[douglas.black@me.com]

Hi, I don’t remember where I found this but it may be a starting point.

Standard DPY Engine 7:1 volume at TDC of 50cc

Racing Engine 10:1 volume at TDC of 35cc

Note at TDC not volume of the combustion chamber

Doug

• This reply was modified 2 years, 7 months ago by douglas.black@me.com.

[douglas.black@me.com]

That’s saved a bit of work. I see a washer of sorts lying in there in the first photo.

[douglas.black@me.com]

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[douglas.black@me.com]

Cheers Lief,  I’ve managed to source another one from Kev Neil , Doug

[douglas.black@me.com]

Hi, thank you. I had thought about this method but it looks as if the bush has already been skimmed before as it is 7 – 8 thousands undersize. Also, I think the surface hardness is gone, it is quite soft. I can get the bush hard chromed and ground but this is expensive and I’m not sure how it will work on the part of the bush that is pressed onto the splines. Last of my worries was the reduced diameter would no longer locate the clutch  bottom plate as required. Anyway, I have the offer of another sleeve gear in good condition and I will go with that. Thank you for the advice, Douglas

[douglas.black@me.com]

Dave, I believe the bracket bolts to the magneto platform using 2 x 1/4” bolts. The pump is driven by a disc and peg (not 100% sure here but you may get the idea) that engages with the magneto sprocket (which has a single hole in it for this purpose). Align the pump shaft with the magneto shaft so that they are concentric. I have 2 coils mounted where the pump should be in the picture but may give you an idea?

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[douglas.black@me.com]

Hi, I contacted Ian Pearce a year ago with a similar question and he replied quit promptly, Doug

[douglas.black@me.com]

BTH electronic mag works well, no issues, but I’d be tempted to get the one you have repaired/serviced if possible …

[douglas.black@me.com]

jakerobbinsvintageengineering.co.uk

[douglas.black@me.com]

https://jakerobbinsvintageengineering.co.uk

[douglas.black@me.com]

Sorry my typo, Jake Robins

 

https://jakerobbinsvintageengineering.co.uk

[douglas.black@me.com]

Try Jake Williams Engineering for girder forks

[douglas.black@me.com]

<li style=”text-align: center;”>Hi I think that behind the gearbox foot change mechanism the gearboxes are the same. Nothing stopping you modifying the foot change pedal to suit different feet. But I think that it will never be like a modern foot change. May I suggest you try it first and see how you get on? Picture of the magneto points. Carburettor is a Lectron. Mikuni are available from Allen’s Peformance in the UK for Scott.

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[douglas.black@me.com]

Hope this gives you an idea of the layout

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[douglas.black@me.com]

Hi Spark Plugs, For 14mm NGK B5ES Avoid any with an ‘R’ as they are resistor and keep the gap small, 15” – 20” Scott Technicalities is a good resource.

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