Speedshop

if you get really stuck we can look at fitting a modern generator to it

We can strip and rebuild starters, we charge by the hour. I will say we do good job rather then 'cheap'. That doesn't mean expensive but my techs will want paying at the end of the week for the work they've done so we charge for our experience, knowledge and time to ensure they are paid! So if you have a starter that needs sorting and a good replacement is silly money then we can help. Ebay is the place for cheap and you pay your money and take your chance there As an aside we've just had a batch of Lucas E3 dynamos in, I'd forgotten just how labour intensive dynamos can be to get right. Its been many a year I've had to undercut commutator insulation and actually machine parts! Hard work, but somehow satisfying when the customer comes back amazed they now all work after being told by other companies they were scrap.

I've got a growler but its used to test armatures not remagnetising (just tested a load of British dynamos for a bike shop, well they were new Chinese copies that didn't work as the insulation was made from bits of what looked like rope). Its an AC device so won't make a magnet. Most modern (anything less the 50 yars old) magnets will still be good unless they've been in a seriously hot fire. Its old the old 1920/30/40's magentos that really suffer from loss of magnetism. I'm not even sure that you can re-magnetise modern rare earth types of magnet.

Depends what year. I know the 1980s models had CDi that is a separate self generating system not requiring a battery.

tinnitus?

This wiring diagram will solve all your problems, study it carefully - it works on most Yamahas and is the the same with 6 or 12 volts.

Or http://www.rexs-speedshop.com/epages/es143131.sf/en_GB/?ObjectPath=/Shops/es143131/Products/R6V

I ride old 500 singles on the road. And the odd 650 twin. When I feel confident I'm not going to lose my lisence I'll break out the 900 triple. I fully accept that discs are generally better then drums. However the 1970s disc and caliper that I removed weighed in at over 5 kilos and were on or off in the dry and off or maybe on (who knows if or when) in the wet - best replaced with the drum option which is far more controllable and predictable. The drum hub weighs less. Remember this is 1978 equipment. I'm no GP rider either! :-) I just do electronics to suit what the fast guys want from the engine. And I play in the workshop when I'm allowed near a lathe/welder/propane torch/drill press......... I did have a BMW with ABS - I could leave the braking so late I'd lead many rocket rider in to a round about too quick for their comfort. Trouble is it makes you lazy and the system failed one day, also if you are on mud or slippery rocks the ABS can leave you with no brakes at all.

We're doing a kit :-)

Sorry to have to ask but,,,,,, if I have read this correct you have converted a disc to drum brake system and if so why? Because the rear brake does less then 20% of the braking. Its there to stop the back end wagging like a fish tail. Its been done but none of the big manufacturers put a twin leading shoe drum on the back when TLS was the best there was. You don't need massive braking in this position as the rear tyre is being lifted the more the front brake is applied. Your front is THE stopper, just need something to balance it at the other end. I recently bought sintered pads and upgraded the rear disc brake on my Daytona. I soon put bought basic pads in as the rear was too powerful and caused the back to lock up too easily

The thing that stalled my project SR was the rear wheel. It needed so much work, I changed the rear disc brake from a drum and fitted an ally swingarm. The rear hub from an XT500 was laced in to a 3.5 x 18" inch rim then all the problems started. The sprocket carrier was worn and let the sprocket wobble badly - so badly i couldn't be sure I'd got the wheel spacer right to get the chain running true. Also the Motolana swing arm fouled the drum brake rod not to mention numerous other things that were needed just to get all the new parts to fit. Well after a long break the sprocket carrier was modified according to a German website: Bearing housing machined down New bearing and spacer fitted to sprocket carrier And I found an oil seal that fits with the standard circlip to finish it off: The fix for the brake rod was increase the length of the brake cam operating arm. I did this using the ally operating arm from an XT600. Adding length to the operating arm might change how the brake feels, but I then compared it to the length of the XT500 brake arm which is the same at the XT600 but in steel. So if they used a longer brake arm on the XT500 compared to the SR500 it shouldn't make much difference. We might do this fix as a kit and if we set up a proper machine shop offer this as a repair service (I had to unlaced the hub after having built the wheel up Grrrrr, and with some expert help machined it on a myford)

