Scooterotica

Not sure how many miles but I originally built the engine over 2 years ago and still on same rings. I use SIP Race oil at the moment but used Rock Oil Groundsman until about a year ago when I swapped. Stripped the top end this morning and found that my reed petals need replacing as well. So, the full top end is getting a overhaul, new reeds, rings, gaskets etc

Scooterdude wrote:Also what's your piston to bore clearance am guessing it should be around .003"

What is the best way to measure this?

Thanks

ive found psi readings from tester to tester all over the place a new one of my friends reads around 40 whilst mine was reading around 100 which on mine is the norm so take each one on its own merit set a datum point from a new build and again with a few miles on it bedding rings in . the reading will vary considerably from engine to engine too as variations in compression ratio and ex port height that provides you with that corrected compression figure ,the same one your foot feels when you kick it off ,, tuned motors are often very light on kickstart for this reason yet a std casa 186 kit more difficult to kick with its high compression and low ex port design

alanscottj wrote:

Scooterdude wrote:Also what's your piston to bore clearance am guessing it should be around .003"

What is the best way to measure this?

Thanks

Not sure how to respond to this, do you really not know or are you taking the p155?

.........yet std casa 186 kit more difficult to kick with its high compression and low ex port design

I'll vouch for that.I have two casa 186's and they're really hard to kick over.I have also got a casa 210 in another scooter and with an 0.5mm base gasket its almost impossible to kick over,even though the squish is 1.20.I have had to fit a larger base gasket (1.00mm)on it and it kicks over a lot easier.It takes the squish to 1.70 and it starts and runs really well now.

Scooterdude wrote:Also what's your piston to bore clearance am guessing it should be around .003"

If the TS is a plated cylinder,MB suggests a piston to bore clearance of .0015" to .002"

HxPaul wrote:.........yet std casa 186 kit more difficult to kick with its high compression and low ex port design

I'll vouch for that.I have two casa 186's and they're really hard to kick over.I have also got a casa 210 in another scooter and with an 0.5mm base gasket its almost impossible to kick over,even though the squish is 1.20.I have had to fit a larger base gasket (1.00mm)on it and it kicks over a lot easier.It takes the squish to 1.70 and it starts and runs really well now.

yes compression is high on both kits yet very low ex port so a dangerous combo

Rings, reed petals etc all changed yesterday(one of the petals was damaged) and she is running seeet. Piston ring gap is now 0.4 on both rings. Will bed rings in for a few miles then I will do a compression test to get a base line reading as suggested by Darrel.

Many thanks all - more learned about engines again!

Nice one Alan it's been an informative thread this I think we've all learned something we thought we we new


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yes compression is high on both kits yet very low ex port so a "DANGEROUS COMBO"




Can you tell me why its dangerous ?