Kawasaki KLR Forum banner

1 - 13 of 13 Posts

·
Premium Member
Joined
·
6,822 Posts
Discussion Starter #3
The dyno graph came from this article,

2008 Honda XR650L Comparison - Motorcycle USA

The EPA lean & clean low speed fuel mixture of that particular KLR650 probably had too jerky of driveline snatch to get an accurate reading below 4000 rpm.
Kind of odd that all 3 of those engines have that little dip-spike near 3800-4100rpm.

If I were in the market for an in-expensive 650 dual sport bike and I were to read that article and see that graph, I'd be scratching my head. "The torque-filled power band will keep the inside of your helmet filled with a grin,,,,".

Stock and Standard, neither KLR or XR-L has changed much mechanically, have they.
 
  • Like
Reactions: DPelletier

·
Registered
Joined
·
529 Posts
What that graph fails to show is the most important area to have torque, which is low rpm. I have ridden my riding buddy's XR650L a lot and it will blow my KLR in to the weeds at lower speeds. Hell, my little XR400 will, too. All of Honda's XR engine are extremely torquey engines, but they run out of steam very quickly. You can make them rev to high rpms, but the bike doesn't really build any speed for it. They love to be short-shifted. Stab a XR650L while rolling along in 1st or 2nd gear and they will stand up on power alone. The KLR needs the clutch dropped to do the same.

That said, the KLR will still beat an XR650L in a flat out dag race ( in my experiences with my buddy), but I credit that to the KLR's ability to rev well... never thought I'd type those words...lol. I know most guys post about keeping revs down while cruising, but I was pleasantly surprised the first time I ripped through the gears on my KLR , going to redline in every gear. It really pulls great! Glorious sounds, too. I fully believe that graph. A KLR will eat a XRL on topend, hands down.


This reminds me of something I've thought about asking several times, but figured I'd get laughed at. lol

Back in my drag racing days we used to play with valve lash to get an engine to produce power where/ how we needed it. Loosening the lash on the exhaust valves ( effectively reducing the duration) will always make more torque across the rpm band. Sometimes the dyno would show huge imrovements. Like, 30, 40 or even 50 ft/lb worth. It depended on the cam profile and other variables, but it was a consistent way to ekk out some launching power without sacrificing too much top end, run-for-the-stripe hp. Has anyone every tried playing with valve lash on the KLR to see if they could find some more bottom end grunt?
 

·
Registered
Joined
·
529 Posts
Kind of odd that all 3 of those engines have that little dip-spike near 3800-4100rpm.

.
Likely operator error. Most dynos don't work well at all below 3k rpm ( no idea why). A dyno operator is SUPPOSED to roll on the throttle quickly, but smoothly, when it's time to up the revs. But you see a lot of operators just whack it to WOT and wait till redline. Considering the nature of CV crabs, I could see that creating this issue here. Simply conjecture, ofc.
 

·
Premium Member
Joined
·
6,822 Posts
Discussion Starter #7
What that graph fails to show is the most important area to have torque, which is low rpm. I have ridden my riding buddy's XR650L a lot and it will blow my KLR in to the weeds at lower speeds. Hell, my little XR400 will, too. All of Honda's XR engine are extremely torquey engines, but they run out of steam very quickly. You can make them rev to high rpms, but the bike doesn't really build any speed for it. They love to be short-shifted. Stab a XR650L while rolling along in 1st or 2nd gear and they will stand up on power alone. The KLR needs the clutch dropped to do the same.

That said, the KLR will still beat an XR650L in a flat out dag race ( in my experiences with my buddy), but I credit that to the KLR's ability to rev well... never thought I'd type those words...lol. I know most guys post about keeping revs down while cruising, but I was pleasantly surprised the first time I ripped through the gears on my KLR , going to redline in every gear. It really pulls great! Glorious sounds, too. I fully believe that graph. A KLR will eat a XRL on topend, hands down.


This reminds me of something I've thought about asking several times, but figured I'd get laughed at. lol

Back in my drag racing days we used to play with valve lash to get an engine to produce power where/ how we needed it. Loosening the lash on the exhaust valves ( effectively reducing the duration) will always make more torque across the rpm band. Sometimes the dyno would show huge imrovements. Like, 30, 40 or even 50 ft/lb worth. It depended on the cam profile and other variables, but it was a consistent way to ekk out some launching power without sacrificing too much top end, run-for-the-stripe hp. Has anyone every tried playing with valve lash on the KLR to see if they could find some more bottom end grunt?
shinyribs,
Are you not yet familiar with, 4 one inch holes in the top of the dirty air box, 2 turns open on the low speed mixture screw, a .020" shim (or 2) under the mid-range needle and drill a 7/64th" vacuum air hole in the bottom of the KLR throttle slide? This improves the low to mid-range power and response.

Then are you not yet familiar with the "MC Mod", "Free Performance Mod", "Exhaust Cam Advancement Mod"?
This mod also enhances the power and response between 1500-6500 rpm on the GEN2 primarily! Sometimes helps and sometimes hinders a GEN1, we don't understand WHY.
This mod advances the exhaust cam ONE full tooth. Simple, Cheap & Easy! And easily reversible if your engine doesn't like it.

