ESE's works engine tuner

[Frits Overmars]

Ok right got you i think. Cheers wobbly. I have read the leaning tower of transfer enough times i can nearly recite it. Awesome piece of work....
Having the exhaust port floor higher than bdc then would in effect create a wall to stop the A ports heading straight out the exhaust.

That's right Wax.
Having the lower part of the exhaust window narrower or non-existent makes it less inviting for the mixture flow coming from the A-ports to turn right into the exhaust. Having the exhaust duct floor higher reduces turbulence in the outgoing exhaust flow during the blowdown phase and it reduces the exhaust duct cross-section,
so the volume of washed-through fresh charge is contained in a longer column, with less contact area with the hot spent gases.
And some time after BDC, that exhaust port puts on a different hat: it becomes a transfer port. The raised exhaust floor guides the fresh charge over the piston top edge, so there is less turbulence here as well. And finally the smaller exhaust window leaves more surface for the piston to lean against, improving load distribution.

[jbiplane]

Simple question
What is correct and optimal gap (clearance) axial and radial crankshaft to crankcase?
How it correlate with rpm? Any study on this?

[Frits Overmars]

What is correct and optimal gap (clearance) axial and radial crankshaft to crankcase? How it correlate with rpm? Any study on this?

About 1 mm clearance, both axial and radial, in order to avoid viscous losses.
As the crankshaft should also have some axial play (0,4 mm for a 125 cc engine), this must be taken into account.
I am not aware of any published studies about the subject, only experimental experience.

[jbiplane]

About 1 mm clearance, both axial and radial, in order to avoid viscous losses.
As the crankshaft should also have some axial play (0,4 mm for a 125 cc engine), this must be taken into account.
I am not aware of any published studies about the subject, only experimental experience.

Thanks Frits, I use 1.5mm before. Will try make a bit less

[jbiplane]

Estimating correct ways to take system ECU of engine with reservation.

What should be happen in case of improbable, but possible breakdown of the IGBT transistor for ignition or injection.
IGBT of the ignition coil... Brains will heated and burn down. And the pilot will not notice this in time.

Permanently open injector will overflow cylinder and could result hydro shock before pilot manages switch manually to reserve circuit of injection.
I.e. operation of IGBT transistors should be under control by some algorithms.

Exists MC33812 for one channel ingition and injection https://www.nxp.com/docs/en/fact-sheet/MC33812FS.pdf
and MC33814 for two channels / cylinders. Exist simple Found Evolution board for MC33814.
http://cache.freescale.com/files/ana.../KT33814UG.pdf

Seems use of MC33814 - is a fast way to make the "protected" brains.

Seems AVR industrial + CAN hardware and ISO1050 for a CAN interface should do the job by the best way.

[Frits Overmars]

Thanks Frits, I use 1.5mm before. Will try make a bit less

Leave it, Valery. 1 mm is just the minimum value. 1,5 mm will be fine.

[peewee]

when installing flywheel on the crankshaft does anyone put grease or oil on the taper ? it never happen to me but i seen people get a seized flywheel

[Frits Overmars]

when installing flywheel on the crankshaft does anyone put grease or oil on the taper ? it never happen to me but i seen people get a seized flywheel

Never. On the contrary, I'd wipe it clean with a petrol rag. But then I also omit the key, if any.

[yatasaki]

Putting oil or grease will make a kind of micro hydrolocks on cone surfaces (anyone seen SKF cone coupling will know what I'm talking) and cone would not be self locking any more. Keys are mostly there for positioning and partly for torque/power transmission.
It is the cone that will spread power/torque around circumference of the shaft.

[breezy]

Never. On the contrary, I'd wipe it clean with a petrol rag. But then I also omit the key, if any.

Frits, would you concur that the advise you give would be relevent to the work you helped with the aprilia engine only and that there could actually be other ways of improving engine power. have you been seen or experienced alternative methods? and if so would you expand on such improvements?........

[wobbly]

Having the ignition taper clean and dry , and omitting the key , works perfectly on an Aprilia and a BSA Bantam.
The key is only needed for radial positioning,the taper has sufficient grip to prevent any slip if done properly.
If that is the question you are asking

[peewee]

Putting oil or grease will make a kind of micro hydrolocks on cone surfaces (anyone seen SKF cone coupling will know what I'm talking) and cone would not be self locking any more. Keys are mostly there for positioning and partly for torque/power transmission.
It is the cone that will spread power/torque around circumference of the shaft.

that makes sense. oil and grease may create a thin layer and prevent the tapers from fully seating. flywheel seizing on the taper might be from corosion of the steels

[F5 Dave]

But boy the key saves time.

[TZ350]

But boy the key saves time.

and tears of frustration, bad language and totally ruined race days ........ .... I just love those little keys that make sure you get the timing right on re assembly, especially when you are in a hurry.

[husaberg]

Having the ignition taper clean and dry , and omitting the key , works perfectly on an Aprilia and a BSA Bantam.
The key is only needed for radial positioning,the taper has sufficient grip to prevent any slip if done properly.
If that is the question you are asking

Thats there is something that caused myself endless frustration until i finally sought sage advice from an elder and simp;ly relaped a Mag taper.
If you ever have any issus at all the bloody taper on. You can check with bearing blue but a fine grinding paste will show up any high spots anyway.
i was making stronger keys loctite and all sorts of stupid shit, when quite simply the key was the key is nor for the lock by only the location.

But boy the key saves time.

and tears of frustration, bad language and totally ruined race days ........ .... I just love those little keys that make sure you get the timing right on re assembly, especially when you are in a hurry.

A few shitty old pommy bikes don't have the keys to make up for it you get to do the nut up with a Hammer.

Many of the old bikes also used tapers for the Crankpins inc manx Nortons
And stupid Harleys