ESE's works engine tuner

[husaberg]

Are there any supplementary "tricks" for minimizing carb vibration and fuel frothing?
Are horizontal shakes better than vertical for the carb too?

Hmm... The vibrations may have gotten worse after I restricted the sideways movement in the engine mounts to eliminate flying belts.

Kevin Cameron discussed (An itailian ducati tuner I can't think of his name edit later it was Actually Gordon Jennings own Aermacchi 250 ) in TDC 1. He was using lead weights on remote float bowls on Ducatis etc. The fuel was vibrated away and formed foam with air at certain frequencies. The theory was to tune to a complimentary frequency or harmony by trail and error much it like a guitar or piano.
I have seen it done with British bikes with TT and GP carbs as well. These generally have a separate mount to isolate them further. from memory the square matchblock float chambers are worse but they may have a pivoting float rather than a pole slider float valve.
(Note the pommy bikes had solid mounted carbs as did the Jenning Macchi.)
Maybe you inlet rubber is just too hard.

[adegnes]

Kevin Cameron discussed (An itailian ducati tuner I can't think of his name edit later it was Actually Gordon Jennings own Aermacchi 250 ) in TDC 1. He was using lead weights on remote float bowls on Ducatis etc. The fuel was vibrated away and formed foam with air at certain frequencies. The theory was to tune to a complimentary frequency or harmony by trail and error much it like a guitar or piano.
I have seen it done with British bikes with TT and GP carbs as well. These generally have a separate mount to isolate them further. from memory the square matchblock float chambers are worse but they may have a pivoting float rather than a pole slider float valve.
(Note the pommy bikes had solid mounted carbs as did the Jenning Macchi.)
Maybe you inlet rubber is just too hard.

Tuning carb weight to a different resonant frequency sounds interesting.

My Inlet rubber is pretty soft, at least when warm.

I suppose it doesn't help that my crank is kinda light, and without a flywheel there's not much Inertia to dampen the vibrations. Then there's the steel rotary valve too.

[husaberg]

Tuning carb weight to a different resonant frequency sounds interesting.

My Inlet rubber is pretty soft, at least when warm.

I suppose it doesn't help that my crank is kinda light, and without a flywheel there's not much Inertia to dampen the vibrations. Then there's the steel rotary valve too.

Maybe its too soft?
You could perhaps stick some hose clips on the float bowl, or try sticking on some wheel weights, It can't hurt (unless get hungry and nibble on the lead )
Do you have a pole slider carb float or a flap valve one?
I am pretty sure almost all the GP bikes that were rotary valve (I think) had poles floats. I muse they were less affected by tilting the carbs)
Wob has also previously mentioned they had problems with he front facing carbs on the BSL500 until they were converted the floats to pole sliders due to the front driving under brakes (and viva versa)

[SwePatrick]

Are there any supplementary "tricks" for minimizing carb vibration and fuel frothing?
Are horizontal shakes better than vertical for the carb too?

Hmm... The vibrations may have gotten worse after I restricted the sideways movement in the engine mounts to eliminate flying belts.

Mount car-tire balanceweight´s on carb.
and have the carb isolated from engine with rubber.

Good luck!

[adegnes]

Maybe its too soft?
You could perhaps stick some hose clips on the float bowl, or try sticking on some wheel weights, It can't hurt (unless get hungry and nibble on the lead )
Do you have a pole slider carb float or a flap valve one?
I am pretty sure almost all the GP bikes that were rotary valve (I think) had poles floats. I muse they were less affected by tilting the carbs)
Wob has also previously mentioned they had problems with he front facing carbs on the BSL500 until they were converted the floats to pole sliders due to the front driving under brakes (and viva versa)

Mount car-tire balanceweight´s on carb.
and have the carb isolated from engine with rubber.

Good luck!

It's an Oko pwk, so flap valve, isolated with rubber mount already.
Good idea with the tire weights, I'll try that or something similar and see if it helps. How about less weight, I could try removing the "velocity stack" first to see if that has any effect, maybe stick on a pod filter too.

Does changing the balance factor matter much for the engine, or is it mostly to minimize the "electric" sensation of riding a vibrator?
What I mean is does my carb/engine care if the vibrations are horizontal, vertical or anything in between?

[adegnes]

Maybe I could attach a rubber piece with some mass to it onto the carb, should act like a damper soaking up the vibrations?
Just like how you dampen drum skins with tape and other stuff to remove unwanted frequencies.

Frits, do you remember what balance factor was used in the Rumi?

[Frits Overmars]

Maybe I could attach a rubber piece with some mass to it onto the carb, should act like a damper soaking up the vibrations? Just like how you dampen drum skins with tape and other stuff to remove unwanted frequencies.
Frits, do you remember what balance factor was used in the Rumi?

No I don't. But for the balance factor it doesn't matter if the cylinder is pointing up or down. All that counts is the deviation from horizontal (and the way it is mounted in the frame, and the frame's stiffness and inertia in horizontal and vertical directions).

