ESE's works engine tuner

[TZ350]

Been helping one of the other guys with another guys F5, now does that make sense .....



The Red line is what we got when we ran his new cylinder, reed, carb and pipe combo.

When we checked the timing we found the Transfers opened 114 deg ATDC (132 duration) and Exhaust 90 deg ATDC (180 duration).

The Blue line is where we are at, after raising the Exhaust port opening to 84 deg ATDC (192 duration)



The ignition curve. More work to be done here yet.



And the carb is a 24mm Tillotson HL360A pumper.



Thought the new super duper reeds might be the problem so we setup for a back to back test with the original reeds.

Blue line is the original AM6 reed block, Red line is the new reed block with splitter and carbon fiber reeds.



Looking at the shape of the curve I was reminded of when I experimented with different length mid sections on the Beast. At the time I was looking to see if it would be useful to make a Slippery Pipe for varying the tuned length.



Well after trying everything from +60mm down it didn't look like it, I didn't get enough increase in low end width (power spread) for the trouble and then there was that weird double hump like we are seeing on the 50's graph.

Next move is to shorten the 50's mid section.

[F5 Dave]

30 deg blowdown isn't much. Transfers too high in relation to ex often cause queer pipe generated curves, but those are some serious revs. What is pipe length for such a low ex?

[wobbly]

The torque hole is just as likely to be a mismatch between the port STAs as it is to be incorrect fuelling from the carb.
Pumpers are notoriously hard to jet correctly for a piped engine even if it is ported correctly.
More often than not you will need seriously big openings on the low screw ( 2 1/2 T ) and 1/8 T on the top or something weird to get it to fuel the mid correctly.
Then spend all day mucking with the lever height and pop off to get the low end clean enough due to the big low end opening.

[wax]

Your very mild on the timing down low. Do you have the throttle sensor hooked up on the ignitech

[TZ350]

Your very mild on the timing down low. Do you have the throttle sensor hooked up on the ignitech

No TPS on the 50 yet, so we were keeping the ignition timing conservative in the hope of staying out of the part throttle death zone.

Any suggestions on how far you think we could go with the timing when we have a TPS would be welcome.

[F5 Dave]

Well I think I'm out of the hole with the dyno. Thanks to the ESE guys, TZ & esp Cully, hopefully this all works.

[koba]

It was suggested I post a pic of it, I'm clearly overly optimistic, but desperate enough. Worse thing is, it isn't mine, but I was last to use it & then next time it didn't pick up a reading from the drum. The sensor pulses when pickup passes through, there's correct seeming voltages to the board from the PC & the other inputs (ign, button etc) seem to work. Traced the sensor track back to the 37 pin connector on the PC card so its not just broken wire.

What does the port on the back look like?
Any chance of a shot of that?

Edit: Me = Slow!

[F5 Dave]

Well answering one of my questions a while back here is a downdraft Mikuni RGV carb bored from 32 to 35. As you can see there is still a 5mm slither in the middle I'll have to finish by hand, but I can live with that.

Also is my solenoid PJ mod made from 7/16" ally hex. I trusted the brass valve to a toolmaker (who also bored the carb) as its beyond my shaky lathe abilities. Also has a bracket welded to it that screws onto the carb so it is secure & hopefully will survive usual abusive race-meet jet changes. Obviously I'll have to trim and slashcut the brass tube when I devcon it in place. The feed will come from the std bowl which has a jet in it. Happens to currently be a Dellorto 30 jet (the std one was missing & it worked) so if they use a mm sizing should be close to the .35 Wob suggested for Av.

Now I just need the dyno going so I can test it. Whether it gets incorporated before the Battle of the Buckets at Ruapuna on the 19th I don't know.

[wobbly]

Dellorto do use mm size as jet ID.
But the #35 I referred to was a Mikuni solenoid jet as used on a TZ250 - these are flow numbers with no relationship to diameter.
You could measure one I suppose and replicate its diameter, that would be close enough I would think.

[F5 Dave]

Thanks man I'll give it a shot, presumably if it is too big the effect will not work or detonate as I reduce the rpm switch point & too small only last a few hundred rpm.

[wobbly]

Yea running Avgas correctly means you will be lean at peak power, and using a powerjet a little too big will for sure detonate in the overev as it turns off too much fuel.
If the set point is too low or the jet is too big,you will feel the switch almost like a 7th gear,the bike takes off as the pipe heats suddenly.
With the diameter and rpm set point on the money, it just becomes a seamless increase in rpm ceiling.

[F5 Dave]

I'm hoping I can tune it to correspond over a decent load and rev range.

Currently due to many other factors the bike is a little more peaky than it could be & signs off pretty sharp.

This isn't going to be ideal on long ccts with tall gearing making the gear changes far apart, but also on low kart track gearing there are gnarly sections that I find myself between gears in ~3rd & changing up to 4th you are almost at the next corner. The 50 is even worse.

[Drew]

The 50 is even worse.

Dunno how much you've done to it since I rode it all those years ago, but the thing was quite narrow in delivery. Felt so bad for the clutch, till I heard you ride it.

[F5 Dave]

At a race meet briefing some years back the organiser said he didn't believe in reincarnation, but if he did - the one thing he didn't want to come back as was an RG50 clutch.

4x (thinner) TS plates & DT175 springs & they are incredibly resilient.

[monkeyfumi]

http://www.cotronics.com/vo/cotr/rm_putties.htm

Hello all, have watched this thread with interest for some time, but never felt worthy of contributing. Stumbled across the above, and wondered if the 7032 (rated to 2000 deg F) putty might be suitable for experimenting with exhaust dams or as an alternative to welding the duct for exhaust flange nozzles. (I have not used it, just found it trawling the net and thought I would share)