|
|
Post by aeroxbud on Mar 19, 2020 4:39:16 GMT -5
Shame about the cylinder. But a good job you checked it before installation.
Nice customer service on the refund though.
|
|
|
|
Post by Kenho21 on Mar 19, 2020 9:58:13 GMT -5
So, last night I compared my cylinder to the port map posted on the forum (shorturl.at/aizJ5) and it lines up pretty well with what 2strokd posted. Maybe 0.2-0.5mm higher, which is likely within margin of error of my eyeballing the placement of my calipers. Then I went and looked at my thread (shorturl.at/sxI02) regarding the piston included in this kit (which is a Dio piston) and it looks like that could be the culprit. Based on what 808ministroke and ryan_ott had to say, it seems like the Dio piston crown may be around 2mm higher in relation to the pin. I had to add almost exactly 2mm of shims to get my transfers anywhere near proper, so that would make sense. However, there is still the matter of the squish clearance. If the piston really was just 2mm taller in relation to the pin, then my squish shouldn't be off when the transfers are flush. So, I'm still kind of at a loss as to what is going on. |
|
|
|
Post by 190mech on Mar 19, 2020 11:53:36 GMT -5
Id love to know the distance from the bore deck to the bottom of the transfers..It may work very well with a long stroke crank!
|
|
|
|
Post by ryan_ott on Mar 19, 2020 13:52:15 GMT -5
|
|
|
|
Post by 190mech on Mar 19, 2020 17:03:34 GMT -5
Ryan,That looks like a dead nuts perfect setup!Ken must have a Unicorn cylinder,just wondering if a 44 or 45 stroke crank would work well with that oddball!
|
|
|
|
Post by Kenho21 on Mar 20, 2020 16:48:31 GMT -5
Deck to bottom of transfers  Piston crown sits about 1.10 mm below deck and the center of the piston protrudes about 1 mm above deck. |
|
|
|
Post by Kenho21 on Mar 20, 2020 18:10:41 GMT -5
|
|
|
|
Post by Kenho21 on Mar 20, 2020 18:34:33 GMT -5
So I got the Athena head from Scooter Tuning and with a ~0.7mm paper base gasket and ~0.10mm shim I'll be lined up with the transfers nicely and at ~0.85-.95mm squish. This is with the Polini head though. With the Athena head, I'd be at 1.3mm squish, so I gotta give it up to Zino for the tip!. Thanks man! Things are lookin pretty good now. Super psyched. Was pretty bummed about that Polini debacle and was slightly worried the cylinder wasn't even my issue. Based on ryan_ott's measurements, looks like mine is 2mm off. Thanks for doing that by the way Ryan. |
|
|
|
Post by 190mech on Mar 20, 2020 18:46:25 GMT -5
Strange!!That would work well with a Jog 90 stroke crank,also the Kymco horizontal motors have a 41.9 stroke and the same stud spacing as the Mina engines..Bet it is a Kymco casting core mixed up with a Mina batch..  |
|
|
|
Post by Kenho21 on Mar 20, 2020 19:26:40 GMT -5
Strange!!That would work well with a Jog 90 stroke crank,also the Kymco horizontal motors have a 41.9 stroke and the same stud spacing as the Mina engines..Bet it is a Kymco casting core mixed up with a Mina batch.. Well... if anyone wants a uniquely bored Minarelli Corsa cylinder, make me an offer haha! I don’t have any upcoming projects where I’ll be able to make use of it. I bet you’re right about the reason though. They must’ve bored the wrong cast with the wrong bore specs. |
|
|
|
Post by Zino on Mar 20, 2020 19:56:44 GMT -5
That polini head trick will make a big difference you should still be good with regular pump gas at .85 to .9 mm squish
Have fun with it .
|
|
|
|
Post by Kenho21 on Mar 20, 2020 20:49:52 GMT -5
You think ~0.75 -0.85mm squish is pushing it too far for a daily driver?
|
|
|
|
Post by ryan_ott on Mar 20, 2020 21:11:26 GMT -5
The idea is to keep the squish as tight as possible to push the combustion into the dome of the head and not at the edge. If compression gets too high then you modify the CC of the head to adjust.
2 strokes are so simple...
|
|
|
|
Post by Kenho21 on Mar 20, 2020 21:21:15 GMT -5
The idea is to keep the squish as tight as possible to push the combustion into the dome of the head and not at the edge. If compression gets too high then you modify the CC of the head to adjust. 2 strokes are so simple... Yeah, I was talking more in regards to 0.75-0.85mm squish being too high of a compression to run pump gas on and risking problems with detonation. I know 0.7mm is usually about the limit before the octane needed in the fuel needs to be so high that I can't run pump gas anymore. |
|
|
|
Post by Zino on Mar 20, 2020 22:29:36 GMT -5
It will be good for a daily driver set up like that
|
|
