ESE's works engine tuner

[TZ350]

Ok ... with the front dropped and the back jacked up a bit we have 18 deg Rake.

Interestingly this did not change the weight distribution much, with a rider aboard in a racing crouch or leaning like they were entering a corner the weight distribution was still 48% front 52% rear, more or less.



By the best eyeball method.



I make the Trail 75mm.

.

After a bit of a committee meeting we figured that to move the engine forward the frame could be cut in either of two places, taking 40mm out of the lower section or 80mm out of the top, or may be both, for a total of 120 which is what I was looking for.

Everyone remembered to bring beers but some one forgot the chainsaw so frame surgery will have to wait, maybe get onto it next week.

[Gigglebutton]

After a bit of a committee meeting we figured that to move the engine forward the frame could be cut in either of two places, taking 40mm out of the lower section or 80mm out of the top, or may be both, for a total of 120 which is what I was looking for.

Everyone remembered to bring beers but some one forgot the chainsaw so frame surgery will have to wait, maybe get onto it next week.[/QUOTE]

The beers where good.
The naked dancing in the car park was taking things a bit to far.
Let me cut it Doctor mwah ha ha ha ha ha ha

[richban]

After a bit of a committee meeting we figured that to move the engine forward the frame could be cut in either of two places, taking 40mm out of the lower section or 80mm out of the top, or may be both, for a total of 120 which is what I was looking for.

Everyone remembered to bring beers but some one forgot the chainsaw so frame surgery will have to wait, maybe get onto it next week.

Now you are keen on the bike setup and making a real custom weapon. I think the first thing you need to do is chuck the heavy wheels and convert to a 415 chain and sprockets. Better acceleration, Faster direction changes, Less unsprung weight. And most importantly they look the shiz. When I did mine the bike lost 7kg most out of the rear. From memory the front and rear RS wheels I have are the same weight when fitted with disks and rubber. Front rotor I have is rather heavy it has a steel centre not Ali like the expensive ones. If you are going to get serous I would always start from the ground up. Wheels. If you don't want to go 415 you can get rear 428 ali sprockets to fit RS wheels these days and really nice light chains.

Would be interesting to do your distribution test without wheels. Few axel stands wired to the forks and rear swing arm should be safe enough for Kel to balance on. Just make sure they weigh the same.

[husaberg]

Ok ... with the front dropped and the back jacked up a bit we have 18 deg Rake.

Interestingly this did not change the weight distribution much, with a rider aboard in a racing crouch or leaning like they were entering a corner the weight distribution was still 48% front 52% rear, more or less.



By the best eyeball method.



I make the Trail 75mm.

.

After a bit of a committee meeting we figured that to move the engine forward the frame could be cut in either of two places, taking 40mm out of the lower section or 80mm out of the top, or may be both, for a total of 120 which is what I was looking for.

A bridge to far perhaps 18 deg and 75mm Frits was at 20 and 85mm ish wasn't it?
Sure it will turn sharp at those figures.so sharp it will probably make you bleed. LOL
But why not start out a little more conservative. 20-22 deg and 85-95mm.

The trail is also a result of the fork offset remember.
That why i mentioned the trailbike yoke to get the offset around to ballpark with the increase rake.

Have a look at the simple rake trail calculators on the Foale site.http://www.tonyfoale.com/ under freeware

[TZ350]

Yes perhaps a bridge too far.

I need to get the Beast running again and finish the engine development with Wobs pipe.

But I am convinced by Frits's argument that hp can only take you so far and that at some point there are more gains to be made with improved handling.

And by taking the seat and tank off, lowering the front and jacking the rear. We now know what we have, what we can get easily and the likely effort required to do it well when we are ready too.

Rich talks about lighter wheels, Chambers made a sister bike (No 21) to the Beast and that has 10-12kg (in total) lighter Junior Motard wire wheels and is parked out in the shed. A lot of the weight saving will be in the rear wheel. Maybe it was this one that was 50/50 with rider, I will dig it out and weigh it again.

