ESE's works engine tuner

[F5 Dave]

What might be interesting is the replaceable needlejet in the Oko could be used to recondition a Keihin. I have worried about that for the 500 (do they make a 35mm Oko & sell needle jets I wonder). . . . On the other hand at this rate the 500 will never wear out.


What are the float jet seats like? Just into ally on the pwk.

[husaberg]

What might be interesting is the replaceable needlejet in the Oko could be used to recondition a Keihin. I have worried about that for the 500 (do they make a 35mm Oko & sell needle jets I wonder). . . . On the other hand at this rate the 500 will never wear out.


What are the float jet seats like? Just into ally on the pwk.

If you go back a few pages there are some links that spell out the differences.
With TZ's oko, The one thing i have noticed with Mikunis of Disk vave engines is there ultra short needle jet ie the shound with vey little cut away where as the the reed and piston ports are longer and have a lager cut away.
The Holes are a bit of a surprise though i wonder why the pictures of some of them show no holes for the 2 stroke trials bike.
Care to whip your one open (The trials bike) if it has a PWK28 Dave...

Whoops i may not have posted the OKO vs PWK 28. It was from a Aussie pitbike thread.
I will find it again the float valve i think was smaller than the PWK28 i think but fixable.

OK here it is..........http://www.miniriders.com/tech-talk/...carb-mods.html


AS a side note Dave on MY cr500 i used a different Diameter and taper (i think )needle to accommodate the wear it is common on the CR500 and is a real bitch as it leaves the 500 with a 125 like powerband and is the direct reason why some of my fingers are not as long as they used to be.........
(Always wear gloves and Always cover the rear brake, kids and Always make sure you really are in third gear )

[F5 Dave]

Sadly I had to sell the trials bike, but that was a 200 GG & had a Dellorto. . .26mm I think. Fitting a Jap carb was supposed to be good for better more power, but got it fueling real nice. An aside, I'll dig out the spare PWK carb.

The problem with wear is it ovalises the hole so you get rich blobuals of gas. Going to a larger needle may end up with too lean + wet hard to burn. With my old Touring bus which had Mikuni CV carbs they ovalised the emulsion tubes, I had bought factory brand plated ones, but it did it again as the bodies were worn enough to rattle the slides.

Built wear up with epoxy & bored the tubes 5mm & glued in inserts that looked largely like the Oko needle jets, just plain sleeves (5mm long) & drilled the right point drill dia.

Same careful boring & gluing an Oko jet should do it. If I ever need to. . .

[husaberg]

Sadly I had to sell the trials bike, but that was a 200 GG & had a Dellorto. . .26mm I think. Fitting a Jap carb was supposed to be good for better more power, but got it fueling real nice. An aside, I'll dig out the spare PWK carb.

The problem with wear is it ovalises the hole so you get rich blobuals of gas. Going to a larger needle may end up with too lean + wet hard to burn. With my old Touring bus which had Mikuni CV carbs they ovalised the emulsion tubes, I had bought factory brand plated ones, but it did it again as the bodies were worn enough to rattle the slides.

Built wear up with epoxy & bored the tubes 5mm & glued in inserts that looked largely like the Oko needle jets, just plain sleeves (5mm long) & drilled the right point drill dia.

Same careful boring & gluing an Oko jet should do it. If I ever need to. . .

I had real trouble with my second CR500 (the first had a Mikuni fitted)
The fueling was so rich mid range it was just about impossible to rev through with dipping the clutch (How i brought it) the effective rev range when it cleared was about 1500 RPM.
It smoked so so bad plus and the pipe was choked full of oil and carbon crud.
It had been diagnosed as haven a blown crankseal and sucking gearbox oil.
I found this thread was hapily surprised i knew the needle jet holder was not replaceable.
But i followed the direction of the thread, only i used a Cr125 needle from a 1993 or so and it was 1000 times better.
The cost $0 as i had one in the shed.(needle)
The pilot i never got fully sorted to many other projects and the hot starting was shit but the bike was ridable without much effort.

Degner possibly a more balanced story than the normal write up.

The second bit i see those Euro types are still copying the Japanese
I had read that Yamaha twin were based a bit on the Adler twins but i had never seen the race version.
Wow..... way ahead of there time.

Fourth attachment DKW's 4 piston 2 cylinders twin cranked supercharged 2 stroke 1940

[TZ350]

What are the float jet seats like? Just into ally on the pwk.

My OKO float jet/needle valve had a brass washer like seat that fell out and was lost now its just a rubber tipped needle in an alloy hole like the original Keihin. It was easy to re set the float height.

[F5 Dave]

oh, ok thanks.

