ESE's works engine tuner

[wobbly]

The solenoid Powerjet does lean off the BSFC curve BUT, what you need to get is that all it is doing is returning the fuelling to much closer to optimum.
Its not really "leaning it out "as such,it is dumping more of the available heat energy in the fuel - into the pipe, speeding up the wave action and thus extending overev available.
I dont think this engine has reached its thermal dissipation limit yet - as evidenced by the power not going away badly under load.
You know when you get there, as I did with KT100 pipe design project I did years ago.
As soon as the pipe produces more than 18Hp at the crank, the cylinder and head cannot get rid of the heat produced, and it will fade badly after 3 laps - hitting the thermal limit wall.
Needing fuel to cool it, not make power.
Thus I worked for months locked in a dyno room in Flat Bush extending the band width, at the expense of peak power.
It worked, as I have sold 2000 of the things in well over 10 years and they have won every Nationals title in that time.
I will slope over on Saturday to Te Puke, and poke a screwdriver in the spokes as a helping hand for you,

[F5 Dave]

Husi, when we were talking of crowded rollers Jennings was dealing with bikes running at sod all revs & presumably cages were pretty so-so back then. Wobblies opinion from memory was that at decent revs the rolers would rub against each other & with load that would cause skidding. It makes sense so I never went that way.

[husaberg]

Husi, when we were talking of crowded rollers Jennings was dealing with bikes running at sod all revs & presumably cages were pretty so-so back then. Wobblies opinion from memory was that at decent revs the rollers would rub against each other & with load that would cause skidding. It makes sense so I never went that way.

Yeah i with you with the crowded VS cadged (I raced old dungers remember) and some of them had no little end bearing either.
I do however understand it is not directly the speed that is the issue rather the variation in acceleration and deceleration that is issue. (YES I KNOW IT IS RELATED TO THE SPEED) The cadged roller bearing that Jennings suggests throwing, may have been a riveted or pressed design, rather than a solid design which i believe is superior. Of course the little ends don't suffer i believe to the same extent.
I understand at least one road bike had silver plated big ends or a least the manufacturer has superseded the original part number with one i also understand some bikes (TZ)at least had titanium cadges. I guess the silver plating may be to stop the work hardening of the Ti?
I would like some one expand a bit on the pro and cons of the other materials though.
I have seen a lot of talk about four strokes big ends failing on overrun which i guess is a result of the engine reaching higher revs due, i guess the engine being revs higher on overrun through the wheel speed driving the engine than it would reach on its own accord but that is just a theory mind you.

Below is a rather crude inaccurate rendering of what i had seen attributed to some early small MV race engines. Not to scale but it will express the design i guess.


Oh yeah Wob thanks for the explanation i wouldn't have guessed the KT100 only made that little power as well. So thanks.

oh yeah i found this as well maybe i should have read it again.

[Ocean1]

Up side of having no cage is that you get more rollers in the same space, giving you less load per roller, so the bearing can take higher loads. Down side is the rollers rub together at twice the speed of that against the inner or outer, so revs are usually limited.


The main function of a cage is to keep the rollers apart, but as important is to keep them parallel to the shaft. There has to be clearance between the inner and outer elements, without a cage the rolers are free to skew slightly until the roller ends touch the outer and the roller centre bridges across the middle of the inner. Even very small deviations from parallel impose extreme loads on the bearing, across very small surface areas. In fact the skew causes side load in inverse proportion to the angle, as the roller tries to "turn" sideways, effectively becoming a wedge. There are actually sprag (uni-directional) clutches that make use of this effect, they can lock a shaft up at very high torque, not a feature you really want in a gudgeon bearing.

[husaberg]

Up side of having no cage is that you get more rollers in the same space, giving you less load per roller, so the bearing can take higher loads. Down side is the rollers rub together at twice the speed of that against the inner or outer, so revs are usually limited.


