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Y2k Sherco 250 With No Spark


jaylael
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I recon I need to ohm check the coils etc, but I have no specs. Probably some really expensive part has gone bad, but which one? Anybody know where to find the ohm specs to help get this bugger diagnosed? So far I have just looked at the connections, disconnected the kill button, and still no spark. She's as dead as a wedge. Perhaps someone would be so kind as to enlighten me a bit on this. I must have about a dozen different flywheel pullers, one for beta, two different ones for gas gas, old bultaco, ossa, Hodaka, on and on. Sure hope one of them will work on this one. Still too knackered from working to have a look at the old girl. Mostly I'm just on here to whine. (Whinge for you Brits) Is it pronounced whing or just mis-spelled? :D

Edited by JayLael
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I recon I need to ohm check the coils etc, but I have no specs. Probably some really expensive part has gone bad, but which one? Anybody know where to find the ohm specs to help get this bugger diagnosed? So far I have just looked at the connections, disconnected the kill button, and still no spark. She's as dead as a wedge. Perhaps someone would be so kind as to enlighten me a bit on this. I must have about a dozen different flywheel pullers, one for beta, two different ones for gas gas, old bultaco, ossa, Hodaka, on and on. Sure hope one of them will work on this one. Still too knackered from working to have a look at the old girl. Mostly I'm just on here to whine. (Whing for you Brits) Is it pronounced whing or just mis-spelled? :D

here's a place to start - click me

cheers

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Jay,

A Beta(ducati) puller should work as I recall.

There is this fellow in the UK that repairs them and had some resistance specs published on his website at http://www.uk-motoplat.com/home.html

I am not sure if any of that will give you a hard answer or allow you to functionally ck the trigger. And I cannot tell you what normally fails, other than a possible stator, but what part?

Find a buddy with another bike, it is easier that way. Wish I could tell you more. :D

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Thanks for the help guys! Cope, It looks as if I will be able to get the flywheel off with the Beta puller then, hopefully. I will try to ohm check all this stuff and go from there. I will post results when I know more. I noticed the 250 uses a different setup from the 290 according to bradford ignitions website. Something I never knew, or wanted to know.

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I found the primary ignition coil, which is the green wire, open. The stator is on it's way to the guy who rewinds them in Spain. Cost will be L 82.50 posted to my door, and takes around 2 weeks turnaround time.

The Beta flywheel puller fits perfectly as it's Ducati ignition. The trigger coil resistance is very close to 100 ohms, measured from red wire, to ground which is the white wire. I have one of these in stock as a spare from a Gasser I once owned. Too bad this wasn't what was needed.

So a quick ohm check would be

white to red= 100 ohms

White to green= not open (No spec obtained)

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Bradford ignitions website= Steve Hardker en Espana.

Oh! Guess I should have looked!

Hey, while you have that thing apart, can you measure the backing plate diameter. OD! You see, we need a calculated referance of MM vs degrees in timing swing.

In other words, if the backing plate were 360mm in circumfrence then 1mm=1degree change(114.6mm dia.) and if the diameter varies then there is a given ratio. I would like to know just for my own info and am too lazy to tear one down just to find out!

If it ain't broke, well you know! <_<

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  • 1 month later...

Cope: The stator is 110 mm OD. The stator primary was rewound and now my Y2K Sherco 2.5 is back among the living. Note the Ducati ignition may be different from later Shercos. I suggest looking at the pics on Bradford ignitions website and compare to your unit for positive ID. Steve is a saint to have put up with my rudeness. I kind of freaked out and sent him a very mean e mail when it never came back in time for an important trial, due to things beyond his control. . He was as tactful as he could have been under the circumstances. I reccommend him very highly. Jay Lael

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Cope: The stator is 110 mm OD. The stator primary was rewound and now my Y2K Sherco 2.5 is back among the living. Note the Ducati ignition may be different from later Shercos. I suggest looking at the pics on Bradford ignitions website and compare to your unit for positive ID. Steve is a saint to have put up with my rudeness. I kind of freaked out and sent him a very mean e mail when it never came back in time for an important trial, due to things beyond his control. . He was as tactful as he could have been under the circumstances. I reccommend him very highly. Jay Lael

Good deal Jay! Gee, you were rude? I thought I was the only one that did that?

Thanks for the measure! You see the ideal stator plate that you could swing 1mm per 1 deg. of timing change would be 114.5949387 mm in diameter which would yield a 360 degree (1:1) circumfrence ratio! As the Ducati and Leonelli units are only 110mm in diameter, this yields a basic relationship of 0.96:1 !!!!! Very close to my original theory that 1mm of swing on the plate = 1 deg. change of timing.

This info is good, and does back my theory, yet all relative as I still set mine by seat of pants off the standard factory mark and it takes at least a 2-3 mm swing to really tell a difference even for an experienced rider. Seems the factory has been all over the board depending on year anyway. I think it was the '02 that came the most advanced at 3mm BTC of something based on piston height.

The only other measurements I have taken was years ago on the '01 bike which seemed to sour when set below 1.75mm BTC by the piston height method.

Cheers,

MC

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