PB1

That bike is really nice, I remember those from when I was a teenager. I think I must have a fetish about shiny spokes. And that Suzuki RM in the background reminds me of my TS250 I had in the '70s, another great bike. Apologies if Suzuki is a swear word on here.....

Just a bit of an update on what's been happening with my RS200 after a few months of being being away.... I've been collecting parts together ready for the rebuild and now have 2 complete sets of painted parts (and some spare headlamp ears), one set in original red metalic and the other in primer. I've also now got a new set of spokes to rebuild the wheels, found a friend of a friend who will soda blast engine parts and wheel hubs for me, have most fixings sorted in stainless and bright-zinc, and so am more or less ready to get on with it. I've also collected 2 spare complete engines along the way, which is handy. I've been using the bike on and off during the summer and it really is a great bike. I've spent some time fine tuning ignition, carb settings and oil pump and the bike is running spot on. I really do think it is the equal to, or maybe even better than, the RD200 up to 50mph; the bike really flies and is great fun. I'll often use it in preference to the CB400SF I've got a couple of projects to finish off in the garage before I start, but hope to get going on it soon. I'll try and post some more updates and pictures as I go.

In theory you can do it that way, but it's going to be hard work. As said above, you are going to have to cut some out as the nipples will be seized to the spokes or may be rounded-off already, and to get some out you will need to remove others first, and then replace them again before moving on to the next one. If you are prepared to renew quite few along the way you could do it one at a time. Just think of it as replacing a single broken spoke 36 times. After replacing each one, tighten the spoke while watching for up/down trueness and in-out trueness. Get the tightness so that it sounds the same, when tapped with a metal object (screwdriver blade, etc) as it did before you removed it. When you are happy all is okay, move onto the next one and do the same. 36 times. You will almost certainly find that it will need some constant tinkering for a while in use, as the wheel settles in, to get it properly true. As I said, it can be done, but will take far longer than stripping it all out and doing it from scratch. I considered doing mine this way, but not for long, as it's much more time consuming than doing it in one go when you look into the practicalities of it. I've now bought 2 sets of new spokes and will be re-lacing my wheels soon.

Has the bike ever run in your ownership? Or was it running fine then suddenly stopped working? This is a critical question as if you have never seen it run then you could be dealing with a previous owner's bodgery. If it was fine then suddenly stopped working, and you are certain it has gone 90deg out, then a slipped flywheel and broken woodruff key look likely candidates as nayruf says.

Excellent. Many thanks.

Does anyone know if the minimum pump stroke setting is the same on all the small twins? I've just reset this on my 1982 RS200 to 8 to 10 thou (0.2 to 0.25mm) as this is the book figure for the RD200 and RD125. It was set at 15 thou, but this was achieved by the previous owner by putting a fibre washer in there instead of the shim washers, and tightening it up until it squashed down to 15 thou clearance, so this was a bodge and probably not the right figure. Not being able to find a manual for the RS200, I've had to assume it's the same as the RD200. The engines seem very similar (except for the single carb of course). I have noticed that the RS pump does not have the white plastic starter plate that the RD one does, and means you have to use the kickstarter to move the pump plunger out to its maximum for measuring the gap, but otherwise it looks the same. Anyone know if the RS200 does in fact use the same setting of 8 to 10 thou (0.2 to 0.25mm)?

Putting these RD200 exhausts on has certainly not blunted the bike's performance as far as I can tell. I took it for a ride up and down a twisty country lane near where I live and it goes really well. I can't get over how tiny it is compared to my Honda and previous Aprillia Pegaso, very nippy and great round the twisty bits. Also, I don't remember small two-stroke twins being so quick and such great fun as this is - it's brilliant! It feels a bit like you are sitting astride an angry wasp...

Shiny secondhand RD200 exhausts now fitted (see the thread "RD200 exhausts on a RS200?" to see the modification needed) and they do make the bike look much better: I've also solved the problem of what to rebuild it as. I now have a second set of side panels and fuel tank in the original colour, bought from eBay. This means I'll keep the best set as originals, and repair and spray the other set in Purple/White. With a gloss black or silver headlamp shell (or maybe I can find another one of them too?) I can swap colours whenever I want. Might be a bit tricky with the V5 and the DVLA though.... I'll have to think about that bit.

