ESE's works engine tuner

[wobbly]

How steep is too steep - depends entirely upon the belly diameter and the end use.
In your case Neil, your pipe will not be fat, and as you are needing wide range power then changing from 18* to 24* will kill all the bottom end dramatically.
There is never a free lunch, and even using a two or three angle rear in your application, everything you gain in front side and top, is taken away from the bottom.
Then there is the issue of overev.
Again, your pipe will be " long " and the shallow rear cone combined with that length easily allows a wide flat band of power, running into overev without shutting off hard at all.

[Flettner]

How steep is too steep - depends entirely upon the belly diameter and the end use.
In your case Neil, your pipe will not be fat, and as you are needing wide range power then changing from 18* to 24* will kill all the bottom end dramatically.
There is never a free lunch, and even using a two or three angle rear in your application, everything you gain in front side and top, is taken away from the bottom.
Then there is the issue of overev.
Again, your pipe will be " long " and the shallow rear cone combined with that length easily allows a wide flat band of power, running into overev without shutting off hard at all.

It's 18 at the moment and has excellent bottom / mid range (with the powervalve in operation) but does go a little flat around 11, 000. I want more but don't want to fuck up what I already have.
My pipes mid section are equivalent to 114mm dia.
My next cylinder (54×54) will have 90mm (×2) mid section. This is the engine I'll run my pipe 'warping' system on. Haha, perhaps I'll call it Warp Drive.
It will also be a disc valve engine with my 'sliding gib' arrangement. Because of rules, it will have to stay carburetored unfortunately.

[F5 Dave]

Is that related to the steamer collapsing thingy you posted a picture of Neil?

[F5 Dave]

Could the powerjet of the very lean carb be an injector?

[wobbly]

Two 90mm pipes on a 125 = 127mm single pipe.
That certainly isnt fat, but is a little bigger than most 125 MX pipes, so could probably deal with a steeper 24* rear cone, especially with a PV and the Gibbs in action.
Again, this approach would need a shorter overall TL as well, or it will make more upper and peak power, then fall flat off a cliff before 11000.

[Flettner]

Could the powerjet of the very lean carb be an injector?

Muddy waters.

[Flettner]

Is that related to the steamer collapsing thingy you posted a picture of Neil?

It's what gave me the idea, while out 'antique' shopping with the good wife.
Even she can't understand why I wanted it. Sort of similar but simpler.
In fact I have several approaches to try.

[katinas]

Cool KR3 photos i had never seen those pics.
the 1989 Cagiva had the atac and rotary PV but there were a lot of cross pollination with Cagiva and Yam.
the Last Cagiva tested extending headers with Chandler in practice with a hydraulic pump by tag and extended 20mm. (100 bar)

From my experience, changing the header by 20 mm corresponds to about 1000 rpm.( in range over 10000 rpm). I checked the notes from my previous tests with 125cc, shortened header 11mm plus 500 rpm and 18mm plus 1000 rpm.
About KR3, did the first type engine (with 2 lower cylinders) really have a combined crankcase chamber for cylinders 2 and 3? It is clearly visible that the two cylinders on the left are closer to each other than the cylinder on the right. The engine should have been narrower than later type, maybe without bearing between two big end pins, what could have caused some crank deformations. I've never seen this first type engine photo with open crankcase, just latest one.

[Wos]

Think with two pipes instead of one the heat loss would be much bigger and for good overrev we need rising temperatur for faster Action/ speed of sound!?

One step forward could be to try to isolate/ wrap the two pipes?
Another solution maybe to reduce the restrictors a little more than calculated in FOS Formula?

Experts what do you think??

Thanks Wolfgang

[Frits Overmars]

Another solution maybe to reduce the restrictors a little more than calculated in FOS Formula? Experts what do you think?

I think you might want to try that solution for yourself before passing it on to others, Wolfgang

[husaberg]

From my experience, changing the header by 20 mm corresponds to about 1000 rpm.( in range over 10000 rpm). I checked the notes from my previous tests with 125cc, shortened header 11mm plus 500 rpm and 18mm plus 1000 rpm.
About KR3, did the first type engine (with 2 lower cylinders) really have a combined crankcase chamber for cylinders 2 and 3? It is clearly visible that the two cylinders on the left are closer to each other than the cylinder on the right. The engine should have been narrower than later type, maybe without bearing between two big end pins, what could have caused some crank deformations. I've never seen this first type engine photo with open crankcase, just latest one.

These are all the photos i have
https://www.kiwibiker.co.nz/forums/a...p?albumid=5025
In that other other of yours Kenny looks like Vlad Putin.

[Storbeck]

https://www.youtube.com/watch?v=8bMb...fXl1N&index=91

Around 38:20 into the video.

A bit off topic but some who have been following this thread for a while may find it amusing, Kevin's way of communicating his opinion of Witteveen "...he's enjoying his retirement now..."

[wobbly]

Yea, funny that Witteveen, dubbed " the great leader " by those who knew ( despised ) him was psychotic about chassis stiffness, when at the same time Mike Sinclair and the other Kiwi
guys at Team Yamaha, and later KR , were cutting holes with large battery drills and saws in the factory alloy beams to increase longitudinal chassis twist.

The first KR3 design was a complete disaster.
Yes it did have a common crankcase ( a la Swiss Auto ) for two cylinders, with a pair of pistons hitting TDC together, via a slight offset in the crank pins due to the odd V angle.
But its downfall was spastic vibration, due to no balance shaft - needing everything to be made stronger ( heavier ) to prevent fatigue failures.
When they were warming one up in the Philip Island pits, I was discussing balance with Askland and he let me hold the throttle for a few seconds- it felt like my hand was burning.

Later when we had the BSL first time warming up, KR strode over, gave me a wink and grabbed the throttle.
His immediate reaction in front of over 100 people including his whole team, he yelled, why cant you fuckers design a proper sewing machine like this fucking thing.
Any width advantage from the narrow crank, was hugely offset by crazy cost of exotic materials, so it would last a race, and the impossibility of stopping carb froth with out clever weird arse
pump around carbs with no floats.

The balance design for the BSL, I got Simon Longdil ( later of Prototipo fame ) to write the code for his PhD thesis to analyze every possible combination of 3 cylinder angle, firing order and balance shaft layout
to minimize rotational inertia and vibration.
Best by far, was a 120*V, cylinders 1 and 3 facing down, with 1 and 2 firing together, that also had the 1:1 drive gears between them to drive the balance shaft and clutch primary drive.
This gave perfect 1st order balance, zero rocking couple, and a constant 2nd order balance vector rotating around the mains.

[katinas]

Ohh, thank you Husa, thank you Wobb.
I just found the beginning of the answer from Husa KR3 photo album, without the continuation (marked in red), but Wobb completed the story.
Yes, nearly impossible to equalize cylinders filling with common crankcase for upper and lower cylinders, especially with different exhaust pipes positions, bends and temperatures.

Thanks