Originally Posted by Mollrik

Hmm, somehow I doubt that. A question about porting and polishing the cylinder head were asked at EX-500.com some days ago. The question was...

and the answer he recieved from FOG (he has raced these machines for years, tried more or less everything to improve HP, and his response was...)

FOG more or less knows this engine "in by out", so I'll take his word for it, and I doubt SPYE (me included) wants go get every last piece of HP from the engine as possible; reliability is also of importance!

According to FOG; if you want to get those extra HP, do the following...

(the last quote may not work with the KLE 500, as the KLE 500 has 254 degrees camshafts, instead of 290 degrees (GPZ/EX 500))

source: Port and polish cylinder head

The reason why SPYE's KLE will max 165km/h, and not more, is most likely due to the exhaust system AND the lower compression (9.8:1). By changing exhaust, you will probably increase the speed, and it will vibrate less.

My KLE runs just fine; but I somehow got the feeling that the 115 main jet is a bit too large, as it runs fine when cold, but as it gets warmer, I can feel "low speed stumbling" going WOT @ ~3000rpm (there's no power down there, but it shouldn't stumble (doesn't stumble when cold, which is a sign of it going rich)). It runs better now than with the 112 main jets, but I didn't use the big snorkel with the 112 main jets anyway, so perhaps it were asking for "more air"(pressure balance) with the 112 main jets.


edit: opened up the airbox with 2x8 mm holes (not much at all), and the low speed stumbling is now gone, and it still goes perfect at the highway. Can't say much about the top speed just yet, but got to 180km/h, before I had to roll off the throttle (still had a little bit more to give), so I am quite sure the jetting is more or less perfect now, but will have to do some more testing, when it's not windy (yes, windy today too) and raining



/Mollrik

Originally Posted by SPYE

Hi

Do you know of any other needle options that can be tried that will work with the 112 jets. I have looked on the net for a sizing chart and other needle options for the keihin CVK carbs on our bikes, but can't find anything.

Perhaps you have found something. Only know N60D, N96J and N96L needles so far. I wonder how the N96L needles will work?

BTW. Do you not think the bike is running too rich at WOT thus causing the lack of top speed as the top speed was better with the old jets/needles (leaner), that is why I was asking about other needle options. The low/midrange is definately better with the new set-up.

Any thoughts?

Originally Posted by Mollrik

Hey!

Actually, I did a lot of testing today with my setup (2 * N96J needles AND 2*115 main jets). I had a feeling that it was running rich, so I increased the intake "a lot", and I was right!

The bike is now more aggressive than it even has been before! 0-100 in no time, haven't tried top speed, but got to 160km/h faster than I ever have (and trust me, it had a lot more to give), so my bike was more or less "begging" for air.

Do NOT use the N96L nor N60D needles with the 112 main jets; those needles ARE leaner, and will most likely not work well with the 112 mains (I mean, the older KLEs had the N96J needles with the 112 mains)!

My tip, increase the intake, little by little, perhaps by adding some holes on the back of the airbox (like I did, 8mm each, but 5mm should work fine too!); did wonders to my bike, specially the low- and midrange, but of course, it feels a lot stronger on the higher revs as well!

About the jet needles; the CVK jet needles markings seem to be just random numbers (more or less), and you can not get much out of reading those. My tip; there are charts around the net, that people have build up, comparing different jet needles, so I took a look at the different "numbers", and couldn't see any relation between the different markings, and same goes for a lot of other people, that went the same approach!

(If anyone can prove me wrong about this, please, do not hesitate to do so, as this is of huge interest to me!)

My tip: keep the N96J needles, if any, shim them (doubt that will be necessary, though)!

(I do not take responsibility for anything that might happen to your bike, but as stated above; my bike was rich by going WOT, and by increasing the intake, the idle, low and middle throttle range seems to run perfect! (no stumbling or whatsoever, but it sure has a better response everywhere! (and sounds a lot better! )))

If you want to make sure you are rich in a particular circuit, you can either do the "plug chop" method, and/or compare the performance. If it runs better when the engine is cold comparing to when it's warm, you are most likely rich in that particular circuit (main jet, in this situation)

I also used other methods, like rolling the throttle from zero to WOT "slowly" (wide out throttle). I noticed that I had more power 7/8 throttle, than when I were going full throttle (this could also indicate a lean main jet, but as my performance improved by increasing the intake, it was obvious it was rich!). An other way is to go from full throttle, and then turn back slowly on the throttle. If it gains power, then it's too rich or lean (again, probably too rich)

A third method: go from zero throttle to WOT "instantly", and see if it bogs. If it does, it's probably rich. If it feels like the engine doesn't respond for a short moment, but will gain power after a small time, then it's most likely too lean (which I don't think will be the case here)

edit: just to clarify; the needles have no (very little) effect at WOT; the main jet is responsible for fuel delivery there, so going rich at WOT means that the main jet is too large, so do not think about changing jet needles if your problem is at WOT!


GS500 Wiki - Rejetting-Lean Or Rich

/Mollrik

Originally Posted by SPYE

Hi Again!

Just to confirm. Are you still using your airbox with the extra 8mm holes drilled in it. This seems like quite a popular modification as I have seen it mentioned on other sites/threads (can't remember where). Did it make a differance in the power delivery? I am thinking of doing it myself.

Where do you drill the holes? The best place for max airflow etc. Do you have a pic. as a example?

It seems that the KLE 500 is still starved of air even with the larger snorkel.

