ok I see, your target here. Looking for bottom and mid instead of high rpm power has its merits, such as riding in sand. one thing that is a bonus with the dropped cylinder is that your effective cylinder volume is larger which should give you better compression? I wonder if adjusting the ignition timing has a role to play in optimizing combustion with a larger compression volume? but which way!?
By the way, I wasnt saying I think you are rich and lucky you woe is me sort of thing, I was meaning mainly time. these things take lots of it and its a process. Life and learn! Its good that you are actively persueing the experiments and not just looking in hindsight when things go wrong
EXACTLY!
Bottom and mid for riding in sand. (which keeps this from being a thread hijack!)
Our favourite test spot is a huge sand pit and hill and this motor works wonderful in it.
This motor is like a trials bike engine, which has its place if you need that power characteristic.
As rpm drop the torque increases. "Grunts" through sand and up hills with ease in 3rd.
The 32hp DT200 would climb hills too but you had to keep it "on the pipe", right in the powerband.
This motor is easy. Put it in 3rd and it does everything!
Nothing comes for free however. This motor just does not make 30hp. It falls flat on top end.
While it will easily carry 6th gear on sand, only to mid-range. Won't rev out and scream like the DT200.
We will need more rpm, higher ports to do that, raising the cylinder. It goes in a circle, doesn't it?
The DT200 engine would rip along in the sand on sheer power if you kept the revs up.
Didn't take a lot of that before it started to get hot. You had to be in the right gear at all times, plus
because of the jump from 5th to 6th, it had trouble getting into 6th unless you red-lined it in 5th,
and even then it would kinda bog in 6th. Really needed lower sprockets, whereas this motor needs higher.
You are right, effective cylinder volume and compression are increased, big part of the power increase.
Would be a much larger part if the pipe tuning were matched to the lower rpm of the new port position.
Ignition timing is more about fighting detonation and keeping the pipe warm.
Advancing it makes more torque in the low and mid-range, retarding it keeps the pipe hot and rpm high.
Larger volume, more compression would be more prone to detonation, perhaps less advance called for.
Son has had no detonation, so next step is shaving the head another 0.020" (0.5mm).
Will do it with a file, 10" hand bastard, affordable machining!
If it detonates, we have learned something. We slip a base gasket under it and feel what a 0.020"
port lift does.
Hmmm, not enough time to do everything is there? Weather is bad for riding here, 2" snow.
Too much snow for wheels, not enough for skis, time to work in the garage.
I have my Blaster torn apart, leveling the carb and better air cleaner.
You are right, live and learn. That is what it is all about.
That is what I like about this place, that is what most of the guys here are all about.
If there is anything useful in anything I post, it is payback for all the information I have gleaned
from the rest of you folks here on Blaster Forum. Thanks.
