I do compression tests on small engines with automatic compression releases all the time... but wether it has a compression release or not, I've never been able to get a small engine to run below about 90psi as a general rule of thumb. I think thats what they mean... if you are below 90psi with the throttle wide open and the engine cranking strong, you got problems. If you got say 120psi like TNC mentioned, ur just fine and ur KACR is working fine. Taking ur KACR off to get a true reading really will only give you a judgement to the wear and life left in ur top end, its not going to help with anything else, mayble cool to know but thats about it.

 

I'm not sure of what you would accomplish with that. Maximum compression pressure is with all of the valves closed. And, any additional volume like part of the exhaust port would reduce the readings.

It may not be an acceptable solution to the problem, but is a very good indication of the problem...........carburetor. Have you pulled and inspected the pilot jet? The hole is very small and can easily be restricted.

Ride on
Brewster

 

amen to this post, mines a pain too. I always figured it was due to lack of fuel. Where did you get the primer bulb? Christ after mines even running warm and i bring it into the woods and I stall out over a tree..i still need to pull the choke to get her pack..middle of summer!

 

Also anyone ever swap out a carb, different kind.. I know Bill sells them as an option with the 351 kit.

 

@Brewster: thanks for the input. The volume of the manifold would indeed reduce the compression reading somewhat which is why I was thinking that at best it would only provide a 'truer' reading as opposed to a 'true' reading. Regardless, it's all just an academic thought. I have no intention of actually trying it.

The carb has been off numerous times for rejetting, drilling, and float level check. All jets have been inspected and cleaned every time. *Indeed I traced a recent high speed misfire back to a flake of aluminum caught in the main jet. All this is to say that I am confident that the carb is set up proper. This is why my su****ions have recently shifted to the KACR

@Likes To Thump: Thanks for the input too! My compression tester only threads into 18mm & 14mm plug holes, so I can't confirm compression until I can track down an adaptor for the KLX's tiny plugs. *In any event I have no reason to suspect poor compression unless of course it's due to the KACR is acting up during starting (the whole point of this thread).

@TNC: Checking the fuel level with a clear tube shows the level to be right at the mating surface between the body & the bowl. With meniscus it's tough to see the precise level but it certainly appears within the +/-1mm *tolerance specified in the manual. I have concerns that raising the fuel level any further would cause a rich running condition (?).

@KLXhunter: I sourced the primer bulb from a snowmobile shop but it's typical of what you might also find for marine applications. *It's not the most elegant solution, but it's the closest I have found in almost a year of troubleshooting this problem to getting the little bugger to start quickly and reliably. *I'd encourage you to give it a try if you've exhausted the common fixes! *Once the choke is engaged, just a light squeeze on the bulb while cranking and it'll fire right up within the first few revolutions.

Typographical errors by*iPhone

 

You might search the KLR650 forum for info on the KACR fix. I owned a new 2008 KLR650 and they had a similar hard start problem. I never did anything to mine, but I read several times on the 650 forum of Kawasaki authorizing the dealers to grind some off the KACR to fix the problem.

Here is a typical post from a KLR650 forum: "Take your bike to Fay Myers they will do the KACR grind. Its done under the Kawasaki warranty, A quick commpression check will tell if it needs to be done. Only affects the bike when it cold out. So they will have to check the commpression."

Norm

 

Hell my 2012 klx250 wont start if its below 30 outside,full tank.

 

Regarding the fuel level, on second review of the photo I took it’s perhaps a tad low (?). The level of the camera lens is clearly above the top of the float bowl so there is a slight perspective distortion in the image making the fuel level appear slightly lower than it actually appeared to the eye.

 

I did the KACR pin grind on a 2008 KLR650 I had. It always started fine until one 26° morning at Yellowstone. When I got back from the trip (Mexican border to Canadian border and back) I ground .020" off the pin. I think the KACR problem only applied to the 2008 bikes.

That being said, I doubt seriously that the KLX bikes have a problem with the KACR. At least mine doesn't. The 2009+ bikes may be different. Mine's a 2006.

Assuming starting technique is good - that is no throttle applied when starting cold, I would look toward carburetion.

What is the warm idle speed?
What is the position of the throttle plate with the idle screw against the stop?
What idle jet are you using?
What is the idle mixture screw setting?
Do you have an aftermarket mixture screw? If so, what brand?

Ron

 

@ Ranger: Thanks for the detailed questions. I don’t have the bike in front of me but I am reasonably confident in the below answers:
• What is the warm idle speed? - ~12-1300RPM
• What is the position of the throttle plate with the idle screw against the stop? – I have not taken a specific measurement per se, but at last check I recall the plate being just slightly open when returned against the idle speed screw stop.
• What idle jet are you using? – You mean pilot jet? Stock
• What is the idle mixture screw setting? ~2.25 turns out
• Do you have an aftermarket mixture screw? If so, what brand? - Stock

As mentioned, once started the bike runs beautifully. It warms quickly with choked idle at ~4000RPM (drilled starter at .019), then pulls well & revs stumble-free up to redline. I have a slight case of the ‘pops’ when shutting the throttle down at mid revs but nothing worrying.

Operation is unaffected by ambient temperature. I am currently riding in -10C to +5C temperatures but unless I use the primer, cold starting remains equally difficult regardless of -30C or +30C…