cam timing question

[jamesrs250]

just done my cam timing on my drz 400

when i rotate my engine to top dead center once the timing marks do not line up at all (miles out).. then rotate it agen to top dead center the marks line up fine,,the do it agen and is dosent the do it agen and it does

so might soud like a silly question is this how it shoud be.it does not say anythink abot it in the manual

[unitynotsocri...]

They should line up at two cycles of the 4 stroke cycle.usually at TDC or top dead centre.what you do is check when the inlet valve is closed and move the crank/flywheel slowly till they line up.They will line up 'twice' because of the ratio between the camshaft cog and the crankshaft cog.If you replace a camshaft cog 180 degrees out what happens is the valves smash against the pistons.
inlet and exhaust 'valve timings' are not symetrical.The chain and cogs are but to get better performance/tuning the 'cam profile' is different for each side of the valves,i.e.inlet and exhaust.

if it gets too confusing then get a CG.they have pushrods to operate the valves but very oddly only use ONE cam for both inlet and exhaust.this restricts the engine tuning but greatly helps with economy/reliability.

BCF members ,please correct if i'm wrong,i've just had my pain killers and some Vietnamese agent Orange cobbler fish!
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[jamesrs250]

[unitynotsocri...]

because the top cog has twice as many teeth as the bottom cog
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[jamesrs250]

think i under stand now.

The cams turn at 1/2 crank speed. Meaning the the crank rotates twice for every revolution of the cams

i have allways had 2 strokes so i have never had to do this

[unitynotsocri...]

one of the beauties of strokers is the relativey cheap repair costs and the ease of tuning,as well as not having to f*** about with timing chains and valves,although modern strokers are pretty sophisticated pieces of kit thesedays,but thin on the ground with new models,
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[jamesrs250]

[unitynotsocri...]

one of my favourite methods to cure knacked or oil burning small singles is to put some slick 50 in the oil.Its supposed to be used as a preventitive for car engines ,which have DRY clutches.i would'nt reccommend it on more powerfull bikes as it may not be very good for clutch plates that work really hard.It coats the hottest surfaces with PTFE,in practice it makes an engine smoother and counteracts the wear in the barrel/rings.

first used it years ago on an old 900 cc vw polo that had 107k on it.before using it the polo would slow down badly on hills and use a litre of oil for every 120 miles.After using it it was fine for another 15k then completly knacked.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS