this fan issue is making me nucking futs. help!

[jwflower53]

Norm, thanks for the analysis.  I may just try it.

-JW

[RobertWichert]

Great explanation, Norm... One thing... Air pumps are dilution. Nothing more. ppmv is less if v is more. Hence the hated air pump. Total B.S. Robert Wichert P.Eng. LEED AP BD&C HERS I/II CEPE CEA BPI CERTIFIED SF/MF GREEN POINT RATER +1 916 966 9060 FAX +1 916 966 9068 =============================================== On 8/3/2014 7:11 PM, 'Norm Keller' normkel32@... [DSN_KLR650] wrote:

I've done more than six Gen1 exhaust cam advances + at many Gen2. It is a "no-brainer" modification, IMO. My 1997 has the exhaust header matched to the head, welding lump removed, snorkel removed, air box top drilled, KLX needle & 142 main jet, air box screen removed, all of these made some improvement. Advancing the exhaust cam picked up the torque across the range, it will now pull 9,000 RPM in 2nd, 3rd & 4th. I've checked tach and matched speed to RPM with this gearing & both confirm. While I don't intend to run those sorts of RPM's it was certainly a confirmation that the cam improvement is significant. It does not turn it into a KTM950. I don't usually do camshaft threads because there is altogether too much nonsense. One way to explain the effect is to compare to the experience with domestic V8's in the 1970's and 1980's. Many of these engines responded well to advance of the camshaft (combined intake and exhaust camshaft) by one tooth of the camshaft sprocket. Inspecting the 460 Ford crankshaft sprocket, for example, showed the sprocket to be retarded by one half tooth so common practice was to install a 429 Ford timing set which had the key way lined up with the index mark. The difference was significant: hot idle had to be adjusted down by as much as 500 RPM. Increased lower end and mid-range torque, increased mileage and seemingly more high RPM torque although can't recall the dyno numbers now. Why did they retard the camshaft? Conjecture on my part but emissions were a problem for the manufacturers at that time. They solved the high nitrous-oxide problem by (EGR) redirecting some exhaust back into the intake. The effect of introducing the already burned exhaust gasses was to increase the mass of the combustion chamber gasses, resulting in lowering the peak combustion chamber temperature below the point at which NOx is formed. CO (partially burned fuel) can be reduced by introducing air into the exhaust as close to the valves as practical so many of these engines used an air pump to pump air through tubes in the manifold runners or head ports. Some used a simple check valve and venturi action to introduce the air as does the Gen2 KLR. The last emission of concern is usually lumped into one description HC (hydrocarbons) which are unburned fuel. Most manufacturers of the time sought a means to provide a longer burn time for the combustion gasses, often by simply retarding (opening later) the exhaust cam timing. The 460 and many other cams were virtually identical to pre-emissions grinds other than to have the camshaft retarded. I know this to be the case from direct measurement and making these modifications on many, many engines. We confirmed the effects in dyno tests and in marine applications. So, here's what I expect that Kawi did: they developed the 650 engine configuration, with camshaft which provided a reasonably ideal engine power curve, then found that emissions were too high. Leaning the air fuel mixture succeeded in reducing CO levels however leaning further in an attempt to affect HC would be ineffective because leaning beyond a critical point results in misfire which increases HC so further leaning would be counter productive. Increasing the burn time by retarding the exhaust cam would reduce the HC levels. While this does not prove the scenario applies, I think it fits the pattern. The positive aspect of this is that there is no risk of damage from retarding the exhaust cam so if you don't like it, just put it back. Not a chance that mine's going back, or any of the ones I've done, according to the owners. Wordy I know, but best way I can think of to relate. HIH Norm

[Martin Earl]

Lamar, and GregI bought the EX500 fan; still have another one for a spare. It did require an extra wire from the fan assembly to a 6mm bolt on the left side of the frame to effect an 'ground'. Works like a champ. Does it work better than the original. shrug.Can a Dalmatian have to many/not enough spots?Some people think so...The EX500 fan works like a Champ. revmaaatin. who had a Dalmatian dog named Champ...he had a taste for killing cats.

On Fri, Aug 8, 2014 at 12:07 PM, 'GMac999' gmac999@... [DSN_KLR650] DSN_KLR650@yahoogroups.com> wrote: Anyone know if these will cool better than the original?[u][/u][u][/u]

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GregM[u][/u][u][/u]

A-9[u][/u][u][/u]

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[b]From:[/b] DSN_KLR650@yahoogroups.com [mailto:DSN_KLR650@yahoogroups.com] [b]Sent:[/b] Friday, August 08, 2014 8:57 AM [b]To:[/b] DSN_KLR650@yahoogroups.com [b]Subject:[/b] [DSN_KLR650] Re: This fan issue is making me nucking futs. Help![u][/u][u][/u] [u][/u] [u][/u]

Thanks to Norm, Mark, and Jeff. I borrowed a wire with alligator clips on both ends from my multimeter and attached one end to a mounting tab on the sweet new radiator and the other to a motor mount. Works like a charm with that addition. I'll be making a proper ground wire this weekend.[u][/u][u][/u] [u][/u] [u][/u]

So, in summary: [u][/u][u][/u]

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eBay has plenty of $15 EX500 two-wire radiator fan motors that will work on the KLR. The lack of a ground wire with the EX500 motor IS an issue that will need to be addressed, however. [u][/u][u][/u]

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Fan relay is a stock Japanese part and can be had at any auto supply store. [u][/u][u][/u]

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Fan switch? It's an expensive little bitch, but don't buy a used one. [u][/u][u][/u]

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As for the ASI Performance radiator, it IS bigger than the stocker so fan blades will need a little adjustment to clear the head, as will all of the mounts, both to the bike and for the fan mount. More capacity should help and the natural aluminum finish is pretty nice to look at. [u][/u][u][/u]

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Thanks again for the help.[u][/u][u][/u]

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Lamar[u][/u][u][/u]

A14[u][/u][u][/u]

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