SR500 (SR400) project

**Wired1** · 8th June 2008, 16:24

This bike is a 1980 SR400 built for the Japanese domestic market. It seems they have a licence or insurance barrier at 400cc so they make a lot of thier own bikes to fit this artificial level. From what I've been able to find out the SR400 is identical in every way to the SR500 except for the crank and conrod to give it a shorter stroke.

This bike had been stored in a shed which caught fire. The bike was pulled out before it was too damaged but it did suffer a lot of heat damage especially to the front end. The speedo and tacho were globs of molten plastic, the wiring melted but still working, and the paint on the tank damaged. The guy I bought it off had bought it from the shed owner, and that was abot 10 years ago. The last owner used it as a hack and was the one responsible for fitting the knobblies and motocross handlebars!

Anyway, my first objective was to determine the history of the bike and see how registered it was. I made sure I got a receipt from the guy I bought it off and even got his receipt from the guy he bought it off - it's easy to do this when you pick up the bike but difficult to do it later I have found.

The day after I got the bike home I dropped into VTNZ to check out the rego status. The VTNZ staff started looking at me funny and asking how come the VIN number didn't tie up with the number plate? I'm sure she was reaching for the hidden button under the counter when the supervisor realised that they had mad an error at some time in the distant past and the bike had actually been listed twice on the system with slightly different numbers. All of the paper records were transferred to computer in the seventies and this bike got mixed up in that process. Anyway the upshot of all this is that they agreed that it had a legitimate history and said that as long as it passed a warrant I could reliven the registration. This is a lot easier than registering it from scratch so I decided to get the bike road-worthy as soon as possible before they changed the rules or forgot what they had said.

**Wired1** · 8th June 2008, 16:53

So the idea is to get the bike road-worthy enough to get a warrant, so that I can register it and then put it on hold while I restore the bike. This may seem a bit unnecessary but I have found in the past that if you can make the rego process easier it is definitely worth doing as registering a bike from scratch is a bit of a pain in the butt.

So the obvious things needed are tyres, a muffler, indicators, lights and brake lights.

The tyres I chose are Dunlop T100's which are a nostalgic tread pattern that I think will suit the bike I am planning on building. I could have just slapped them on but as I will eventually be powder coating the wheels I decided to do it now rather than later so that meant stripping out the bearings whioch of course means new bearings as there isn't any point putting the 28 year old bearings back in. So off the the bearing shop and the powder coater. The wheels cam back this week on Thursday and I had the week off so I had the new bearings in Friday and tyres on that day balanced and ready to roll.

The front end of this bike had blown fork seals which had spewed out all over the fork lowers and brakes so I had to clean this off, fit new fork seals and put new brake pads on the front disk (the fork fluid buggers the pads). Since I had the forks apart I decided to paint them black along with the front guard as this is the eventual colour scheme and it makes sense to paint them while they are off. I used engine gloss black which looks better than I was expecting and worked well over the chrome. I may eventually get the front and rear guards powdwer coated black too but for now this will do and if it stays looking good I won't change it.

I needed a muffler so as a stop-gap measure I pulled the supertrapp off my TT500 and made a short pipe extension to the header to bolt it on under the foot rest. I like the look of it so much I think I will keep it on this bike now - as long as it passes a WOF with it on! It is a little loud but I think it should be OK, crossed fingers etc.

I forgot about the speedo until late into this stage so after looking around NZ ended up buying a very nice one off a guy in Germany on ebay fo about $100 including shipping. I also ended up having to buy a new headlight as the original was partly blown so that made another dent in the budget. I maganed to add the brake switch to the rear brake, bought a new battery and with a lot of dicking around got the front brake switch working (there is another very boring thread about this in the brakes forum if you are interested). The indicators work now that I have fitted a new indicator flasher relay, and I added a simple high beam light indicator to the instrument cluster to satisfy that bizzare requirement. I got a cheap chinese horn off fleabay and wired that into the new left hand switch block I found in Aussie.

