ESE's works engine tuner

[husaberg]

Pics that would not fit of the home spun flying web

[TZ350]

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Suspension tuning .... well I do not have a clue but need to learn so here is a collection of recent posts about Squat and Anti Squat. I have posted all the comments and have no idea about what is right. Interesting enough though, so worth picking through it for yourself.

NSR250 suspension tuning:- http://nsr-world.com/tuning/250-tuning/suspension/

ktm all but ready to fire up

That Sir, is a seriously serious looking bike, I had better get a move on, Team ESE's 2T's are being left behind.

Watch closely how the frame / suspension responds to being loaded up... No squatting in the backend under acceleration. Well done Scott, those frame modifications have made it even better.

Some squat is accepted as an absolute must on proper bikes. If it is tuned out with a steep swingarm such as that bike, the drive force is fighting the suspension and you sacrifice traction.

Might be alright with twenty or thirty ponies to ride (but could be better), but pump a hundred and ninty through the tread and things get...interesting on corner exit.

Drew is right about having so much anti squat the bike rises and pulls against the tiedowns on the dyno. All this is good for is stopping dyno wheelspin. I made that mistake with the Frepin TZ400.
As it was setup it had too much anti squat, via the swingarm angle.

Around the sweeper at PI it would step out the rear when Discombe powered it into a 2 wheel slide. I dropped the rear 10mm ,as much as I could on the Ohlins mono shock,and it would then almost take full power in a controlled slide
all the way onto the front straight.

Denis is about to shorten the shock so it can be dropped a little more, so then it can be set up each side of pro or anti squat in testing.

The big angle can be fine, so long as the front sprocket is high and the line between axle, swinging arm pivot, and front sprocket centre are close to in line with the rider on it.

But the geometry of the bike is effected more with big compression, ie when the bike is leaned over and there's large g's acting on the suspension. This could be used to an advantage I suppose. By crikey there'd be a shit ton of testing and data logging to paw through. In real terms I expect GP is the only environment that would or has happened.

we are talking about the bike in the video not tz400 etc , the bike is built for bucket tracks didifferentrom standard track , i don't got looking for shit on the net and post it. i go for what a have learn't building frames and racing and there is always more to learn , i look at it as the rear end rise's it pushes the rear into the track which keeps the front on the ground for better turning( not running wide). as g forces come into effect and different weights of the bike it will change ( heavy bikes more lightly to swat but a well set bike like motor gp bike look to sit neutral . i don't have the time to sit her blabbing on as i have bike to build and learn more . think about what i have put? , i raced guys bikes over the years that say there bike it sliding out , doing all sort of crap , i ride it , go 5 seconds a lap faster and think it go's like a dream . best to get out on the track and do what suits you to go fast

As is the case with every single aspect of suspension and geometry of a motorcycle. They cannot be built to do everything to it's potential.

bang on if you can win with what your on its working

" as the rear end rise's it pushes the rear into the track whichs keeps the front on the ground for better turning".

Thats dead correct except its back to front thinking in my opinion. If you have an issue with running wide on exit then you need to look at gaining some front end turn - drop the forks thru. Gaining front grip by killing the rear end with anti squat does "work " but in the example I gave with the Frepin, it was loosing rear grip under power when tipped over hard.

So I didnt try to fix that by reducing the front grip, I dialled in some more natural rear grip by reducing the anti squat % - dropping the rear ride height. This works just as well around the sweeper at Mt Welly where even at those slow speeds the suspension is heavily compressed.

No Mates bike initially used to step the back out when leaned over going as hard as he could around the sweeper.
Dropping the back gained some rear grip by reducing the anti squat.

It then started to run wide on turn in,so rather than reduce the good rear grip we had just gained he dropped the forks thu to steepen up the front. Now it steered, and had rear edge grip - seemed to work OK, he won on Mt Welly 3 years in a row.

Same idea with Discombs TZ350 around Hampton when he won the Sheene last year. It was pattering and loosing front grip when hard over exiting the sweeper under power - that bike has near on no anti squat at all, so all we could do was reduce the squat by winding in a heap of preload and a couple of compression clicks.

