Suzuki gt750 vibration

Post your Kettle problems here and cures
Post Reply
Suzy57
Posts: 26
Joined: Tue Jul 25, 2017 8:53 pm

Suzuki gt750 vibration

Post by Suzy57 »

Hi,

After many months I have finally got my bike on the road, however when I get it to 50mph, the vibration is bad and if I go faster it gets worse.when the bike is on its stand and is revved over 2000rpm it will vibrate.
I know this could be this can be attributed to a number of things but my gut feeling is it is the crankshaft.
I would appreciate it if anyone knows a good mechanic that would be able to take a look at this for me, I live near Norwich but would be able to take the bike anywhere to get it fixed.
Thanks in advance, Andrew
User avatar
BAZ
Posts: 3599
Joined: Thu Jun 18, 2009 7:35 pm
Location: Dudley west midlands
Contact:

Re: Suzuki gt750 vibration

Post by BAZ »

Are the pipes rubber mounted and not bolted to the frame direct..if you can get it here DY1 2ST I will have a look for you who did the crankshaft?
Suzy57
Posts: 26
Joined: Tue Jul 25, 2017 8:53 pm

Re: Suzuki gt750 vibration

Post by Suzy57 »

Chris Appleby did the rebuild but I think the guy who had the bike before me must have put it back together.
Suzy57
Posts: 26
Joined: Tue Jul 25, 2017 8:53 pm

Re: Suzuki gt750 vibration

Post by Suzy57 »

Baz, I’m no,t sure the exhausts are rubber mounted - what type of gasket do they have?
User avatar
BAZ
Posts: 3599
Joined: Thu Jun 18, 2009 7:35 pm
Location: Dudley west midlands
Contact:

Re: Suzuki gt750 vibration

Post by BAZ »

See this from my restore film https://youtu.be/V2L7EKeSdHg
teazer
Posts: 1035
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: Suzuki gt750 vibration

Post by teazer »

Baz is absolutely right that if the exhaust is touching the frame, vibration will be bad. You could try loosening teh rear mounts and rev it on teh stand and see if it is any better.

All triples have a shake and it's typically worse around 1800 rpm and smooths out above that. That's a function of crank balance/dynamics. If yours gets worse above that and the pipes are free enough, it suggests something well out of spec.

I would start with the simple things:
Make sure all three cylinders are firing. Yes. I know that sounds daft but you would be surprised how often a rider does.t realize a pot is not firing. A simple check is exhaust pipe temperature.

Check timing on all three cylinders

Remove the airbox and use a carb sync tool to see that all three are opening together and pulling a similar vacuum.
Kettletimes3
Posts: 1620
Joined: Thu May 03, 2012 12:58 am
Location: Sunny Wales

Re: Suzuki gt750 vibration

Post by Kettletimes3 »

It could also be poor rubber bushes in engine mounts.
Suzy57
Posts: 26
Joined: Tue Jul 25, 2017 8:53 pm

Re: Suzuki gt750 vibration

Post by Suzy57 »

Ah yes I see what you mean regarding the rubbers on the exhaust brackets - these are there but I will check they are fitted correctly.
Also thanks for the advice re the cylinders/timing and will check this. The engine mounts were replaced not long ago but will also check them.
I might have to still come back guys if I am struggling, thanks Andrew
User avatar
PaulD738
Posts: 3962
Joined: Thu Sep 25, 2014 6:57 pm
Location: Warrington Cheshire

Re: Suzuki gt750 vibration

Post by PaulD738 »

I always found my Kettle was very smooth when the ignition was turned off :roll:
They're rubbish them Jap bikes lad they won't last five minutes! you want to get yourself a nice Royal Enfield!
A quote from my old dad 8-)

I started out with nothing and I’ve got most of it left!
Post Reply