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KLX140L Build

By Jerry Matta


New KLX140L build.  I'm going to build a fairly cheap and reliable bike that would be great for any type of mini fun.  The suspension came with it, so that is taken care of.  At least I hope.  I haven't tried it yet.  But its going to be a simple build with the following: Exhaust, carb, cam, 170cc kit, CDI, Pegs, graphics, powder coated frame.  That's it.  Very Basic and straightforward.  

I ordered a Big Bore Kit, pegs, CDI, small intake, and exhaust.  It's coming from Indonesia, so we'll see how long it takes.  But, everything cost me just about $100 more than a Yoshimura exhaust. 
*****I ordered it on June 27, it got here by July 3.  That is crazy fast!!!


July 4th update.

Stock pipe is 6 lbs 4 oz
Norifumi Pipe is 4 lbs 12 oz.
Upon initial start up, it started instantly, which it didn't before.  
Tomorrow I'll ride it around my street and field to see if I can tell a difference. After that, I'll swap out the CDI, then start on swapping out different carbs.

For the carb test, I have two for the stock set-up: a 200x carb and a KX65 carb. When I get the 170cc kit installed, I'll test a XR200 carb and a PWK KX100 carb.


*Note: Carb my have been richined up before I bought it.

Pipe with *stock everything.  Cold starts much quicker. You can barely hit the button and it starts up. Seems to pull through the gears better.  There's a difference but not night and day.  

Next: CDI

The CDI can be swapped out without removing anything, which is nice.  However, it's bigger than the original one, so a bracket or something needs to be made.  How did it work?  It's hard to tell, it didn't rev out any different.  Maybe it pulled through the gears a bit stronger, kinda like a street bike, but I can't make that claim.

With the KX65 carb, it did help it mainly on the bottom and mid.  I ran a stock 25 pilot, stock needle , and a 150 main.  (stock is 180).  I used a bigger intake manifold ($12 from indonesia),  and a 1 1/2" coupler from Lowes.  I also, used the end of a TTR125 airboot over the carb, and a machine aluminum piece that goes inside the end of the KLX airboot to keep it from squishing, with the rubber coupler over everything with a couple hose clamps.

**Update:  The bike is torn down to powder coat the frame. At the same time, I'm installing a 170cc big bore, cam, roller rockers, and a PWK 28 carb. 
NOTE: The Cam bolt is a LEFT HAND THREAD.   That would've been nice to know.​


With 170cc kit, cam, pipe, cdi, I've been trying to get a number of carbs to work.  I've tried a PWK 28, XR200 carb, KX65 carb, and the only carb I can get to run is the stock carb with a 105 main and a 40 pilot.  I don't know what the deal is.  I think it's the nearly three inch intake track on this.  There's not much of a way around it, since the fuel tank is cut away towards the rear part and drops down in the front thanks to the perimeter frame.  I did or a normal short spigot manifold just to test it out.  Those are a pain too.  I think it's a Amal to Mikuni conversion manifold.  JetRus and Sudco want $80 for them, but I think I found one on ebay for $13 plus shipping.  I hope it's the right size.  

Update:  PWK28
Because of the horrible stock airboot, I went to a pod filter.  (I'm not a pod fan)  
Here is the final jetting: 
Temps in the 90's, not much humidy

42 pilot
clip middle
100 main
1 1/4 airscrew

Revs bottom to top really good and starts.  

I am going to have Dave Miller make me a stainless airboot. Around a 3" - 2". That's about 400% increase in surface area over the stock one, which is only 1.4" at the airbox. 



Latest Update:  Dave Miller passed away. RIP

This bike got stolen, but about 4 months later, I got it back.

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