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Author: Subject: BEC high rev vibration?
flanders

posted on 14/3/17 at 03:35 PM Reply With Quote
BEC high rev vibration?

took the car out for a good run yesterday first decent dry run since fitting the new engine (zx12) i noticed quite a severe vibtation through the chassis which seems to be high rev related but it may be speed related. it feels like a 'frequency' vibration

im going to be going over the engine mounts, diff mounts and prop flange tonight to check them, and ive just had my diff serviced/checked also the prop balanced with a new UJ end fitted onto the front, so they should hopefully be ok, but Ive read that the prop ends can be out of phase causing vibration, anyone know more on this subject?

any advice on what else to look at?

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CosKev3

posted on 14/3/17 at 05:22 PM Reply With Quote
If you put the clutch in whilst it's vibrating does it still vibrate?

That will narrow down the areas to be checked if it stops with the clutch in.

You have got a slight angle on all UJ's?

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flanders

posted on 14/3/17 at 05:42 PM Reply With Quote
Yeah there angle on the prop. That's a good idea, I'll run it up on axle stands and dip the clutch see if disengaging the drive train makes a difference.

Runs well apart from rattling my teeth out lol

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CosKev3

posted on 14/3/17 at 07:48 PM Reply With Quote
Be warned if you have never run a BEC up on stands before they sound awful!
You will think something is about to drop off

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flanders

posted on 14/3/17 at 07:57 PM Reply With Quote
lol don't worry I have, they sound 10 times more clunky.

I think I'll just take it out on the road tomorrow instead, I've had the whole drive train out so I'm hoping it's something I've missed or not line up correctly. What's the chances though? Lol

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flanders

posted on 15/3/17 at 04:58 PM Reply With Quote
Took the car for a drive this afternoon and it was quite informative.

I'm 99% sure it's not the drive line and it's totally rev related. The vibration starts around 7k and continues to redline.

It does it in all gears. It is more apparent in higher gears as I'm in the rev range longer. It is also worse when on the throttle/under load

I think I'll go over the engine mounts and manifold studs to eliminate those but I'm stuck after that

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CosKev3

posted on 15/3/17 at 05:19 PM Reply With Quote
Not liking the sound of that

Do you know history of engine?

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flanders

posted on 15/3/17 at 05:28 PM Reply With Quote
I bought the donor bike and it as running ok in that.

You thinking engine issues?

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CosKev3

posted on 15/3/17 at 06:19 PM Reply With Quote
If it's Deffo rev related and not speed related it must be something internally on engine.
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flanders

posted on 15/3/17 at 07:14 PM Reply With Quote
Yeh that Seems logical

My engine cradle dosnt look very sturdy, most cradles I've seen are one piece but for some reason the one I got was 2 piece. I'm inclined to think it's not internal since it ran perfect before removal.

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CosKev3

posted on 16/3/17 at 08:07 AM Reply With Quote
I think that's a ZX12 thing,if you want to use all the mounting points on head you get a smaller bracket /cradle above the exhaust manifold?

Hoping for your sake it's not internal!

So you rode the bike at high RPM where you are getting the vibration now?

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flanders

posted on 16/3/17 at 09:57 AM Reply With Quote
yeah thats the type of cradle ive got Kev.

I didn't personally ride the bile but my Bike mechanic did, and he confirmed it was totally sound.

one thing ive thought of is i have drilled holes in the clutch hub as per a common mod on the early 12 to assist with clutch pack oiling, maybe its now too far out of balance?
see this link - http://kawasakiworld.com/racing/37186-not-enough-oil-clutch-pack-how-fix.html

im off work tomorrow so im going to go right through all the mounts, front to back , check the prop flange etc any thing you can recommend checking while im there?

it just found out today that the engine has an 'engine balancer' which im going to look into - http://www.bikeland.org/board/viewthread.php?FID=13&TID=35981

[Edited on 16/3/17 by flanders]

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CosKev3

posted on 16/3/17 at 02:05 PM Reply With Quote
Does your engine look like it's been opened up?