So I took apart the KR1S PWK 28mm. I won't bother to post a pic as it is prexactly like the pics above. Even the needle jet is removable. i'm sure they aren't in my GasGas 39mm PWK or the 35s on my 500. Cost saving I guess.

[TZ350]

Over the weekend Thomas put together the Det Ear.



The essential parts.



The pickup is sensitive enough to listen to a watch tick. The padded 80's stereo headphones act like earmuffs as well as headphones, I brought them at a garage sale for $5, like new and still in their original box.



Closeup of the inside.

Now that we will be able to hear detonation we can have another go at setting up the IgniTecs det sensor and optimizing the timing.

[F5 Dave]

So have you run the Knockgauge as is? Do you think it needs adjustment?

Couldn't you just run it on the dyno & advance the ign until the power JUST starts falling off & turn the dial till it reports det there?


Pity you can't run the knock gauge on small batteries, everything 12V is huge.

[TZ350]

So have you run the Knockgauge as is? Do you think it needs adjustment?

Yes, but I don't know where in its adjustment range it sees det or not, and I want to find out. It would give me some confidence if I can hear det and see the Knock Gauge detecting it.

Couldn't you just run it on the dyno & advance the ign until the power JUST starts falling off & turn the dial till it reports det there?

I think you might be able to get detonation of the end gases in the squish area before you see any real loss of topend power on the dyno, anyway it was detonation in the midrange on part throttle that killed the engine last time and we sure missed that on the dyno.

There is quite a range of adjustment of the Knock Gauges sensitivity. I am sure someone who is familiar with these Knock detectors can set one up easily, but I am new to this.

And I feel I need to hear det and see the Knock Gauge detecting it before I can have any real confidence in the detector, anything else would just seem like guessing.

[Bert]

.....
And I feel I need to hear det and see the Knock Gauge detecting it before I can have any real confidence in the detector, anything else would just seem like guessing.

Good thinking Batman... nothing better than seeing it for yourself with your own eyes.
in one of those earlier articles (the source of your project); there was a section on connecting it up the pickup mic to a PC and looking at the full acoustic range using mixing amp software. My thinking was it might be useful to record this every so often (one the dyno say every couple of hours use) and see if (when) a part fails there is an acoustic signature (or change etc) that change be identified. kind of like a CSI trace analysis for noise; if you get my drift. it would be very useful for future use and resolving issues before they turn out to cost $$$$.

Many of us have heard and felt changes in engine tone/vibration (usually right before one ends up on one's a55) i.e. main bearings, big ends & new knocks etc. each will have a different signature....

[husaberg]

Am i the only one who has experienced the death silence.

No, not the one from the significant other in your life.

But just before the engine nips up.

It seems to go quiet is it just the clearances closing up or something else or is it just in my head

Is this a real phenomena.

Oh yeah i just watch 6 vidoes on Youtube describing the difference between an OKO and a Genuine PWK don't watch the vids.
He found there is not much difference the oko casting and slide are a it rougher but as TZ has said they seem to machine better.

All the rest was how you should clean the carb and use a filter and not get Carbclean in your eyes.

[Yow Ling]

Am i the only one who has experienced the death silence.

No, not the one from the significant other in your life.

But just before the engine nips up.

It seems to go quiet is it just the clearances closing up or something else or is it just in my head

Is this a real phenomena.

.

I had 2 seizures at the weekend, does go quiet, and the back gets queer till you get your shit together, maybe my brain just stops listening while its yelling at my clutch hand. getting closer with the jetting I think !!

[husaberg]

I had 2 seizures at the weekend, does go quiet, and the back gets queer till you get your shit together, maybe my brain just stops listening while its yelling at my clutch hand. getting closer with the jetting I think !!

Yeah go way leaner till it is one piece
Funny but No i was meaning just before it seizes. Maybe its just me.

Me mum always says i'm special

Not so sure about the queer rear though not my area.

[wobbly]

One thing you wont get is deto of the end gases without loosing power.
The phenomenon of deto is caused by temp/pressure creating free radicals,this process eliminates a huge amount of the available energy in the combustion fuel.
And once the radiacals are formed, they are self sustaining,and cause a runaway reaction process - consuming more energy.
This is exactly why the egt drops when you are too lean, and deto starts - no energy left to create heat - ie no power.

[F5 Dave]

So the method of calibrating on the dyno with tiny timing changes till the power just drops off would seem doable.

If I understand correctly from what Wob has said (I haven't had gauge on running engine yet, maybe next week -ho ho) then:


Peak power you get the 'warning' just chiming in a little,
& with a bit more timing that the power just starts to drop off = Deto.
If you get deto at another rev range it should still show on the gauge.

If you never see 'warning' then you are not close enough with the timing in that area, but caution, as have to build a TPS aided model to get it that close for all conditions.