[wobbly]

18*/75 is for sure to steep and short, and remember that jacking the back will affect the squat geometry - but I hope you will fix that when you move the engine about.

[wobbly]

18* with 75 is for sure too steep and short.
Jacking the back will affect the squat geometry, but thats fixable when you move the engine.

[TZ350]

More on Rotary Valves.

Traditional Wedge Inlet, a Square gives more Area and requires a different shaped disk.

EngMod2T allows a top and bottom dimension for the port window but seems to prefer that you take a mean average width and use that, in this case its 32mm.

New and Old RV

Its possible to go quite a bit bigger with the RV on the Suzuki GP engine.

105 113 117

The std 105mm RV gives an easy 30mm equivalent diameter port window

The 113mm RV gives 33 and the 117 gives 34 only 1mm more.



The 113 diameter RV for a 33mm effective Dia inlet port is easily done just by gluing up the "o" ring grove in the cover and fitting a new inner plate. Its not to hard to do and the most practical. The 117 means making a new outer cover and is hard work for another mm.

Given the other limitations within the engine, EngMod2T simulations that I have done point to 30mm as being OK and 32 as the most effective and any bigger as a bit of a waste of effort on my engine.

Although this post is about matching the inlet port window to the inlet tract and the amount of work required to gain 1mm, I think one needs to also look at the STA's to get the full picture of what 1 more mm will potently give you, and if its worth the effort power wise.

[SwePatrick]

I´m having a wonder again.

Can´t remember if it already have been discussed, but i´ll write it down for you to see.

I´m thinking of the rejecting gasses in the carb at high rpm´s
Physics says to me that you are 'cutting' off the flow premature.
A reedengine shouldn´t do this if it´s correctrly setup, but reedengines have other restrictions in flow.

So lets solve why it´s rejecting on your disc engine.
Clearly you are wasting kinetic energy from the gasflow, that could have filled the crankhousing(cylinder) instead.
But cutting the disc for later closing might harm the broad powerband you want.
and worth a test is 'smooth closing'.

Then lets concentrate on the exhaust, a really effective pipe sucks gasses through the whole setup when into the tuned register of the pipe.
Is there a way of letting the pipe 'hit the wall' harder and letting it suck earlier in the rpm range?
A pipe tuned slightly lower in rpm with harder pulsetuning, can be hard to reach thou.
But isolating the header to keep the heat in the belly on the pipe helps.
I´f you are loosing heat in pipe you are loosing pressure, and the tuning is lost.
Here in Sweden people have starting to wake up and trying more steep degrees on header and diffusers.
this allows us to use bigger and bigger carbs as the flow is really hard in tuned register.(you are sadly restricted, and building hard flow that 24mm carb cant give, easliy said)
A friend of mine runs 32mm carb on a 65cc setup, this one pulls out about 25hp at the wheel.(actually it could be even more)

My testing would be:
Smooth closing on the inlet, or even later closing.
A pipe with slightly lower rpm tune with harder degrees to get the desired volume, and then isolate it with 'headerwrap' to keep up the heat in the pipe.
And finally put an pressureguage at the very middle of the belly to tune the pressure in pipe with different stingers.

This is a picture of my pipe by the way:
Doesn´t show much thou, but i think i posted a picture earlier in the progress.