This stopped the rear from squatting so much and unloading the front - then it steered at full noise onto the front straight - seemed to work, he was 3 secs a lap faster than anyone in his class.

Its always best to try and gain grip to balance out a lack at one end, reducing the grip at the opposite end can and does work - if that all that can be done to fix pig handling.

Niges real problem is the spring at the rear is too soft for his fat arse. I spent a bunch of time watching at the last GP as my bike had welded it's clutch. And you could see it going full stroke and stepping dread fully at Tokaroa which is a severe track. He hadn't noticed but was still frothing at the mouth post race. Ahh we're all getting too old. To be fast again.

I actually thought it was an interesting thing to discuss.
Given late model RS125s and TZ125s tend to show this as well. The GPR frames feel great on track.

Wobs post above makes good sense, I can imagine that the more mass (weight) and more power - loads up the front with too much anti squat and if front end is not setup to deal with it then it will all go pear shaped.

It's not the front that it goes pear shaped at. The rear lets go in a hell of a hurry, because the suspension isn't working due to the torque fighting it. So there's no give and when it hits a bump the wheel leaves the ground.

The distance between the two sprockets is at it's greatest when the swingarm pivot and sprocket centers are all in a straight line. When you put the rear sprocket lower than that straight line and apply the gas, the torque is trying to pull that sprocket forward by shortening the distance more as the swingarm further extends.

Loading a tyre more is the goal, bump compliance is the unfortunate requirement for suspension.

What many forget is that there is a finite mass of bike and rider. Using antisquat to transfer some of that finite amount to the front - MUST by definition reduce the rear. Less or neutral anti squat by dropping the ride height and the swingarm angle ,allows more weight transfer to the rear - increasing grip at that end.

The anti squat rising force is an internal frame vector, the actual result of the frame rising ( thus the rear wheel pushing down ) is weight transfer off the rear and onto the front - counter intuitive I know, but increased FRONT grip is what actually happens in the end.

Add to that the dramatic increase in effective rear bump rate under power, and anti squat although intellectually an obviously useful tool, suddenly becomes a very sharp double edged sword.

One thing to be careful of TeeZee is that the rear wheel will try to climb up the dyno roller under power - giving the illusion of a big anti squat %. To get an idea of the squat rate you have to be aware of the wheel position.

Thanks for the tip.

Attachment 302649

I can see the possibility of a headache coming on, while trying to get to grips with understanding suspension tuning.

Get the spring rate right, set the sag with rider, and static the swingarm should be pointing close to the middle of the front sprocket or slightly above.

Adjust the tendency to run wide or tip too fast with fork height. This is the start point. From it you are in the crazy land of suspension damping, and the endless trade offs you are forced to deal with.

You're pissing in the wind with the wrong springs.

Have fun.

squat with ant squat working together is what gives traction , remove ant squat out of it and let it squat under power will i think go from unloaded to overload as it bottoms out , i bit of both is a good controlable ride

Could you explain where this increased grip on the front wheel is coming from?

Anti squat causes an increase i frame height (or in reality pitches the bike forward) when accelerating. Under steady acceleration the only affect this will have is to raise the COG height of the bike+rider, which will increase normal load on the rear wheel (due to pitching moment from acceleration), and take it off the front - more rear grip, less front.

Under a transient acceleration (acceleration of acceleration) the chassis will be accelerated upwards, and a reaction force will be seen at the rear wheel (D'Alembert's principle). This reaction force stops when the acceleration becomes steady or begins decreasing. This is more often a smoother affair and is unlikely to happen during a corner. So - More rear grip followed by maybe less rear grip if you decide to shut the throttle.

I am struggling to see in all this a reason for the front wheel to see increased grip. What am I missing?

EDIT: Is it inertial moments causing the bike to pitch about some point ahead of the COG, causing a larger reaction force at front wheel due to a shorter moment arm? That would mean that the motion increases load on both wheels (but more so at the front) and the reverse motion (springing back to neutral position) unloads both wheels. (Not sure I explained that too well)

With the rear shock unable to compress, as soon as the tyre reaches the top of a bump YOU LOSE TRACTION. Not gain it.

