ESE's works engine tuner

[SwePatrick]

Nah.. i guess i will win power
this is a 'dragrace' machine so 'low end' torque isn´t important.
and i wanted to keep torque low as the gearbox will have problems enough

The gearbox is really closeratio, it´s setup for an 80cc machine.
So i wanted to keep the rpm range as an 80cc.

I also got an other moped that you can see in the background of first pic i posted, this is an hybrid from an MT5 and an CR80 liquidcooled engine, bored out to 88cc
that one got even harder durations. spool opens at 111 and boost at 109.5.
This one revs about 15k.
Really nasty one, hehe.

As for regaining area with porting out the dividers is true.
But i havent got the tools to get it proper ported all the way to the crankhouse.
I felt it might be unaligned in directions i want the flow.
More important than area i have learned through the years.

as it is now i have already altered the A spool to get them more aligned to the back of the cylinder.
If i want more area i have to port it all the way, my tools don´t allow that to be done nicely.

always compromises in porting an already existing cylinder.
If i had the knowledge and tools of casting my own, then the story will differ a lot.

Rgds.

[speedpro]

I'm running an MB5 6-speed box in my MB100 with a modified MB100 clutch with an extra pair of plates. It's making good power and the gearbox handles it without a problem. I don't think you will have a problem with the 6-speed from the original 50cc engine. FYI - the MB100 clutches drop straight in as all the shaft diameters are the same and with the extra pair of plates handle high 20s hp with stock springs. I've had a couple of MB100 that revved to 14,000rpm and nothing has come apart yet, except when I screwed up.

[SwePatrick]

Yes.. ~ 20hp is good..
But i reckon i will double that atleast.

My 88cc machine got 5disc clutch with uprated springs, it slips from time to time.
And in dragracing the dog in the gearbox are living an hard life.
any defects and the shiftforks takes the beating and snaps.
My 88cc machine is in the area around 20hp at the wheel.



that´s a pic of my 88cc hybrid.
from the beginning a watercooled cylinder, shaved off the waterjacket and replaced it with cooling fins like an std MT5 cylinder.

Quick spec 88cc:
CR80 crank
NSR50 gearbox
5disc clutch
PVL ignition
Mikuni TM28ss bored out to 30.8mm
V-force reeds
Modified Suzuki RM85 -04 exhaust.(to raise the rpm level, not perfekt i know but the moped runs hard)
Wiseco piston

PICS: 88cc




My 136cc project is an 'hybrid' that too.
I have built an clutchcase that gives room for 8discs.

[speedpro]

Yes.. ~ 20hp is good..
But i reckon i will double that atleast.

You will definitely have to keep us up to date with how that goes. Couple of us have cracked 30 at the wheel and Rob is looking at even more. 40hp would be quite an achievement.

[TZ350]

Red line is Speedpros 30hp at the rear wheel MB100 which has a better spread of power than my 30hp GP125 Blue line.

[Moooools]

Yes.. ~ 20hp is good..
But i reckon i will double that atleast.

My 88cc machine got 5disc clutch with uprated springs, it slips from time to time.
And in dragracing the dog in the gearbox are living an hard life.
any defects and the shiftforks takes the beating and snaps.
My 88cc machine is in the area around 20hp at the wheel.



that´s a pic of my 88cc hybrid.
from the beginning a watercooled cylinder, shaved off the waterjacket and replaced it with cooling fins like an std MT5 cylinder.

Quick spec 88cc:
CR80 crank
NSR50 gearbox
5disc clutch
PVL ignition
Mikuni TM28ss bored out to 30.8mm
V-force reeds
Modified Suzuki RM85 -04 exhaust.(to raise the rpm level, not perfekt i know but the moped runs hard)
Wiseco piston

That is very interesting.

Is there a good reason why this couldn't be done to get a 125cc aircooled cylinder that is all nice and modern. I don't know what is the best starting point but maybe Aprilia RS125? Surely you could stack it full of cooling fins too if you bunched them up. And machine a new head from scratch.

I kind of like that backwards thinking. And seems an easier option than resleeving/destroking.

[TZ350]

That is very interesting. Is there a good reason why this couldn't be done to get a 125cc aircooled cylinder that is all nice and modern. I don't know what is the best starting point but maybe Aprilia RS125? Surely you could stack it full of cooling fins too if you bunched them up. And machine a new head from scratch. I kind of like that backwards thinking. And seems an easier option than resleeving/destroking.

We have thought about it and there were some early aero cylinders with copper finning pressed onto them. Unfortunatly the way the cylinder head studs are arranged on the RGV cylinders we have, make it difficult. There is an Aprilia 125 cylinder somewhere here at work, I will dig it out and have another look. Interesting to see someone has actually done it, good work.

[cotswold]

That is very interesting.

Is there a good reason why this couldn't be done to get a 125cc aircooled cylinder that is all nice and modern. I don't know what is the best starting point but maybe Aprilia RS125? Surely you could stack it full of cooling fins too if you bunched them up. And machine a new head from scratch.

I kind of like that backwards thinking. And seems an easier option than resleeving/destroking.

