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Viewing 15 posts - 1 through 15 (of 21 total)
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  • in reply to: 596 cylinder head wanted #16386
    Steve Gibbon
    Participant

    Hi Keith,
    there is a very expensive head on EBay; item number: 401475217143.
    The add does not say whether its 500 or 600cc.
    Steve

    in reply to: Test #16048
    Steve Gibbon
    Participant

    Quite right, I think this one also starts!!
    (actually it belongs to a mutual acquaintance of ours).
    I wanted to post a photo of a good looking machine.

    in reply to: Test #16046
    Steve Gibbon
    Participant

    I can see Kevin’s photo also.
    Not sure why you need photo bucket (or equivalent) as long as you make your photo files less than 1mb you can load photos directly into SOC forum posts using the ‘upload attachment’ tab /browse/ add file. You can easily make photo files smaller by emailing them to yourself. That is what I used to upload the following ………….

    in reply to: Gear change conversion #15999
    Steve Gibbon
    Participant

    Yes, I am still looking for a foot change box bell-crank arm.
    If anyone has one to spare please PM me.
    Steve

    in reply to: 2 speed rear brake drum for sale #14703
    Steve Gibbon
    Participant

    Pete, please see my PM, regards steve

    in reply to: Broken crankcase door #15594
    Steve Gibbon
    Participant

    Hi Nick, try Richard Blackburn at Scottparts. He lists crank case door castings on his website. He may be able to machine one up for you.

    in reply to: Bentley and Draper fork "Stabilizer" fittings #15396
    Steve Gibbon
    Participant

    Hi,
    in 2015 Barry Jackson refurbished a pair of kite forks for me. He did a great job.
    The set I had were missing the top yoke and stabilisers.
    Although the central forks were fitted with the attachment for the stabilisers, the kite forks were not – see attached photo.
    [attachment=2:3qswra8k]IMG_1052.jpg[/attachment:3qswra8k]

    Barry fabricated a new top yoke and brazed on the attachments for the stabilisers to the kite forks. He also supplied the stabilisers – which are not stamped -see attached photos.
    [attachment=1:3qswra8k]P1050114.jpg[/attachment:3qswra8k]
    [attachment=0:3qswra8k]P1050115.jpg[/attachment:3qswra8k]

    hope this helps
    Steve

    in reply to: THE SHUTTLEWORTH WEEKEND 2016 #14367
    Steve Gibbon
    Participant

    Hi, I just got back home after attending the “Scott Gathering” today. I just wanted to say how much I enjoyed it, great weather, great venue, great motorcycles, great company plus a free flying display by a Spitfire. Even my wife enjoyed it. Many thanks to Richard Martin and anyone else who helped organise the event. 😀

    in reply to: Spring washer on gearlever pivot #13847
    Steve Gibbon
    Participant

    Hi Brian, sorry I cannot help – but if you find a supplier of these washers I need two, one for my current road bike and one for a project. I have spent some time looking on the internet, but not found a supplier of these washers. Regards Steve.

    in reply to: Scott 3-speed gearbox parts #10945
    Steve Gibbon
    Participant

    Hi,
    new kick start bosses, kickstart pawls and kickstart springs are avialable from the SOC spares scheme ( or at least they were last year when I purhcased one of each). The boss nuts were out of stock. Suggest you contact Graham Moag ( graham-moag@utvinternet.com ).
    regards
    Steve

    in reply to: Exhaust #11396
    Steve Gibbon
    Participant

    Hi, I had been looking at the alloy manifold on EBay too. Does anyone know what the approximate exhaust port dimensions (measured on the outside of the block) are for long and short stroke engines ?

    I have two blocks both of which I was told were 600’s . The external exhaust port openings measure :

    block 1, 51mm wide x 21mm high with 69 central space between them (this block has approximately 75.4 mm bores and curretnly fitted to a ‘FZ’ numbered originally 498cc engine with approx 68mm stroke) – presumably this is a ‘short (68.25mm) stroke’ block ?

    block 2, 49 -51mm wide x 24mm high with 70mm central space between them (This is a spare block – told it was a ‘DPY’ has a bore of approx 73.3 mm – presumably this is a ‘long (71.4mm) stroke’ block ?

    So if I have a long and a short stroke block, the difference as far as the exhaust manifold is concerned is the height of the exhaust ports, which are ~ 21mm high on a short stroke block and 24mm on a long stroke block?

    regards
    Steve

    in reply to: Decompressors #10402
    Steve Gibbon
    Participant

    Richard, thanks for the information. I have never looked behind the decompressor plugs on my Flyer – so did not realise that the decompressor vented directly into the exhaust system via another port internal to the block. On a previous two stroke I had, the decompressor valve simply vented to atmosphere, so foolishly assumed that must have been what the missing decompressor valves on my flyer did.

    This may be the revalation I have been looking for. Ever since I have owned my Flyer, it has been difficult to start and did not run well (spat back violently through the carb except when running at speed). Not sure this could be responsible for the spitting, but I am thinking that the low compression could be causing or at least contributing to the starting problem.

    Presumably the insert need only seal on the surface around the cylinder port, and there is no need for it to seal the port leading to the exhaust also?
    Do you know of anyone that has a drawing/scketch of the required part? I don’t have access to a lathe so will have to get someone to make me some inserts.

    Whilst it would be nice to have a single piece thread screw plug encorporating the insert piece, I am thinking a simple length of round bar with square ends should suffice if used with my existing caps? What do you think?

    regards
    Steve Gibbon

    in reply to: Decompressors #10400
    Steve Gibbon
    Participant

    the decompressor ports on my 29 flyer are simply capped off with screw in caps as shown in the attached photograph. There are no inserts inside the ports. Is this likely to casue any problems? regards Steve Gibbon

    in reply to: Offer of copies of Yowls and Technicalities…… #10280
    Steve Gibbon
    Participant

    Hi, just to let other members know – Mick has agreed to sell his Yowl collection to me.
    Regards Steve 😀

    in reply to: Overheating/Boiling Radiators #10203
    Steve Gibbon
    Participant

    hi Brian, I am not sure what you have written is entirely correct.
    Yes Ethylene Glycol has a higher boiling point than water, so a water/glycol mixture will have a higher boiling point than water. But Glycol has a lower specific heat than water, so a water/glycol mixture has a lower specifc heat than water alone, hence all things being equal, any water/glycol mixture will require a higher flow rate to achieve the same heat transfer. As our Scott’s do not have water pumps, we rely on convection, so coolant flow rates will be limited and fixed by system geometry and temeprature differences.

    I have not had chance to think in detail about this issue, but it may be possible that the increased boiling point of a water/glycol mixture effectively increases its useful range as coolant, to the extent that even though the engine will run hotter, the radiator may not boil over. I think modern automobile cooling systems run under pressure for the same reason – i.e to increase the useful range of the coolant ( the higher the pressure, the higher the boiling point).

    Wikipedia ( https://en.wikipedia.org/wiki/Ethylene_glycol ) has an interesting article on ethylene glycol.
    You could also try ‘the engineering toolbox’ ( https://www.engineeringtoolbox.com/ethylene-glycol-d_146.html )

    Without a lot more thought/analysis, I would not fill my radiator with neat glycol antifreeze – it may be an invitation for overheating/seizure.

    regards
    Steve (may be we’ll meet at Abbotsholm on Sunday).

Viewing 15 posts - 1 through 15 (of 21 total)