Ps. Weight distribution is where tye extra front grip comes from. But it is important to realise that this is a different part of the turn. Corner entry is where raising the rear gives more front grip, the trade off being less exit grip at the rear.

The spring is constantly pushing the wheel onto the road. Corectly sprung you should be able to tune with damping for nearly any track.

Antisquat is getting to the uppermost technical side of suspension tuning. 99% of riders need never worry about it unless they get a bike that's been set up too high to begin with.

Anti squat doesn't remove the ability for the rear shock to compress though , unless you were to run a shit tonne of it and topped the shock out. The spring can still compress just the same, it is just sitting higher than it was.
Bumps aren't the only transient concern on a motorcycle. In fact they are a pretty small factor compared to inertial loads when you are riding around on billiard tables i.e. a racetrack.

Wrong - anti squat force is obtained by the chain trying to pull the rear wheel forward, or put another way - to shorten the swingarm. When the swingarm is at an acute downward angle, as the chain pulls harder the resultant anti squat reaction forces the rear of the bike upward.

By the obvious physics of action and equal re action, then rear wheel is being pushed downward at the same time with the same force value. Thus it is this reaction force ( an internal frame force ) that prevents a bump or track ripple from compressing the rear shock, via the rear wheel rising in relation to the seat height.

So although the shock/spring combination may actually physically able to compress, it cant due to the high internal frame force trying to lengthen the shock.

When in this powered on state, a bump will have to lift the rear of the bike AND the riders bum mass as well, this is not called suspension, its called a jolt in the arse closely followed by an instantaneous slide, closely followed probably by a highside - they hurt.

To prove any theory, go to the nth degree. With a lot of pro squat dialled in via front sprocket height, and or swingarm angle - under power on conditions ultimately ALL the bike/rider mass will be transferred to the rear tyre.
ie a wheelstand.

Watch MotoGP today and on virtually every corner exit the front tyre is just off the deck, thus they have just enough weight transfer ( and auto Hp control ) to give the absolute
maximum rear grip available - the front tyre is off the ground, directional control is then only via counter-steering and rider weight.

Attachment 302661

Squat Anti Squat


Attachment 302660

The calculations for anyone game enough to risk brain damage.

Attachment 302662 http://supermotojunkie.com/showthrea...tric-supermoto

Remember that guy who was building an electric bike in Wellington.

Well I came across this one, 137kg with rider and by the looks of it an electric bike could be very competitive on a Kart track.

Electric bike kicks arse:- https://www.youtube.com/watch?v=xC9KYF-SJkU

Electric bike dyno run:- https://www.youtube.com/watch?v=bwoGXQDzB-s

So as I understand it so far (and probably incorrectly):- If the back squats down under power it puts more weight and therefor traction on the back wheel and un loads the front.

Wrong. Squat will lower the Center of Gravity, which reduces the load transfer during acceleration and deceleration (not the weight transfer; the masses of bike & rider don't shift in a horizontal way under acceleration and deceleration, unless you're riding with a half-empty fuel tank without slosh restraining).
Summary: the more squat you have, the less the rear wheel will be loaded and the less the front wheel will be unloaded under acceleration.

Let me rephrase that for you Wob: the antiwheeliecontrol gives them just enough power to make the front wheel float - any more power and the bike will back-flip.
There is no shortage of rear wheel grip; they just can't use it.
The acceleration could be a lot fiercer if the CoG was lower or farther forward, but that would give problems with insufficient roll velocity or with front-flips.
It's all about finding the right compromise (as Ducati seems to be discovering now after years of struggling).

I just knew this was going to give me a headache.

Well explained as usual Frits.

The main point of my rant about anti squat really was that it acts just like the old idea of using the front brake torque reaction to try and stop the forks from compressing,with push rods and lever arms etc.