About the various float guidance systems: In the Aprilia disk-valve racers the floats were pole dancers. Mikuni also employed pole dancers, though their carbs did not appear on disk-valvers. Keihin used hinged floats on their Honda works carbs.

[adegnes]

No I don't. But I think for the balance factor it doesn't matter if the cylinder is pointing up or down. All that counts is the deviation from horizontal (and the way it is mounted in the frame, and the frame's stiffness and inertia in horizontal and vertical directions).

About the various float guidance systems: In the Aprilia disk-valve racers the floats were pole dancers. Mikuni also employed pole dancers, though their carbs did not appear on disk-valvers. Keihin used hinged floats on their Honda works carbs.

Ok, thanks anyway!

I'll tear down the engine and check what the factor is now, then go from there. (read: balance it to what wobbly suggests)

[AndreasL]

Ok, thanks anyway!

I'll tear down the engine and check what the factor is now, then go from there. (read: balance it to what wobbly suggests)

Note to self 2: Check balance factor of the new Rito crank.

Thanks for the reminder adegnes.

[karter444]

Wobbly
kartsport NZ have just made the latest CIK muffler compulsory for anyone running a KZ2 regardless of the year the pipe and engine were homoligated . The importer of the mufflers is giving 2 options for sale a mid range and a top end muffler . I would have thought that if a pipe is designed correctly with the correct stinger dimensions then the muffler should not have any impact on engine performance .Am I correct in thinking this ??
cheers

[wobbly]

Ha ha, an assumption is usually an error waiting to be revealed.
On a KZ2 the muffler core/stinger makes a huge difference.
There are ( or was ) 2 types, those with the perf slightly larger than the stinger OD ( what I would call a normal type )
and another that had a perf around 40mm ID.
The big core muffler is identical up to peak power, but past 13,000 the power curve simply flattens out, without diving off into a vertical line
at say 14000.
By using thin inserts in the front of the stinger, and varying the length of stinger inside the muffler core I gained nearly 25 Hp at 14,000
ie it was 15 Hp that became 40, rolling down from a 47.8 Hp peak.
Its legal also to machine back the spigot face of the cylinder to shorten the pipe, if you happen to want it to spin the 15,000 - who wouldnt.

[MotleyCrue]

By using thin inserts in the front of the stinger

Cool, can you describe what you are referring to.

[wobbly]

OK, so here is a sketch in the style of DaVinci.
I varied the insert ID in 0.2mm increments,balancing the power output with deto level and jetting on the dyno.
There are 2 stinger sizes available, I started with the larger size, and this tube with the step formed by the insert makes more power than does
the smaller tube stinger on its own.

[husaberg]

No I don't. But for the balance factor it doesn't matter if the cylinder is pointing up or down. All that counts is the deviation from horizontal (and the way it is mounted in the frame, and the frame's stiffness and inertia in horizontal and vertical directions).

About the various float guidance systems: In the Aprilia disk-valve racers the floats were pole dancers. Mikuni also employed pole dancers, though their carbs did not appear on disk-valvers. Keihin used hinged floats on their Honda works carbs.

Right you are with the Keihins, some further pics of the NSR500's.
I do wonder though if the float pivots were mounted the other way around to close off on hard braking.
I can't remember if they were $25,000 or $100,000 US

I will post Wobs Quote (when I find it)


I found it

http://www.kiwibiker.co.nz/forums/sh...post1130134206

The air solenoids on the RGV/RS250 type Keihin carbs are there for emmission and air fuel correction at part throttle settings.
One feeds air into the primary circuit to lean off the mixture at just off idle conditions and the second one feeds air into the emulsion tube to lean off the mixture at higher rpm/part throttle.
The switching points are set by the ECU depending upon rpm and TPS position.
The F3 race kits blocked these off, and used a different jet setup for high perf usage.

The KR3 had special carbs on a few bikes, as they had nightmares trying to get the Keihins off RS125 Honda to work running around the wrong way.They used a pump around system to keep the fuel level at a constant height.
I finally figured out what was happening when building the BSL.
The floats were being pulled down under hard braking - flooding the bowls.So I had CNC bowls made up with floats from TMX carbs running on rods, instead of pivoting.

This was posted on another thread Turbo CR500
Looks neat
http://sandiego.craigslist.org/csd/mcy/5481564457.html

[JustHarry]

at a bit of a loss at the moment.
wallace and i are putting a new ignition onto my kr150 using an ignitech dc-cdi-p2. its only in the testing phases at the moment. idles beautifully, it has a nice clean signal on idle. but when the revs get up a bit the signal is getting a lot of noise and around 6000 the ignition starts jumping between 6000-17000rpm so going on the rev limiter. the way the pick up is at the moment is that its getting a signal off a small hole in the flywheel, probably a balancing hole. so rather than having no signal then a pulse, im getting a signal then a pulse of no signal, is this still good enough way to have it set up?
any reason why the ignition would be jumping up and down the revs so much?
i may not have explained this quite right but its best as i understand it

soz for crap pictures it was dark and my phone is shit