Originally Posted by Mollrik

Yes, 6 holes, 8mm each, drilled on the back of the airbox, facing the rear of the bike. Do not have any pictures of it at the moment, but if you search
around this forum, you'll see where the holes usually are drilled (which is also the case here).

As stated before, my KLE both runs and sounds better (well, I love the new "growling" sound, but some dislike the sound, though there are ways to fix it, if one doesn't like it), specially the bottom and medium RPM-range has improved a lot!


/Mollrik

Originally Posted by SPYE

Hi

I asume you are using the airbox with the 8mm holes using the DNA filter and large snorkel.

Originally Posted by Mollrik

OK, more info...

I have driven around with the new settings for around 1000KMs, and this is what I've gathered...

The fuel consumption has actually improved (or the same as before, but not more, which is a big bonus!) , 0.5l/10km while driving around with different speeds and some "hard" (7k-8k) accelerations. Haven't done much highway cruising yet, as I've been testing my carb settings a lot, but it all seems fine now.

OK, how about the performance? I must say that I'm impressed. I haven't tried to top my KLE 500, but there's some new found power that has NOT been there before! Got to 170km/h quickly, got to 175km/h today before I decided to shut down the throttle due to traffic (highway), but I'm confident that my KLE 500 can reach at least 185km/h right now (190km/h might be too positive). Just to clarify. The acceleration is improved, going WOT @ 140km/h, and my KLE actually feels like it has a lot of power stored for use! (going from 140km/h - 160km/h really fast!) Never felt this before!



I'll give you people more updates about the top speed later, when I have the time and the mood for such driving, but I'm really impressed so far!


SPYE, how's it going for you? Modified the airbox? The results? Keep me updated!

/Mollrik

Originally Posted by Mollrik

Hey!

Well, I really don't know about the extra airflow with that setup by adding "tubes" inside the air box, but it should lean out the mixture (in the sense of opening up the air box, but the "tube" part is something I do not have much knowledge of), which should result in more horse power and probably better fuel economy, of course, this only applies if the bike is rich. Are you sure you are reading your spark plugs correctly?

One thing I don't like with that setup is that you actually have to drill the snorkel. Either you could just ignore that part, or duct tape it in case the results would be for the worse!

Have been speculating around about the snorkel. It really can't be good, as it more or less makes a "U-turn", which should result in more restriction, comparing to a "straight" snorkel, but the reason why I am not removing the snorkel, is because of all the hot air from the engine, which should then enter the air box. I rather make holes in the back then.

I still think that you could drill 2-6 (probably max 4, as I have a bigger main jet) (8mm each) holes in the back instead, and see how your bike performs, as it seems a lot easier, but if you want to try that setup (Rimfire), go for it!

Keep my updated!

edit: translated version can be found here (google translate!): English version of the air box mod , of course; this can be hard to understand!

edit2: about your exhaust. It may not be the only reason for your top speed. I mean, how does it accelerate if you go WOT @ 130-140? Quick and powerful response, or do you barely feel anything, except that you can see the needle moving slowly? I'm quite sure your KLE is running rich, but yes, your top speed is of course restricted due to the exhaust, but a rich mixture can make the KLE 500 lose horse power as well (I mean, going from 4 to 6 holes, and it felt like an other motorcycle!)


/Mollrik

Originally Posted by SPYE

Hi

I started the "Rimfire" mod. today. I drilled the two 16mm holes on the side of the airbox as indicated and could'nt help taking the bike for a spin as is, with only the holes. Well, the bike certainly pulls quicker. High speed run was better. Now 170 km/h! Accelaration between 120 and 140 a lot quicker now. I will continue the mod. tomorrow. I am sure I am on the right track now. The bike was air starved!

Will keep you updated.

Originally Posted by Mollrik

Hey!

Nice to hear about the new top speed of 170km/h. A 5km/h increase in top speed is actually nice, and remember. You both have drilled holes, and have the DNA filter installed!

What does this say about the full power KLE 500 in general? That there are some extra horsepower to get, just by letting it breath more! (when I bought me KLE 500 -99, it was more or less as lean as it could get, without making it stumble, as I just drilled 1(one) 8mm hole, and that was enough to actually make it stumble!)

One cannot fully blame the camshafts for the "low" horse powers, as they are by no means the reason for the 10hp difference between the full power KLE 500 and the GPZ 500. The camshafts increase the HP by around 5hp; the rest comes from better breathing! I'm quite sure that if you would take GPZ 500 carbs, drill the airbox for a good air-fuel-mixture; you'll probably get around 56-57hp (crank) (the GPZ itself has 60hp, and notice that I said there is a ~5hp difference between the camshafts! Well, the GPZ 500 is also rich from factory, and modifying the airbox grants another 2 hp!)

I have no idea how many horse power my KLE 500 delivers right now, but I am quite sure it's a bit over 50hp (~54? No idea, actually, just speculating, though I have no real need to get it dynoed, as I think it goes just fine, and have no desire to get those last horse powers you probably could get from this engine, as I love how my KLE performs)!

If you, by any chance, will get it dynoed, please, post the dyno graphs, as it could be interesting to see how well it performs now, as you have dynoed it with stock settings! Then, one can truly see the the performance gain (hopefully, you have not lost performance with these modifications)

edit: An other interesting thing to point out! With these modifications, the low and middle RPM-range is probably (well, I think it pulls a lot better in that region!) a lot better too! Peak horse power is not always interesting when tuning, as a better low to mid performance can result in a more pleasurable ride!

/Mollrik