The idea is a great one, to stop the front dropping, but in execution the result is in effect the same as ramping the spring rate thru the roof - thats why no one uses it ( nor the idea of controlling front damping with brake pressure )..
Using this effect the forks wont react as " suspension " when the brakes are on, so any surface irregularity makes the front loose all wheel control.

Anti squat % in concert with the proper ride height/spring rate for the correct static rider squat is a great tool, but thinking that seeing the rear rise a heap under acceleration is a short sighted interpretation of a "good thing".

The more squat, the less weight transfer. Kind of. But most of the time not in real life. The shock will compress until the spring is tight enough that the front comes up anyway, most of the time. On real bikes anyway, possibly not with buckets because of their low power. But in the terms of this thread, 25-35 ponies will lift the front wheel to near on zero load in the first three gears.

Garelli's had that as well as a few other 80cc GP bikes, then there was the famous Preston Petty anti dive on mx-er forks. The only person I ever heard of that rode a bike with one fitted said the most difficult thing was the weird feeling of front forks rising when the brakes were applied. No wonder they went as fast as they appeared

It gets more complicated when ya start fiddling, and what everyone says is the right direction takes you into worse handling. Then, to really fuck with ya the lap times don't reflect what the rider is telling you. Oh the fucken joys of it all.

Lets step back from the complicated for a moment and start at the beginning.

First step. Establish a clear vocabulary with your rider. Identify the four parts of a turn, braking, tip in, tranition from brakes to gas (apex), corner exit are what I call them.

Loads of people call difderent stuff by different names, it's frustrating and counterproductive at times. Be clear with one and other.

Riders are pricks. If thet start questioning what and why you're doing some thing, chuck the toolbox at their head and let them figure it out themaelves. Mind, since you're just learning about it that might be a touch drastic.

KSS have a booklet free for download. It's for beginners but explains a lot. Everyone should have it handy.

Great, found it (I think):- http://www.yssusa.com/suspension_problems.html Thanks.

That looks quite good. Dunno where I got YSS from, Robert Taylor has also done one for racers. KSS is what I meant, but full credit for finding that.

NSR250 Engine Tuning:- http://nsr-world.com/tuning/250-tuning/engine/

Ed Tuck racing (NSR250):- http://edetuckracing.blogspot.co.nz/...5-pistons.html


http://www.twostrokeracelab.com/


http://www.2strokers.com/index.php?topic=184.0

[senso]

Here is the front tunnel.
The crank spins forward as normal, so the ramps over the crank shield the intake flow from the turbulent boundary around the wheels.
The rear slot lets "flow" from around the crank up under the piston.
Mr Thiel tried the shields on the Aprilia and found some power as well, but dont know if the sideways slot was tested at the time.

One quick question Wobbly, does that TM kart engine have a balance shaft or not, I suppose it does, but I cant find any information about that.

Best regards.

[Haufen]

I am trying to sum this up in my head

What we've learned so far:
on a horizontal case reed, induction in crankshaft direction is favourable vs inducting against crankshaft rotation. On the latter, having a rear slot is beneficial, and shielding the crank webs is probably beneficial, too.

What if induction is in crank direction? Is shielding beneficial there, too? Would a rear slot be a good idea? Or maybe a front slot?
And what if the reed is aligned vertically? Which setup would you say is best, depending on crank rotation?
And given you could choose the best (reed) setup there is, which one would it be? e.g. horizontal reed, induction in crank rotation direction? shielding? slot?

[wobbly]

