XL500s project - 12v conversion questions

[epidemiks]

Picked up an 81 XL500s last week, don't see many customs around so thought it would be interesting to turn it into some kind of street version of the sweet SA Svart Gevaar thumper.

Before I start tearing this thing apart, I'm wanting to get it up to 12v. Done lots of reading on the topic, and now I'm more confused than ever.

Can someone more fluent in electrons please tell me what I'll need to replace? Stator, coils, rec/reg, bulbs, battery?

Read that the FT500 Ascot runs the same engine but 12v electrics, so does that mean I can just put in an FT500 stator and swap out all the 6v bits for 12v and ride off into the sunset?

Planning on a full rewire, running LEDs all round, and may well ditch the battery.

Any advice appreciated!

 

[Bert Jan]

As all parts on the xl are designed for 6v, its not more than logic to replace all parts with wires sticking out bulbs aswell.

If the stator of mentioned model fits, it should be easy. The engine conversion is the hardest, rest is easy.

 

[epidemiks]

As all parts on the xl are designed for 6v, its not more than logic to replace all parts with wires sticking out bulbs aswell.

If the stator of mentioned model fits, it should be easy. The engine conversion is the hardest, rest is easy.

Thanks. Yeah, have a whole load of shopping list for the replacements. I guess my confusion surrounds the stator and whether it's necessary or unnecessary to replace. My reading tells me necessary if I want to run a battery, but not necessary if I don't. Just need some clarification from anyone who can tell me if I'm on the right track

 

[xb33bsa]

why change it ? is the 6v broken ?

 

[Attatoy]

Did it a long time ago......got fucked cause the 6v used a mechanical advance and the 12v runs a cdi. make sure you change the crank trigger. Build it, i love dem bikes!

 

[epidemiks]

why change it ? is the 6v broken ?

No one looks for bikes on the roads here in Melbourne, day or night.. Not being able to see or be seen due to a naff 6v headlight at night means I'll be broken.
Also, if I do this project, I'll be doing redoing the wiring anyway, so why not bring it up to 12v and save hassles of finding 6v parts and bulbs down the line.

Did it a long time ago......got fucked cause the 6v used a mechanical advance and the 12v runs a cdi. make sure you change the crank trigger. Build it, i love dem bikes!

Nice, thanks!

 

[epidemiks]

So it appears the 82 XL250 stator cover will bolt straight on to the 500 engine, so I can use the 12v stator from the '82 250 and swap out the CDI & coil, rec/reg, globes, battery and have a 12v system for around $300 all up. FT500's seem to not exist down here, so the xl250 option seems like a good alternative.

Last question I have : If I swap out the stator & cover, will I need to change the flywheel too? I can't find any decent specs/measurements for either, so finding it hard to answer. Anyone know?


Then there's the option of leaving the stator as is, and doing the conversion using a Trail Tech 150W R/R (http://www.trailtech.net/electrical/electrical-accessories/7004-rr150). Here's a thread on Thumper Talk with such a conversion (http://www.thumpertalk.com/topic/910174-80-xl500s-restomod-project-pics/). Unfortunately the details of what was done besides the R/R swap to complete the conversion. Thoughts?
Cheers!

 

[Attatoy]

And you need the cdi trigger too, the 6v pick up is not the same and will double your total ignition advance resulting in detonation and hard starting and ultimately and engine failure.

 

[epidemiks]

And you need the cdi trigger too, the 6v pick up is not the same and will double your total ignition advance resulting in detonation and hard starting and ultimately and engine failure.

Is the coil not the trigger? I'm not familiar enough with engines & electrics. :-[ can you elaborate/shoot us a link to what this is?

 

[epidemiks]

PM sent, Attatoy, Cheers.

 

[epidemiks]

So I've got a 12v stator coming in the mail, and now stuck on what ignition trigger to swap.

CDI trigger from a 12v XL500 like this:

or

Crank shaft ignition trigger from an FT500 (same engine as the XL500 except for the electric start)

It's got me stumped..



