My son has a 2003 KFX50 (LT50A) I removed the Exhaust from the cylinder and eliminated the washer that restricts the exhaust flow. That helped with the top end, but where he rides it is sometimes deep loose sand. Getting started off is sometimes impossible and he needs to be pushed to get going. Will putting on a Htrick Pipe help increase his Low End Power? What else can be done to Increase the Low End? I have also heard that FMF makes a Pipe for this little 50, has anyone heard about this pipe? I looked thru his Maintenance Manual and there isnt any mention of a Brass Sleeve located between the slide and slide cover in the Carberator. Also on these newer model 50's is there a slotted steel Restrictor in the Intake Manifold? when removing this, is it necessary to rejet the carb? Thanks to anyone who responds. Rick

rickscheid@***.net / If someone whats to give me some advise on getting his liitle 50 up to speed. He wants to start racing in the
50 class, but right now it just doesnt have much

 

Raptor720 Said:
Pro Rider
Southern California, California


Sat November 02, 2002 8:24 PM


LT-50, LT50A, etc.


Here you go:

1. Remove the exhaust from the cylinder and eliminate the washer that reduces exhaust flow. You will now experience more top speed.

2. Remove the stock air filter and install a K&N or Uni 2 stage foam pod. This requires that you get an air filter adapter. I use my own adapter but you can also get the filter adapter used on the Go-Peds. It will work just fine but use should use some red thread lock on the two screws (if they back off, they will go into the motor).

3. Pull the intake manifold and remove the hardened steel slotted restrictor. I heat the manifold and then place a large screw driver in the slot and turn -- The screw driver was kept in the freezer so that it would draw the heat out of the steel restrictor. Once you get it out, you can back fill the void with JB Weld and then remake the hole so that there is no transition. It is very easy.

4. Pull the carb. Remove the slide cover and eliminate the brass sleeve located between the slide and the slide cover. Next, raise the needle one clip position (make the needle higher). While you are there, pull the float bowl and locate the pilot jet. Remove it. You will see that there is a second pilot jet located just behind the one you removed. Leave that one alone -- it is the correct size for the unrestricted engine. NOTE: On occasion, the fuel needle and seat is too small. If you are skilled at jet work, you can attempt to drill it and hone a new seat for the needle. This may only be necessary if you cannot get full throttle to hit without falling off within 15 feet.

5. Oil injection. Remove it if you want. Your engine will be alot happier. At a minimum, you can reduce the rate of oil.

6. Clutch. This is slightly more involved but can be done. Simply increase the spring tension on the clutches. If your clutch is old, just buy a new one and modify it before installation.

7. Exhaust baffle. Remove it and cut the last 3" off. That will eliminate the spark arrestor function so drive safely. I braze a down turn on the exhaust tip just to direct the exhaust away from the plastic and to direct the noise into the ground. I hear a couple of people have made pipes for this machine by why???

8. So you want more power ---- Pull the cylinder. Raise the cylinder so that the transfer ports are fully open when the piston is at BDC. Then correct the squish by decking the cylinder to achieve a .030" squish. I forgot the head cc number I use so just go with a static compression number of 160. Watch the jetting and the spark plug heat range. That B6 is a burner!

Now, after you consider all of this work realize that for about a grand, you could have had a Kasea super mini 50. It is the same size as the LT50 but offers electric starter, auto choke and a CVT transmission (just like the full size Skyhawk 50). It also has front and rear suspension and full floor boards. I have one as a pit bike that really moves. At Pizmo, I can haul my 200 pound rear just about anywhere.

-------------------------
Slow riders please stay to the right!

MY QUESTION: After doing ALL these Mods, should you replace the Spark Plug with a higher plug? Also after cutting the exhaust Baffle, is it necessary to put the remaining end back in the pipe or just leave it out and the pipe completely open? I wasnt able to heat the intake manifold and pop out the slotted restrictor, rather I had to put a rotary file in my high speed and grind it away, I opened it up to the same size as the inside diameter of the intake manifold itself. I will put a #70 Main jet in place of the #55, I hear that produces good results. And replace the Air Filter with a Foam Pod type filter. I'm wondering if using a slightly higher octane gasoline may help it out some too??? Washer has been eliminated from the exhaust manifold also.
When he graduates to a 90cc I will look at either the Eton (Eton Racing has produced some awsome quads) or the DRR 90, I have heard that they are hard to beat, with or without Mods.

 

Im presuming if i do this, i will have to add the two stroke manually to the petrol.

What difference does this make?