Dyno, What do the 'specialists' think?

BelgiqueBasterd · Aug 18, 2008

Got my bike back from the dyno. Main jet is 190, pilot jet is 42, needle is obvt 3rd from top.

Pilot is still too lean(wich causes the air to fuel ratio to be off the charts in lower rpm), will change that too a 48, the dyno guy didn't have a 48 jet at the time.

I know the general concensus on this forum is to go lean, I've tried that, lineaweaver needle, 35/38/40 pilot jet, 150/155/160 main jet, but the results were terrible, VERY hard starting, and a very rough ride, especially in lower rpms.

But anyway, what do you guys think about these results 53HP and +/- 60nm, is that acceptable for a freshly rebuilt 2002 650?

Changes made are X2 cam, 450 hp piston, FCR carb.

Regards, Christof.

steve · Aug 18, 2008

The shape of the curve doesn't look too different to mine,
http://www.husaberg.org/index.php?set_a ... _photo.php

Don't get too concerned about the absolute numbers, its the shape of the curve and the difference between before and after that matter. the bottom line is out on the trail, is it rideable? How does it respond to the throttle? Will it wheelie past everyone else?

Mine apparently equates to 63hp on a Dynojet if that helps. Can't see what your dyno is from the plot.

I have yet to pull my carb down to check its jetting, but it does have the Lineaweaver needle with which the dyno guy was quite impressed. When I do check it out I'll post my specs. Certainly with the AP at 1 mm, reduced from standard prior to the dyno work, mine became unrideable. It is now set at about 0.3-0.4 mm for a nice controllable snap.

Your AP setting may be gude to how effective it now is if my experience is anything to go by.

Steve

BelgiqueBasterd · Aug 19, 2008

steve said:
The shape of the curve doesn't look too different to mine,
http://www.husaberg.org/index.php?set_a ... _photo.php

Don't get too concerned about the absolute numbers, its the shape of the curve and the difference between before and after that matter. the bottom line is out on the trail, is it rideable? How does it respond to the throttle? Will it wheelie past everyone else?

Mine apparently equates to 63hp on a Dynojet if that helps. Can't see what your dyno is from the plot.

I have yet to pull my carb down to check its jetting, but it does have the Lineaweaver needle with which the dyno guy was quite impressed. When I do check it out I'll post my specs. Certainly with the AP at 1 mm, reduced from standard prior to the dyno work, mine became unrideable. It is now set at about 0.3-0.4 mm for a nice controllable snap.

Your AP setting may be gude to how effective it now is if my experience is anything to go by.

Steve

That's a big difference 53 for mine and 63 for yours? Is yours a stock engine? Or is it tuned? What kind of HP are you talking about SAE or DIN? Are you talking rear wheel or crank HP?

I tried the lineaweaver needel with about a million different jet settings and couldn't get it to work properly! Don't know what was wrong.

My FCR is from a Honda CRF, wich has the shorter duration AP, so i didn't mess around with it.

The bike rides beautifully, no hesitation, smooth power delivery, even the snap wheely test is ok. Only remark could be that the idle floats a little bit when coming off the throttle before returning to normal.

Simon · Aug 19, 2008

Well, here's my two pennies worth.

1. Don't worry about what other's are saying about what you should and shouldn't have in your carb. By all means take note but don't go by it, go by your own observations as your main guide. FYI, I have a 48 pilot in my 650 also. If it's any consolation, I'm having some difficulty getting my 650 to work properly with the FCR.

2. You have a fairly flat torque curve but what worries me about it is the dip at the beginning which says to me something is not quite right. This dip coincides with your a/f ratio too. Generally speaking you'd normally be looking at 13 for max power and 15 for efficiency but that's just a general kind of guide. However, you also need to be aware that in order to properly measure a/f ratio you need to conduct steady state dyno testing, not sweep testing because the equipment doesn't keep up on a sweep test.

3. What exhaust system have you got on there?

4. Looking at where max power is on the curve, are you running a higher compression piston than oem?

5. There were improvements over the 01/02 engines that resulted in better power output, particularly in 03 and 04.

All the best,
Simon

BelgiqueBasterd · Aug 19, 2008

Simon said:
Well, here's my two pennies worth.

1. Don't worry about what other's are saying about what you should and shouldn't have in your carb. By all means take note but don't go by it, go by your own observations as your main guide. FYI, I have a 48 pilot in my 650 also. If it's any consolation, I'm having some difficulty getting my 650 to work properly with the FCR.

2. You have a fairly flat torque curve but what worries me about it is the dip at the beginning which says to me something is not quite right. This dip coincides with your a/f ratio too. Generally speaking you'd normally be looking at 13 for max power and 15 for efficiency but that's just a general kind of guide. However, you also need to be aware that in order to properly measure a/f ratio you need to conduct steady state dyno testing, not sweep testing because the equipment doesn't keep up on a sweep test.

3. What exhaust system have you got on there?

4. Looking at where max power is on the curve, are you running a higher compression piston than oem?

5. There were improvements over the 01/02 engines that resulted in better power output, particularly in 03 and 04.

All the best,
Simon

1) I've had a lot of problems with my MK2 also, in the end it was the missing hotstart that was the cause of all this! I had plugged the hole with a bolt with the appropriate thread, but apparantly there is still some air leaking in via the threads, leaning the mixture considerably!!
What problems do you have with yours?

