MCP carb kit for KLR 650 - Page 3 - Kawasaki KLR 650 Forum
2008+ KLR650 Wrenching & Mod Questions For repair, maintaining or modifying discussions related to the newly updated 2008 and beyond, Generation 2 KLR650 Motorcycle.

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post #21 of 43 Old 03-04-2020, 09:33 PM
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Location: Melbourne, Australia
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I have a 2004 KLR. As far as the carb goes I replaced the fixed fuel screw with a variable one and a 42 pilot and a cableless choke. Intake including snorkle is std as is the exhaust. It runs the std 145 main jet. Apart from the above and a Thermobob the bike is stock. I used to work as a photographer, journalist and bike tester for various motorcycle magazines in Australia some years back. I managed motorcycle racing teams with good success nationally and we even made a trip to race at Daytona and scored a 4th place in the Battle Of The Twins. It was a lifestyle of late nights, flow benches, dynos and test days and I loved it. When I got a KLR I never once mistook it for a performance bike, I just wanted it to run as well as it could. With that in mind I ordered an MCP kit. I had read what my fellow KLR riders had written and I had no reason to doubt their word that were happy with the improvements. I didn't care about numbers, I wasn't going to race it, only that they believed it was an improvement over stock and they were happy with their purchase.

As the bike still has stock intake and exhaust and main jet I knew I wouldn't get any more total hp but if I could get cleaner carburettion and make the bike more enjoyable to ride then I considered it money well spent. I am happy to say I got what I wanted. I am still running the same jets as previously but I have to say I was surprised at the difference the needle made. It has a very strong idle, pulls cleanly from a few hundred rpm less than before and revs quickly and cleanly to the redline. It is the clean carburettion that makes the difference for me, it feels crisp. It without doubt makes the bike more enjoyable to ride for me. The off/on throttle response is really good and I find that riding through the twisties in the hills, that improved response is really noticeable. It feels like it has some real zap between corners. I have also found that not only is the idle stronger but it is far more consistent and returns to the idle setting far better. I had noted this idle speed variation since I bought the bike new.

A couple of things that surprised me. I can ride the bike much slower and not have to ride the clutch. I have a regular test circuit that includes some second gear hairpins that I have always had to ride the clutch a little on the way out, not anymore. A couple of weeks ago I was riding through a small town and got stuck in a traffic jam. It was barely moving stop/start stuff. I found at one point the road was almost flat with a very slight decline. I was able to ride in first gear with the clutch out just chugging along at idle. I have never been able to do that before. My idle is set at 1100rpm. I have also discovered that I find the bike easier to ride in the dirt and I certainly didn't expect that. I have a regular dirt section ride which has some deep gravel on the track with plenty on a number of corners. The crispness I described does make the bike feel more nimble and the more instant response at low revs is a real bonus to the confidence in the loose stuff.

My regular test circuit road is 160kms (100miles) and my fuel consumption on this has always been around 20.5kms/lt which I believe is 46.5 US mpg. After fitting the MCP kit I got exactly the same mileage, 20.5kms/lt running 91 octane unleaded. It's not complex and exact science but it is the same guy on the same bike on the same road, trying to ride the same way with 2 different carb needles and getting the same fuel consumption result. It is certainly a good indication and over time I will test it over a much greater distance.

Does the bike have more power? I know in terms of outright hp it can't unless I change some more things which is not my intention. It does however feel like it has more power but that can be deceptive. It revs so quickly to the redline and in a couple of drag start tests I did, it felt much quicker. I would think that what I may be seeing is not more horsepower but a more consistent output through the rev range. Gotta say though, it's a lot more fun.

While some in this thread appear concerned with power improvements, that's not my priority. It's a KLR. For me the real world improvements are as I have stated. They are very noticeable and make the whole KLR experience a better one. The MCP kit is not going to cause anyone to start ripping knobs off but I am very happy with my purchase and would definitely recommend it to others.
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post #22 of 43 Old 03-04-2020, 10:00 PM
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@Melbourne Mike, your description of your experience echos what I found on my 2014.5

Love the smoothness and response on the road and dirt! Loving this great riding, MCP kit KLR!



