Everybody: your squish height, Vcc and CR?

[franco]

Hi.

1) what squish height are you on?
2) this figure of yours is related to stock engine or what kind of mod?
3) what squish height is/was your engine, when in stock form?

[Luther]

Mines at .028" to .03" Squish cut parallel to piston, close to 50% area, I get 135 pounds on gage. It was low 120's stock with .065" squish. My first try I was at 155 pounds but it didn't feel better so I cut more out. Port heights matched, ignition 4 degrees advanced, Jolly motos. Runs really good

[franco]

Tks, Luther. I'll post my findings soon.

[franco]

These are figures I found yesterday on the bike I bought second-hand in 1991:
front bank: 1,0 mm
rear bank: 1,2 mm.

I am in rebuilding stage, aiming 1,0 mm for all of them.

[phildu31]

On mine, I found these :
front bank : 1,6 ~ 1,7 mm
rear bank : 1,4 ~ 1,5 mm
Obviously, original values I think.
Heads lowered by 0,6 and 0,4 mm respectively to get 1,0 mm on all cylinders.

[franco]

On mine, I found these :
front bank : 1,6 ~ 1,7 mm
rear bank : 1,4 ~ 1,5 mm
Obviously, original values I think.
Heads lowered by 0,6 and 0,4 mm respectively to get 1,0 mm on all cylinders.

And what Vcc at TDC, Phildu, please?

[phildu31]

Depending on cylinders, volume varied between 12,7 cm3 and 13,3 cm3.

[Motolli]

My engine is in rework, will switch to O-rings, no more head gasket. As soon the parts arrive, I will provide my measurings.
Olli

[franco]

My engine is in rework, will switch to O-rings, no more head gasket. As soon the parts arrive, I will provide my measurings.
Olli

Hi Motolli, is the bike in working order by now?

[Motolli]

Hey Franco,

Sorry for not continuing my notes, had big trouble with misfiring on the first rides after. 10-20 km. Checked all ignition components, and replaced coils and cables. Saw some sparks jumping off the Top plugcaps to my electric support under the tank. but In the end, I had to rejet significantly. Without the head gasket the squish height is 1.0 mm now, compression ist slightly higher. Haven’t measured the pressure, but could feel it on the kicker. Changed to premix ( 1:40 Motul 800 ) and expected to use bigger jets Than last year. That was not true overall . I am now at PJ 42, AIr screw 1.15 Out, MJ 126, and Needle JJH on second groove from bottom. Now Throttle response is great, runs smooth without any 2 stroking in town at 2500 revs. Burns like hell at WoT and plugs are turning from oily black to dark brown now. Can switch to 124 or less. All with Keihin PWK 28, with elephant ears. And K&N filters plugged on them. Zeeltronic is now involved in improving and testing. Have ridden it without fairing, to be faster accessing the carbs . But now it is complete, and polished !

[Motolli]

And before I forget, the oringed heads do not leak !!

[franco]

I am experiencing no firing in my lower bank right now, exiting rebuilding. But I swapped coils, plugs and wires between banks and still lower one is silent.