Yamaha RXS100 rebuild

[.Chris.]

After nearly selling it, I've decided to start rebuilding my RXS100. I thought it would be best to start quickly before I change my mind!
There isn't a great deal actually wrong with it at the moment, it's just a bit tired and deteriorating cosmetically.

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100beforewebres.jpg


The plan in the short term is:
Completely strip the bike down and clean it up
Re-paint / powder coat the frame and swingarm
Top-end engine rebuild
New C&S
Tidy up the electrics

In the longer term I'd like to (possibly) get new mudguards, a new headlight surround and a new seat. If I can come across a spannie for it at a decent price then I'll stick one on. It would also be quite cool if I could get another engine or barrel and tune the bollocks off it. An RXS100 with ~20bhp would be amazing fun (and pretty lethal with the standard brakes). Some new rubber wouldn't be amiss either.

Anyway, I started by removing the seat and petrol tank, then the rear rack, lights and the exhaust. I'm now in the process of removing the rear wheel, chain and swingarm. The paint on the frame is in quite a bad way; there are plenty of rusty bits especially around the joints in the frame. Gave it a good poke with a screwdriver though and it all seems sound with no acutal rot.

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100stripdown1.jpg
https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100stripdown2.jpg

Both mudguards are pretty tatty:
https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100rearmudguard.jpg
https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100frontmudguard.jpg

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100engine.jpg

The black paint on the engine is flaking off a bit, not quite sure what to do with it. Originally it would have been bare polished metal - ideally I would like to go back to this sort of finish but I'm not sure that's possible.
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Chris
1985 Kawasaki Z550F

[.Chris.]

Thought I'd make the best of the good weather we've got today so I cracked on with a bit more this afternoon. Managed to get the rear swingarm and mudguard off. Encountered my first problem in that half of the mudguard bolts just sheared off when I tried to undo them.

When dismantling everything it's pretty apparent that this is long overdue - the whole bike is covered in a horrid black slime, which won't be much fun to clean off I imagine.

One potential problem I have noticed is that the pivot for the centre stand and rear brake pedal is pretty worn, giving quite a bit of play in pedal. Not yet sure whether it's the spindle or the pedal bush that's worn, or even if new bushes are available.

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100stripdown3.jpg

When I took the rear brake apart there's some strange looking crap in there - not quite sure what it is. The friction material of the shoes themselves looks OK though so I think I'll re-use them.

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100crapinrearbrake.jpg
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Chris
1985 Kawasaki Z550F

[Whosthedaddy]

WD40 eats the aforementioned black grot.

Just try and poke and 'scrape as much dry stuff off and then bathe the bike in lashings and lashings of WD, work in with a paint brush so thats all smeared and looking worse. The best bit, spray again with WD and you'll see the dirt just fall off the bike.
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Current : MSX 125 Past : CBR 900RR Monkeybike : c50 LAC : ZXR750 H2 : FZR600 : ZX7R P3 : YW100 : TRX850: Trophy 900 T309 : GSXR 600 L0: Monkeybike : XJ6S Whosthedaddy

[Spearson]

Excellent to see someone else restoring a 100cc stroker. Bet it will look awesome once its been sorted. Ill be doing exactly the same again to our H100 (3 men and a dog) over easter and summer.

https://i171.photobucket.com/albums/u318/Spearson18/PIC_0005.jpg

Can't really see it but thats its current state (one at the back)
Good luck with it.
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'05 Yamaha Jog R (in fancy plum) sold to a chav, '91 Yamaha SR125 (stripped and rebuilt) sold to an Australian, '88 Honda H100S (crap) bought by 3 retards

[Endless Nameless]

Oven cleaner (poundland is your friend) applied generously to frame etc is also good for de- gunking bikes, well it worked on the H100 anyway.

Watching your progress with interest!
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A2 passed 22/07/08; restriction up 22/07/10 (just so I don't forget)
'79 Suzuki GS550E. Yes, that's a GS550, not a GS500.
Supersports "In a video editing competition I'd kick your sorry ass"

[.Chris.]

When I rebuilt the engine in my car it was covered in a similar black filth. I used several bottles of white spirit to clean it off but I don't think I'll be doing that again as the fumes built up in my garage and made me feel really rough (had to lie down for a bit). WD40 or oven cleaner sounds like a better option!

I'm not turning into a chav, but I really do like the idea of tuning the engine - I was wondering if anyone has any experience of doing this on these bikes? I want to try and find a nice loud 'sports' exhaust for it if I can. I also wonder if it's possible to enlarge the capacity at all?
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Chris
1985 Kawasaki Z550F

[Blau Zedong]

A mate built a field bike from a stolen recovered RXS. Micron spanny with cut down can, gutted airbox, RD350YPVS 31K carb (choke side) and some porting work. No clocks so never sure how quick it was, but it felt bloody quick. He seized it doing burnouts at a rally, and planned to 125 it but it got nicked.
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[.Chris.]

Interesting, how was he planning to 125 it? I know Yamaha made an RS125 alongside the earlier RS100 - I wonder if it's possible to overbore the RXS barrel to accept the 125 piston?
I woudln't mind getting the front end from an RS125 complete with disc brake if I could, but they seem to be fairly rare bikes.
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Chris
1985 Kawasaki Z550F

[.Chris.]

Cracked on with a bit more stripping down this morning.