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post #23 of 43 Old 03-05-2020, 03:06 AM
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Originally Posted by pdwestman View Post

+ 3 mpg with similar or better over-all drive-ability is worth considering.
If 6 % fuel mileage improvement is important, you have a point!

What additional power output would you expect simultaneously with the improved fuel mileage?


I'd assume the fuel economy improvement and simultaneous additional power available from the MCP needle would be as effective and fit Harley CV40 carburetors. This commonality (between Harleys and KLR650s) would open up a considerably larger (than KLR650s only) market for the product.

“You better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, you’re gonna be dead.” "John Russell" (Paul Newman), Hombre
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post #24 of 43 Old 03-05-2020, 09:58 AM
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Melbourne Mike,

Good post. A couple thoughts;

- we are talking about a couple different things; the MCP kit vs. stock and the MCP kit vs. the KLX kit. I have zero problem believing that the MCP kit is an improvement over the stock needle. The question for me is how much of an improvement it is over the KLX kit, if at all.

- You have the experience to know that you can't have gotten the big power increase some have claimed. While it's true that the KLR isn't a racebike, will never make big power, yada, yada, etc. the tools we use, like dynos, are what can PROVE (or disprove) what we think we are feeling......I've lost count of how many people believe their KLR is way faster after a louder silencer is installed where the proof shows something else (for eg.)

- Paul makes a good point in that the engineers that designed the KLX needle did so for a slightly different setup and therefore, even though it's far better than the stock needle, it's logical that something else out there could be even better......could a guy figure that out in his garage in the middle of the prairies in Canada? Apparently so if these reports are to be believed. I still struggle with the fact that once MCP tried the KLX needle (which happened after he developed his modified stock needle) he said, right in this forum, that the KLX needle did the same thing and there was no reason to modify the stocker.......I'm not sure what's changed since but info has been sparse.

It's too bad that I have my 2001 ripped apart for a 685 install because, up until now, I had two identical KLR's - down to tires, gearing, jetting, would have been easy to install the MCP kit in one and leave the KLX kit in the other and drag race them side by side with my son and I swapping bikes.....not as good as a dyno, but it would have given me what I would like to know. Too bad...

2 cents,
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post #25 of 43 Old 03-05-2020, 10:12 AM
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excerpt from previous posts from MCP for consideration;


What i can tell you is this.

My kit won't change peak horsepower on a properly jetted bike.

The stock jetted bike the difference is DRASTIC to say the least (I'm sure similar to dropping the KLX needle mod)

My modified needle i'm sure is very very similar to the KLX needle, a couple large differences but essentially the mid range power will be the same or very close to the KLX set up ya'll are runnin.


2) So

Ya'll going to be surprised at the result. Guess i won't be opening an online mod business. The answer is all too easy.

All along i've insisted the stock needle / slide at rest position created a very dangerous off idle lean area right around the 30-40 mph cruising speed. ALL STILL TRUE

All along i insisted the O Ring was the answer, - STiLL IS

The O ring allows a 42 pilot jet to run on a stock bike without creating a "RICH" spot right below where the lean spot used to be. 1.75 turns out on the mixture screw (2nd or 3rd clip from the top on KLX needle) OR Stock needle with 0 Shims.

The stock main jet is a bit rich and a 140 works perfectly on my stock 09 (snorkel yank only)

Pls note, the stock non adjustable needle negates the main jet having any effect. The KLX needle is the way to go. The stock needle can easily be modified to work fine, but the KLX needle is the answer.

I ended up in nearly exactly the same place with my stock needle custom grind and a 40 pilot compared to the 42 pilot and the KLX needle. (the latter does work better and less fuss) BOTH WITH THE O RING INSTALLED.

All this messing around because of not checking my jet drills. This is the set up i thought should work in the FIRST PLACE before i started messing with grinding the needle.


O Ring installed
42 Pilot jet
1.75 turns out on Mix Screw
Klx needle clip on the 2nd or 3rd groove from the top (I'm running 1st groove with 2 shims = 2.5 clip positions)
140 Main Jet
Snorkel Yank is the only mod to the airbox/exhaust

in other words get the EM klx needle kit and add the o ring and you're done

Sooooo, perhaps after reading this some of you can understand some of the skepticism being expressed. I'd also point out that MCP isn't the first to try his hand at a different needle; Dynojet and JD have their own needles too......predictably, they work about the same as the KLX needle.