I've been looking forward to riding with my long time friend Keith Collins, who purchased a 2016 XR650L, last spring. He purchased a 2009 KLR650 (his 3rd KLR) from us after riding his KTM620 RXC with me and friends. (I like to compare "performance", side by side.) He used to race AMA District 37 Hare & Hound.
 

·
Registered
Joined
·
529 Posts
Hey Paul, I've heard about those things, but never did them. I do have a KLX needle kit setup from EM, but it didn't do anything for low rpm. Around 2500rpm and up saw a nice improvement, though. Before that I had shimmed the stock needle, but never drilled the slide. Notable difference between a shimmed stock needle and the KLX setup.

I haven't opened up my airbox. If the bike can run 7k-8k rpm now ( and it does), then I cant see how its restricting any power in the sub 2k rpm range. But I could be wrong. A free flowing muffler has been the #1 thing I've done to improve off idle grunt on my KLR. World of difference. For a quick and dirty test I once ran around a few miles with the air box door off. I saw no difference, so I pooped the door back on and decided against drilling any extra holes.

Also, on the MC Mod, since you are advancing the intakes...that always showed us more upper rpm hp on the dyno, not low end tq. Maybe bike motors resond differently than the engines I am used to. I have no idea. It's not an area I feel my bike needs any improvement in. I'm perfectly happy with how my bike is now ( bone stock other than KLX needle kit/muffler and XR650R forks/ XL brakes). On road power is more than enough. No complaints here.

The XR-L is very torquey compared to a KLR, unless my KLR is just sick. lol. But I think the KLR is a better bike, so don't think I'm KLR bashing!. The XR-L is stuck in no man's land IMO. Gobs of off idle tq like a true dirt bike, but no gearing to take advantage of it. It sits like a dirt bike ( read: uncomfortable), but its too heavy and geared to tall to be used like one. I'd say the XR-L is a little better offroad if you are tall and strong enough to handle it, but it's no fun on road at all. The seat is narrow and hard, the pegs are in an odd position ( behind you and cramped...almost sport bike-ish), the grunty low speed motor feels completely tapped out above 60mph and the bars are extremely low. I can't stand on a XR. JMO, ofc.

For sake of full disclosure, I have only ridden my own KLR and the only XR-L I've been on is my buddy's. I can handle my KLR offroad better than I can handle his XR. To me, the XR feels very awkward and top heavy as soon as it hits dirt, which doesn't make sense. I searched for an XR650L for a long time before finally giving up and buying my KLR. I just couldn;t find any at an affordable price. After riding both bikes extensively, I'm happy with my choice. And I bleed Honda red!
 

·
Premium Member
Joined
·
6,822 Posts
Discussion Starter #9
Double Over-Head Camshafts.
We are NOT advancing the Intake numbers in anyway! The Intake remains 100% totally stock and standard.
 

·
Registered
Joined
·
529 Posts
Double Over-Head Camshafts.
We are NOT advancing the Intake numbers in anyway! The Intake remains 100% totally stock and standard.

Ah, it's the exhaust cam that gets advanced, not the intake cam. Ok. Hmm...I knew that, but got mixed up. I need to ponder on that for awhile.

Didn't I read somewhere that the exhaust timing was actually retarded on the Gen 2's for EPA reasons? So advancing it would just turn it back to normal, right? My brain gets fuzzy, so maybe I'm remembering that wrong also.

Learning disability ftw. lol
 

·
Premium Member
Joined
·
3,024 Posts
I haven't opened up my airbox. If the bike can run 7k-8k rpm now ( and it does), then I cant see how its restricting any power in the sub 2k rpm range. But I could be wrong. A free flowing muffler has been the #1 thing I've done to improve off idle grunt on my KLR. World of difference. For a quick and dirty test I once ran around a few miles with the air box door off. I saw no difference, so I pooped the door back on and decided against drilling any extra holes.
Yes, the airbox mod definitely does far more at higher rpm's than it does at lower ones but it is a much greater restriction than the muffler is. Pulling the airbox door (even for testing) is a bad idea and people that have tested it have come to the conclusion that at higher speeds the airflow past the door and/or the riders leg can actually create a low pressure area that DECREASES air flow. Another thought to consider is that your "butt dyno" works OK at lower speeds but not so well at higher speeds. As long as you've pulled your snorkle, you've got marginally/almost acceptable airflow for a stock KLR.

I'm sure you've read this before, but here it is again;

A lot of missunderstanding with airbox issues.

First, the screen. Airflow gains are not linear. Removing the screen with an otherwise stock KLR airbox will only gain you 2 cfm. The engine won't know the differance. However, with a heavily modified airbox, the gain from removing the screen is 8 cfm. Depending on what else is done to the engine, you may make more power. I doubt that you'll feel it, but a dyno will show it. Butt-dyno's can detect very small low rpm changes, but don't detect higher rpm changes very well at all. You'll likely not detect it, but that does not mean it's not there.

