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What in the H_ll is the 22 cent mod? Will my bike last till morning?
Two 11 cent #4 washers installed under the button head of the mid-range carburetor jet Needle.
This helps reduce the EPA induced lean/clean running in the most used portion of throttle opening, 1/4 - 3/4.

Works best at sea-level to 3000 ft. 3000 to 5000ft one should only use 11 cents worth. 5000 ft & up not needed, IMO.
 

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Two 11 cent #4 washers installed under the button head of the mid-range carburetor jet Needle.
This helps reduce the EPA induced lean/clean running in the most used portion of throttle opening, 1/4 - 3/4.

Works best at sea-level to 3000 ft. 3000 to 5000ft one should only use 11 cents worth. 5000 ft & up not needed, IMO.
I think inflation has upped that to at least a $.60 cent mod.
 

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You'll have to define your terms. What do you mean by performance?
 

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Horsepower and torque cannot be improved in any meaningful sense.

The bike starts with 36 horsepower. For $1000 you can get 40. That would be a big bore kit, ported head, and a freer flowing exhaust.

Modest improvements in driveability can be had with a KLX needle, removing the snorkel from the airbox, adding four 1" holes to the airbox, and a modified stock exhaust. Figure $50 for that. After that, you quickly run into rapidly diminishing returns.
 

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Discussion Starter #8
I did not expect much, maybe a carburetor or cam. I am satisfied with stock. Thank you.
 

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The cams are good for moving the powerband around. Fun to play with. They can provide a bit more power and torque. Remember, though, about the diminishing returns stuff.

I'm not sure if Chris is really doing the small-port heads, but it is very interesting work.
 

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I agree with Tom. Cams.....not much there for the cash or effort.....carb swap even less. Do the stuff Tom said for a few hp, better throttle response and elimination of the emmissions required jetting compromises.

Despite reports to the contrary, I believe a good silencer can get you another hp or two......not much bang for the buck but you can lose up to 5 lbs. Next up would be a big bore kit, but again, at 2-3 hp it isn't worth ripping into a perfectly good running KLR to do one IMO......fixing excessive oil burn and the side benefit of reduced vibes are the real benefits of the 685 et al.

At the end of the day, the quest for big power is best fulfilled by removing the gas cap and driving a KTM690 underneath! ;-)
FAR more functional upgrades for your dollar can be found spending the money on suspension instead.

Cheers,
Dave
 

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I don't know much about aftermarket mufflers; Dave, Paul, and others are far more qualified to answer.

What I know is that a SuperTrapp makes life horrible and depressing and they should never be put on anything except a coffee table.
https://www.klrforum.com/1987-2007-wrenching-mods/18066-supertrapp-ids2-exhaust-while-touring.html#post167474

The silencer that I have been using for almost 10 years is a Suzuki GSXR 750 muffler. I have tried a couple of different generations.
https://www.klrforum.com/2008-klr650-wrenching-mod-questions/7176-gixxer-pipe-mod.html
 

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Are performance mods to a KLR over wishful. If not , please tell me more.
Let us say, after conscientious Internet research, you actually APPLY all the performance-enhancing, power-gaining modifications you find to your KLR650 (including the vaunted PCV valve modification). Even, advance the exhaust camshaft one sprocket tooth.

THEN WHAT???????????

Ride downtown Saturday night, and drag the Harleys at the stoplight? Go to Bonneville for the World Land Speed Record? Or, closer to home, run the Daytona Mile (if that's still an active event) or enter the Daytona 200 (again, if that race is even held nowadays)?

This cynicism and sarcasm aside, as others have posted on this thread about the limitations in unleashing the tremendous power held captive within the KLR650 engine: Modify your bike to suit YOU. Best of luck, but as posted above: Be WARY of the KTM690 rider offering to drag-race you for pink slips (vehicle titles)!

(The expression, "Drag for pinks," originated in California, where motor vehicle titles were printed on pink paper.)
 

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Yes, Supercrapps are a poor choics.

