pics wanted for cutting the head

[hannesd]

so after the adjustment (no base gasket) the gasser ran rich off idle.
so i swapped the 45PJ tot a 42.
MUCH better now!!
feels like it's running smoother all over the revs.

tomorrow i have a day drive planned.
allso changed gear oil. i mixed 50/50 5w30 engine oil with atf oil (dexron III H)
i'll report back after the ride.

ciao, Hannes.

EDIT : so here goes the (short) ride report.
the bike runs very strong compared to previous setting.
strong bottom as can be expected from a 200, good mid power, bit short up high in the revs.
idle is allright but not as i want it, might go even 1 step leaner from 42 to 40.
to try to clean up the top revs i might try allso a leaner jet, from 180 to 178.

about the gearoil i mixed, it's k but not as good as it should.
i can start in gear but it drags,smooth shifting is ok.

ciao, Hannes.

[(F5)]

Originally Posted by hannesd

so euhmm i chicken'd out about cutting the head.
i was talking about this to some local riders and they said i had alot of guts doing that :-p.
. . .

Meeow


Actually I was thinking I must get around to it myself (as I descended down a nice tight forestry section in the weekend, maybe that's why I'm slow in the tricky stuff, brain is off thinking about all sorts of random stuff), it's been about 8 months since I put in a new piston & didn't have the spare time & haven't since with other projects on the go (including modifying heads on other bikes on my 1940s lathe).

[andy176]

Can this b done on a 300? I just bought one that I want to supermoto and think its gona b abit short on power? I have a lathe but prefer not to touch the concave wat results/problems would u expect just by machining the mating surface and is there a standard amount to remove?

[hannesd]

Originally Posted by andy176

Can this b done on a 300? I just bought one that I want to supermoto and think its gona b abit short on power? I have a lathe but prefer not to touch the concave wat results/problems would u expect just by machining the mating surface and is there a standard amount to remove?

i'd say, just measure you current squish and go from there.
if it's excessive like over 2mm, you could do the same as me, leave the base gasket out and use some liquid gasket.
not sure many others would do the same but mine just woke up by doing that !!! (ec 200 with squish now at 1.35mm instead of 1.85mm)

ciao, Hannes.

[andy176]

Cheers for the reply. Wats the easiest way to measure the squish and wat roughly should it be? Bike had a piston kit fitted before I bought it. I'd b happy enough to try wat u have done it would mean not having to touch the head or take very little of it. Can the base of the barrel not b machined to save touching the concave part of the head?

[(F5)]

if you're going to SM it you don't really want to drop the barrel. in fact you may want to raise it till the ex floor is level with the piston at BDC from previous posts for good top end.

Then decide what gas you are going to run & that could help decide what compression you want to go to. There is heaps of info on the web to help with this decision.

Seriously if you want to maximise power then it is worth a little effort for this type of power gain, that is improving the efficiency throughout the range.

measuring a big cylinder is easy, do a google on how to & maybe there will be a youtube 'how to' for 2 strokes.

Cutting the cylinder head isn't that difficult, but you need to learn in steps. I'm a muppet with a 1940's Sheldon lathe & old style tooling & never really learnt how to properly grind a cutter, but I ended up with a nice curved shape & with some care can remove a bit from the dome & make it match ok. Then finish off with sandpaper (carefully can stick some paper on a shape).

[hannesd]

i'll see if i can find an old cil head to practice and later on get my 200 done afterall, see what's more to gain