ESE's works engine tuner

[TZ350]

30 hP Comparison

Attachment 247544


Green line is where I am now with the Tillotson pumper carb and single exhaust port barrel. Red line is Speedpros 30hP MB100.

Blue line is a cylinder that was modified for extra side exhaust ports. When I tried it a while back the crank needed balancing and the engine vibrated so badly that I lost my nerve and shut off before it had reved out.

Interesting its so close to Speedpros curve, now the crank has been re-balanced and runs smoother at big revs I might have another look at the triple porter with an eye to the Taupo GP.

[TZ350]

Inlet Manifold Dyno Test

Attachment 247545

Red line is the original inlet manifold, Blue line is the manifold with the divider fitted.

I have put a curved divider in my inlet manifold. The idea is that (1) in a curved inlet like mine there tends to be a traffic jam on the outside wall as the inlet charge tries to turn the corner. Basically the divider (2) makes it into a two lane highway insted of a one lane bottle neck.

[husaberg]

No I think the 100 mill is what buys the eggs.


TZ have you done an all-gears run to see the kart carb transitions nicely when thrown a bunch of gear changes?

You can't have both Dave "Bob" has been getting some bad press lately and is having er...Difficulties accessing funds From Zimbabwe. He also asked me to ask about any farms avail in NZ

The pumper carb my mate ran, was sweet all around on a MB100. It was off a jetski and huge though. Disk valve may be more problematic.

The only problems he encountered with it were as I had discussed with TZ earlier with overrun. He was admittedly a Kart guru type.You would be best as suggested above to find a chainsaw or kart Guy is my two cents worth.
I will take it out of Daves sponsorship money.

Did you get around to modifying the pop off?

BTW what sort of CHT does it run TZ i have never seen any figures for it it must be getting up there now underload. Even with cooper fins and all.

[bucketracer]

BTW what sort of CHT does it run TZ i have never seen any figures for it it must be getting up there now underload. Even with cooper fins and all.

I have been helping TZ with the dyno tonight, the hotest part is the copper fin next to the exhaust, the copper head fin is much cooler, both are easy to touch. I can easily keep my hand on the alloy part of the head near the plug after a heavy dyno session. But then it does cool fast, I will have to get the lazer thermometer out and try to get some readings while its under load.

Did you get around to modifying the pop off?

Tried 9psi then 7 then 12, on 12 I had the low out three turns and the high one and a bit. So I guess 12 is to high. will go back and try 10 next.

Problem is to get it to come back onto the throttle properly, with the pop off at 12 and the low out three turns it would pick up then there would be a mild patch then it would take off again so we guess 12 is to high causing a mild mid lean out.

Its like the pop off is the pivot on a seasaw and High and Low are the ends and adjusting the pop off is like adjusting the overall height of the seasaw.

I will have to do some reaserch on the net about tuning pumpers and see what I can come up with.

[wobbly]

Pumpers are pretty easy to suss.
The pop off pressure simply sets the amount of fuel passed up to 1/2 throttle, transition from closed throttle,and around idle.
This should be set such that the bottom jet is no more than 2 1/2 turns out for the correct fuelling in the bottom end.
The pop pressure should be set with the needle and seat wet, and should hold its set pressure right up to the point of blowoff.
The top jet sets the fuelling past 1/2 throttle and mainly affects the ratio delivered at peak and beyond.
This should be less than a turn.
The pop off lever height sets the overall amount of fuel able to be delivered, the higher the lever the sooner, and further the needle is pushed off the seat, allowing more fuel to pass to the jets in total.

[TZ350]

Pumpers are pretty easy to suss.....

Thanks Wob for the tips........ probably get to look at this again in a few days.

[bucketracer]

TeeZee some pumper carb tuning tips to go with Wobblys info. Attachment 247635

And here is something if we really cock it up..... ...... piston seizures explained Attachment 247636

[koba]

may be a game changer as KT100s are single gear of course, not that I have aqny kart experience aside from seeing AND HEARING them in the pits at Bike/kart meets.