Here's a shopping list to finish the conversion:

CDI: http://www.rexs-speedshop.com/Honda-XL250-XR250-XL500-XR500-CDi-Unit
Coil: http://www.rexs-speedshop.com/epages/es143131.sf/en_GB/?ObjectPath=/Shops/es143131/Products/HTC4
Reg/Rec: http://www.trailtech.net/electrical/electrical-accessories/7004-rr150

+ globes

 

[xb33bsa]

the xl500 uses a rotor on the crank with a centrifugal advancer the ft does the advance with the black box

 

[xb33bsa]

if you are looking for xl500/ft500 parts i have some at fair price let me know what you need

 

[epidemiks]

the xl500 uses a rotor on the crank with a centrifugal advancer the ft does the advance with the black box

So it is possible to bolt on the black box? XL's from 83 onwards have the electronic sensor/trigger too, so should be able to use that, right? Based on a discussion with Attatoy, I need the black box to avoid frying valves.

I appreciate the help. I'm better at riding than wrenching, but hoping to balance the two!

if you are looking for xl500/ft500 parts i have some at fair price let me know what you need

Got a few wreckers local with XL's, hoping to avoid int'l freight to keep costs down. Will be in touch if can't source it local.

 

[Attatoy]

What he said......remove the mechanical spring advance and instal the solid fixed pick up....this locks your timing pick up at (what ever the fuck it is )degrees, then when you rev the bike it advances the timing int he black box or CDI as us murcanics call it

Buy the used shit from XB33bsa.

Hurry up too.....then build this sassy biotch in to a mean cafe!

 

[xb33bsa]

So it is possible to bolt on the black box? XL's from 83 onwards have the electronic sensor/trigger too, so should be able to use that, right? Based on a discussion with Attatoy, I need the black box to avoid frying valves.

I appreciate the help. I'm better at riding than wrenching, but hoping to balance the two!

Got a few wreckers local with XL's, hoping to avoid int'l freight to keep costs down. Will be in touch if can't source it local.

pretty sure the xl with a mech advancer would only need the simple trigger box/coil...
for sure if there is no mech advancer then you need a cdi with a brain like the FT has
i dont think you can mix,pretty darn sure you would need 100% parts from one design or the other

 

[epidemiks]

So after sitting down with an mech engineer friend he suggested instead of head off into uncharted, or at least undocumented retarded timing territory, why not just use a resistor between the CDI and coil to alter ignition timing and leave mechanical side of things as is. Any thoughts on whether this will work.

 

[Sonreir]

I doubt it will work. Most electronic ignitions are digital, not analog. They use a rising or falling wave trigger and a resistor doesn't change that, only the amplitude.

 

[epidemiks]

I doubt it will work. Most electronic ignitions are digital, not analog. They use a rising or falling wave trigger and a resistor doesn't change that, only the amplitude.

Thanks Sonreir.
After a good long read through the Haynes book, the earlier advice is now much clearer. Reading instructions without looking at the parts just doesn't work for me.
Will update the build thread once I'm done.

 

[Parkwood60]

Before you get too far into this, are you doing this BECAUSE you want to switch to a 12v CDI ignition and away from the points? Most of these old dirt bikes even though they are 6v electrics will actually put out 12v from the stator at a certain RPM given the right reg/rec. That's why you need a regulator in the first place, to limit it to 6v. I haven't studied the XL500, but most other old dual sports I have played with (bike made as recently as the late 70s by Honda) didn't even have didn't even regulate the voltage to the headlight. Look at the wiring diagram here: http://www.xl500.8m.com/cgi-bin/i/images/1979thru1981xl250and500.jpg

Notice the yellow wire goes direct from the alternator to the headlight switch and not to the regulator/rectifier. The headlight therefore runs on AC and not DC current, and the voltage is limited only by how much it revs. I think this is actually the dirt bike version, not the dual sport. So look at your manual. If you have close to 12V going to the headlight at normal riding RPM you can run a 12v light and bobs your uncle, as they say. Typically the only thing keeping the 6v bulb from burning out due to too much voltage is a controlled short via a resistor wired in parallel with the bulb.

If all the power does go thru the reg/rec on the street version, measure the raw output before the reg/rec at normal riding RPM. Is it is around 12v at like 3000rpm, you can just swap the regulator rectifier, battery and light bulbs and you are fine. The coil/points/condensor don't care if its 6 or 12v.

I like that "Swart Gevaar" bike except for one thing. It has almost no trial in the front suspension geometry. At anything approaching freeway speeds I would suspect it would be extremely nervous. They moved from a 23" front wheel to a 18" front wheel without lowering the back end at all. If you plan on using that small a front wheel you need to increase the trail, and/or rake. Swapping to a front fork without leading links, and less offset from the frame would help.