While searching around the globe for various bits I came across the left hand switch block on ebay Australia which had a horn button I needed anyway so I bought that and it is better than the original Yamaha part. I also got some brand new norton handle bars and retro grips off a guy in the UK for bugger all so these have been fitted even though they aren't strictly necessary - the original motocross bars were a bit of a laugh.

So later this week I'll try my luck with the VTNZ. I'm sure they'll find something I haven't thought of but you never know - once they hear I'm going to strip it all down next they might just cut me some slack.

**Wired1** · 19th June 2008, 17:58

Well I went off to the VTNZ today to get my lapsed rego renewed for which I needed an entry certification. I paid my $177 and left them the bike for half a day and they phoned me at about 3:30 to tell me it had failed for the following reasons:

1. Front brake hose is damaged at the master cylinder end - Ok it is a bit buggered.
2. The side stand doesn't retract with the flick of you foot - Ok CRC will fix that.
3. Check steering head - clunk! - Ok I'll check it and adjust it.
4. Excessive noise exhaust - wankers. Ok it's a supertrapp so do I take out disks or do I just find a legal exhaust?
5. Indicator warning lamp missing from instruments - really? so you can't just look at the flashing lights by your hands, you have to have another flashing light by the speedo?
6. Secure headlamp - Ok it is missing the screw that stops it tilting, fair enough.
7. Secure right foot peg - the other VTNZ guy wasn't sure wht this means and he thought it was Ok so I guess I'll take it off clean it up and reinstall it?
8. Rear foot rests to fit - whatever. I've got a solo seat for this bike but I've also got a couple of old pegs I can slap on it for now.

At least I now have a difinitive list. I did ask them for a list of what they would be checking originally but they wouldn't give me one! What a great system. So basically I've got to quiteten it down and replace the front hose, all the other stuff is petty crap that I can fix in an afternoon.

Anyone got a nice quiet exhaust or know how to quieten down a supertrapp?

**Buddha#81:Me** · 20th June 2008, 11:50

Originally Posted by Wired1

Anyone got a nice quiet exhaust or know how to quieten down a supertrapp?

Yeah take the disc's out.......massive back pressure but it will keep the feds

happy untill you get it home

**xwhatsit** · 20th June 2008, 13:02

Originally Posted by Wired1

Anyone got a nice quiet exhaust or know how to quieten down a supertrapp?

I was about to post up this thread but you've found it.

The dashboard indicator/highbeam requirements seem bizarre; I don't have any dashboard warning lamps, it's never been mentioned. Maybe it would be a problem getting it VINned, but for a WoF?

**Wired1** · 20th June 2008, 20:29

Priced up the genuine Yamaha front brake hose today - $156 from Japan (5-10 days) so I asked them for an aftermarket alternative. They could do stainless braided lines for about the same price, delivery about a week, but they said I should check with VTNZ first. VTNZ said they don't comply because even though they are stamped on the swages with the correct standard, the new rules say the ends must be one piece, not able to be unscrewed with common hand tools. These lines had crimped ends and screw in banjos of various shapes and angles so don't comply.
So I went to the local brake shop (Nelson Brakes) and they made me a new one on the spot for $78 with the correct hose and the right ends. Simple as that.

**Wired1** · 24th June 2008, 18:45

Spent the weekend fixing all the things that needed fixing. Added an indicator-indicator light and reduced the disks in the supertrapp from 13 down to 4. I added a couple of rear pegs I had in the shed which even though they are completely useless with the rear-set pegs so close, at least they meet the requirement! I pulled the front end off and cleaned and repacked the bearings (I'll get tapered rollers later) and got it all back together. The bike is noticeably quieter now.
I took it back to VTNZ and they passed it in about five minutes flat. I could have registered it and got a new plate but I'm planning on tearing it apart and it's $300 + for the first years rego so I may as wait three or four months until after I have had the frame powdercoated etc.

I also managed to find a set of original footpegs to replace the rear-sets. I got the pegs from trademe and found a full size brake pedal on fleabay. Now all I need is a gear shift to replace the linkage one for the rear sets. I'll list the rear-sets on trademe as soon as I can photograph them.