My silencer post;

A subjective topic but to recap recent discussions;

I don't like loud but I've replaced the stock silencers on both KLR's for several reasons, namely; lighter weight (5 - 7 lbs), better tone, better looks. .....I wouldn't recommend it thinking there will be a noticeable increase in power, nor would I put much faith in manufacturer's that claim much in the way of HP increases (with no other changes).

After much research and some testing, I like the LeoVince X3 which is relatively quiet at 94db, doesn't require repacking (the only one that doesn't AFAIK, except for the ridiculously expensive Staintune out of Australia), looks decent and has a spark arrestor and USFS compliance. Runner up would be the Lexx with the optional trail insert; also around 94db but it does require periodic repacking. I also like the FMF Q4 but it is a bit louder (though still trail compliant) at 96db (keep in mind that the increase in decibels isn't linear).

There are a great many aftermarket silencers on the market that are far too loud IMO and you'd do best to avoid them.

Good luck,

Dave
 

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Check out his latest project. FI and 60HP. Quite a deal. James
Link?

FI doesn't increase horsepower, necessarily . . . a properly-tuned carb, yielding optimum Air/Fuel mixture ratio, matches FI in terms of power output. That said, FI offers other advantages, depending upon design and complexity; such as responsiveness to ambient conditions, delivering appropriate air/fuel ratio under various conditions, etc.

I'd expect modifications other than FI are primarily responsible for the increase in power output to 60 HP; would like to read the article.
 

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Link?

FI doesn't increase horsepower, necessarily . . . a properly-tuned carb, yielding optimum Air/Fuel mixture ratio, matches FI in terms of power output. That said, FI offers other advantages, depending upon design and complexity; such as responsiveness to ambient conditions, delivering appropriate air/fuel ratio under various conditions, etc.

I'd expect modifications other than FI are primarily responsible for the increase in power output to 60 HP; would like to read the article.
Ditto,


Also, not to be a negative nellie, but Chris' results have always seemed a tad high and I suspect the dyno he uses may be more optimistic than most; he reports almost 7hp from a KLX kit, airbox mods and silencer which is around twice what I've seen elsewhere.

Dave
 

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A dyno can't create delta-hp unless it is out of calibration to a horrible and depressing degree. If the bare-bones-stock numbers are there and the after numbers are there, then the delta-hp is real (after considerations for differences in temperature and humidity are taken into account). Since there are before and after numbers, though you have to hunt them down, that's what needs to be looked at. The delta-hp is not solely the result of the EFI, there is a metric shit-ton of tuning that has gone into that engine. You have to read everything on the site to appreciate it.

I agree that some dynos are more optimistic than others and if you take a vehicle in and get three runs and walk away with a slip that reports horsepower it doesn't mean much out of context.
 
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I know the "60+ hp" engine has a ton of mods and I agree with Damocles that the EFI doesn't do much for peak hp compared to a properly tuned carb - there are other advantages, of course, but peak power isn't one of them. They basically say the same thing on their site: "Although we have not tested our self, we believe that it is possible to come close to the same power using an appropriately sized carburetor. It will have to be something in the 44 – 46 mm range."

On their dyno results in general, they claim 6.8 hp from "First stage mods consisting of KLX needle, 142 main jet, air box mod with 2/3 door removed, FMF Power Bomb and PowerCore4." We've all seen Patman Racings dyno testing; Patman's Kawasaki KLR650 KLR 650 Dyno Results Now this data is much older and there were some differences (DJ vs. KLX needle, Big Gun vs. Powercore, etc.) but despite having similar stock hp readings (33.6 for KLRChris and 33.9 for Patman), Patman saw about 2hp in the midrange but less at peak with those same level of mods (the K&N cost him the peak number IMO).....so almost 7hp is a bit of a head scratcher for me. Having done these mods myself, my admittedly unscientific testing (drag racing stock vs. modified KLR) seems to support a modest 2-3 hp increase with those kinds of mods rather than 7hp (a 20+ % increase). It took Patman installing the 685 to get to 38hp.

I'm not suggesting any conspiracy theories or nefarious intention but though I'd like to think you can get to 40+ hp with a jet kit, free airbox mods and a silencer, I have my doubts.

....OK, I'll go back to playing with my suspension now. :)

Dave
 
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