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Post by fredperrybruce on Feb 21, 2015 17:43:50 GMT
Hi all,,
Long story short, started to rebuild the engine again this weekend installed brand new Mazzi CRANKSHAFT installed everything else then kicked the engine over a few times and the engine kept miss firing and exhaust fumes pouring out of top of Carb.
So after closer inspection pulling off the flywheel I found the brand new woodruff key has totally sheared off,one half in the flywheel one half in the Crankshaft recess (recess totally filled with half the key)
Obviously being a brand new crank I'm sh**ing myself hoping its no knackered so the question is??
1. Can the crankshaft be salvaged
2.Would the flywheel spinning around with the woodruff key broken had caused the engine to misfire
All comments welcome
Thanks
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Post by vespasco on Feb 21, 2015 19:12:29 GMT
Oh no!
First the easy one, yes, if the woodruff key has sheared it would affect the timing considerably. So thats likely explains your symptoms
If youve got to strip it down again it would be worth see how true your crank is.
What flywheel and clutch are you using?
What make of woodruff key was it?
Does/did the flywheel bind on the cases? Does/did it run true and free?
How much play is there on the crank bearings?
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Post by fredperrybruce on Feb 21, 2015 19:25:50 GMT
First of all I took the flywheel of twice and the the time I took it off the nut was totally lose so I'm thinking I didn't set to the right torque "well I didn't as I don't own a flywheel holding tool so just done up tight as I could"
Piaggio Flywheel standard 125
Cosa clutch 7 spring
Mazzi race crank
The crank was installed dead true and was turning free I'm sure it's down to me not torquing properly.
It was getting real dark in my garage so haven't really had a good close inspection of the damage but am hoping all is good and I've just going to have a fight tomorrow morning taping the remainder of the key out of the keyway .
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Post by vespasco on Feb 21, 2015 19:38:17 GMT
Once you clean up the keyways and bolt it together it needs to be torqued to something like 65Nm, which is 'almost' as tight as you can get it without stamping on it!
Ideally those keyways should have a nice square, sharp edge to them.
It would probably be worth gently smoothing down your crankshaft too, incase it was scored by the flywheel spinning loose.
Unless you have a power torque driver then you really need a flywheel holding tool. They are quite cheap and make the job a doddle! Whatever a doddle is.
If youre unsure with the nut and are happy with your ignition timing, then try a bit of threadlocker.
It sounds like the loose nut could have been the cause of all your symptoms. If you only tightened it as much as could before the flywheel starting turning then, it definaitely wasnt tight enough!
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Post by fredperrybruce on Feb 21, 2015 19:48:51 GMT
Cheers Vespasco ,, I should have know better, I was racing against the clock today trying to get the scooter running before it got dark and really should have waited till I got a flywheel holding tool. I'm going to give the broken key ago tomorrow I'm hoping a small punch/screwdriver and some light taps on the angle will release the key and it will pop out.??  |
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Post by bryno on Feb 21, 2015 20:00:58 GMT
As said, flywheel nut not tight enough or a poor fit between crank and flywheel will have caused the key to shear. If you didn't use a holding tool the crank nut will just not have been tight enough. Personally I think thread lock is not necessary, if you do the nut up properly, it won't come lose.
Check it has not burred the edges of the slot in the crank. The old key will come out easy enough, sure it will be fine..
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Post by pxguru on Feb 22, 2015 5:34:44 GMT
Unlucky but not uncommon. The crank will clean up ok just be careful not to damage the slot when you get the old half out. New crank with an old flywheel is the issue. Get all the burrs and rust off the crank and in the flywheel. Do up as tight as you can. Run it for 15 minutes on the spot then tighten up the flywheel again. Expecting it to be fine  |
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Post by henri on Feb 22, 2015 9:52:03 GMT
same as above ,reckon you'll be fine , i use threadlocker/bearing locker on the key an on the nut , but i'm a belt/braces/an bit of binder twine kind of guy, cant do it today but nxt weekend could pop down for 10 mins with my flywheel holder ,make sure the nuts done good , H
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Post by fredperrybruce on Feb 22, 2015 10:53:57 GMT
Cheers guy's Key came out dead easy this morning ,little tap and it popped out. Keyway not damaged at all. Henri I have cheated this morning and wedged a piece of wood against the flywheel and done the thing up mega tight, I'm replacing the flywheel anyway as the thing has few broken fins already. I'm real keen on getting the engine running this morning so I can make some tweaks and make sure there's nothing out of the ordinary going on with the new build. Thanks for the offer of coming down though H I'm sure at some piont I'll need your advice/eyes on something  Will post an update/ video later today |
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Post by fredperrybruce on Feb 22, 2015 20:19:09 GMT
Ok quick update,,, Completely assembled the whole scoot today,,, got to the point of kicking the engine over and it started after the 20th kick then realized I left the fuel tap on over night and flooded the dam thing completely. So once it started ticking over and spewing fuel out the exhaust it sounded pretty good. Jumped on the scoot shot down the road 100 yards later cough cough splut splut "oh crap" what now?? Pulled the carb apart checked all the electrics and "Nothing" Checked the fuel tank and......... "empty" totally empty so that was the end of that, I had no money on me so gave up and came home. lol not the first time,not the last  |
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Post by stevievespa on Feb 22, 2015 22:46:53 GMT
Yo fred ready for a rideout wed weather permitting
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Post by henri on Feb 23, 2015 10:46:30 GMT
at least it ran long enuff to "run-out" , good news , H
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Post by fredperrybruce on Feb 24, 2015 17:35:45 GMT
Finally all done ,,,, runs like a dream took out for a sneaky spin today round the estate happy days |
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Post by henri on Feb 25, 2015 8:34:30 GMT
gone posh eh an got carpet in ya shed now ,careful if ya make it too nice you'll get squatters , sounds sweet , get the cowlings on a have a proper spin around on it , an ya brake cable looks untidy ,but thats just me being picky this morn , nice job mate , H
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Post by fredperrybruce on Feb 25, 2015 17:40:44 GMT
Ha ha ha .....Henri you way to picky although I have put the cowl on now and sorted out the untidiness of the cable.. things like that do my head in also.lol Very very relieved its all sorted now, by the way you don't have a px flywheel knocking about do you H  ? |
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Post by henri on Feb 26, 2015 10:06:28 GMT
only crackered ones ,worse than yours ,lml genuine lectric start ones , scooter republics where i got my last one an it was 45 quid i think ,left the starter ring on as it evens the tickover a bit , but 2 cuts with a hacksaw n bingo a "lightened flywheel" which beedys charge 85 for, H
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