OK. Now that it's established that doing the intake side is only a half a loaf, I decided to do the exhaust side, too.

The cam timing was very easy, but I found out that I don't have anything in my garage tooling ensemble that will remove the ACR from the shaft. It's gonna take an arbor press or similar fixture to do it right. Went ahead and continued with the cam timing part anyway but knowing that it would likely be coming out again later for ACR work. It's no big deal now to get in there fast and get things done.

Got the engine assembled without incident, with no spare or missing parts during the process.

On starting, it had a little different exhaust note. Also, I have stock 42/14 gears and it seemed to want to feather itself along in 1st gear (although weakly) where it wouldn't do that before.

After it was warmed up, I shut it off to try a restart and sure enough, I had to go with Marcelino's advice to go have a cool drink for a little while (couldn't remove/reposition ACR on shaft, remember?)

After I went inside and got properly dressed for a ride, and waited a while, went out and got it started, but still with a little difficulty.

Like yesterday, did a short loop in town to make sure that nothing catastrophic would happen and then took it out on my longer testing road. All the while I was remembering yesterday's clutch incident and knew that if the bike stalled for any reason I would be screwed due to inability to start it hot. Nonetheless service and sacrifice in the name of my fellow KLX'ers kept me going.

Yesterday with the intake mod only I was holding 1/2 throttle against a 15 mph headwind. Today I was holding 1/2 throttle against a 25 mph headwind. I'd say there was some power gained from the mod. Can't quantify it with charts but the paint marks on my throttle grip confirmed it well enough for me.

The bike was getting knocked around by the wind hard enough that my seat of the pants dynomometer wasn't able to feel the extra power. Maybe someone doing the full mod in a more hospitable environment might be able to report on it that way.

I have a small windscreen on my bike and from time to time I'd duck my head down below it to listen for any weird engine noises but everything sounded fine.

This mod looks like the real deal. Just make sure you get the ACR thing taken care of when doing the mod, unless you like long waits between starts.

I won't play with jetting until it's been ridden a while in different conditions. Definitely gonna take care of the ACR thing, though. We have an arbor press at work (plus a full blown machine shop across the street) so I'm gonna remove the cam shaft and take it in tomorrow.

Already the tank and plastics are off the bike to help it cool down...

Hope this is helpful.

 

Honestly I don't know. What I do know for a fact is that now my intake noise is negligible...and it easly pulls the front tire up...without ANY convincing. And I have stock gearing. After seeing what the intake cam did... im going to dive in and do the exhaust. This week.

 

Yeah, I did both cams and rejetted.

I did exactly what you said with the spark plug and the bike is definitely running lean.

NOTE TO ALL: I just completed this mod with the BB 351 kit. I have the stock pilot jet with the kouba fuel/air screw 2.5 turns out and the biggest main jet that came with the Dynojet kit (132 main) along with the needle clip 4 notches down from the top with two washer on top of it and the bike is still running lean. I'm going to my local bike shop to see if I can get a bigger main jet and try to figure out the conversion for the Dynojet kit so I get the next size up from Dynojet's #132 main jet. Just know that your bike will be running lean if you do this mod with the BB 351 until you really up the main jet. It should also be noted that I live in Ohio which is about 900ft average above sea level.

 

before you go and get a bigger main,,, get a bigger pilot.
Remember that the main is 3/4 to WFO throttle.
Are you lean in that range?? does the bike kinda surge when WFO?
don't go fattening up the top when you need to fatten the middle to low.
what makes you think it's lean? the plug? it is difficult to read plugs these days with all the junk and no lead in the fuel. FEEL what the bike is doing. if it's twitchy and surging it is USUALLY an indicator of lean. BTW how did you break in the 351?

 

Be careful about how you clamp the cam when using the press. A few years ago, a fellow KLXer had his dads shop try to do the ACR retiming and ended up breaking off one of the tabs that hold the timing sprocket on.

Make sure you have your stock cam position marked before you get near the press and know where you want the ACR to end up.

Just in case you haven't seen the ACR writeup:

KLX ACR mod

Ride on
Brewster

 

Thanks for the heads up!

 

I know it is lean from middle to low for sure. The throttle hesitates if I give it a quick turn. If I leave it sit for too long idling(1300-1600 RPMS), the fan will kick on because it's getting hot due to it being lean. I'm going to start off with upping the pilot jet one size and see if that helps. Also, there is a lot of decel popping so that leads me to believe that it's too lean as well. You'll have to elaborate what you mean by twitchy and surging because I don't think the bike is doing that. I ran the bike as hard as I could, ***** to the wall and got the motor nice and hot and then just cut the power without letting it idle or anything. I then pulled the tank and checked the plug. It is a new plug, but it looked the exact same as when I put it in there. And it was dry and clear.

When I broke in the bike, I initially started and let the bike idle for about ten minutes and then shut it off and let it cool completely down. I then started the bike and just rode the crap out of it for about 15 minutes.

 

Can someone do a post on the ACR work? Post some pics of
The whole process. I've read about past ACR issues and this
Part of the mod is holding me back.
Marcelino, check your pm's!
Is a new valve cover gasket necessary? Sealant?

 

Yeah I agree with brownie2.... I need more info on the ACR part of this. I’m fairly mechanically minded but don’t quite understand the ACR part of this mod....

I’m also a little concerned that this mod may take away some of the reliability of the machine/easy maintenance.

I don’t really need the mod for power more just to get the intake noise down a little cause it annoys me.

 

You need to make a wodden clamp to hold the camshaft , drill a hole and then use a reamer to mimic the profile of the cams , then use 2 long bolts with big flat washers to tighten the 2 halves together . Caution ! the camshafts are the strongest at their lobes and the weakest at the sprocket tabs .
I used two wooden bloks from a pallet , I threw them away so I canīt show you any fotos .

Brownie2 : You donīt need a new gasket unless the old one is too dry or itīs broken . Use a little silicone ONLY at the half moons .

Brewster : Youīre from California , could you do the ACR for the people who donīt have the skills or the means to do it ? I think you did quite a few ACR mods , have a press and also an aluminum support for the camshaft . I donīt doubt that you understood the mod perfectly .