wayne_weedon

The original Ground would of been a green wire if I recall correctly and would of started at the grounded ends of the stator coils and via the connector block terminated at the coil mounting bracket. LT was Black I think! and was connected to the points and the other end of the LT Stator coil. To make the ignition work you only need a Good Ground and the LT wire connected. Wayne....

It's a common mod. Makes life easier when changing them and also will be in a cooler enviroment. You only need the one wire coming up from the stator to coil and a ground. Wayne...

I would recommend you change the condensor and put fresh crank seals in it even if just to remove those from the equation. Both are simple parts likely to cause much frustration for no known reason! On Bults laid up for a while I have also seen sticky points pivots cause severe frustration! Wayne....

Nice Find! Now to get some of todays top stars recreating these on Flat Tank Vintage machines Wayne....

Well that frame is much later. Model 199A from 79-80 last 325cc trials version before the 340cc 199B. Shame they dont match, but it's pretty common. Wayne.....

As I said in PM. 1974 350 Sherpa. Does the frame Number match? JB-125 etc etc Wayne....

Montesa fold? It folded effectively in the 80's surely? It's Montesa Honda and I'm quite sure they build a lot more models than the Cota, couldnt say if in the same factory though. http://world.honda.com/group/MontesaHonda/ They are probably quite safe. Wayne....

I'm sure they have, but I did say "but usually left the factory" with the single plug hole. Out of many heads I have in my parts store only a few 9:1 Sherpa heads have 2 x 14mm threaded holes, and most likely they were drilled and tapped out for compression releases. I do however have a twin spark 370 Pursang in my Bultaco collection and it is really that, ie twin spark. The motoplat coil has two ht leads and both plugs spark simultaneously. Until we know the OP's model number we will never know what he has. Wayne...

Dave Most if not all Bultaco Heads have the bosses for the extra plugs or comp releases, but usually left the factory with just the vertical central plug boss machined on Sherpa's. The twin spark Pursangs etc usually used the alternative angled bosses, both plugs at about 60 degrees. Wayne....

Tell us the 1st few digits of the frame and engine Numbers (after any Letter digits)and all will be revealed! 360 & 370 Fronteras and Pursangs were often twinspark. But it could be anything without knowing the model numbers. Wayne....

Have you used a centre gasket? Can't see one. Wayne...

If you drill right through you can't easily punch it out Yes magnesium burns well! Wayne....

In Addition to the suggestion above, if the bolt is now useless it does help to drill a hole into the bolt concentrically just smaller than it's outside diameter but not right through. Effectively turning the bolt into a blind thin wall tube. It will then tend to collapse and free off much easier. Preferably use a hot air gun to do the heating on Mag Alloy. Wayne...

Did you ever sort this out? Noticed you never had a reply! I just stripped a pair myself, You need to warm the top of the slider and unscrew the seal carrier/top bush. I had a battle with mine but not in that area, mine have to come completely apart for rechroming and the bottom of the tubes has a steel wear strip carrier screwed into them and it was a bitch to remove as Telesco in their wisdom deliberately disrupt the thread though a hole in the tube, Loctite would of sufficed! Take a good look at the condition of the roll pins holding the "damper rod" assy together, they can shear with exciting results! Damper rod my AR&%!! Did they really have damping qualities? Hard to imagine! Wayne....

Steve I think the 242 one is basically the same. Dave Renham has them at InMotion it appears. I'm not sure where I put the original from my airbox when I cleaned the box out. But it's here somewhere! Wayne.....

Not so sure it's criticism really. But there is a certain amount of irony considering the Centrally Speaking post this week. I have been more interested to see how my pals have gotten on personally, and thanks to the Todotrial site I'm more aware. Next year maybe we'll make the Pilgrimage Wayne....

The Irony eh!

If its a steel silencer then a hot air gun works a treat to burn off the oily deposits and make the rest fairly easy to remove. It's smoky and dramatic once the stuff starts to burn off. I wouldn't use any fuel to get it going, the oil alone will do that. Wayne....

Almost like the KLG plug in my 1925 Triumph Funny how these things have a 2nd or 3rd life. Admittedly the vintage plugs didn't have the electrodes joined. Wayne...

Should a fiddle speedo be accurate or waver all over the place to be authentic Maybe you should take that ferrite back out after all! Wayne...

Fiddle Speedo Hilarious! You get him to and I'll make em for half the price eh and bring Jeff Bungay back just to sell them. Wayne....

Thats good Alan. Is it stable now? How much effect did the Ferrite have? Did Maplins have one? or did you get it elsewhere? One would ASSume that if the other device you talked about is designed for motorcycle use then they have designed it with at least some RFI precautions. Wayne...

Nah, but I did a few years ago make alloy bodies for these speedos to be used on road bikes There was a weird chain of events leading up to that work, all because a lost German biker got chatting to me at traffic lights while I was riding my Morini 500. But I digress... A lot of RFI issues can be reduced with good earth bonding techniques, I see issues like these on my cnc machines when bonding issues rarely arise. Wayne...

Alan Your problem is almost certainly RF noise coming from your ignition. The signal levels in the bicycle speedo are low and the RF is swamping the signals from the wheel sensor and probably being picked up in the cable from sensor to readout. As they are two separate circuits you also have a floating ground in the speedo, so another option to try and may be the simplest is to somehow ensure the Battery Negative in the speedo is bonded to your frame assuming you are Negative Earth, which using PVL? I would of thought so. This will either work, Not work or rare chance it fries the speedo depending on how well it's designed. Wayne...

Are you using a resistor plug or cap? That may help. Another option may be to wind the sensor wire through a ferrite ring a few times. They can be found in dead PC Power Supplies or maybe at a Maplin electronics store. Wayne...