The next major hurdle is to replace the wiring as this bike has extensive loom damage from being in a shed fire. This should be straight forward as I'm a sparky but there are some differences in wire type and wiring systems. I'll reduce it down to about 8 or 9 wires and get rid of all the crap they normally stick needlessly in looms like side-stand interlocks and redundant wiries for optional extras. Photos to follow of the before and after wiring.

**Wired1** · 21st July 2008, 19:52

Anyone know the speedo ratio for this bike? I'm looking at these mini instruments on fleabay and wondering if I can use them - they all seem to be 2:1 so I'm hoping that Mr Yamaha uses this ratio too. Alternatively, does anyone have a source of japanese mini speedos?

Update on the SR400 project:- The bike has been completely stripped down for sand blasting and paint/powdercoat. I have added brackets for the solo saddle and cut off all the extra bits like the centre stand and some of the electric bits. I will drop it in to the blasters tomorrow hopefully. I need to clean the engine up as it was covered in mud and grease so I've started doing this with the dremmel and an assortment of wire brushes. I will remove the outer covers to polish them on the rag wheel but I'm not going to overhaul the engine just yet as it is running so sweet. I'll do my TT500 motor up first then come back to this later. I've also painted the gas tank and it looks pretty sharp. Photos to follow, two videos of progress so far are on my youtube page - click the link below.

**FJRider** · 21st July 2008, 20:04

As I understand, Speedo conections are pretty much universal... try a "spare" from somewhere...

**xwhatsit** · 21st July 2008, 22:22

Originally Posted by Wired1

Alternatively, does anyone have a source of japanese mini speedos?

Hey man -- here's how I got mine. It'll take a while, but it's worth it. Cheaper than I could find here at least.

It says on it, 60kph=1400rpm. I find it's dead-on accurate -- doesn't under-read like the stock speedos I've tried. I've seen them on Japanese café SR400s, so unless if they've changed the speedo drive or they're a different model speedo I'd assume they'd work. As far as I can tell, they're the same as the quite common `Daytona' ones, just without the logo (I think it was on the box), which is not what I wanted.

**xwhatsit** · 23rd July 2008, 00:27

This one's pretty bloody fancy; got all the dash lights too, highbeam, indicators etc. Price a bit higher too to match. 6720 yen, that's $70. Would get it to NZ for a little over $100 I'd surmise.

They really are miniature and look a treat.

If you have a look in this category you'll find plenty to like. There's quite a few good second-hand ones for under $30 or so.

**Wired1** · 25th July 2008, 17:22

I got the bike parts back from powder coating yesterday. Unfortunately the sand got into the oil tank so I spent a couple of hours today cleaning it out. First I tried using old turps I use for washing parts but it did bugger all and I lost a lot of it so it would have taken gallons of it. Then I had the bright idea of using water and detergent. The first fill got most of it out and left a very slight residue so I repeated it twice again and it is like new in there now. I blew it out and rinsed it between washings so I think it should be fine. I'll leave it in front of the fire over night to get rid of the water residue and then flush it tomorrow with new turps and it should be fine.
Lucky the wife is away for the weekend...

Update on the speedo thing - I have bought a couple of items through my new agent in Japan so they will be the test case for the costs etc. You just can't tell what it's going to cost to ship it or what they will add on for charges but if this goes well I'll bring in some more bits including the speedo I've been looking for.

**Wired1** · 28th July 2008, 20:25

Spent some quality time in the shed on Sunday and got the bike back to a rolling chassis again.
New vid here: http://nz.youtube.com/watch?v=Zf0SoiAQYtw

I started cleaning the motor after work tonight. It had a good layer of dirt, grease, cow shit and some sort of plant fibre stuck all over it - the previous owner had been using the bike as a poor man's TT500. I took the motor outside and propped it up on a couple of saw horses and proceeded to scrape the outer layer off with an old hack saw blade. Then I hit it with the wire brush (by hand that is) and then with turps and an old dish washing brush. Finally I sprayed CRC engine clean all over it and left it for 10 minutes then hosed it off. It is pretty much back to the original paint now, so tomorrow I'll start with the wire brush in the dremmel, and Autosol by hand. What a shit of a job.