2) are you talking about the fuel air curve? It's indeed off the charts with lower rpm's. My dyno guy advised me to go from a 42 PJ wich it has now to a 48, he didn't have any spares at the time. I've driven it a good 60km's this afternoon and it revs beautifully and very smooth in the 2/4 till 4/4 throttle position. But 1/4 position, it's not quite right, the idle floats, this worsens when the engine is getting hotter. So I'll experiment a bit with the PJ, needle position, and fuel screw.

3) stock system, funds were depleted after the engine rebuild

4) yes, it's the Husa 470 domed piston

5) what improvements?

I see in your gallery there are a lot of dyno runs, have you done runs with a stock 650 fitted with an fcr? Couldn't find one.

Thanks a lot for the info.

steve · Aug 19, 2008

Hi BB,

My 43hp is Dyno Dynamics hp which is a constant load dyno like Simon recommends. The conversion to a sweep dyno like the common Dynojet is supposedly a bit less then 1.5. My engine is stock with the standard muffler being opened up with a modded end cap, performed by the dyno guy as part of the service. The big deal for me was the improvement from stock. The stock curve is the Lineaweaver kit with AP at 1 mm and 33hp. After tuning with end cap mod, 43 hp on the same dyno. It wasn't slow before!!!!!!!! The 63hp is for bragging rights, the 43 is what was measured. The reality is that something like a 525 KTM feels like a good 250 in comparison.

Steve

Simon · Aug 20, 2008

BelgiqueBasterd said:
1) I've had a lot of problems with my MK2 also, in the end it was the missing hotstart that was the cause of all this! I had plugged the hole with a bolt with the appropriate thread, but apparantly there is still some air leaking in via the threads, leaning the mixture considerably!!
What problems do you have with yours?

I'm experiencing a dip in power at the 1/4 throttle transition upwards a little while and power "oscillation" at full throttle. Then, when these are ironed out I experience poor running at pretty much half throttle. It's proving difficult to balance the circuits properly. Unfortunately, this is a problem that doesn't get highlighted on an inertia dyno but on real world testing.

BelgiqueBasterd said:
2) are you talking about the fuel air curve?

Yes.

BelgiqueBasterd said:
3) stock system, funds were depleted after the engine rebuild

Then the results you have are good, nothing to complain or worry about at all - apart from what seems to be the slight jetting issue.

Keep in mind that your rear tyre will also play a role in the results but by and large it's giving you good power output.

I have my own datalogging kit that fits onto the bike and calculates power output by measuring acceleration and engine speed in the real world and compared to the Dynojet dyno I have about 6 - 7 less horsepower - but then it is working in the real world.....

BelgiqueBasterd said:
5) what improvements?

The details should be in the doc about this but they include such things as a longer conrod, new camshaft in 03 (the 08 cam), new piston and a host of others other items in 04.

BelgiqueBasterd said:
I see in your gallery there are a lot of dyno runs, have you done runs with a stock 650 fitted with an fcr? Couldn't find one.

If you go to my gallery all the charts starting with 07-12-14 OEM show stock 03 650 with FCR as the line in bold. I have some old charts somewhere of my 01 650 but they're not readily to hand and it would take an expedition to find them I think.:wink:

BelgiqueBasterd said:
Thanks a lot for the info.

You're welcome.

Simon

madero · Aug 20, 2008

Hello all,

I am the dyno guy,

There were a lot of problems to get the engine right from BB,but now the bike is rideable.

The air fuel ratio is too poor on low rpm ,that is the reason I adviced him to put a 48# jet,also change the screw a bit.

The engine starts now very good cold or warm,in this temperature and pressures.
and wheelied very easy.

I hope BB can make some KM without problems.

Greetings MAdero

BelgiqueBasterd · Aug 20, 2008

madero said:
Hello all,

I am the dyno guy,

There were a lot of problems to get the engine right from BB,but now the bike is rideable.

The air fuel ratio is too poor on low rpm ,that is the reason I adviced him to put a 48# jet,also change the screw a bit.

The engine starts now very good cold or warm,in this temperature and pressures.
and wheelied very easy.

I hope BB can make some KM without problems.

Greetings MAdero

As i said earlier, low rpm's the engine ran rough. I've now changed to a 48pj and the fuel screw 1,5 turns out, as you advised, and it runs a lot more smoother, idling is perfect no more float, no bog when snapping open the throttle.

Starting is a little harder now, but that's probably more from not having the correct technique than jetting. With the 42 if I used the choke it started right up, now with choke it won't start, without choke it's ok.

BelgiqueBasterd · Aug 20, 2008

Simon said:
Then the results you have are good, nothing to complain or worry about at all - apart from what seems to be the slight jetting issue.

Simon

Thanks, this put's my mind at ease, since i've rebuilt the engine myself and never did something like that before, the doubt that i have done something wrong is always at the back of my mind!

supertireguy · Aug 20, 2008

Here's another dyno graph for comparison...

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Dyno, What do the 'specialists' think?

BelgiqueBasterd

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