damaged piston

[wardy941]

i decided to take off the head and barrel to see the condition of the piston today, the piston on 1 side has a groove where it has been hitting the head ( the part were spark plug is )

i believe it has been bored out as a standard piston is 41mm and the piston that is in is 44mm

should the head ( were the spark plug is) be opened up to allow for larger piston?

[Kickstart]

Hi

Conventionally for a normal rebore and over size piston then no. But I would only expect a standard oversize piston to be available up to 0.5mm over size, maybe 1mm at the most.

If it is 3mm oversize then I would suspect the piston is from some other bike, in which case it all depends on the actual piston design.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[wardy941]

okay do you know why the piston would be hitting the head and leaving a grove it the piston

[Kickstart]

Hi

What engine is it?

If it is caused by a fault I would suspect possibly the big end bearing has gone.

But if it is a random non standard piston then it could easily be a different height and so hit the head

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Pete.]

if it's connecting only one side of the top of the piston then the piston must be quite loose in the bore.
With the head off does the crown stand proud of the barrel? There should be about 1mm of clearance between piston and head at TDC
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[wardy941]

its a ts 50 the piston seams ok in the barrel,

When i took off the head i noticed there was a gasket between the head and barrel but no gasket between the barrel and bottom end of engine, it had been sealed with sealer but no gasker. could that be the cause

thanks

[Pete.]

Well yes it could make the difference between the piston hitting the head or not.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[wardy941]

oka thank you i am going to buy a new barrel head and piston & rings, will the big bore kit with a 47mm piston make any difference to power?

[wardy941]

and would it be worth stripping the enging and replacing bearings etc, like big end bearing and crank etc

[Pete.]

You'll get more power from the big bore but you have to make sure the jetting is right because it will produce a lot more heat too. If the piston's been hitting enough to damage it then you should check the big-end and main bearings for up and radial (up and down) play.

Why not put up some decent photos of the damaged piston?
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[wardy941]

ill get some photos later on todayy
thanks

[wardy941]

should there be any side to side play when i wobble the con rod? is seems to move quite a lot

[Kickstart]

Hi

Side to side play is normal and fine. Vertical play is what you do not want.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[wardy941]

seems fine then think i am going to buy the big bore kit and a new head along and small end bearing

can i use stock head with bigbore?

thanks

[Kickstart]

Hi

What bike is it?

It will depend on the bore kit (which may even come with a different head). Most will probably be fine but you would need to check with the ones you are buying?

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[wardy941]

its a ts 50 the kit dosnt come with head

this is the kit

https://www.ebay.co.uk/itm/Suzuki-TS50X-Mitaka-Big-Bore-Piston-Barrel-Kit-TS50-/230655059849?pt=UK_Motorcycle_Parts&hash=item35b41ce789#ht_610wt_905

[Kickstart]

Hi

Can't say for certain, but I would expect it to bolt on fine and use the stock head. Probably a decent power gain (although think the TS50 carb is a bit on the small side).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[wardy941]

thanks for all your help

Really appriciated