Just my 5 cents worth, his bike is a 1/4 mile drag bike which would be run for 10-15 secs am guessing, we would be looking at running 10-15 minutes, cooling is not such a big deal for a few seconds but is quite important over 15 minutes.
Will be keen to see how this goes as an A/C 125 Aprilia or Cagiva has a certain appeal.

[Moooools]

Just my 5 cents worth, his bike is a 1/4 mile drag bike which would be run for 10-15 secs am guessing, we would be looking at running 10-15 minutes, cooling is not such a big deal for a few seconds but is quite important over 15 minutes.
Will be keen to see how this goes as an A/C 125 Aprilia or Cagiva has a certain appeal.

Well TZ seems to be managing okay with air cooling. And if you are making the fins yourself it would be easy to get it right (radially protruding fins on the head and closely spaced fins on the barrel. Plus you would get the benefit of an Al bore.

It would be best to cut the jacket off and then have it 3D scanned, CAD up the fins and have them laser cut so they are a nice fit. They wouldn't be the easiest thing to get looking good by hand.

[dinamik2t]

Question: What difference a Drag curve is supposed to have from a RoadRace curve?
In a 125cc engine for Roadrace, say the best would be 50hp at 12.5k, with lots of overrev. The corresponding Drag best what should be like? Lower revs for more torque and as much power as possible?

[F5 Dave]

Hello guys..

I just have to say, a really really interesting thread.
took me 2 weeks to read it.(on sparetime at work)
And when i´m saying interesting i mean INTERESTING!!!!

Still taking i glimpse here and there to see if it has been updated.

I´m building a 'overkill' Honda MB5 here in Sweden and got much much good info here.

A preview pic:



Not complete at all on the pic,, but in progress.

Aww, I'm coming over all nostalgic like.

Those front ends are dreadfully bendy, even if corners don't figure. I bored the top plate & welded on some clamps cut from another bottom clamp & this stiffened things up & allowed me to drop the front end down an inch or so. The rear sw mount is pretty unconnected & a brace above the pivot works wonders, but watch the chain run.

[jasonu]

TZ350..

I have ported my Kawasaki cylinder like this:


Hard to see, but the A transfers are a couple of degrees higher at the rear end.
And then the B,C ports are all equal as rear of A port.

Mine are open in 138Degree duration and the front of A transfers are open 136.
Exhaust is 198degree´s

Kawasaki what?

[husaberg]

Just my 5 cents worth, his bike is a 1/4 mile drag bike which would be run for 10-15 secs am guessing, we would be looking at running 10-15 minutes, cooling is not such a big deal for a few seconds but is quite important over 15 minutes.
Will be keen to see how this goes as an A/C 125 Aprilia or Cagiva has a certain appeal.

It certainly does have an appeal but the 24mm carb with a reed valve is off putting. i am musing the reed valve motor may suffer more with the restricted carb size than say the Disk valve engine such as Tz's does.
Peter Jones (oyster) i understand has previously done a AC RG125 conversion. I have no details regarding it's performance maybe Yow or Kicka can add something?
I would also guess the fuel rules for the drag motor could allow methanol as well. I remember some 70's drag bikes used to cut off fins and also some water cooled ones used to run without water to allow for faster warm ups so as to minimise the running time of the highly strung engines.

[F5 Dave]

I am a bit stuck with the timings as I cut the secondry exhaust ports a bit big. It was my first effort and more about seeing if it could actually be done.

At 116 the front transfers come very close to the underside of the side exhaust ports so I cant move any more there and the rear transfers need to open a little later than the fronts, so its all a bit compromised really.

I originaly wanted to make a broad spread of power but have allowed myself to get distracted by the side show of building a racing Bucket engine that reliably makes over 30hp and my tripple port is aimed at that.



50hp 125 Aprilia racing engine.

Side Ex boost ports are the way to go to get the blow down STA needed to make real power and to allow a smaller width main exhaust port for piston/ring reliability.



But in all fairness, there are some people with experiance in the Tuning Industry that have differing ideas about how worth while extra Ex boost ports are for racing .....

Attachment 262570 Attachment 262571

I don't like wasting good cylinders on experiments, so I used an old damaged cylinder to see if it was actually possible to cut these side ports, turned out OK but not to sure about racing reliability. Although the main exhaust port is not as big as the 31hp cylinder that failed at Kaitoke so that must help.

Should be interesting on the dyno ....... and if its any good then we will see if it holds together on the track.

TZ, just looking at the pics (which look well cut) it would seem the subs will bleed into the transfers, have you made flush pin plugs? I am surprised at Wob's comments about the hot bridge, when I'd done it I'd assumed the extra area would give support & not overheat, but I suppose it isn't attached to a particularly well cooled area.

My CPI barrels have some area there. Hmm Perhaps that's a clue. There have been some issues there.

What engines have had this indicate the behaviour Wob? It is easier to cut them further forward, but I'd been scared to & wanted to connect as much ally into the passage as possible.

[SwePatrick]

Kawasaki what?

Kawasaki KX125 -86/87 something.
cylinder got KIPS, i have kept it to see if i can adjust the curve with different settings on valves.
But no automatic adjusting, as it is hard to build it onto the Honda engine