Kawi2strokes.com Forum

BUY a set of three LB05EMH plug caps and use them on your efforts with the H2's. This will stop electronic noise. Use the small inductive pick up on the PRIMARY side of the coil for your rpm. Spread out the primary wires and keep the inductive pick up away from the other wires. You will not fry anything by using the inductive pickups it is just measuring the collapsing magnetic field, not grabbing volts. On that old girl (dyno) where are you putting your temp probe? Do you have air fuel measuring? How do you jet correctly?

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I am just a man working in a tin shed.

Gotta be some misunderstandings (is that a word) here

Normally, I don't have any rf noise issues at all, as long as I use r plugs.

This bike did not have that, and I did not bother buying a set before the dyno run. That's why I don't have any rpm or torque readings for this run.

I don't have any temp probe, and I have an external air fuel ratio probe. But I seldom use it. And yes, I always use the small pick uo, on the primary side as Neville just said

..j.

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72 H2, 72 H1B, 74 H2, 74 H2 Cafê Racer, 71 F8 Bison

Maybe my misunderstanding, I thought you could not get a reading of rpm. Seemed like an easy fix to have a set of caps in the drawer for those occasions?. With the DJ dyno of that age there should be a lead from the weather station with a white tube on it which contains a air temp probe. One usually hangs it on the wall in dyno room. Do you not have one? I am trying to assist , not criticise. I am surprised you do not value the air fuel data.

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I am just a man working in a tin shed.

Your inputs Nev, are much appreciated. Achieving all those good results, by documentation, very impressive. Not just thrown out numbers like "king cobra 120 hp", or all the Denco claims. Not supported by any dyno sheet at all. Not even what pipes to use getting the claimed numbers are mentioned. Seems like all those claims are nothing but assumptions.

Yes, there are a temp probe and a gadget measuring air pressure so the corrected numbers can be calculated. Located at the side of the dyno "cage" itself.
Before using r plugs, I used the NGK 5K ohm caps.

On this bike, the US original caps are still on. I did not wanna take them off just for this test. I now know the bike makes 67 rwhp, but will put in r plugs when finished porting so a rpm and torque Reading can be done.

Maybe I should play more with my air fuel ratio device. From how I read what you wrote, it is very useful.
Jørgen

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72 H2, 72 H1B, 74 H2, 74 H2 Cafê Racer, 71 F8 Bison

Most dyno operators around here will not use the fuel/air probe on 2 strokes as the oil damages the sensor. One guy told me the sensor was like 450.00. Maybe Nev has more info on this.

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

Put on some shielded caps today and did another run.

It seems those pipes really need some more blowdown and perhaps also higher exhaust duration. I think the suction pulse from the SpeccII's are kind of weak. But that's just an assumption.

Gonna be interesting if this quite moderate portwork can reach 90 rwhp. I doubt it though, but one never know before the job is done. We'll see

Studying the torque curve is quite interesting. You can tell from the curve, the returning pulse reach the cylinder just when piston opens transfers at downstroke, at 2800 rpm. All the way to 5200 rpm, this pulse messes up. That's why the torque does not climb very much. At 5200 rpm, the pulse reach the cylinder at the very same time piston closes transfers on upstroke, and you enter the powerband, the fun begins. Some variations though, as the piston speed varies at different crank positions. This is only a VERY basic guideline, and not very accurate. But it helps understanding what is going on in the engine, and why.
Cool ehh???



Jørgen

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72 H2, 72 H1B, 74 H2, 74 H2 Cafê Racer, 71 F8 Bison

To get a "3rd opinion" on RPM calibration...if you have a Fluke with frequency, you can pick up off the coil and convert Hz to RPM

To buy a new AF sensor from Dyno-jet you need also to pay for ultrasound to remove the pineapple from your anus. From them it is , last time I tried over $500Aust. I can buy the identical Bosch sensor for about $185 from a shop 80kms away. Depending on which sort of Air Fuel pump one has it is no real drama to sample a two stroke. If one is doing proper and frequent development it has to be done really. So the customer will need to partially contribute to a new sensor. There really is no drame with the coil pickup either, just need an inline resistor for the plug cap..

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I am just a man working in a tin shed.

When you dyno bikes how is it done, what gear do you use and then do you roll on the throttle? What are all the factors involved to get good usable info?

I have had only one bike dyno'd, 4 stroker with CV carbs. I have had it dyno'd a few times in different engine configurations.
Once on two different dyno's, one at the Buell factory and one at a local shop, very different results with the same engine configuration, that I can accept different dyno's.
But also once I had it dyno'd, same dyno,a week apart, different operators.
They were having trouble giving me a torque curve for some reason so they said if you come back we will try again. I went back the next saturday.
The graphs were completely different with a 20HP difference!!! , bad curve, major dips on one, good curve on the other.
I was told it was because they used a different gear and a different roll on time, and it had to be done in a certain gear and the operator had to "know" how to apply the throttle.

Haven't had a dyno run since then, that was 6 yrs ago, and I have been skeptical since then of any graph I have seen.

PLEASE don't take this as anything but an inquiry, I know you are a very good technician with many skills.
I have wanted to ask this question for years but I know no one that I trust to give me straight answers. It seems from reading the posts lately you and others may know the answer.

Thanks Jorgen!

I will ask you these questions, assume you are going to buy a dyno. Do you say," Ill have that one it looks faster" ? Of course not they are all the same. Each BRAND may differ, but each machine is made the same, they will read the same. You are going to but a PC to hook to your dyno,do you say," that orange one looks better" , of course not. You accept that the machine is equal to the one next to it of the same spec. So then you have a group of people who operate dyno machines, now they are all the same right?

Yeah, right. Just like when you take your bike/car to a mechanic, they are all the same, none better than others?? You should not blame the machine for your results. A dyno is a tool to assist with measuring data so you can tune bikes. The final measurement is one which tells the operator if he/she has succeeded in improving the bike under a wide open throttle condition, a hp measurement. Folk are hung up on that and cling to it without seeing that the machine like any other needs to be MAINTAINED and OPERATED correctly in order for everything to work well. I find as with many things that reading the instructions of the machine will help you get close to a good result.

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I am just a man working in a tin shed.