The main function of a cage is to keep the rollers apart, but as important is to keep them parallel to the shaft. There has to be clearance between the inner and outer elements, without a cage the rolers are free to skew slightly until the roller ends touch the outer and the roller centre bridges across the middle of the inner. Even very small deviations from parallel impose extreme loads on the bearing, across very small surface areas. In fact the skew causes side load in inverse proportion to the angle, as the roller tries to "turn" sideways, effectively becoming a wedge. There are actually sprag (uni-directional) clutches that make use of this effect, they can lock a shaft up at very high torque, not a feature you really want in a gudgeon bearing.

Yeah if i remeber right the Vincent had small diameter half width crowded rollers 2 sets of short rollers with a divider in the middle i guess to stop the skewing.

Yeah the starters on 50 cc chinese crf50 have the set up as you desribe. I thought it was rather clever and i said that to a mate thats a Cat mechanic he wasn't impressed he said lots of starters have them.
I couldn't find the bit where jenning said to throw out the Bultaco cadged wrist pin bearing though.

[TZ350]

Entry list for the GP
http://pacificmccracing.wordpress.co...und-5-entries/

There looks like more than 30 Moto 4's (Buckets) lining up for the GP at Taupo, and F4 is looking like the biggest field, considering the entry fee I was not expecting so many of us would bother to make the trip.

I am glad so many have, and considering the names on the list, it should be an exciting meeting as its wide open, there are several potential winners this year.

[koba]

There looks like more than 30 Moto 4's (Buckets) lining up for the GP at Taupo, and F4 is looking like the biggest field, considering the entry fee I was not expecting so many of us would bother to make the trip.

I am glad so many have, and considering the names on the list, it should be an exciting meeting as its wide open, there are several potential winners this year.

I know, I'm gutted to have to miss it due to budgetary constraints.

[Yow Ling]

I hope they have the live streaming for the Moto 4's

Maybe now is the time to start asking for it, I think Jellywrestler on KB has something to do with it, Ill call him

[richban]

I hope they have the live streaming for the Moto 4's

Maybe now is the time to start asking for it, I think Jellywrestler on KB has something to do with it, Ill call him

What would be cool would be a guest commentator that knows a bit about the riders / class. TZ?

[wobbly]

On the over run with the gas closed - there is no combustion pressure on the piston, and this combined with riders that hook down thru the gears
when doing a corner entry, the extra rpm kills the bottom end.
This in effect doubles the cyclic peak load, at TDC and BDC as well.
Bartol said that they regularly saw 16,000 on a 125 when on trailing throttle, and this was killing the cages.
So they added an injector that was rpm and TPS driven, such that over a set rpm on trailing throttle it dumped fuel/oil into the case.


Where is the live streaming - someone got a link.
BTW - several Euro sports sites have live streaming of Moto GP, practice sessions and all.

[F5 Dave]

The ESE guys need to extend their GP entries to include the F5 bikes. Surely if entered in F4 they wouldn't late entry charge you. $70 for extra class, not the full $100.

Edit, hey hold on I don't see TZ or Greenie entered in F4 either?! (Pacific club website) How can you 'do-the-deed' on these mega buckets if you're not entered?? I see Ned & Av.

[TZ350]

The ESE guys need to extend their GP entries to include the F5 bikes.

The last 4-5 months have been very busy preparing specialist CNG equipment for export to China and India, and we can't do much more than field two bikes at the GP this year. Next year we expect to have at least three F5's or possibly five of them as there is a whole bunch in the pipe line, three RG50 based and two with RS chassis and 18 rwhp Aprila 50 engines.

[F5 Dave]

But one weekend & surely your & Greens bike are ready to ride?

I would say that might the RS50s in RS frames might spur me into fitting my Derbi engine. . . .but I've been saying that for, shit it must be 7 years & the engine has been finished for over 1/2 that. Next year, I keep saying. RG still battles on, but at least its out there.

[TZ350]

It isn't going to happen ....

[F5 Dave]

What? - you going to the GP, or me finishing the 50?

I keep having to sticky tape the 100 back together in between the dirtbike & trying to get some time to do the 500. I'll get to the 50 sooner or later. But then the roadbike needs maintenance, or some mod I've read about on the internet, heck the Trials bike occasionally needs attn. Must start that resto project I've been collecting parts for. . .