Well, I’ve now modified the RD200 exhausts so that they fit onto my RS200 and use the existing RS200 downpipes. The picture a couple of posts above shows the difference in size between the RD’s smaller threaded end (left), and the larger RS’s one (right). This is only a few mm but enough to make modification necessary. Firstly, I cut these ends off the RS200 exhausts so that I could use them to make an adaptor collar: I then parted this off in the lathe, very close to the weld line, and counter-bored into the collar to a depth of 8mm and a diameter enough to get rid of the remaining bit of downpipe inside . This would be difficult to do with hand tools, although a hacksaw and die-grinder in a drill could possibly be used with some care. I then trimmed off the threaded part of the RD200 exhaust so that 10mm remained as a stub, and filed the threads down until it was an interference fit with the bored out collar. The new adaptor collars fit really tightly onto the trimmed down RD exhausts. I was planning to weld it all the way round inside, but was worried about to much heat ruining the chrome. As these fitted so well, I used exhaust assembly paste on the join, hammered the adapters on with a rubber mallet, and put four small tack-welds on the inside. Luckily, the chrome has remained intact okay. There’s also now a step in the end that is the same size as the downpipe’s wall thickness, which means there’s minimal gas-flow interruption. I’m not sure what the effect on performance will be from the slightly smaller diameter of the exhaust at this end, but it soon reaches the same diameter as the RS one within an inch or so. I’ll no doubt find out when I ride it if has decreased performance! As said before, the rest of the exhaust silencer part fits the bike perfectly, and the baffles are the same too. The only downside is that with the modified adapter collar on, the exhaust is now 15mm or so longer than standard, so 15mm needs to be cut off the end of the downpipes so that it all lines up properly and fits into the barrels okay. This is easy with a hacksaw. When fitted on the bike, they almost look standard and don’t look bad in my opinion. Sorry If I’ve taken too much space up with all this, but I thought I’d put it up on here in case anyone’s interested, or is thinking of doing similar. RD200 exhausts are far easier and cheaper to get hold of than RS200 ones, and it might just be of help to somebody at some point to know that this can be done.

Well, that's one of my possible options for rebuilding out of the window..... I'd bought a set of Ace clubman bars thinking I'd try them, and if I liked them, I might do a white/red/black era cafe type bike. While I'm still modifying the RD200 exhaust threaded end rings to fit the RS200 downpipes, I thought I'd try out the new bars on the Honda to see how they felt. I spent a bit of time fitting them, getting the cable runs nice and smooth, then took it out for a ride. I got about 8 miles from home but had to turn round and come back. My wrists hurt like hell, as did my back, and my left thumb (which I broke 30 years ago and now is a bit weak) was so painful I couldn't use the clutch after a while. I think my big mistake was thinking that a 56 year old body could ride a bike with dropped bars and rearsets like it could when it was 17! The standard bars are now back on the the Honda and the Ace bars will go back on eBay. So now it's down to rebuilding it as standard (and I quite fancy this as they are relatively rare) or rebuilding to standard spec but with purple/white CS5 type paintwork.

Ah.... I understand now. Thanks for the replies and the link guys.

On my RS200, and I assume most front drum-braked '70s/'80s bikes that used the same front brake lever, the righhand mirror has a lefthand thread and the lefthand mirror has a conventional righthand thread. What's going on here then? Anyone know the reason for this? It can't be so that wind pressure at speed does not unscrew them, as they both have the wrong handed thread for that, so what can be the design reason for this? It buggers me up a bit as I have a very nice pair of chromed mirrors to put on the bike, but both have righthand threads. I think it's going to be a case of drilling, sleeving and recutting a righthand thread in the righthand brake lever.

So, £80 lighter and a pair of pretty good RD200 exhausts have turned up from an eBay seller. They are in good condition and will polish up well enough for me, without the expense of re-chroming. That's the good news. Not so good is that they don't fit the RS200's downpipes. The RS ones are 35mm ID at the collar and the RD ones are smaller at 32mm. This means that RD200 have smaller downpipes than the RS200, which was a surprise. See pic below They physically fit exactly the same on the frame though, so I shall modify the collars to fit my existing downpipes. I can't use RD downpipes as I'm told the angle of the bend is different between RS and RD (strange - I thought RD barrels would fit an RS? Maybe not.). I'm lucky to own a lathe so I can cut off the threaded collars from the old RS silencers, which are scrap anyway, and bore them out a bit. I'll then grind down the new collar to make a stub spigot with just enough left to weld them on from the inside. A bit of trimming of the downpipe ends should allow me to fit them without altering the brackets. Part numbers are the same on both types except for the RS ones starting with YAMAHA 3L2 and the RD ones starting with 1E8. Numbers are 14711 and 14712 (Left and Right).

Excellent - thanks very much for this. If there was a slight mismatch in this positioning, it probably wouldn't take much to fabricate some new brackets, or extensions to the original ones.

I had to sit down when I found out how much silencer re-chroming was. It was nearly as much as I paid for the bike. This afternoon I bought a pair of RD200 silencers off the bay, which seem to be in pretty good condition. They are 87cm long, the same as the RS ones, and the bracket fixing points look right, so I bet they are the same parts. The only issue might be the pipe size where the castle ring screws on. If not, they can always go straight back on eBay.