650 - A Couple Of Questions

[G0FHM]

I'm at the "snagging" stage, of the restoration/rebuild now.

Firstly:

Valve timing. When I rebuilt the engine, I followed the manual. There was some debate as to where to count the 20 pins from, and I lost the argument. Having looked at the manual again, I'm not so sure it is right. When I was turning the engine over "on the button", I was watching through the exhaust port, and at one point both inlet and exhaust valves were open a fraction, allowing daylight to be briefly seen.

Should there be any "overlap"?. I know there is on some engines (Turbo immediately springs to mind) to allow cooling air to flow through.

I'm worried the timing is a tooth out. No valves collide with the pistons.

Having studied the manual, with the timing arrow pointing straight upwards on the exhaust cam the first pin of the 20 to count is on the exhaust side of the arrow, and the 20th pin is directly above the arrow on the inlet cam.

I cannot remember how we counted it now. Would it run a tooth out? Or would the valves collide with the piston crowns? I'm not in a position to pull the top cover off and check it at the moment.

Secondly:

The 3 wires that come from the alternator coils seem to be getting dangerously hot, too hot to touch. My AVO meter is "suspect", and I've ordered a new one as when I measured the AC voltage phase to phase it was reading 180v!. I've checked it against a known 13.8vdc source, and it's miles out of calibration.

Until I get a new meter, what should I be suspecting? Reg/rec?. The actual reg/rec shows no sign of getting hot. I've "bell tested" the alternator coils and none are down to earth, and there is good continuity between the phases. Until I can get a new meter, I can't measure the resistances of the reg/rec.

I'm no stranger to electronics and soldering, and am wondering if it can be repaired?

Has anybody managed to gain access to one before? Suzuki give a circuit diagram in the manual, so I'm assuming it cane be.

That's it for now!

Cheers,

J

[johnr]

reg recs cant really be repaired, though they arent expensive. electrex are the best known and imho best value. ive got them on my own bikes. iirc a reg rec for a kat will be about 55 or 60 quid, so not the end of the world if your own is fecked. how does it run? if it runs ok, then i wouldnt fret about the valve timing. if you get it a tooth out, then it will run like a bag of spanners.

[G0FHM]

Thanks for that John.

Electrex looks like it could be a good bet. I did find a US site last night who were selling them for $75, but by the time the shipping is factored in it will probably be no cheaper. I'll know more when I can get the AVO on and check things out.

As far as the valve timing goes, I'm going to check it anyway just to be sure. I've got a twin cam timing belt a tooth out before now on a car, and it ran like a bag of proverbial at idle and low speeds, but went like a rocket above 4000rpm. Kind of what the Kat is doing. Getting it to rev at low speeds is hard work, and when the revs are lifted, they take a while to drop again - But rev it past 4000, and it revs and drops cleanly.

I've checked all the carbs, checked for air leaks round the inlet stubs (stethoscope and WD40) and all appears good.

Watching various youtube videos on the 650, I know that they sound a little "rough" on tickover, a bit like the Triumph triples do.

I'm going to check it anyway, just for peace of mind!

Thanks,

J

[G0FHM]

Well, I'd say the reg/rec is shot.

Just measured the resistances as per the manual, and where I should have 5-6ohms I'm getting circa 180 ohms, and where I should have 35-45ohms I've got an open circuit!

Stator coils check out ok - Full continuity between the phases, and none down to earth.

Have managed to score a used H*nda CX500 unit for £15, so that will get us out of the woods for now with a bit of wiring work (i'm going to do away with the multiplug as it's ropey, and remake with bullet terminals and heatshrink).

When the budget allows, will go for a new Electrex unit.

J

[bobster]

Have you actually balanced the carbs yet?

[G0FHM]

Yep... All balanced.

Running a lot better, I'd even go as far as to say the idle is mildly smooth!

J

[fossie]

When you wire in the CX unit take the 3 yellow wires from alternator direct to the rteg/rec avoid the wires in the loom for the original reg/rec.
The CX black wire you can join to the red then join to the red of the bike in the circuit.
the CX green is Earth! run that direct to battery.

suzuki had a mad idea of running the charge circuit through the lighting phase...........but here in the UK we don't turn the lights on so burn out the reg/rec.

[G0FHM]

Hi Fossie,

That's what I intend doing.

I cannot see any logic in routing one phase via the lighting circuit whatsoever!

Normally, on the road the lights are on, being responsible riders - But for general running up in the shed etc there may be times where they aren't on.

Still not sure what caused the existing one to fail. I'm just wondering if that misfire had anything to do with it, as it was fine until that developed. I've read stuff elsewhere on the net that GSX-R's had issues with HT getting sent down the LT circuit and frying the reg/recs.

Still, it's going to be done properly. All new bullet connectors, a soldering iron and plenty of heatshrink on standby. I just need to find the motivation to get out in the shed and do it!

J

[G0FHM]

All done

14.4V at 1000 rpm with the lights on. Sounds about right to me!

All heatshrinked with new connectors.

The added bonus, the H**da unit has exactly the same hole centres as the existing unit so no mounting issues to overcome. Much chunkier unit with the heatsink twice as big as the unit that was on there, too.

I'm going to break into the old unit and give it a bit of an autopsy later. My guess is one of the shunt resistors has failed, or one of the transistors has gone short circuit. Rectifier diodes don't *normally* give that much grief!

J

[bobster]

Thats seams rather a lot at 1000 rpm...........Is your battery OK and charging now?

Id expect to see that sort of DC voltage at 4500 rpm............not at 1000rpm.