Perhaps someone has removed the balance shaft?

Deffo worth a look over the clutch assembly, and if you've got one try a undrilled one?

Also are you 100% sure all the clutch fittings/springs went back together exactly right?

[Edited on 16/3/17 by CosKev3]

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flanders

posted on 16/3/17 at 02:49 PM Reply With Quote
To be honest no lol

I had the whole clutch assembly removed, Hub, basket the lot so something might not be quite right. There's a split-sprung gear on the basket which I was t 100% sure about tbh and it looks like you need an alignment pin which I don't have

I'll check the crank balance shaft tonight and make sure it's there

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flanders

posted on 20/3/17 at 09:41 AM Reply With Quote
Hi kev, i wont bore you with all the details but after a decent inspection and a good 65 mile run at the weekend in now convinced its the drive train. its only at high speeds 70+ and when on throttle/under

im thinking the prop but its just been refurbished and fully balanced, what im thinking though is my new engine sits at an angle, in-line with the outer chassis rails (my old one sat straight in line with the center line of the car) and im wondering if the prop angles are causing the problem

Prop Current
Prop Current
this is the angles im running but also with the prop angling upwards to the sprocket adapter.

whats your thoughts mate?

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flanders

posted on 20/3/17 at 09:42 AM Reply With Quote
i found this interesting/worrying lol

https://youtu.be/gmV4qwLfOMY

[youtube]https://youtu.be/gmV4qwLfOMY[/youtube]



[Edited on 20/3/17 by flanders]

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flanders

posted on 20/3/17 at 09:47 AM Reply With Quote
[youtube]https://youtu.be/gmV4qwLfOMY[/youtube]

https://youtu.be/gmV4qwLfOMY

[Edited on 20/3/17 by flanders]

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CosKev3

posted on 20/3/17 at 01:26 PM Reply With Quote
Have you got a angle onto the rear UJ by diff?

Has the size/design of centre bearing changed on new prop at all?

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flanders

posted on 20/3/17 at 02:39 PM Reply With Quote
I dont think so, it looks very straight from the centre UJ back.

its not a new prop its the same one i used on my zx9 just sorter and re balanced.

Ive been on the phone to Bailey Morris who manufacture BEC props so im going to pass on some pics to them to see if they can assist

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CosKev3

posted on 20/3/17 at 02:54 PM Reply With Quote
Pretty sure UJ's need to run on a angle,not straight
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flanders

posted on 22/3/17 at 02:06 PM Reply With Quote
I sent baliey Morris pics of my prop and he thinks it looks fine but asked about my centre bearing so I sent this video. [youtube]https://youtu.be/-W8ASBtxgsc[/youtube]
https://youtu.be/-W8ASBtxgsc
This excessive movement may well be my problem

[Edited on 22/3/17 by flanders]

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CosKev3

posted on 22/3/17 at 02:50 PM Reply With Quote
Pretty sure there is a lot of play in them moving them like that by hand.

When its spinning from the engine it won't move about like that.

Did you send them the whole props haft, or just the front part for modding?

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flanders

posted on 22/3/17 at 03:16 PM Reply With Quote
neither, i sent them pictures

im getting prices for repairing this one and a price for a new unit with TRT

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CosKev3

posted on 22/3/17 at 07:34 PM Reply With Quote
No I meant for the refurbishment!

If the whole prop was done the bearing should have been checked/replaced if req

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Toprivetguns

posted on 22/3/17 at 08:14 PM Reply With Quote
Evening mate,

I'd say your centre bearing is shagged from the video shown. It looks like the retainer on the front end has migrated and the bearing is no longer being held correctly.

Sent you a U2U as I've just bought a TRT from Bailey and Morris.

[Edited on 22/3/17 by Toprivetguns]





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