine’s fun factor that has convinced him - he’s never around when the Yam explodes.
After replacing the holed piston I put some bigger main jets in the carb, which left a 2000rpm hole in the midrange until I’d put the baffles back in the expansion chamber (it had previously refused to run above 6000 revs with them fitted), which then cut the motor dead at 8000rpm. No fun, but sometimes it was a good idea to cut into the edge of the wildness for a time; the RD was one of those hustlers that demanded to be used to its full by its rider.
This makes life interesting, as it’s the sole means I have of getting to work each day. Very anti-social, for sure, but when you have a job that bores the shit out of you there’s a need for some way of letting off steam in between the routine of slave labour. There are probably a lot of modern bikes that are even crazier than the old RD, but for the kind of spare dosh I can afford to spend the alternatives are so bland I’d probably kill myself trying to ride way beyond the capabilities of the machine.
One of the big problems with the RD is the riding position. If I didn’t have to commute I’d go for rear-sets and clip-ons as they give maximum control over the chassis as well aiding the aerodynamics of the naked machine. However, in town, where most of my commuting takes place, they place an intolerable burden on my wrists. The seat offers minimal support; I’ve had to resist the temptation to fit a solo saddle with a bum-stop as the wife would not be amused. So I ended up with quite wide bars that rise about four inches and the rear-sets, which help with the wheelies but are only tolerable for 80mph cruising. As every dummy knows that’s a waste of time on the motorway! It is possible to contort my body wickedly and end up with my head between the clocks, but that’s even more painful than using clip-ons in town. Fitting a fairing would help but would ruin the whole nature of the beast.
Vibration isn’t much of a comfort problem on a well sorted RD4000, too many ruminations at high revs being a sign that something is about to fail inside the motor. Long acquaintance with the Yam means I can spot failing main bearings by the thrumming set up in the petrol tank above 5000rpm. I was quite proud of myself when I pulled such a motor apart to find just the slightest amount of slop in the crankshaft. Letting it go for a few more miles would’ve allowed the pistons to slap around and ruined the bores and maybe the whole bloody engine.
Even more vibes hit the pegs when the clutch came loose, giving off the kind of knocking noise that convinced me I was going the exchange crankshaft route. When I pulled the cover off I found a huge crack in the drum casing, looked like it was moments off exploding. This happened 200 miles into my annual holiday in Gwent. I couldn’t believe my luck when the first breaker I phoned had one for a fiver! The breaker even rode four miles to where the bike was stranded and refused all offers of a tip. One up for the Welsh.
Most of that holiday was spent screaming around the mountains of North Wales. If I spent more than a minute vertical it was a rare occurrence. I don’t think I’ve had more fun riding a bike along narrow, twisting roads than in those two weeks. Helped by being April without the tourist hordes cluttering up the area. It seemed to perfectly match the Yam’s abilities, although I could have done with 10 degrees warmer weather.
Owners of middleweight fours that run around the clock without any hassles will be chortling to themselves over all the trouble involved with this fierce stroker. I'm often tempted to throw in my lot with them when something goes seriously wrong but when the motor's running cleanly there's nothing quite like the directness of a highly tuned, lightweight stroker's power delivery. Kawasaki H1 owners will know what it’s all about, even Suzuki RGV250 riders will have experienced the ecstasy.
Dave Thomas