I think we can make a deduction from what has actually been tested.
The Maxter engines under Roland have been made identically with vertical and horizontal reeds, and I assume now that due to the rod position
they have "gone back " to the horizontal reed as the best compromise.
Jans rear rotary valve engine worked very similar to what would be regarded as a normal rear case reed, but I have never seen a crosswise slot in an RSA or
in the ramps of any of the rear reed type engines - plenty of examples of ramps with the longitudinal rod slots though.
Probably not a good idea in that IF there is any actual flow upward away from the crank thru a crosswise slot, it will be directed into the path of the incoming
tunnel flow from the reed tips.
But hey, more power is gained with the new generation of kart engines with the reeds pointing at an upward angle toward the piston, so having upward flow from the
crank as well might end up being an advantage - anyone got a spare RS125 I can try it on.
They dont like a bigger case vol though - been there with reed spacers, so cutting a slot in the case would have to be done adding vol somewhere else, for a true
back to back - but its not allowed under the rules.
Maybe I can cut mill the KZ10 reed mounting face to reduce the vol, now there is a thought for the day - off to the bench now to have a look.
If that doesnt work I can respace the reed with a plate - thats allowed as the " intake " is open.
No kart engines have balance shafts - not sure if thats by design or in the rules, they dont vibrate at all anyway especially with heavy cranks with added Mallory.

[richban]

Well after checking re checking and checking again. Looks like the engine was running 2 degrees advanced. So 16 degrees at peak power with no sign of det. That Avgas sure seams to need lighting up early. Now fascinated with this I am sorting the det gauge and will very interested to find out what the engine really wants to get her humming.

[F5 Dave]

strange shit can happen. I'd set the new engine up last night with a flat 15 & then introduced the curve of the old one (which the old one had liked, itself a mod of the RZ400 one posted a while back) adjusted a bit for the change in revs but still flat 15 at peak

but peak went down & spread went down. Flat 15 brought it back. More testing required.

While I was a it I was running a 310MJ, 300 went better, 290 was better still, better spread but knock gauge flashing and all gears a big fall off in upper gears. 320 was just as good as 290 and no det, no fall off. I might have to build a jet flow tester.

[wobbly]

So Rich did you add or reduce the base timing to get the lines aligned?
But yes, Avgas has alot of additives to stop freezing at 35,000 ft etc that slow the burn speed, but even LL100 is a shit
load better than even our souped up 98 Pump with ethanol.

[richban]

So Rich did you add or reduce the base timing to get the lines aligned?
But yes, Avgas has alot of additives to stop freezing at 35,000 ft etc that slow the burn speed, but even LL100 is a shit
load better than even our souped up 98 Pump with ethanol.

Reduced the the base to get it lined up. Don't tell me I have round the wrong way again. I am dyslexic so easy done. Also I live next to wellington airport straight from the pump is good.

[wobbly]

Reducing the base timing advances the firing point, so you were retarded ( probably in more ways than 1 ) by 2 degrees.
ie if the curve said 15 you were at 13.
So mate, if you thought it was fast before, then hang on.
Makes complete sense re the high temps you were seeing without any piston distress.

[husaberg]

Wobs post earlier made me think of this engine, I had it in with some Aprilia pics
Anyone know what is it?
likely off pitlane, I forgot to include the link code....

[husaberg]

RSA and RSW

[richban]

Reducing the base timing advances the firing point, so you were retarded ( probably in more ways than 1 ) by 2 degrees.
ie if the curve said 15 you were at 13.
So mate, if you thought it was fast before, then hang on.
Makes complete sense re the high temps you were seeing without any piston distress.

Well sheeeit.

She will be pumping 90 before the cemetery circuit. Really looking forward to the Tri Series. I will be hunting down some A747 for the Street race. Smells like fast.

[Frits Overmars]

No kart engines have balance shafts.

None of the shift-engines, as far as I know. But all of the non-shift engines, as far as I know. And those have mechanical coolant pumps too, and most if not all of them have electric starter motors.
What amazes me most is that Maxter for example builds 125 cc shift-engines without balance shaft and without pump, but also 125 cc non-shift engines with balance shaft and with pump. So I guess it's not a design issue; it must be in the regulations somewhere.

[Frits Overmars]

Wobs post earlier made me think of this engine, I had it in with some Aprilia pics
Anyone know what is it?

Your unknown engine is an ADM (built by Charlie AufDerMauer), a Swiss clone of the Aprilia RSA125 engine, in Honda RS125 frame.
In your pictures a Honda RS250 cylinder was fitted. Here are some more pics of that engine, this time with a proper ADM cylinder.