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Hi there, excuse my ignorance. In real world riding terms what difference would changing 58/107 crank for a 60/107 or 60/110 crank make (ts1 & Indian stage 4 reedvalve)

Cheers Super

you will gain 5 cc . col

basically not possible without fitting packers (either head or base).....this in turn will alter port timings.

The 110 rod will need a 3mm packer + a bit more (maybe) if fitting a 60mmm crank.

An excellent way of decreasing performance if you get it wrong

increasing the stroke can increase torque, but as stated port timing/duration do need to be considered, many fit base packers thinking the longer stroke requires it, when infact it would be better to remove material from the base to lower the cylinder to bring back port durations to a more conservative opening period. as stated can have a negative affect on performance if not done correctly.

Thanks for replies peeps!

Super

dscscotty wrote:increasing the stroke can increase torque, but as stated port timing/duration do need to be considered, many fit base packers thinking the longer stroke requires it, when infact it would be better to remove material from the base to lower the cylinder to bring back port durations to a more conservative opening period. as stated can have a negative affect on performance if not done correctly.

Interesting stuff. I have a 60 X 110 crank in a TV engine case. It's got a Casa 185 kit with a packer at the base and it's pretty flat to be honest. It only seems to come in well up the revs. I presume this is exactly the sort of thing you're talking about? Sounds to me as if the cylinder needs to be lowered. Do you add it at the top?

ToBoldlyGo wrote:

dscscotty wrote:increasing the stroke can increase torque, but as stated port timing/duration do need to be considered, many fit base packers thinking the longer stroke requires it, when infact it would be better to remove material from the base to lower the cylinder to bring back port durations to a more conservative opening period. as stated can have a negative affect on performance if not done correctly.

Interesting stuff. I have a 60 X 110 crank in a TV engine case. It's got a Casa 185 kit with a packer at the base and it's pretty flat to be honest. It only seems to come in well up the revs. I presume this is exactly the sort of thing you're talking about? Sounds to me as if the cylinder needs to be lowered. Do you add it at the top?

try a thinner packer & thicker headgasket, aim for a 1.2 - 1.5mm Squish
i run a 2.5mm packer on my TS1 with 60x110 crank ............ great ride

Thanks Norrie. Sounds like the way to go. My only concern would be the Casa head is recessed. How would that work?

if the head is recessed, just raise it with a head gasket, these are available for RT/Mugello etc, whilst getting the squish clearance is important the duration of port timings will have more of an effect on the characteristics and performance of an engine, there are often discussions around squish clearance were raising/lowering of the cylinder has been advised or undertaken, particularly with longer stroked crankshafts, longer rods do give you an advantage in that there is more leeway for raising/lower port heights without the need to machine cylinders or heads.

Thanks Scotty and Norrie. That's the plan then.

Flipping hell, I'm lost. I'll stick to 58/107

superhooper wrote:Flipping hell, I'm lost. I'll stick to 58/107

Ask Martin

Paul, I have already put my phone on silent.

Martin

Knowledge wrote:Paul, I have already put my phone on silent.

Martin

Very wise

Hey Martin your not picking up my calls. Are you avoiding me?

We all are.