I am edging closer to doing the MCM but I haven't worked up the courage quite yet. I feel like I'm standing on the end of the diving board with all the other kids yelling "jump!".

 

Come on in, the water is fine!

It's all in your head... it is really no different than adjusting your valves. To get to the shims, you have to pull the cams... and then make sure you get them back in correctly. Only difference is that you are changing the picture of how they are supposed to look when aligned correctly. I pulled the picture of the correct alignment for the MCM up on my shop PC and compared it at least 20 times before I hand-spun it the first time (where are the EX and IN letters, do the notches in end of the cam look right, are the lobes pointing correctly, how many teeth can I see, etc, etc)...LOL

I took another short ride after work last night..... No way I will ever put it back to original, too much grunt down low where I like it



Next subject: I got some of that washable green A/C filter material and bolted it on top of the lidless airbox. As best I could tell, it ran just fine... but at idle in the shop I caught a whiff of maybe it running rich.. so I pulled it off. The intake noise was reduced (I really only wanted to filter out any large globs of mud), but that may have been my ear just getting used to the extra sound. I'm gonna just run it lidless as God intended, digging ruts all over the farm with the new-found torque.

Unrelated addition: I swapped out the front Scorpion XCMS for an S12-XC..... YES! Not DOT rated (and won't last long on pavement), but I'm more likely to bust my a$$ off-road than have an officer take the time to search for the tiny DOT stamping on-road (rarely ride on-road, have a Versys for that).

 

Ok, about running lidless, I've been "fighting" the "armchair quarterbacking" about this subject for years. I know that "common sense" seems to drive much of the negative assumptions - But since I never accept someone else's idea of common sense - I researched the subject and studied the issue on the bike.

My results were that the shielding provided by the various panels +rear fender around/surrounding the top of the airbox is such that any "activity" that would cause issues with a lidless airbox would also cause issues if the snorkel were still in place. If all panels are fitted properly, there is very little to no increased exposure to a "engine damaging" event. Any water intrusion event that would stop a running engine, would do so whether lidless or not.

Obviously, non-oem rear fenders that do not seal the airbox area correctly will actually funnel everything you are riding over/through directly into the area above your airbox - not an optimal situation whether you run your snorkel or not..

I never found any post, by anyone, that had personally experienced a (bad) situation whereby a snorkel would have "saved the day" over running lidless.. Xcrcarpenter's situation certainly suggests that all those running lidless should check the integrity of the panels and rear fender fitment in order to insure the proper "shielding" of the area above the airbox..

FYI, there is also a "notion" out there that lidless running will foul the air filter quicker than running a snorkel - HELL YES IT WILL! A 23-24 hp lidless KLX will process waay more airflow than a 18-20 hp snorkeled KLX. So, if you don't want to keep your air filter clean, rejet back toward stock, put the snorkel back on, and ride your wheezing KLX...

While I'm "on a tear", running a KDX snorkel obviously allows more airflow than the stock snorkel - But it is only a small incremental increase. KDX snorkels are still more restrictive than running the lid w/o snorkel - as per DJ stage II - so the performance offered with a KDX snorkel falls between DJ stage I and DJ stage II.

Side note: Others that have studied this subject have determined that lidless is not enough - That the area above the airbox is shielded TOO MUCH for best results - and some have perforated/drilled the airbox for even more breathing capacity, reporting positive results. While my riding "style" would safely allow such additional breathing mods, such mods do increase the possibility for water intrusion.

 

That reminds me, I need to order up a spare filter or two to keep on the basecamp trailer for long weekend rides

 

Dump a bucket of water on your air box or spray up under the seat with a hose and no lid and snorkel and see how it runs!

I have drown a bike without a lid. Now you know someone who has drown out a bike in a creek. It wasn't fun getting out of the creek and being towed to the truck.

You ride the street, no lid no big deal. Go out and blast through some water crossings, get up around the edge of the seat with the splash. Lid and snorkel may be what keeps you from having to push out of the water, then try to clean out the engine.

You clearly are the "arm chair quarterback" when it comes to the snorkels and where/when they are needed. I have actually measured and know that the KDX snorkel is near 2 times the size of the stock snorkel and is within a few tenths of a square centimeter the same size as the air intake boot to the carburetor. For off road it is sufficient for the need if not adequate for all conditions. Do the measure, do the math. And try it. Did you ever actually try the KDX snorkel, or did you just toss the box lid? I'm betting the latter... since that is what I'd do if I had the SF model and didn't splash around off road with it.

 

You'd have drowned your engine with or without a snorkel.
I don't just ride the street.
Your posit and conclusion regarding the KDX snorkel and intake boot is flawed - a restriction at the airbox inlet cannot be justified (from a performance standpoint). The removal of induction system restrictions CAN be justified.

Wow, my posts today show a need for an attitude adjustment.. Perhaps I'll give alcoholism another try - I've never been very successful with alcoholism.

 

Don't bet on it, the snorkel channels water behind the air filter. What is flawed about a duct that is as big as the biggest inlet going to the carburetor? What part of calculating area did I miss? I do realize there may be a bit of gain from not having the direction change of the air, but I also realize it is entirely possible that the size of the duct may cause minimal effect. I see that there may just be minimal effect at the highest rpm and none in the middle.

Now, when did you actually do any comparison using the KDX snorkel for your judgement? I just don't see you going out and buying one. I see you just tossing the lid the way a lot of people do. Then poking fun at anyone who sees value in the part due to the possibilities that may be out there where they ride. No proof, just pure assumption.

 

So I rode around all day lidless... and between the MCM and DJ144 setup... I LOVE the power. But in the end, the noise issue won out as I just didn't like the extra intake noise. I put the lid back on without the snorkel and went back to the DJ128 setup.

With the DJ144, I spent most of the day in third gear as opposed to my normal 2nd gear for tight woods. The extra grunt meant I didn't have to use the clutch as much and could tractor out of places easily. The the DJ128, I'm back in 2nd, but the MCM makes the throttle feel snappier to me.

No wire for me on KACR.. went with just spring removal. Next time I go in to adjust the valves (as i mentioned above, they are close to the tight end of spec), maybe I will find someone to press the KACR off the cam.

QUESTION: Does the 351 setup benefit from the KACR? I will most likely eventually go for the 351 kit, as that was my original plan. Will the electric start handle the kit without the KACR?

 

Ahh, sorry I brought it up KLX678 - I had a bad attitude day..

Obviously, running lidless is not for everyone. E.G. What offended Abrams is sweet music to me, and waterboarding couldn't get me to replace my airbox lid..lol


Starter motor strain/stress on 351 w/o KACR - this is an unknown.. It would certainly seem that you'd want the KACR functioning.. Also, the whole subject of 351 with MCM vs Non-MCM is debatable..

 

On open course days, the noise wouldn't be too bad, but I ride around my cousins' houses most of the time and don't need to annoy them any more than I have to (they own the land I live on...lol).

I read your posts about 351/MCM and had it in my mind to reverse it if/when I do the 351. That won't be anytime soon... I still can't outride the MCM'd 250... and suspension work comes first