Removed the exhaust downpipe, battery and airbox first. I couldn't quite believe how small the batteries for these bikes are!

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100stripdown4.jpg

Disconnected most of the electrics, the speedo and front brake cables. Note the crap headlamp rim, hopefully to be replaced. I took quite a few photos of the wiring so with any luck I'll be able to put it back together again.

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100stripdown5.jpg

Next I removed the front wheel. Used my car jack to lift the forks up, which worked really well!

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100stripdown6.jpg

The front brake shoes look to be in good nick, so they'll be re-used. I'm a bit puzzled as to why the brakes were so crap before I took it apart, given that they all seem to be in reasonable nick. Maybe I've just got too used to the disc on the CD250U.

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100stripdown7.jpg

This is how the bike is at the moment. I've removed the centrestand and rear brake pedal and covered the engine's orifices (ho ho).

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100stripdown8.jpg

The main problem I'm coming across now is Mr Yamaha's finest camembert fasteners. Not quite sure what do to with them to be honest, as I can't get any purchase on them with a screwdriver without just rounding them off. I don't really want to have to drill them out or chisel them.

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100crapfasteners.jpg
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Chris
1985 Kawasaki Z550F

[ms51ves3]

Uses a hack saw across it so you can use a flat head screw driver in it.

[Albion]

Nice, looking forward to future updates!

[19van71]

Nice work RXS100_Chris, will keep a keen eye on this as I have one myself (selling soon).

Can't wait to see it when it's refurbed!
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Living the dream....on my little 'ol CG125

[Whosthedaddy]

[MaybeGuy]

[ms51ves3]

[.Chris.]

I managed to get one of them out by gripping it with a pair of pliers. The others don't have enough access to do that. I don't have an impact driver either.

I'll try the hacksaw method tomorrow - thing is the metal is so incredibly soft that I suspect the slot might just distort.
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Chris
1985 Kawasaki Z550F

[Blau Zedong]

Hi Chris - when my mate was looking into overbores we deceided the RS125 barell won't fit the RXS in a million years. He was working in the motor trade at the time so he had the Grampian book with all the various piston dimensions in it. I have a feeling it might of involved a con rod swop too but i'll email him and see if he remembers anything.

Be warned that the RXS clutch does not like being asked to play short stop to power outputs greater than those Yamaha originally intended.....
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[.Chris.]

Hmm, if going bigger involves a conrod swap then I think that's a bit more work than I can be bothered with to be honest. I was wondering it might be possible to simply overbore the RXS barrel to accept the RS125 piston, but that would work on the assumption that the stroke is the same as the RXS. I'll take a look at the manual when it arrives as I'm sure that's got the dimensions in it.


Bit of an update on the stripdown.

This morning I removed the clocks and the left hand switchgear. The horn button needs some attention as it's currently stuck in. I also removed the YEIS unit and the oil tank.

https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100noclocks.jpg
https://i31.photobucket.com/albums/c390/chrisd87/RXS100/RXS100oiltankYEIS.jpg


Went into town this afternoon and bought an impact driver, which has done the trick on all but one of the stubborn bolts (the one holding the CDI). This has allowed me to remove the wiring loom completely apart from the CDI.

Unfortunately I've also noticed that one of the fork seals looks to be on the way out as there's a fair bit of oil on the stanchion, so that's an unwelcome extra job!
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Chris
1985 Kawasaki Z550F

[19van71]

OMG!!! what the hell is that disgusting silver thing behind the pliers???

Looks like something my old boss would kick you in the ass for using!
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Living the dream....on my little 'ol CG125

[ljwalker]

looking good so far cant wait to see it finished it will look the dogs.

[Steve-D]

Coming along nicely.
You didnt happen to be on the moors the other day did you think it was tuesday, was on a purplish/blue diversion saw waved at someone on a bike that looked like your benly, was gonna turn round and chase but didnt wanna seem like a nutter.
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www.southwestbikers.com
Tristan The said 'Dunno what my pace will be like, fastish slow puncture on the rear and if I go too fast I risk my 'keys' falling out'

[nrml76]

Yamaha sold this model in huge numbers in the far east until fairly recently as the RX100, until it was replaced by the RX125, and then by some 4 stroke model (YBX....). Nearly every spare part you would need to build a new bike would be available in these countries. Try India or Srilanka; you are guaranteed to find all the parts you need. Don't bother ordering over the internet though; you won't receive anything you order for several months, if at all you ever receive them. Use friends or acquaintances heading that way on holidays. A favourable exchange rate means it would cost pennies to get most of what you need.
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Everyone who lives dies, yet not everyone who dies has lived. We take these risks not to escape life, but to prevent life from escaping us.

[.Chris.]

nrml76, interesting to hear that. I love the way models sold in the West invariably get pensioned off to developing markets. They still make the Maestro in China for example (poor sods)!

Steve, I can't remember if I was out on the moors then but it quite possibly was me. Was the person wearing a red and black jacket, jeans and a silver open-face lid? If so then that'll have been me.

Good news on the bits front - I've manged to get a spanny for it off ebay! Cost £50 so I hope it's worth it (for that read I hope it's loud enough). I've also managed to get a barrel that's been rebored to +0.25mm with piston for £30.
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Chris
1985 Kawasaki Z550F

[TUG]

Store the engine inside when you've taken it out of the frame as water will find its way into the engine and take a dislike to the inside of it.
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Haz ER-5, innit!

[ms51ves3]