KX VS 150R

[tang8u]

KX vs  150R

I am new to the board ??. Great INFO Here!!!

My son rides a 100 in stock form. Stock is easy for me to take care of. We once had a FMF fatty on the bike. Worked great at the track, but the stock pipe worked better in the woods. Makes more low end toque to hop stuff. With out putting  weight on the flywheel.

I have a buddy that has a 150R that rips in the woods. All 4 stroke Grunt. It just grips.

My issue is Tyler runs Cross Country JA races. OMRA.com   It is a series like, ISDE?s cross country 70 mile loops in the woods or desert. The 150 just pulls on the KX.

The KX is more lighter and nimble, and once it is on the power band the 150 is gone, but?.I want to build a engine that will walk away from the 150.


Tyler's  Bike



Stock
133 main
Stock pipe
FMF 92 Ds Forestry Muffler
Lowered 5 mm more oil added to front forks
Runs 40 to 1
125 clutch lever,and perch
125 clutch spring
Berrent basket and clutches
Light coil 40 watts...runs a 35 watts pencil beam head light

Races OMRA series JA
Looking for any Help on a Rebuild
http://www.omraoffroad.com

http://www.hookit.com/members/foleytyler/default.aspx

[Sapper]

Like I said in the other post, try a stroker, you'll be surprised what 3.8cc's can do.

[tang8u]

Sorry Sapper I am new to the sight

Like I said in the other post, try a stroker, you'll be surprised what 3.8cc's can do.

I search 3.8cc's I have not found any info On a big bore

I search 112 this what I have found

Has anyone here converted their KX100 to 112cc?  If so, did you do it all by boring it or does it also require a new rod?  How did it change the power (low end, top end, all over, etc)?

First off what year 100 are we talking about ? The 95-97 kx100s had alot different power delivery than the late model ones, since they came with powervalves. The bigbores on the 100s usually give you more low-end grunt. If you are looking for a screamer then you want a 92-97 BW kx80, send that topend to Ecir Gorr at Forward Motion the Delta Vforce3 reed cage will fit and a 28 mikuni TM off of a rm80 bored to 30mm and FMF makes a rev pipe. That combination will clean any late model kx80 or 100 up.CBX

We have a 2009 KX100.  We'd like to keep all of the grunt we can since he mainly races cross country.  Most of the bikes he races against are either 105cc, 112cc or 150cc.  He does pretty good against them with a stock bike (2nd and 3rd places since we bought it) but were just doing a little research on how to make it faster.

My ? are ??..Is the stroker worth the $$$ spend?what I mean by this is?What is involved. Is it an easy task or..

I love 2 strokes?.easy Cheap    I do not mind spending money , But if the thing start braking. Hmm  Tyler used to race a 65 ?Bullet prove in the mud or snow?..

I have gone throw 2 cylinders on the 100 because  of cracks on the intake side runners. The bike has never left Tyler in the woods. But ?.I have never got a real good Reason why they cracks in this area. vibration, we have never flamed the exhaust side even in Bend. That would be are desert high speed, in the main for ever area.If I go to a bigger bore that means there is less heat  transfer. I know buddies that cart these engines and steel sleeve them. But a cart motor is made to run at???8000000000 grand forever. One power band no bottom no mid not upper..    Get my drift hear.

Any info or sight links would be Great?..

Tang

[Sapper]

sorry for such late replies. Been busy and haven't been on here much.

Anyhoo. A 150 and 100 are dead even. My suggestion is for better grunt in the woods, drop a tooth in the front. It will lug around then pull like madd.

[dirtjunkie85]

it sounded like you didn't want to throw a heavy flywheel on there but it may help give it more luggability. My biggest recommendation would be a Rekluse auto clutch. Mine never ceases to amaze me. On hills and nasty trails that i think my 250 wont handle it just continues to get traction. other than that if you can find a big bore go for it and spank those dirty 4 jokes!

[squeak]

I know this is VERY late, but i built a kx100 stroker and it will run dead even with an 03 kx 125 untill i run out of gear and the 125 has about 2mph top speed on me. its got a stock pipe, a rad valve, stroker crank, ported by eric gorr, and a 428h conversion with a 2 tooth smaller rear sprocket. i dont race it, just use it as a play bike in the woods and on dirt roads, and have never raced a 150r, but feel like i could outrun one