ESE's works engine tuner

[Jannem]

Capacitance is often expressed in microfarads ufd or Mfd.
The cap you mentioned is in millifarads mfd, so 470Mfd?

Just checking as upper or lower case makes a difference. Neat trick I’d like to try.

[dutchpower]

Why lost of power

When changing blowdown data to 34
Bring it back to 31 .99 get the power back

[Haufen]

Why lost of power

When changing blowdown data to 34
Bring it back to 31 .99 get the power back

Need more info to tell you what exactly happened. Looking at the curves, I'd try 30 and then widen the port to the max in the blowdown area.

[acr]

Capacitance is often expressed in microfarads ufd or Mfd.
The cap you mentioned is in millifarads mfd, so 470Mfd?

Just checking as upper or lower case makes a difference. Neat trick I’d like to try.

0.47uf = 470nf is the same value its like kg and grams . Wobbly it looks like the mylar cap is a ac/dc cap like the main cap in the CDI units 1.0-1.5uf so there is no possitive or negative terminal on it i tried a .47uf DC cap and it moved the retard approx 10 degrees total with the + terminal conected to the trigger and - terminal to earth when i turned it around there was no reaction to the retarding i shall try a mylar type and see if the movement is the same with both types


Thank you for sharing this info Wobbly

[Jannem]

0.47uf = 470nf is the same value its like kg and grams.

Yes, the SI system is what we use here.
You could also express that as:
0.00047mf=0.47uf=470nf

Based on your results it sounds like .47uf is in the right ballpark.

Thanks.

[Lbracing]

Question here away from piston holes , I know the ideal rod ratio is said to be ideal around 2.1 times stroke but what if for fitment reasons I have to go upward in the 2.22 range ? Is it detrimental ?

Thanks again !

[Frits Overmars]

I know the ideal rod ratio is said to be ideal around 2.1 times stroke but what if for fitment reasons I have to go upward in the 2.22 range ? Is it detrimental ?

I didn't know that.... And I'd prefer 2,2 over 2,1 .

[wobbly]

The mylar type cap ( 470nf )I used has no polarity, I would imagine that a polarized type would only work one way around.
I fitted the cap across the trigger wires ( inside the loom to hide it ) as most triggers are floating ( not connected to earth ).
Just to remind you - this trick is only used to make an analogue straight line ignition ( as is an old TZ ) into a retarding type.
It works by advancing the hell out of the spark at lower rpm, then retards it at a pretty much constant rate/1000 rpm.
So you need to set up a pair of reference strobe marks that align at a set rpm, then working from this base advance you can work out
what advance curve ( line ) you actually have.
As I said, the TZ350 ignition was checked by the factory as 2mm BTDC @ 10,000, but we could never run more than 1.6 when modified from stock.
From memory this was 17*, so with the mod in place I set up new marks that aligned at 17* @ 10,000.
Thus it had alot more advance before this, and less after, that increased the power dramatically, especially down low where the piston
port really struggled.

[wobbly]

Re the blowdown power loss, Dutchpower - could be any one of a hundred things that would cause that,so I have no idea.
Post the pack file so we can have a proper analysis.

[peewee]

You're joking, aren't you Peewee? Please tell me you're joking.
Methanol flow should be 16 cc per hp per minute. That's easy enough to check, but you must flow all relevant parts simultaneously, starting with the tank breather and certainly including the float valve. And if you add nitromethane, the flow requirement increases steeply, depending on the nitro percentage of course.

.

hi frits I think its just a couple weeks and the engine will run once again . I checked everything in the fuel system to make sure .

heres what I know today.

tank breather is plenty large enough
tank valve flow is 1L per 15sec
3.5mm float valve flow is .24L per 15sec
bowl capacity is .24L. its actually much more than .24L but the cylinder inlet makes the carb tilt alot forward so .24L is the limit while the bike is on level ground.

heres what I figure for full throttle fuel consumption in 15sec, which is the very most the engine will have to endure. mostly I think its over estimated to be on a safe side

delivery ratio of 1.5
525cc engine capacity
afr of 4:1
8k rpm
.001261 g/cc air density

with this numbers it seems fuel consumption will be approx .5L per 15sec. the bowl already holds .24L at minimum and the float valve will supply .24L per 15sec, atleast when its fully open. I think everything is ok. what do you think frits ?

[wobbly]

On every engine that I have changed to methanol I have used the optional float valves as supplied by Dellorto,Keihin etc.
These are always 4.2 or 4.5mm for gravity feed systems.

[Frits Overmars]

hi frits I think its just a couple weeks and the engine will run once again . I checked everything in the fuel system to make sure .
heres what I know today.
tank breather is plenty large enough
tank valve flow is 1L per 15sec
3.5mm float valve flow is .24L per 15sec
bowl capacity is .24L. its actually much more than .24L but the cylinder inlet makes the carb tilt alot forward so .24L is the limit while the bike is on level ground.
heres what I figure for full throttle fuel consumption in 15sec, which is the very most the engine will have to endure. mostly I think its over estimated to be on a safe side
delivery ratio of 1.5
525cc engine capacity
afr of 4:1
8k rpm
.001261 g/cc air density
with this numbers it seems fuel consumption will be approx .5L per 15sec. the bowl already holds .24L at minimum and the float valve will supply .24L per 15sec, atleast when its fully open. I think everything is ok. what do you think frits ?

According to your data the fuel flow bottleneck is the float valve with 0,24 L per 15 sec, or 960 cc/min. That's good for 960/16 = 60 hp.
A 525 cc engine running on methanol should produce way more than 60 hp, so you're in trouble.
Don't fool yourself regarding the fuel volume in the float bowl. The fuel level will drop as soon as the engine starts to produce power; it will run leaner and leaner.
You may get lucky and reach the finish line before the engine seizes, but this is not the way to go.

[peewee]

thnx for the advice frits. wob these lectrons use mikuni float valves. 3.5mm seems to be the largest they make. I can drill out a 3.5 to a larger hole but im wondering how I could accurately recut the taper so the needle seals correctly ? maybe adegnes knows how. seems he might of drilled out his keihin float valve

[wobbly]

Trust me, a 3.5 Mikuni float valve will NEVER be enough as I have run 250cc MX engines on Meth in karts making over 60 Hp
and they absolutely for sure need the 4.5 valve as is made by Dellorto for this purpose or instant seizures is a given.
Keihin make a 4.2 for FCR on Meth.
On gravity the bowl will drain empty in no time with smaller needles.
I have had shit fights with Lectron about this over petrol carbs, and was only then I found out that they do make a " high flow " needle
that is 3.5.
I needed them for the 485 cc RZ engines I made that had over 60 Hp ( crank ) per cylinder.
Lectron were adamant that the std 3mm float would be fine - but the first run on the dyno , as it clicked 3rd gear at 8,000 the bowls were all but empty.
The 400cc RZ racebike engine has 3.5 floats on 40mm Lectrons and at full noise in 6th making 96 RWHp the level drops over 3mm.
Scary, but as it is consistent, it can be jetted reliably by having very high static levels in the bowls.
Having a bike tank sitting on top of the carbs is VERY little pressure head to keep high flow rates going - more especially when the fuel is getting low.

[TZ350]

Bit of Sundays Mt Wellington action, shot from a drone piloted by Wil Killip.