Honda XR500 81 and wring from a Suzuki

[red_rooster]

I am eying up a specific XR500 for conversion to Road legal, and then possibly/probably converting to motard.

One issue it has is lack of indicators and the presence of a headlight, which from memory the stock lights are better to be turned off and use moonlight instead anyway. WOF guys might ask that there is one though.

There was the offer to strip down a Suzuki farm bike (of unknown model) sitting next to it which has the same voltage (6v), and a big Round Suzuki headlight with battery box.

Is it a good idea to take the loom (but swap CDIs) and use it on the XR?

EVEN BIGGER QUESTION:
Is it possible to run a 12v system using parts from something else?

And because its road, I might sacrifice airbox space to put a small battery or put it somewhere else. Doesn't have to start it, just keep the lights on at idle.

Some other info for anyone who wants to know, and maybe guide me.
Guy wants $1200 for it but it has a few probs.
Manifold is close to stuffed with a few pinholes coming through.
Backfires a lot on engine braking. Been sitting around for a while, but sparkplug was fairly clean on inspection.

[xwhatsit]

EVEN BIGGER QUESTION:
Is it possible to run a 12v system using parts from something else?

OK -- well it might be possible to use an alternator setup from a CB250RS. I really don't know if it's that compatible, but given how similar the 250 and 500 motors are in all other respects it might have the same dimensions. Does anybody know? From looking at parts fiches it seems that they used both a generator design and an alternator design in the XL500s and XR500s.

Want to get it road legal? Sell it to me and I'll put it in my spare CB250RS rolling chassis

[CookMySock]

Take the frame number to LTNZ and ask them. They will tell you immeditely and for no cost, what the isses are registering that from for the road.

Steve

[red_rooster]

Take the frame number to LTNZ and ask them. They will tell you immeditely and for no cost, what the isses are registering that from for the road.
Steve

I had a talk with the a guy down there and He said I had to find the import docs for it, or previous reg if I can. So far this hasn't happened.
I know what I need in terms of a bike as I have road legal'd a '90 XR250 once 10 years ago. Just that import stuff that would stop me this time.

OK -- well it might be possible to use an alternator setup from a CB250RS. I really don't know if it's that compatible, but given how similar the 250 and 500 motors are in all other respects it might have the same dimensions. Does anybody know? From looking at parts fiches it seems that they used both a generator design and an alternator design in the XL500s and XR500s.

Want to get it road legal? Sell it to me and I'll put it in my spare CB250RS rolling chassis

So what type of setup does the XR 81 use? I am really keen to hook the suzuki loom into it because its a strange thing to do and its always fun to be the first to get it to work (or first to blow something up). It was a 250 of some sort, but I forgot to look at the Chassis plate.

Would you pay $1200 for it knowing what I have told you?

[CookMySock]

I had a talk with the a guy down there and He said I had to find the import docs for it, or previous reg if I can. So far this hasn't happened.

Looking all that crap up will be a wild goose chase - dunno quite why he sent you to do that.

That chassis/frame number should be on their system, even if it was an "offroad use only" bike, again, I would tempted to roll in there armed with the chassis/frame number and see what their pooter system said.


Steve

[xwhatsit]

So what type of setup does the XR 81 use? I am really keen to hook the suzuki loom into it because its a strange thing to do and its always fun to be the first to get it to work (or first to blow something up). It was a 250 of some sort, but I forgot to look at the Chassis plate.

Would you pay $1200 for it knowing what I have told you?

I'm not sure which one was which -- on cmsnl.com , which I use for parts fiches, it shows the 81 only using an alternator. But that's for US models... and one year is not a lot of difference. If the 81 is actually an 80 (shipped to NZ later because leftover stock or whatever) then it could have generator etc.

At any rate if you're swapping a CB250RS alternator rotor and stator in, then I suppose it's not too important what you had originally? As long as the dimensions of the shaft you're fitting the new rotor onto are the same and you can either use the existing brackets to bolt the stator on or fab up your own (wouldn't be too hard, surely, wouldn't want it to come off and stick itself to the rotor whirling around at 6000 rpm though).

If you want I can dig out my box of bits and measure the inside diameter for the CB250RS rotor and other dimensions.

The other thing to think about I suppose is that the rotor is the flywheel too of course... using a CB250RS rotor (which is already slightly lighter than the XL and XR250... at a guess?) is surely going to be lighter than the XR500 rotor. Some people might like a lighter flywheel but it's probably nice to have a heavy flywheel on a big old-school single like an XR500.


Paying $1200... who knows what an XR500 is worth these days. They're pretty rare... always talked about fondly... I know a guy who paid similar amount (maybe $1500, a couple of years ago) just to pull the engine out and stick it in a CB250RS frame intending to go roadracing in Post Classics.

A good, used manifold you could have from Econohonda for $50-100 at a guess (we are talking intake manifold? If exhaust, you could get a pattern exhaust, probably not cheap). That would solve the backfiring too probably.

[RDjase]

Hi all, i vaugely remember from when i was doing WOFs the there is a exemption with XR Honda's ,TY yamaha's and KL Kwaka's for blinkers and something to do with there (crap) lights,(and lack of battery)
There was alot of XRs used on the road back then, my cousin had a XL500s and everyone gave him shit coz it wasnt a XR ;-)
Its good your playing with a real bike, get it ready and come Post Classic racing, Pre 82 is a blast

PS ,has it still got the 23" front wheel?

[xwhatsit]

The 1981s are apparently 21" front wheel... 1980 was the last year of the 23".

I wouldn't worry about putting a battery in, if you get a decent 12V alternator, as long as you've got 1500rpm at idle it'll put out heaps. I run my CB250RS battery-less (just a big capacitor), and it's got substantially higher-wattage lights than you'll run on a dirt bike. It's fine at idle... sure when you put the indicator on it'll dim the headlight somewhat but it's not too bad. Forget about using the horn until there's 2000rpm on the clock if you have the lights off, but the WoF guy doesn't care.

With the CDI... the pre-RFVC XR250 and XR500 motors are funny. There's a little centrifugal advance unit next to the clutch on the RHS of the engine (it's referred to as the ATU, automatic timing unit). The pickup comes from there and goes to the CDI -- there's no advance within the CDI itself. So it's a hybrid system if you like. If the CDI really requires 6V electrics to run, you may need to source a CB250RS CDI and coil perhaps as well... are CDIs normally a problem between 6V and 12V? Given that there's no advance within the CDI, then it should be no problem using a 250 CDI on a 500. The Haynes manual only mentions matching the ATU to the pulser coil, I think the CDI is a simple primitive little thing and doesn't much care.

[red_rooster]

Looking all that crap up will be a wild goose chase - dunno quite why he sent you to do that.

That chassis/frame number should be on their system, even if it was an "offroad use only" bike, again, I would tempted to roll in there armed with the chassis/frame number and see what their pooter system said.


Steve

Went into VTNZ and asked about the Chassis this morning - said that they had no record of that number.
Also tried to find it using CARJAM.co.nz (which is a very cool/scary free chassis and plate lookup site that even has WOF records) and it has no record for that Chassis.

So unless the guy can come up with some records, I am out of ideas.
Anyone registered a bike without any records before?