Cruzzer in UK

Discussion in 'Whizzer Motorized Bicycles' started by dave#22, Jan 19, 2013.

  1. dave#22

    dave#22 New Member

    Since finding the MB site I have been trying to gather as much info as possible to try and make my Cruzzer reliable with a modest increase on power. I have removed the m7 studs, fitted m8 inserts into the crankcase for m8 12.9 allen cap bolts and will replace the other head bolts with longer m6 12.9 allen cap bolts. I will also make some inox washers 2 & 3mm thick, max dia. I have worked on the inlet and exhaust ports to flow as much as possible, I could find no evidence of movement in the valve seats, but to be on the safe side I drilled and tapped two m4 retaining screws at a tangent to each seat 180 deg apart. I have had the head face machined 1mm (0.040") and will lap in on glass before fitting. I also lapped in the cylinder top face and was surprised how distorted it was. I will fit the original head gasket as I don't have easy access to spares as the Cruzzer is very rare in the UK and no spares are available and to order from the US or China would take weeks. I am now looking at the crankcase ventilation. The volume is too small for a single cylinder, so I have removed the std breather fitting on the case and am in process of making a bigger dia elbow into a vertical chamber to increase volume and I have ground two grooves at the base of the cylinder from the rear cavity on the crankcase to each cam follower gallery, also to aid breathing.
    I should know if it all works within the next few days.

    Dave.
     

  2. dave#22

    dave#22 New Member

    Hi all, an update.....the bike is now running, following advice from Quenton, I didn't use the long m8 bolts, but put in short studs to take m8 nuts, machined 1mm from the head face, lapped in both the head face and cylinder top face, opened the inlet and exhaust ports as much as possible, pegged the valve seats, reassembled, set the valve clearance to 006"in 008"out and it started first time, but was running rich, so I lowered the needle to max, tried again, better but still rich, so I removed the #80 main jet and made a #70 main jet....much better, but still rich, so made a #65 main jet and it ran fine, so took it out for a good run and it performed well, took it to 45mph (a bit vibey after 40) and the plug is a nice medium grey colour....result.
    Dave.

    Hi Quenton, I've just posted this on the MB Forum, thanks for the advice, it's saved me finding out the hard way.
    One thing I forgot to mention is that it developed an oil leak from the decompressor spindle, so I removed the spindle (5.9 shaft in a 6.3 hole), counterbored the housing at both ends and fitted 2x 6x10 O rings, then took it out again and all seems well.
    Regards.
    Dave.
     
  3. dave#22

    dave#22 New Member

    Another update....I did make a breather tube out of 1 1/4" stainless tube x 5" long with an inch of mesh baffle (care of Suzuki again) in the top and then a hose to the original pancake filter. It seems to perform well with no oil loss.
    I also found the mixture a little rich on part throttle, so I had a dynajet brass needle (Harley CV carb), decided which part of the taper I wanted to keep (bigger dia lower down) and machined the rest to the same dimensions as the original, did some testing and now the throttle response is nice and progressive.
    I wanted to try a fine wire plug, but they are not available in m14x1/2" so I made a brass spacer 1"dia x1/4" and fitted a 3/4"Bosch platinum plug and the tickover increased without adjustment, the next problem that arose was the primary belt was starting to slip with the increase in power, so I copied a belt tensioning device with two ball bearings, fitted it and was surprised how much quieter the bike ran with no slip.
    I am now fitting a pair of saddle bags.....roll on Summer.
    Dave.
     
  4. dave#22

    dave#22 New Member

    Hi all, another update,I did a 15mile run last week at between 35-45mph and after I stopped I noticed oil dripping from the air filter onto the chain guard...b******s I thought. I realised that the oil was being splashed up into the beather and crankcase pressure was holding it there because it was not able to drain, so I looked at a solution and tried to find a tee to replace the elbow at the base of the breather, but found nothing, so I made an 8mm tail and fitted it to the base of the breather and then an 8mm banjo to m10x1.25 banjo bolt replacing the sump plug, connected with a length of 5/16" fuel hose.
    I've done a couple of 40mph + runs and no oil has come from the air filter, so maybe it's fixed at last. fingers crossed.
    Dave.
     
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