It seems that while the cam mod adds some bottom end pull, I never got the bike to run great since. Spent alot of time with jetting...lid on/off...
I`m just wondering if any of you have returned to stock (undone the cam mod) with the exception of some jetting and exhaust. I`m also wondering if my lean surge has anything to do with the cam mod as I`ve tried larger pilot and main jet settings as well as needle heights with no change really.

Just looking for thoughts. I have a few months now before I pull the bike out again.

 

Not an easy answer to that, ian. The preference for or against many of the modifications to any bike can be somewhat subjective. Many/most of the known mods like a pipe, jetting, etc. when done properly do increase performance, but probably the real takeaway for doing those is the improved drivability and response more than any big leap in raw, measured power. For me personally, I'd find it hard to go back to what I felt what a flat, dull response inherent in the bone stock bike. But people are different, and some don't like the increased sound from an aftermarket pipe. It's your bike. Set it up or take it back to stock if it satisfies your enjoyment level for the bike. I've questioned the logic at Richard for the 40mm carb deal, but in reality he shouldn't give a flying flip what I think about it because it's his bike, time, and money. Pure, Star Trek, Spock-like logic doesn't always apply to hotrodding bikes, cars, or other machinery at the enthusiast level. Much of it is pursued just because we want to "see what happens".

 

Based on reading the MCM thread, my own experience, and your post, It seems your MCM did not work. It was my first mod - dead stock bike - on one afternoon - took 2 hours - the before and after was very noticeable. As I got the AFR more and more correct ( using a DJ 136 now ) the entire powerband continued to "wake up", especially the top end. The bike has never run poorly - It always ran just fine - it's just that the dyno charts had me continually richening the AFR's and finding mo-powah...
if your experience is radically different than mine, you should recheck your cam timings carefully. (You don't have to post your findings..LOL)

 

I did mods one at a time so I would be able to see what each upgrade provided the stock and in my opinion underpowered machine. I added a powercore 4 without a rejet and was surprised how much that alone did as I wanted more but knew I was going in the right direction. Next came a high flow air filter and snorkel removal and a rejet as intake mods will lean things out quick. Those changes alone make it a different bike and no longer a dog. I then added the powerbomb header and it was noticeable but not a big leap like the two previous mods. It did help the front wheel come off the ground. I rode the bike like that for 6K miles with some gearing changes to see what I liked. Went back to stock gearing as I do more road than off road in my old age and that was street friendly. I never messed with the cams as I was good at stage two but finally did the 351 BB. All of mod previous mods worked with it and I only needed to jet again and it is no longer like the bike I first bought, it's sick, in the lower gears the front comes up and in 6th I can pass nearly anything on the road without a down shift. So it's up to the owner to decide what to do and how far to go. Myself since I knew it would be a 351 sometime I'm glad I never did the cam mod as I would have to undo it anyway down the road.

 

I pretty much had the same experience, I never could quite get it dialed in. The last straw was when I was riding in Nevada with a 13T sprocket and I had to slip the clutch in 2nd gear to get up steep dirt climbs. Mind you, thats not the MCM fault, thats a jetting at altitude issue. Non the less, it was never an issue before with stock gearing pre MCM. I put my timing back, jetting back to my original DJ 128 stage 2 specs, still got my Q4 slip on, filter, lid on with snorkel removed and the bike is back to its old self. I got terrible fuel economy with the MCM and the jetting I had, below 3K sucked, it was always cold blooded and it was very temperamental to changes in altitude. I'm not discrediting the MCM and I truly believe the problem was getting the carb dialed in but I got sick of taking it apart and dealing with jets. Plus, my old set up was tried and true for the SF Bay Area and up to 7 or 8k feet and I liked that. I'll just order up a big bore and be done with it. One last thing, I know some people might be thinking "oh he must have done something wrong". Not saying I'm the greatest tech because I'm not, BUT I have been working on cars for 15 years and I've been a professional tech for over 7. I work on a lot of European vehicles with no key ways or specific timing marks so things can get hairy fast. I know timing and I understand it well, I also know I did the MCM correctly. I did one last check before I returned the timing back to stock and indeed I did it correctly. Honestly, I wish it had worked out for me because who the hell doesn't want "free power".

Just my two cents.

 

Interesting, as I've been going back and forth about whether to do the mod since there'd already been reports of people not happy with it. But since I am running out of odd mods to fool around with at 250cc, I might play around with it just for the exercise, and to be able to determine proper a/f mix with the stock carb/MCM.

Marcelino has already said the gain was more pronounced when combined with other usual mods on near stock bikes; less to zero on bigger bores due to restrictions downstream of the carb.

So I may gain little to none, but there's only one way to find out!

 

I have roughly 28 hp in my klx, I rode a buddies 100% stock (minus 13 tooth front) and it is a slug! I was plain shocked how slow it was. I almost got sick to my stomach, I literally gave it full throttle and it didn't go ANYWHERE! Never. Again. Back. To. Stock.

 

NorcalKLX, with your bike running tip top again, it would be nice to see a dyno chart on it.
You are running the DJ kit the way DJ designed it - for stage 2.

Or perhaps try duplicating the power wheelies in my video with your bike...? Video link is on my signature line..

 

Hey, long time no talk. I still plan on dynoing it. I want to do a BB kit in the future and I definitely want to dyne the differences. Honestly, if time allows, I wouldn't mind doing the MCM and checking it...just to see where it was as best as I could get it. I've been busy getting married, going on my honey moon and going to school so I just haven't had time for much...and to be honest money either. I'll definitely keep everyone posted on any changes though, believe me.

On a side note my wife bought me Wolfman E-12's for the KLX. Already got them mounted up! I'll update my blog soon as I get some photos.

Oh, as for the power wheelies. It was hard as **** to loft the front end with a 13T and the MCM. I had to REALLY slip the clutch around 6K. The 13T with my current mods it lifts 1st and 2nd with minimal effort. I love it! Not sure why my carburetion was so awful with the MCM. I really wanted it to work damn it.

 

I had no problem with the MCM, but did have a bit of issue with the jetting as done per the general KLX300 needle and pilot. I was using a Dial-A-Jet to compensate on top, but it was just a bit too much a reach, I had a bit of a surge. I did the ground wire deal, to no avail. Then I did the bigger main with the other jetting per the general set up, plus the Dial-A-Jet in middle setting - no more surge. It pulls fine in general even with the 15/39. I have the KDX snorkle, the needle, richer pilot 2.5 turns, 128 main, Dial-A-Jet, drilled slide and air jet, and stock exhaust with the MCM.

The one major plus is that the bike starts nearly instantly so far in weather down around 45-50F, choke off in less than 30 seconds running time, that with the compression release disengaged. Stock, the bike had to crank over probably 10-15 seconds to start and was cold blooded. I think the compression release is pretty much a waste on the small bore with electric start, as I've said, Honda and Yamaha don't see a need on their 250s with electric start. Honda did use it on their kick start 250s though. The general 250 cheap mods seemed to do well, although swapping between the 650 keeps knocking the snot out of any seat of the pants impressions on the modded 250... just no comparison, but still the 250 is sooo light feeling... the reason I have it for off road. Not too sure about mpg, haven't really checked. That'll be done in the spring.

From what I gathered the MCM isn't a negative with the bigger bores, just not any noticeable gain. That's what I thought it said.