This shows my homemade silencer with exchangable inserttubes with different diameters to adjust the pipepressure.

aim at 120-130Kpa, you can go higher, but watch the exhausttemp carefully, you might melt pistons

[Frits Overmars]

A bridge to far perhaps 18 deg and 75mm Frits was at 20 and 85mm ish wasn't it? Sure it will turn sharp at those figures.so sharp it will probably make you bleed. But why not start out a little more conservative. 20-22 deg and 85-95mm.
The trail is also a result of the fork offset remember. That why i mentioned the trailbike yoke to get the offset around to ballpark with the increase rake. Have a look at the simple rake trail calculators on the Foale site.http://www.tonyfoale.com/ under freeware

You can get away with the 18°. If you take a look at Tony Foale's projects, you may find that he even experimented with zero degrees and got away with it.
But the 75 mm trail will give too little feedback, even if the front is heavily loaded. Like Husa says, yokes with smaller offset can help you out; you should strive for a trail of at least 85 mm.
Light wheels will make a difference like you won't believe. It goes so far that in MotoGP brake disks are substituted with smaller ones on tracks where you do not need the brakes so much.

[Frits Overmars]

I´m thinking of the rejecting gasses in the carb at high rpm's. Physics says to me that you are 'cutting' off the flow premature. A reedengine shouldn´t do this if it´s correctly set up

Any engine, whether it's disk, reed or piston controlled, will blow back to some extent. Maybe not so that you'll notice, but it will happen. That's physics too.
When the inlet opens, the pressure difference between the outside air and the crankcase pressure causes mixture to start moving into the crankcase. This inlet flow will accelerate as long as the crankcase pressure is lower than the atmospheric pressure. So when both pressures are equal, the flow will just have reached its maximum velocity. It does not want to stop suddenly, so it keeps on flowing, thereby raising crankcase pressure to above atmospheric pressure. This negative pressure difference slows the flow down until it finally stops.
Ideally you close the inlet at exactly that point in time. But even if you do, the pressure on the crankcase side of the inlet tract will be higher than the pressure on the outside world side. This pressure difference between both sides of the inlet tract will accelerate its contents back to the outside world.
Summary: there will always be some blowback; whether you close the inlet too late, at the optimum timing, or too soon. In the first two cases it may be so slight that it's movement is caught by the next induction event before it can be noticed. In the latter case, the blowback will be really violent.

[husaberg]

You can get away with the 18°. If you take a look at Tony Foale's projects, you may find that he even experimented with zero degrees and got away with it.
But the 75 mm trail will give too little feedback, even if the front is heavily loaded. Like Husa says, yokes with smaller offset can help you out; you should strive for a trail of at least 85 mm.
Light wheels will make a difference like you won't believe. It goes so far that in MotoGP brake disks are substituted with smaller ones on tracks where you do not need the brakes so much.

Yes long ago i had the Foale book (Long lost) he had a BMW with a weird adjustable set up for rake and trail from memory he went sub 20.
but i think the forks which were std style forks became real harsh and didn't cope that well.
I also hazard a guess that the GP bike fork's are also slightly more sophisticated than TZ's Yamaha FZR250 forks as well.
How much total weight difference are the wheels on chambers bike. I think you said 10kg but was that the bike surely not the wheels?
I brought a cheap set of KX85 wheels with the intention of building a super light weight set of wheels with rims with mini supermoto rims but got scared with the price of the rims plus i don't like tubes.

From memory size for size Suzuki i think used to have the lightest wheels with Kawasaki the heaviest and Honda, Yamaha somewhere in between.

Oh swedepatrick nice end cap on the silencer mmm... billet

[richban]

Light wheels will make a difference like you won't believe. It goes so far that in MotoGP brake disks are substituted with smaller ones on tracks where you do not need the brakes so much.

I do remember the first proper race after I changed to light wheels. Everything seamed really easy. The bike felt super responsive and changed direction faster. After that I was kicking myself for not doing it sooner. I am a little obsessed with light wheels.

[husaberg]

I do remember the first proper race after I changed to light wheels. Everything seamed really easy. The bike felt super responsive and changed direction faster. After that I was kicking myself for not doing it sooner. I am a little obsessed with light wheels.

Not so much light motors though I reckon you could ditch about 10kg if you got rid of all the extra stuff on the top end Rich

[F5 Dave]

What about a light arse? Maybe a salad for lunch instead of a pork pie?