ESE's works engine tuner

[TZ350]

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I have been playing with my rotary valve converted Suzuki RG50's inlet timing. Rotary valve timing was changed and ignition and jetting optimised for each run. Everything else the same.



Red line inlet timing, opens 135 btdc closes 75 atdc. Blue line inlet timing, opens 145 btdc closes 85 atdc. So more is not always better.

[wobbly]

You are dead right TeeZee , but 145 opening is too much for " any " engine , and the results are skewed by the fact that any 50cc race engine making 13Hp at only 12,500 is
not even in the ballpark yet.

[lodgernz]

https://www.youtube.com/watch?v=utEKKox2WHA[/video]

My father's solution to slightly misaligned shafts was a chain pulley on each shaft, with a piece of double-row chain around both. Worked well.

[Grumph]

My father's solution to slightly misaligned shafts was a chain pulley on each shaft, with a piece of double-row chain around both. Worked well.

See my post on the previous page.

This chain on sprockets joiner is traditional in speedway TQ's where a driveshaft comes off the end of a bike motor crankshaft.
Still in use today.

[Flettner]

Yes, but here in Siberia we use more safe and practical machines like

My friend is owner of company which produce such toys and sell a lot each month

I have a bit strange question.
Anyone have an experience to connect 2 crankshaft by some type of couplings which allow small misaligment like 0.05mm?
may be Oldham will work for?

Practical?

[karter444]

You are dead right TeeZee , but 145 opening is too much for " any " engine , and the results are skewed by the fact that any 50cc race engine making 13Hp at only 12,500 is
not even in the ballpark yet.

Hi Wobbly at what angle BTDC does a reed valve start to open . Im guessing that it depends on rpm and load ??
cheers

[ken seeber]

My 2 stroke fuel injection ran 20:1 oil mix. No problems with the oil fouling the injectors or my O2 sensor. But not sure what it will do to any catalytic converters or O2 sensors long term.

From what I can remember at Orbital, the catalyst, particularly, was affected by 4 stroke engine oils cos they contained both zinc and phosphorous. These are use in the 4T oils because of the EP (extreme pressure) requirement, I guess at the camshaft and followers.

So, from this, 2T oils don't contain the additives and are therefore fine with a catalyst and one could reasonably assume the O2 sensor.

We had no issues in this respect.

[F5 Dave]

Cool. Old premix will go in van. I dont have a lawnmower. Thanks.

[wobbly]

The Lambda O2 sensors are affected by oil ( and we were told - lead ) residues coating the element. We discovered in SKUSA racing with CR125 stock classes
that if it was put into a hollow threaded bung in the very front of the muffler with its tip just short of the perforated , it lasted for years and the readings were very reliable/stable.
Stuck in the belly we had nothing but problems with reliability and inconsistent readings.

Yes , Rotary Valve timing is based around rpm and the STA required to generate the power needed at that rpm.
A few examples I have knowledge of - 300/400/600cc Jetski cylinders running up to 9500 - open 130 to 132 close 65 to 75 depending on the tune , the early Rotax 256 that
made about 40 Hp/cyl at 12200 , open 134 close 86 ( or 88 if tuned higher to 12500 ) and of course the RSA ( plus the modern 250 Superkart clones ) that make 50 - 55 Hp at 13,000
opened between 140 and 142 and closed at 90 to 92 ( depends upon who you believe ).

EDIT - shit I misread the question - in the vast majority of sims I do the reeds do not start to open until the piston is getting close to closing the transfers. This opening point is determined pretty much solely
by how well the intake tract is tuned for the wave action and the column inertia to have max effect around a specific rpm. When the tuned length is perfect , the case pressure ratio goes negative at the same time
as the intake wave , bouncing off atmosphere , arrives back at the reed tips at the same time. This double effect opens the the reeds fast and early, then the column inertia holds them there. The intake tune
works over about a 2000 rpm band , its efficiency is off course subject to the old Pareto principal , 80% of the power is in the pipe , 20% is available to be optimized in the intake system.
To have this work we need the intake in 125 race engines to be pretty much as short as is physically possible , unless the end use is MX where upper mid power is needed . But the issue in bigger 250cc MX is that
it is impossible to get the length correct as the rear suspension is in the way - so they end up with 125 style short angled intakes.
The example shown is a 200cc cylinder at 10,000 rpm. It has a long 40mm Lectron with a big bellmouth extension and a 52 mm long intake manifold. This combines with the end correction plus the reed box length to have the 3rd harmonic
intake effect peaking at the 10,000 rpm shown.

[TZ350]

.
Been having a little issue with my 50 running on after a hard pull and not shutting off when the throttle is closed.

This is what the tip of my Champion G52V 10mm plug looks like new.

What it looks like now.



The heat line on the threads looks to be further down the plug than they should be and it also looks like the spark has been tracking over the porcelain.

Just goes to show how tuff these Suzuki RG50 engines are.

Time to do something about fitting an exhaust gas temperature gauge as an aid to getting the jetting right.

[F5 Dave]

Airleak introduced with new inlet?

[Grumph]

Put the plug in the lathe and take a light cut off the outer ring face.

Enough to remove the plating and expose base metal.

[wobbly]

The porcelain is shattered - hello , Mr Deto is in the house - the center electrode is probably operating like a glow plug.
I have said it a thousand times - if you are not using data to tune - you are playing with yourself in the dark , well I didnt say that but you know what I mean.

[TZ350]

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Suzuki RG50 with rotary valve conversion.

I was asked if the rotary valve conversion was worth it (Red line), initially I did not think so. But now, with the new timing (Blue line) I am looking forward to riding it Sunday.

Blue line is where I am at now with the RV timing at 135/75. Av Gas.
Red line was my initial RV timing of 145/85. Av Gas.
Brown line was with the original 145/85 Av Gas and a squirt of Nitro. Only on the Dyno of course.
Green Line was with the 145/85 timing and an experimental mix of 25% Methanol + Av Gas. Again, only on the Dyno of course and in the interests of science.

[jbiplane]

The Lambda O2 sensors are affected by oil ( and we were told - lead ) residues coating the element. We discovered in SKUSA racing with CR125 stock classes
that if it was put into a hollow threaded bung in the very front of the muffler with its tip just short of the perforated , it lasted for years and the readings were very reliable/stable.
Stuck in the belly we had nothing but problems with reliability and inconsistent readings.

Do you have any picture how correctly install?