Suffolk Roughcut

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  • December 10, 2013 at 4:16 pm #3927
    vhgmcbuddy
    Member

    Can anyone point me in the direction of a maintenance manual for a 1960’s Suffolk Roughcut fitted with a 98cc Suffolk engine. I’ve got info on the 75cc engine but can’t find anything on the larger one.
    Timberjack

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    December 10, 2013 at 5:57 pm #3930
    wristpin
    Participant

    Same for both 75 and 98cc. Not sure that the Suffolk engine was original equipment on the Atco. Suffolk marketed several similar machines such as the Squire and Corporation.

    December 10, 2013 at 6:03 pm #3931
    vhgmcbuddy
    Member

    Hi Angus,
    Must be just the bore and/or stroke that makes the difference and the sump capacity then?
    Keith

    December 10, 2013 at 9:48 pm #3934
    wristpin
    Participant

    When I said “the same” I was referring to valve clearances and points gap. Bores are different but as far as I can remember the crank throws are the same. Sumps on both depend on the application and are interchangeable to raise or lower the crank centre line to suit the machine.
    Your pic of the Suffolk engined machine is a bit small to see the detail but I suppose that it is an Atco chassisand not one of the Suffolk variants which were totally different mechanically. The most obvious difference, as far as I recall, was that the Atco had a multi-plate manually operated clutch where as the Suffolks had a centrifugal one.

    December 13, 2013 at 6:10 pm #4010
    vhgmcbuddy
    Member

    Hi Angus,
    Just an update on the Suffolk project.
    Started on the engine,cleaned it externally,The piston was seized solid but finally got it free. Took the sump off and removed half a pint of water and a cup full of sludge. All looked suprisingly good. Standard piston and not any obvious sign of wear. Seizure looks as though it is due to being stood for a long time rather than lack of lubrication.
    Put it all back together and gave it a quick lick of paint to make it look better.
    After cleaning out the carb, tried to start it and it fired up first time and runs well, needs a bit of fine tuning, however after about 5 minutes oil started seeping from the main bearing, anyway shouldn’t be too much of a problem.

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    December 13, 2013 at 6:12 pm #4015
    vhgmcbuddy
    Member

    Angus hopefully a bit better view

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    December 13, 2013 at 7:14 pm #4023
    andyfrost
    Participant

    Regarding the oil leak , check and thoroughly clean the breather , I would suspect from your description of the engine internals that it’s not working.

    Andy.

    December 13, 2013 at 8:24 pm #4025
    wristpin
    Participant

    Just to expand a bit on the importance of a correctioally functioning crankcase breather. It is not only there to allow air to exit the crankcase when displaced by the descending piston but also to close and maintain a slight negative pressure when the piston ascends.
    Venting the crankcase prevents oil being forced out around valve stems and crankshaft seals and the partial vacuum further assists with keeping the oil inside the engine.
    All this is a long winded way of saying that the sealing is every bit as important as the venting.
    On your Suffolk engine the breather lurks inside the valve chest. Undo the nut securing the cover just below the inlet and exhaust manifolds and the breather is in the middle secured by a compressed sping hooked asound the cover securing stud. Inside the little alloy breather body is a small paxolin disc or poppet valve. If this is working properly it should allow crankcase air out but not in. The alloy bodies wear as do the discs and as neither is still available you are probably stuck with what you have but some improvement may be achieved by turning the disc over to present an unworn face to the valve body. If you are really keen the face of the body can be skimmed to square it up and present a better sealing face to the disc – the smallest cutter from a bath/basedin reseating cutter kit can be reduced in diameter to do this. Also using a straight SAE30 oil may help.

    December 13, 2013 at 8:55 pm #4026
    andyfrost
    Participant

    Angus , very well put , it’s amazing the ammount of “perfect paint jobs” you see around being spoilt by oil leaks , often caused by not enough attention to relatively minor points like a correctly working breather.

    Andy.

    December 14, 2013 at 10:50 am #4037
    vhgmcbuddy
    Member

    Thanks Guys,
    Looks like I’ve got a job for this next week then along with mastering the Shrinkpic system to improve the quality of the photographs.

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