Gt550 ignition timeing

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Alan H
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Re: Gt550 ignition timeing

Post by Alan H »

He was just showing off though.
Proof that four strokes are over complicated
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Harrymail
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Re: Gt550 ignition timeing

Post by Harrymail »

mizzytheman wrote:
Harrymail wrote:
Alan H wrote:I've used the timing marks on GT550s since 1972 when I bought my first J model. I've restored a K and an A since and also have another J in resto. The GT750B that I also run also gets timed to the marks and all run well after.
Using a dial gauge is OK if all the plug 'holes' are vertical - they aren't - so you have to use a bit of trigonometry to work out the angle of rotation unles the head is off so as to do it directly vertical to each piston and then work out degrees btdc (before top dead centre) as Suzuki recommend (+ or - 'a bit'). Or use a dial gauge and a degree disc. Too much faffing about IMO, so just use the marks FFS, then get out and ride it. :roll:
I used a dial guage on mine Alan, but never realised the plug holes are not vertical. It was a faff though, and quite difficult to find TDC accurately. The timing marks were slightly out, but that could be just the inaccuracy of the non vertical plug holes. Think I will stick to the timing marks in the future.

H
Mr Suzuki has already worked out the maths which allows for the inclination of the spark plugs on the left and right cylinders. This is why the centre cylinder is set at 3.42 BTDC (vertical plug) and left and right cylinder 3.64 BTDC (inclined plugs).
Thanks Mizzy, will reset my outers at 3.64.
Currently without a GT, but looking
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2020 Triumph Street Twin Red
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mizzytheman
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Re: Gt550 ignition timeing

Post by mizzytheman »

Harry,

Those settings are for the GT750. I’ll see if I can find the settings for the GT550.
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mizzytheman
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Re: Gt550 ignition timeing

Post by mizzytheman »

mizzytheman wrote:Harry,

Those settings are for the GT750. I’ll see if I can find the settings for the GT550.

Looks like the timing is set the same for each cylinder on the GT550. 3.37mm.
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Harrymail
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Re: Gt550 ignition timeing

Post by Harrymail »

mizzytheman wrote:
mizzytheman wrote:Harry,

Those settings are for the GT750. I’ll see if I can find the settings for the GT550.

Looks like the timing is set the same for each cylinder on the GT550. 3.37mm.

Thanks Mizzy. 3.37 is what I have set mine at, for all three. Does that mean that the plug holes are all verticle on the 550 ? I have not noticed mine being angled. Maybe we have gone full circle on the discussion !!

H
Currently without a GT, but looking
2003 Yamaha Fazer 600 Blue
2020 Triumph Street Twin Red
1968 BSA Bantam Sports Red
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mizzytheman
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Re: Gt550 ignition timeing

Post by mizzytheman »

Hi Harry,

All vertical on the 550.
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slosher
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Re: Gt550 ignition timeing

Post by slosher »

mizzytheman wrote:Hi Harry,

All vertical on the 550.
:? :? well mine aye Martin middle is vertical the left and right plugs both angled slightly but the cylinder bores all appear to be vertical
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Alan H
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Re: Gt550 ignition timeing

Post by Alan H »

slosher wrote:
mizzytheman wrote:Hi Harry,

All vertical on the 550.
:? :? well mine aye Martin middle is vertical the left and right plugs both angled slightly but the cylinder bores all appear to be vertical
Yup.
Proof that four strokes are over complicated
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