Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Careful with that grinder Damo mate!
That head has got a stage three gas flow with 1mm oversize valves, Kibblewhites Black Diamonds, rather trick they are too!
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Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Spoke again today with Wiseco and they've got rings to suit this 102mm piston. Now, here's where I'm getting a bit lost, ring gap?
I've got two pistons and two liners and intend using the best. I can measure the piston and liner for wear but I don't know what they were to start with? Seeing as the motor was smoking a little I could have wear with piston, rings or liner?
Am I over thinking this?:unsure
I've got two pistons and two liners and intend using the best. I can measure the piston and liner for wear but I don't know what they were to start with? Seeing as the motor was smoking a little I could have wear with piston, rings or liner?
Am I over thinking this?:unsure
Joined Aug 2016
166 Posts | 85+
NSW Australia
:-D I'm a wild man with power tools that's for sure but I'll exercise restraint when I do mine! I think the general rule with porting is 'less is more' and to not go crazy. That head looks lovely though.
Maybe just check piston to bore clearances, and ring end gaps as per factory specs and don't worry too much more. That's what I'd do. If it's a hi comp piston maybe run them clearances on the larger side? Check for the bore being oval too when fitted to your cases.
Damo
Maybe just check piston to bore clearances, and ring end gaps as per factory specs and don't worry too much more. That's what I'd do. If it's a hi comp piston maybe run them clearances on the larger side? Check for the bore being oval too when fitted to your cases.
Damo
Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Took some measurements, the standard width of the small end and rod are 19mm and 9.24mm respectively. The JBS are 22mm and 13.12mm.
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Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Borrowed these gauges from a mate to check wear and clearances......hopeless! Different readings each time! Will take the parts to an engineering firm down the road, if they measure the very top of the bore and half way down, X and Y, I can determine the amount of wear and oval-ity unsure
So, got it all measured.
Top of the bore 102.12mm X and Y
Half way down 102.14mm X and Y
So not much wear and not oval.
Piston A 101.81mm
Piston B 101.86mm
That's piston to bore clearances of 0.33mm and 0.28mm
Way too big?
Different readings each time! Will take the parts to an engineering firm down the road, if they measure the very top of the bore and half way down, X and Y, I can determine the amount of wear and oval-ity unsureSo, got it all measured.
Top of the bore 102.12mm X and Y
Half way down 102.14mm X and Y
So not much wear and not oval.
Piston A 101.81mm
Piston B 101.86mm
That's piston to bore clearances of 0.33mm and 0.28mm
Way too big?
Attachments
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Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Clutch and gearbox, the friction plates were all between 1.8mm and 1.91mm, worn, so they added an extra steel plate to take up the slack. Ok, got spares to sort that!
The countershaft seems to have excessive float? Seems to be around 2mm! Can't find any info on this but 2mm must be way too much? What's worn?
Pictured from the other side.
The countershaft seems to have excessive float? Seems to be around 2mm! Can't find any info on this but 2mm must be way too much? What's worn?
Pictured from the other side.
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Joined Sep 2013
369 Posts | 209+
canolbarth cymru
So got it all measured up.
Top of bore 102.12mm
Half way down 102.14mm
Not much wear and same dimensions X and Y
Piston A 101.81mm
Piston B 101.86mm
Piston to bore clearance 0.33mm and 0.28mm
That's way too loose, yes?
Top of bore 102.12mm
Half way down 102.14mm
Not much wear and same dimensions X and Y
Piston A 101.81mm
Piston B 101.86mm
Piston to bore clearance 0.33mm and 0.28mm
That's way too loose, yes?
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Joined Aug 2016
166 Posts | 85+
NSW Australia
Cheers Bushie, that's what I feared, dunno what to do now!
Is it a standard liner that's been bored or is it cast iron?
I dont think re-coating will take up enough of the clearance but it may be worth checking?
Taffy is talking about doing a 102mm piston soon I think for his 700? (I'm neutral by the way in the little tiff) Might be worthwhile getting in touch with him. Or maybe get another used liner and bore/ get coated to suit your piston? Again, I'm not sure if this leaves enough meat on it but maybe? It's only approx 1mm....
Good luck,
Damo
Joined Aug 2016
166 Posts | 85+
NSW Australia
Bugger mate.....
I think that 0.19mm clearance is a bit too much. The manual for my 2005 says 0.12mm mounting wear limit if I'm not mistaken? Hmmm
Deck height is 1mn lower than standard 24.5mm right? Not sure....Only issue I see thinking out loud is your cam chain length and possibly slightly ******** cam timing??
Thoughts anyone?
Damo
I think that 0.19mm clearance is a bit too much. The manual for my 2005 says 0.12mm mounting wear limit if I'm not mistaken? Hmmm
Deck height is 1mn lower than standard 24.5mm right? Not sure....Only issue I see thinking out loud is your cam chain length and possibly slightly ******** cam timing??
Thoughts anyone?
Damo
Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Bugger me canolman
Just re-read that and checked my measurements!!
The 102mm Wiseco is 24.06mm!! Lower deck height than standard, dunno where I got that from!
12.8:1 and 23.5mm are figures from a potential replacement piston using the correct deck height of 24.06mm calculated by someone who knows what they are doing!
Yes the bore clearance is still a bit big, just wondering if I could use this liner.
Get an early night canolman.
Just re-read that and checked my measurements!!
The 102mm Wiseco is 24.06mm!! Lower deck height than standard, dunno where I got that from!
12.8:1 and 23.5mm are figures from a potential replacement piston using the correct deck height of 24.06mm calculated by someone who knows what they are doing!
Yes the bore clearance is still a bit big, just wondering if I could use this liner.
Get an early night canolman.
Joined Aug 2016
166 Posts | 85+
NSW Australia
I think we might be talking about 2 different things mate? :scratch: Haha all good. Your basically wondering about the space between the top of the piston and the combustion chamber right? Maybe it's compression height? (gudgeon pin centre to top of piston)
Sorry, my understanding of deck height is the distance between the top of the liner and the centre of the main crank journal but even thinking about that 24.5mm is not right either!!
I must be just confusing you mate!
Damo
Sorry, my understanding of deck height is the distance between the top of the liner and the centre of the main crank journal but even thinking about that 24.5mm is not right either!!
I must be just confusing you mate!
Damo
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Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Joined Aug 2016
166 Posts | 85+
NSW Australia
Hehe nah no problem my friend! It's easy to get a bit mixed up with all the terminology..... but I should've gathered it from what you were quoting anyway. I'm sort of looking at it while I'm at work so I should pay a bit more attention really to the posts!
Well I suppose it can only be all the better for your piston/valve clearances.....
Not sure how much it will affect your squish though?
So what are you thinking? Running that cast iron liner and this other piston(23.5) you refer to with a more ideal piston/bore clearance?
Damo
Well I suppose it can only be all the better for your piston/valve clearances.....
Not sure how much it will affect your squish though?
So what are you thinking? Running that cast iron liner and this other piston(23.5) you refer to with a more ideal piston/bore clearance?
Damo
Joined Sep 2013
369 Posts | 209+
canolbarth cymru
Yes, that's what I'm looking at the moment, trying to use what I've got and off the shelf parts. I've got a couple of irons in the fire as well, waiting to hear back.
Not the end of the world if I have to get another liner, got a mate who will copy what I got and can size it to suit.
As we say in Wales "every day is a school day"
Thanks for your help
Not the end of the world if I have to get another liner, got a mate who will copy what I got and can size it to suit.
As we say in Wales "every day is a school day"
Thanks for your help
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