Comparing screen removal to other models is wrong, particularly with the newer sportbikes. With them, the screen often serves another purpose as well. Air distribution in a 4 cyl sportbike can be a real problem, particularly with "ram air". Removing the screen on them can cause very real losses, depending on the model. That does NOT apply to the KLR.

Same thing with air filters. There is only about 2 cfm differance from the best filter (UNI), to the worst (K&N). With a modified airbox, that differance grows to 9 cfm.

Here is the flow chart:

Completely stock - 64.8cfm
Same - Remove snorkle - 74cfm
Same - With UNI filter - 76.2cfm
Same - Remove screen - 78.6cfm
Same - Small "L" cut - 85.1cfm
Same - Large "L" cut, open snorkle area further - 92.4
Same - Remove door - 103.2

Alternate - UNI filter, No snorkle, With screen, No door, No "L" cut - 95.4

All at 2" of water, tested at 1 1/2" and 3" and averaged to 2"

To answer the larger question, how much air can the KLR really use?
....................
A stock KLR about 70-80cfm. With a good pipe about 75-90cfm. A modified motor about 90-100cfm. Having a bit more capacity than you you need will not hurt anything. The effects are not linear though. Going from 65cfm to 75cfm you will likely notice, but going from 75 to 85 cfm you likely won't.

Part of the confusion might be due to the effects of the carb shimming. Since that mod is for a stock needle, the snorkle removal serves not just to add air, but to lean out the top end. The stock KLR till 07 is rich on the top. ( The 08 has a smaller main jet.) Airbox mods have much more effect on top end mixture, so, with the stock needle it also helps straighten out the fuel curve.

Finally the airbox door. You've got to carefull there. You don't have clean air there. It's flowing past that door when riding. You can easily create a partial low pressure area there, depending on wind direction, and where you place your leg!

Cary"


I do not recommend removing the backfire screen (PITA) or running without the airbox door for reasons that should be obvious.

Though a KLR isn't going to have a bunch more power no matter what you do, a KLX kit combined with the snorkle-ectomy and L mod or 4 - 1" holes will have it running properly. don't bother with the little 1" foam filters if you drill the holes - they are useless.

Cheers,
Dave
 

·
Registered
Joined
·
529 Posts
Thanks, Dave. I can't honestly say if my bike has a screen or not. I hope it does, and I didn't remove it if it is gone, but I just cant remember. Bad part of that is I just cleaned my air filter a few weeks ago. lol

I've considered drilling the extra holes, but I ride in so much dust and dirt that I hate opening them up. My bike parks outside and I worry about critters getting in the airbox. I put some mesh over where the snorkel should be. Probably paranoia, but it is what it is. Peace of mind, at least. I'm riding more roads nowadays, but many of them are gravel. My engine spends the vast majority of it's time running 3500 rpm or less. Oh, and my test w/out the airbox door was just around the farm. As suspected, no difference for just trail riding.

I pondered on the MC thing some more and I guess it makes sense to reduce the overlap ( increased cylinder pressure) for more bottom end tq, but I wouldn't know how to contemplate the lack of scavenging, if any. Odd that there isn't more feedback on this topic.

Back to the idea of playing with lash to create more low end torque, I'm not sure how much lash would be a good idea anyway. The factory gives specs, I know, but there's more to it than that. Surprised there are no aftermarket cams for the KLR along the lines of "towing and RV" cams. Maybe there is and I'm just not aware.
 

·
Premium Member
Joined
·
6,822 Posts
Discussion Starter #13
Thanks, Dave. I can't honestly say if my bike has a screen or not. I hope it does,,,, lol

I've considered drilling the extra holes, but I ride in so much dust and dirt that I hate opening them up. My bike parks outside and I worry about critters getting in the airbox. I put some mesh over where the snorkel should be. Probably paranoia, but it is what it is.......
My engine spends the vast majority of it's time running 3500 rpm or less. Oh, and my test w/out the airbox door was just around the farm. As suspected, no difference for just trail riding.

I pondered on the MC thing some more,,,,,,,,,, but I wouldn't know how to contemplate the lack of scavenging, if any. Odd that there isn't more feedback on this topic.

Back to the idea of playing with lash to create more low end torque, I'm not sure how much lash would be a good idea anyway.-------
Surprised there are no aftermarket cams for the KLR along the lines of "towing and RV" cams. Maybe there is and I'm just not aware.
shiny,
With 4 holes behind the battery box, the air filter will Actually be Breathing Cleaner air from under the seat. It will stay cleaner longer.

A rodent guard can be Very beneficial.

I haven't located the 1st thread yet,
http://www.klrforum.com/2008-klr650-wrenching-mod-questions/43777-cam-advance-mc-mod.html

Too much additional tappet clearance can be very detrimental to an engine, especially with shim On Top of bucket. Could 'spit' a shim and break the head.

Exhaust cam advancement may mimic a 'torque'er cam'. And it is Free!
 
1 - 13 of 13 Posts
Top