KLE 500 Twin Exhaust

[ROB825]

Ive read a lot of posts here and there about the KLE500 and mods to liberate the stifled ponies.

Here is what Ive found along the way in the course of discovery, research, testing and trial and error.

The first thing I tried to do was modify the stock exhaust and fiddle with stock carb settings. In short, there's very little to be had from this. I tried gradual more and more severe, non reversible mods to existing muffler, in the end, having both ends of the original removable with riveted caps and a "core" packed with glass wool. The sound is pretty good, nothing harsh and certainly much quieter than aftermarket mufflers of this type. (and basically free!) But by the time you have suitably packed a bucketful of glass wool (the really fine stuff) into the muffler combined with the original steel walls of the original muffler casing, which by the way, have an inner perforated "lining" bonded to the inside of the walls, the weight is substantial. There is however, a noticeable improvement in response and low down torque. It is smoother off idle and easier to start. I removed the tiny snorkel, raised the needle with some very small washers and adjusted the idle mixture screws.
Encouraged by this, I decided to go a bit deeper. There's a ton of info out there about modifying the airbox but when all is said and done, basically they all revolve around getting more air into the airbox and ultimately the cylinders. You cant have too much air.. only not enough fuel. I bypassed all the hole drilling etc and went straight for a larger inlet hole. I removed the screen completely and installed a DNA filter. Next I used a heat gun to modify a 3" PVC plumbing fitting to shape into a new Oval shaped bell mouth. This does smooth airflow into the airbox and increases air in by a significant amount. (you can research this on the net)
I then installed a Dynojet stage 3 carb kit. You can work downwards from the supplied jetting with the stage 3 kit. I currently have 130 mains installed and this works very nicely. This yielded a bigger improvement again. Of course there's a bit of testing and I wont go into all that - needle clip position etc - but in short, much better everywhere.
But the nagging issue of header pipe compromise is still there. That was the next challenge. I tried cutting the pipe into smaller sections that could be joined with temporary clamps for refit and testing so that I could find these much talked about "cat cons" fitted to some models. I determined that mine had something of this type inside since when the pipe was off the bike (prior to cutting it up) I slid a tube down it to find the position of the cat con. Sure enough, there's one in each header near the Y junction and one also in the throat of the muffler. I duly cut the pipe, pried these out, (not easy!) and refitted with temp clamps..tested. .. a further improvement.
But still, the pipes themselves are a very poor design, left header being longer than right and the junction very much less than ideal, more like TEE than a Y and certainly not conducive to flow. So a bold decision was made to fit a dual exhaust.
This entails moving the side stand bracket which sounds like a big job but in reality is probably the easiest part of the whole deal. The KLE has an unusual footpeg design which lends itself very well to welding the cut off sidestand bracket to the lower side of the footpeg bracket. Add a bit of additional bracing here and there and you're good to go. Best part is you can do all this off the bike then simply bolt it on.
For me, living in Brunei (Borneo), having pipe bent to suit was a much bigger problem and as it turned out there isnt anyone in this country that could do that. In the end I used flexible washing machine drain hose (which so happens to be about 32mm correct size) and taped four peices of 1/8" fencing wire along its length spaced around the pipe equally ie at 12oclock 3 oclock 6 and 9.. This allows you to bend the flexible tubing and have it retain the shape you wish it to be. Then you can go find someone with a 32mm mandrel bender. In my case I took the left and right pipe sections to Australia on next visit and had them bent. No probs. Fitting was a bit of a fiddle. I had some little brackets made up in stainless here and there etc but all came together eventually. I found some elcheapo Chinese made SS car mufflers for $50 each and modified the inlets down and made up inserts for the tip. I installed a balance tube at front to distribute exiting flow into both pipes... smooths out minor differences, better flow and less noise. (also research on net)

Result is much smoother bike all round. Instant starting, perfect idle, great low down grunt in 6th gear from 1900rpm, strong middle 3500 to 5500 and mad top end. I usually sign off around 7500 since I dont see much point in gong higher but you could I guess.
The low end is where I wanted it. Its great uphills.. that little 500 can up those devils at ridiculously low rpms now with nice chunky thumper type torque pulses from very low down in tall gears! Impressive!

cheers from
Borneo doug

[sebo]

Woah! Nice job! Is it possible to get more pictures on the routing of those exshaust pipes?