Obtain a full M/C license then a bigger bike

i'd say that was entirely repairable with the tooling/experience

If your bike has a 2 phase regulator that'll work, if not it won't. But at 21 quid it'll have a computer powersupply voltage regulator in it (rated at 10 amps max) - good luck with that

It might be OK but its not designed for such harsh charging as its a standby battery, not a vehicle battery. It should have a fixed current, variable voltage charger attached to it. People do use them but its definately outside the battery's spec and you'll invalidate the warranty using it in a motor vehicle appliaction.

Did your mechanic warm the generator and look for fluctuating readings?

OK as mentioned the one marked 'the right regulator' is not suitable for your application - its for mopeds. Looks like someone has fitted a Superdream regulator to your bike. This is a popular mod as the Superdream regulator is a solid reliable unit. With these things the mounts and type of regulator are important - not what bike it fits - if the wires are different - its easy to change. Looks like you need a 3 phase permanent maget type (not field controlled like the Honda CB550 or XS650) You can use a 5 wire unit or a 6 wire, the extra wire is a voltage sense, Yamaha like to use this type of regulator (the CB250 wetdream uses the same type) The sense wire must be connect to the main circuit after the ignition switch. If you tie it to the red you might find if works well but after a few days the battery will be flat as the regulator circuit will be 'leaky' and the battery can drain through it. Thats why the brown wire is used as its is switched off with the ignition off.

Thats a very simple generator and it will be very easy to sort out. If you plug the lighting coil into the CDi it will blow it. It may actually work but this coil is capable of producing a lot of current which will burn out the SCR in the CDi box. I've not tried the other unit. What I will say is the reason we started making CDi units for the SR500 was their one for this bike was shockingly bad. What they call a 'performance timing curve' is a joke as they keep the ignition fully retarded until 5,000 RPM when it swings full advanced We've a nice little 12 volt conversion for the XT250 ;-) http://www.rexs-speedshop.com/epages/es143131.sf/en_GB/?ObjectPath=/Shops/es143131/Categories/Products/12_Volt_Conversions

You've got the high and low speed source coils wrong way round or the wrong polarity. Or a combination of both. With the stator off the bike I could probably work it out - but if its been messed about with its likely to have other issues (in my experience)

Measure the shims, work out the clearances then take the cam out, its quicker in the long run.

We use NGK as I've never had a problem in competition or road on many bikes - DTs, ITs, YZs, TZ racing bikes, Kawasaki triples........I could go on We can get racing plugs but they will be hard on a stock motor - a simple Iridium will work well.

The type magnetos used on these bikes are actually very good (both Cdi and points versions). in fact for a 2 stroke its very difficult to improve on what you have fitted. All the parts are repairable (we can look at CDi units if they give up the ghost). The charging can easily be upgraded too. I'd leave it well alone. As already mentioned if PVL stop making the parts (and they do as we get sent PVL generators for repair that the factory no longer makes the parts for) then what are you going to do? Go back to the original as you'll still be able to get parts! One thing that is worth doing is ensuring there is a good connection between the wiring loom/engine/frame. Don't assume the engine mounts will do this. There should be an actual wire on the back plate of the magneto to ensure a good earth return. Without a good earth the ignition performance will be down.

Too modern for us, we tend to stick to 1970's and 80's systems but are starting to see some early nineties yamaha singles Not sure what number you found when you searched - it should have been 01580 880768

There is a lot of vibration on the XT - but its worth checking the engine mounts are tight, particularly the head steady. The XT and the SR500 are pure singles with no balance shaft so the faster you rev them the more they vibrate Japanese suspension is soft but this can be changed. My next task is getting the SRX going

I'm sure your wife was out when you took those pictures (on top of the hob......) :-) We can fully recondition the original windings for those who don't want to go making thesesorts of changes