OzVMX Forum
Marque Remarks => CZ => Topic started by: Stormer on July 02, 2012, 07:52:32 am
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What ignition timing would you use for a 360 CZ, it's running on one spark plug with a decomp valve in the other plug hole, and does it matter which plug hole the decomp vavle is in, front or rear.
Cheers Pat
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run the spark in the rear.how have you got your coils wired
jim
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On my bikes I have a single plug head with the front hole blanked off and a dual plug head 360,so I guess if your going to use a decomp you'd put it on the front.From memory points are barely opening (use a cigarette paper) with the X of the flywheel between the middle of the stator plate marks and piston at 3 to 3.2mm below TDC.Verify this with a manual as there are some steps I probably missed or my memory could be a bit rusty. :)
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When I bought the bike only the rear plug was being used with the front plug hole blanked off, not sure how it is wired. my problem is when I accellerate from start the engine just dies almost like putting your hand over the carb intake, it is running rich but plug is not wet, new 34 mm mikuni carb fitted with 280 main jet.
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Hi,
Does the bike idle?
What size slide cutaway>
Does it have an air jet fitted?
what size needle jet/emulsion tube?
cheers
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Dr Bamford is onto it.Sounds like the dual coil system has been changed to a single plug system,a lot less wiring and one less coil,so simpler.Don't bother with decomp unless you're really light.Airflow??a mate wanted to make his airbox watertight but also succeeded in making it airtight so the seat base actually closed off the top of the airbox restricting flow when the taps were opened.An earlier thread "need answers"oct 2011 delves into the sinister causes of lack of ponies such a s seal leaks etc.
The 34 should work on the 360 but check all internals maybe against the czmadness Mik spec sheet as 69 has suggested.
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Hi
Yes it idles ok
Needle jet Q6, Pilot jet 45, Slide 3.0, Needle 6GH2
Pat
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Needle is quite different to what I run & all the needles I've seen listed as being used by other people, the needle that comes in brand new mikunis seems to work well. Mine has a 6FJ6 in it with a Q5 needle jet but is a 36mm
34mm runs 6DH4 needle & Q2 needle jet. Remove the airjet if it's fitted
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Thanks for all the info much appreciated, Tony if I remove the air jet would it cause too much air to enter and would I lose the idle.
Cheers Pat
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Not totally sure on what effect the air jet has but all the jetting specs I've seen say to remove it for CZs
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Any word on what was wrong yet stormer?
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Unable to test, but timing ok ' removed air jet, new air filter should be here this week,starts ok going to CRC this weekend fingers crossed will either ride or Marshall ???
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Hi,Pat,
If I can find time Sat morning, I'll Have a look at it with you,
Cheers
Noel
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Hi Noel
Thanks for the offer
Pat
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Just a quick update, seems by removing the air jet and changing the air filter it has fixed the problem the bike went very well all weekend at the C.R.C.meeting, once again thanks for all the useful info.
cheers Pat
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Good result! ;D
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That's good to hear it worked, one question did you change type of air filter or just put in a new? I might try that on mine and see what happens
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im running the front plug on my 360 sidepipe what advantage is there to run the rear?
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Hi Guys
Changed filter to a different type to get away from the paper element, don't know whether it makes a difference to use front or rear plug but thought i adjusted the ignition timing on the rear plug so thats how i will run it.
cheers Pat
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Stormy,I didn't know you could even get a paper filter anymore :D Unifilter makes an excellent 2 stage foam one.Stumpy I vaguely remember something about better combustion with the rear plug due to the elliptical shape of the combustion area in the head but could be mistaken. ???
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Personally I use twin air filters, my uni filter only got used once before a hole appeared at the bottom of it caused by a bit of fuel sitting there dissolving the foam
The 74 onward bikes that only run a single plug use the rear hole, I have 1 for a 74 & it is very obvious that the front hole could be drilled but wasn't at the factory.
The way the transfer ports work may have something to do with the rear plug being preferable
I'm running a rd400 coil on my hybrid ignition firing both plugs, starts first kick every time but for the initial start of the meeting which seems to be more fuel related than anything
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If you look at the shape of the head combustion chamber the rear plug is right at the deepest part, away from piston, where as the front plug although in the middle of the piston is on the edge of the combustion area,
My bike even has a different exhaust note if I use the front plug, but interestingly it sometimes starts easier on the front plug ::)
I use the rear plug when riding.
Noel
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right then chaps rear plug it is then cheers