ESE's works engine tuner

[TZ350]

Thanks for that, I am sure I will be able to muddle through as I have a friend who loves the tuning side of things.

Its very interesting watching someone else making one of these. I will post a few pictures on the basic steps/tricks we did, like the gluing if that helps.

[cotswold]

Its very interesting watching someone else making one of these. I will post a few pictures on the basic steps/tricks we did, like the glueing if that helps.

Every scrap you send me will be accepted with gratitude

[TZ350]

27 hp Inlet Port

Inlet port opens 145deg BTDC closes 80deg ATDC, the port is 45deg wide and was opened out to a 30mm equivelent dia and feed by a modified 24mm carb.



To get the inlet port as large as possible a small sleeve was glued onto a spigot machined on the rotary valve covers inlet, the clutch cover was machined out so the sleeve could poke through it.



The area of the port window was maximised and the rotary valve cut for slow closing. This may or maynot be a good idea and it might help reduce mechanical wear at the port closing point more than help performance, we don't realy know, we copied it from an early Benelli racer.



The inlet side crank wheel was champhered for a better inlet flow.



Modified OKO 24mm flatslide with a rubber wind shield fitted to the bell mouth and a filter setup as a header tank with a tap (unseen in photo) between the filter and carb. And another (main) tap is in the black hose between filter and tank. The clear hose on the top of the filter is a breather and has been added so the filter fills properly.

[Gigglebutton]

56 hours of measuring, grinding, filing and machining

Rear sets made and fitted

Altered port time area and angles to "Wobbly Spec"

Altered reed block with new reeds to "Speedpro Spec"
Inlet port bogged and filed to match new reed block "Speedpro Spec"

Cases ground to "TZ350 spec"
Head welded and re machined to "TZ350 specs"
Barrel skirt cut away to "TZ350 Spec"

Barrel bored and honed

The bike started first time. Feels way fatter. A bit of a cough at high revs. I will put it on the Dyno tomorrow and let Rob play with it and see what we have achieved

Cheers Guys . A few pies, beers and loads of theory hopefully will show results

[Gigglebutton]

After a bit of a thrash on the dyno....... Red is the old curve, Blue new.
Well worth the hours worked on it. Next step a better ignition. Thanks guys

[ac3_snow]

Thats wicked! next stop a grade..

[wobbly]

What pipe is on that dyno run, looks as though it would make alot more power yet as something is making it sign off early???
Ignitions will be here any day.

[gamma500]

few interesting videos:

GP125 cylinder casting by Gnani

http://www.youtube.com/watch?v=I-2rJtnkYq4

http://www.youtube.com/watch?v=Lj4h9...eature=related

http://www.youtube.com/watch?v=A50p3...eature=related

[kel]

What pipe is on that dyno run, looks as though it would make alot more power yet as something is making it sign off early???
Ignitions will be here any day.

looks like a big suck pipe with a shallow taper reverse cone?

[F5 Dave]

um, are you sure that isn't a std GP125 run you have transposed there by mistake?

peak power at 10,000 & above 10hp for 3,500rpm? Sheesh!

[Gigglebutton]

looks like a big suck pipe with a shallow taper reverse cone?

You got it. An odd mix but works well for an average rider like me. No spike of power to try and ride on. Teezee has some ideas on how to get a bit more Hp and the ignition from Wobbly will help a whole lot. The current one has way to much retard up top. Still coughs up top
Just taken it for a ride. It picks up the front wheel in 1st gear off the throttle with no clutching. Did it in 2nd a couple of times ridding over bumps in the road
I will have to play with the setup next practice day

[RMS eng]

um, are you sure that isn't a std GP125 run you have transposed there by mistake?

peak power at 10,000 & above 10hp for 3,500rpm? Sheesh!

i know Dave it kills my RG50 dyno sheet,maybe its a 70,my RG50 made 11hp at 12400 and reved to 14000,and made 6.5hp at 9000,that thing makes 11hp at 9000.

[Gigglebutton]

What pipe is on that dyno run, looks as though it would make alot more power yet as something is making it sign off early???
Ignitions will be here any day.

I got it about 6 years ago. I think your wright a bit of a miss match. I want to build a full reed motor, so will get you to have a look at that when i have all the bits.

[TZ350]

i know Dave it kills my RG50, mine made 11hp at 12400 and reved to 14000,and made 6.5hp at 9000,that thing makes 11hp at 9000.

Like yours, mine makes its most hp about 13,000 and revs to 14 before falling flat.

[TZ350]

Still coughs up top ....

Some thoughts on the over rev cough...........

….. high rpm coughs between gear changes? sometimes they appear on bikes with tame, well, not radical inlet durations (piston port & rotary).

See this all the time in kart racing - reeds as well, usually its the needle/tube combo going lean as you pass thru 3/4 throttle, when backing off for the change.
Get an Ignitech on there and do full throttle shifts - easy.

Also happens when an engine is reved too far past peak power before a gear change. The airflow drops in the overev, the carb goes lean and it will backfire as the change is made ( even using a speedshifter). RS125 engines in karts do it with steep baffles, as soon as you rev them too hard.

Its not scavenging that’s directly the issue, its lack of blowdown time, that effects scavenging efficiency and delivery ratio. Means the cylinder is full of exhaust residuals, as much of the mixture waiting in the ducts is reverse flowed back into the case.

Jan Thiel
At high rpm there is some reverse flow, the transfer ducts becoming black, and even the crankcase and carburettor bellmouth because of the entering burned gasses. This happens because with raising rpm. the pre-exhaust flow (blowdown) becomes insufficient. When rpm raises still more there is no more transfer flow and the engine stops completely. So transfer flow depends completely from what is 'allowed' by the exhaust flow!