ESE's works engine tuner

[TZ350]

There is good news and bad news.

The good news is, that after 40 liters of fuel and hours on the dyno the exhaust port dam and Belzona epoxy are still there and I am starting to get somewhere with setting up the EFI. The Beast idles at 3000 rpm and I can snap the throttle open to 100% and it will pull away very nicely.

Fiddled with the ignition and fueling but it it still detos around peak torque. The good/bad news is, my recent problems with the EFI look to have been pretty much self inflicted. I just checked the port timing and the exhaust and transfers are opening way to early and I am beginning to suspect that the compression is way to high for the fuel too, I will check that next.

[Frits Overmars]

There is good news and bad news.

The good news is, that after 40 liters of fuel and hours on the dyno the exhaust port dam and Belzona epoxy are still there and I am starting to get somewhere with setting up the EFI. The Beast idles at 3000 rpm and I can snap the throttle open to 100% and it will pull away very nicely.
Fiddled with the ignition and fueling but it it still detos around peak torque. The good/bad news is, my recent problems with the EFI look to have been pretty much self inflicted. I just checked the port timing and the exhaust and transfers are opening way to early and I am beginning to suspect that the compression is way to high for the fuel too, I will check that next.

Even if the fuel would tolerate a high compression ratio I would keep it low in the interest of power and flexibility (overrev).
Too-high transfer ports are a sure-fire recipe for detonation; they take away blowdown time.area and hot exhaust gas will enter the transfer ducts, quickly heating up the cylinder and the fresh charge in the transfers.

The exhaust dam plus Belzona, while very good for flow and exhaust pulse efficiency, may play a deto-provoking role too. There is bound to be a resistance in the heat-path from the dam to the cylinder metal, so the dam will heat up and in turn heat the washed-through and pushed-back fresh charge. In a watercooled cylinder I would try to wet the underside of the dam but in your case there is not much you can do about it, apart from welding the dam in instead of screwing/glueing it in.

[Haufen]

There is good news and bad news.

The good news is, that after 40 liters of fuel and hours on the dyno the exhaust port dam and Belzona epoxy are still there and I am starting to get somewhere with setting up the EFI. The Beast idles at 3000 rpm and I can snap the throttle open to 100% and it will pull away very nicely.

Fiddled with the ignition and fueling but it it still detos around peak torque. The good/bad news is, my recent problems with the EFI look to have been pretty much self inflicted. I just checked the port timing and the exhaust and transfers are opening way to early and I am beginning to suspect that the compression is way to high for the fuel too, I will check that next.

Sounds good to me. I found that Weicon titanium works good in an exhaust duct, too. At least in a race engine which is looked after rather often. Which type of belzona did you use on your exhaust floor dam?

I also used some product of 3M with surprisingly excellent adhesion to the piston skirt. What flattened me was that the area where I applied it was rather large (about 2cm²), the layer was several mm thick and it was not surrounded by piston material or the cylinder bore in every direction ,yet it withstood every thinkable abuse. Unfortunately I forgot it's name, I will do a search later on. It was greyish, single or dual compound and turned brownish after a while.

[koba]

I also used some product of 3M with surprisingly excellent adhesion to the piston skirt. What flattened me was that the area where I applied it was rather large (about 2cm²), the layer was several mm thick and it was not surrounded by piston material or the cylinder bore in every direction ,yet it withstood every thinkable abuse. Unfortunately I forgot it's name, I will do a search later on. It was greyish, single or dual compound and turned brownish after a while.

Edit: Got pics?

[F5 Dave]

It seems to be magnetized to the fridge!

Now that sounds like my 3yr old daughter, convinced that there must be more Popsicles in there if we keep dragging tall people over to look.

[TZ350]

OK its humble pie time, turns out I am responsible for most of my problems with getting the EFI going.

my problems with the EFI look to have been pretty much self inflicted. I just checked the port timing and the exhaust and transfers are opening way to early and I am beginning to suspect that the compression is way to high for the fuel too, I will check that next.

Not only has the port timing been way out with the Ex opening at 70 deg ATDC and Transfers 110, when they should have been Ex 80 and Trans 115.



I had to go and stuff up the compression ratio too, at 16:1 swept it was never going to work.



After changing the barrel this squashed plug was a clue about the compression ratio being to high.

Over compression and wrong port timing have been the biggest source of my problems all along and my only excuse is that the motor must have been rushed together after a few drinks on a Friday night in a fit of enthusiasm to start playing with the Ecotrons EFI kit.

I guess if I had of been working with something more familiar like an OKO carb I would have twigged that there was something fundamentally wrong with the motor much earlier.

Fitted a new barrel with exhaust at 72% wide and opening 80 deg ATDC, Transfers open 114 ATDC, Inlet Opens 145 BTDC Closes 70 ATDC and Std head.



Adjusting the fuel curve and ignition is real easy now, just requires time and a bit of patience. This is a really rough first cut but I expect to be able to polish it up nicely.



The blue line is after a couple of runs to improve the pickup.

I am starting to feel optimistic.

[fatbastd]

Going back a page - nice little TA125 in the Trademe ad...looks very straight. makes me keen to assemble mine - it's half-done and sitting in the back of the shed, thoiughy running it might be embarrassing these days -it'd be eaten by a modern bucket! No brakes, no tyres and an optimistic 24hp!

Last time I rode it I suspect I was the last person to gain National 125 points on a drum-brakes, air-cooled 5 speed bike!

[TZ350]

TA125 Beautiful bikes If only we knew then what we know now ......

[speedpro]

Probably make an OK bucket. You'd have to chuck a fair bit away of course.

[Frits Overmars]

turns out I am responsible for most of my problems with getting the EFI going. Not only has the port timing been way out with the Ex opening at 70 deg ATDC and Transfers 110, when they should have been Ex 80 and Trans 115. I had to go and stuff up the compression ratio too...

Seems like you have used up your quotum of blunders for 2014. It should be downhill-going from now on.

[jasonu]

Probably make an OK bucket. You'd have to chuck a fair bit away of course.

But that is not within the sprit of the rules...

Dunno if it is worth $8k but I would sure like to own it.

[TZ350]

Seems like you have used up your quotum of blunders for 2014. It should be downhill going from now on.

Yes, feels like this part of the project will be straight forward now .....

[jasonu]

TA125 Beautiful bikes If only we knew then what we know now ......

Can someone post the tardme link to this auction. I am curious to see how much it goes for.
Cheers in advance.

[TZ350]

Can someone post the tardme link to this auction.

ta125 .......

http://www.trademe.co.nz/motors/moto...-686119218.htm

[twotempi]

I admire all the innovation and work that goes into 'buckets"

BUT ..................

Anyone who uses a TA125 as the basis for a bucket is a VANDAL"

Keep it original with its warts and other failings , and use it with the Classic club as a genuine 1972 GP bike in events for historic 125's with others of its kind.