I've amended that post for you Dave...

[koba]

And here is something if we really cock it up..... ...... piston seizures explained Attachment 247636

Looks a great read...

It's sad when I can instantly scratch together 4 or 5 examples of seized pistons to apply the article to!

[wobbly]

One thing I completely disagree with in the piston seizure write up is that air leaks cause a lean condition.
This is utter bollocks, any engine with a case leak will run richer, the bigger the leak the richer it will run.
Caused by the fact that the case "pump" no longer works and the fuel air mixture isnt being transferred thru the ducts.
If the engine is then leaned up to "fix" the incorrect mixture - then it seizes.

[husaberg]

One thing I completely disagree with in the piston seizure write up is that air leaks cause a lean condition.
This is utter bollocks, any engine with a case leak will run richer, the bigger the leak the richer it will run.
Caused by the fact that the case "pump" no longer works and the fuel air mixture isnt being transferred thru the ducts.
If the engine is then leaned up to "fix" the incorrect mixture - then it seizes.

I could have got this wrong but when he says air leak could he have been referring to a manifold air leak and if it does will this still cause it to run rich as in your analogy Wob?.
I am not challenging you. Just curious? because I always was lead to believe a manifold air leak runs lean and it always seem to on four strokes.

Piston specs here inc ring peg locations
http://www.pvlsverige.se/vrm/kolvar/kolvar.html

Also below a very old way of securing circlips. Which I think its quite cool. Clever bugger that Phil Irving

[wobbly]

A leak between the carb and the reed or any intake will always add air going into the engine and create a lean condition.
A leak anywhere in the case, be it a gasket, a seal, or a pin hole in a casting will cause the engine to run rich.
Problem is that they then seize for no apparent reason when the jetting is then "fixed".
So its always wise to make a set of blanking plates and or use a rubber bung with a bolt that expands it into the pipe manifold, so that a leak down test can ensure no case problems exist.

[bucketracer]

Attachment 247722

Last attachment contains past the main jet 3 times I believe this was raised earlier.

When TeeZee first talked about fuel passing the main jet three times. SS90 was most adamant that it couldn’t possibly happen as he had never seen a carb fog at max power on a 2-stroke, you know, real life experience and all that.

And he made his usual song and dance about having to have real Industry experience to know what your talking about.



This is TeeZee’s bike making 27-28 hp complete with carb fog at max power. If its not fuel passing the main jet at least three times then what is it, maybe SS90 the Industry Man himself could tell us.

Attachment 247723

After seeing the fuel line being sucked down in the vid, TeeZee added the filter/header tank, it works a treat and keeps the line full.

[TZ350]

The fuel tank had a 4mm hole drilled through the fuel cap for an extra breather and I expected fuel flowing down from the tank to keep the 6mm id fuel line full as it would be more than the smaller float needle valve could pass.

Yes, I was pretty shocked when I saw the air in the fuel line during heavy runs on the dyno.

The fuel line seems a resionable size, there was a good head of fuel in the tank and because of the big bottom entry on the tank for the fuel line it seemed unlikely that the carb could be draining the fuel line faster than the fuel tank could re-fill it, and if it did where did the bubles come from, outgassing? possible, but my guess is the air was getting into the fuel line via the float needle valve.

The bubbles look like they are being sucked down in the vid but I think they are just denoting where the incoming air has almost completely filled the line forcing fuel to run down the inside walls, its easier to see in the flesh than the vid. And the bubbles go back up again as the accumulated air bleads through to the tank.

And if air is going up into the fuel line that way it must be reducing the area left for fuel to flow into the fuel bowl, what should have been a one way highway for fuel is being reduced to two smaller lanes going in opposite directions.

Anyway thats my take on it, and if any one has seen this before and can tell me more I would be very interested.

Its a scary thought, the float needle jet becoming the main restriction of fuel being carburetted to the engine.

Whatever, the modified filter header tank stopped it.

[husaberg]

As Dave said earlier on Yamaha were instrumental in keeping the 500GP's interesting.