The setup I am running on my KLR's is almost identical to the setup Dredd posted in his last post. One difference that I can see is this O-ring idea and it's effect on off idle throttle response.....

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post #26 of 43 Old 03-05-2020, 10:20 AM
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In fairness to MCP, one of his last posts; (emphasis by me)

Thread update

small recap >

stock jetting (08+) seems to be designed for max fuel economy and almost seems like its being used as a governor also. The bike is slightly lean from 1/8 - 2/3 throttle but from 2/3 - Full throttle its very lean and not very healthy for the engine. The needle is so bad you can put in as large of main jet as you want in because the Needle won't allow larger main jets to have any effect .... running the 22 cent mod (washer under the needle) helps lower throttle applications but has little effect from 2/3 up. Throttle response is also improved with the 22 cent mod.

The KLR Jetting Is Horrible Out of the box !!!! Luckily there is a race bike that uses the same motor and carb. the KLX650R.

The KLX set up, which pretty much gives you all the power at once, is pretty nice for sure. But I've adapted my own needle set up that gives you the best of both worlds. All the power you want when you turn the throttle, but nice smooth power increases in relation to throttle application, which improves handling/ride ability, all the while helping to preserve fuel economy especially at higher speeds. You end up in the same place as the KLX set up you just have a throttle that is a bit less sensitive and much more manageable.

I did a lot of riding towards the end of the season and dialing on the needle, i still have a couple ideas i'm working on in other areas but the needles are done. Dialed in perfectly. If anyone wants one let me know, the roll on power is nice n smooth not abrupt like the KLX needle but you end up in the same place when you open it up.

The o ring mod mainly helps machines with erratic idle issues. It doesn't hurt either. (it does require a half size larger pilot jet)

As stated before, needle version 1 was too aggressive, even more twitchy than the KLX needle, My custom needle version 2.0 is spot on.

I really like the MORE manageable throttle response of my custom needle set up. The KLX needle is nearly all or nothing (meant for racing), the stock needle gives you a DUD for a ride. I'm surprised someone hasn't developed something somewhere in between before me.
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post #27 of 43 Old 03-05-2020, 10:27 AM
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Having read these reports and having gone through all the threads again, I'm thinking of giving the O ring a try - he may be on to something there. It seems pretty clear that any advantages of the MCP kit/needle are related to delivery, throttle response and feel and as long as one isn't expecting or proclaiming big power or mileage increases, the rest is believable (to me)....we will see. I'm thinking of trying the whole MCP kit but I'm not sure I like the non-adjustable needle idea.


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post #28 of 43 Old 03-05-2020, 10:29 AM
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Originally Posted by Damocles View Post
I'd assume the fuel economy improvement and simultaneous additional power available from the MCP needle would be as effective and fit Harley CV40 carburetors. This commonality (between Harleys and KLR650s) would open up a considerably larger (than KLR650s only) market for the product.
I will suggest that due to the HD being a 2 valve cylinder head, different cam profile, longer stroke engine that the needle profile would need to be quite different from a KLR.

That was my point about the newer designed dirt bike model KLX needle verses the KLR requirements. In carburetion fuel flow, those requirements are measured in tens of thousands of an inch along the entire active length of a needle.

Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
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post #29 of 43 Old 03-05-2020, 11:34 AM
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Originally Posted by pdwestman View Post
I truly wish MCP the best of success.
Then, if you buy, install, and test the MCP kit, reporting your experience and conclusions, I will reimburse you HALF the cost (in US dollars) of your acquisition expense!


Don't know about subtle differences between CV40 and CVK40s; perhaps a special, model-specific needle for Harleys is in MCM's future! Given the similarity between the two Keihin carburetors (CV40 and CVK40), I'd think the same principles providing additional power and fuel economy simultaneously would apply. The Harley customer base appears considerably larger than the KLR650 prospect population; surely, the HD riders would appreciate the same advantages.

“You better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, you’re gonna be dead.” "John Russell" (Paul Newman), Hombre
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post #30 of 43 Old 03-05-2020, 04:43 PM
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I've been in contact with MCP and I'll be ordering a kit to test out when I have some time.

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