Yz 144?


14 replies to this topic
  • Kibles

Posted September 30, 2006 - 04:20 PM

#1

I got an 05 yz 125 and I am looking to get it bored and ported. I was wondering if anyone had any good input.

Does anyone here have a YZ 144? Any companies I should specifically avoid? Any companies that you would recomend?

Thanks

  • pamatt

Posted September 30, 2006 - 05:45 PM

#2

Athena sells a very nice kit. It is a simple bolt on system. No porting is needed.

  • Kibles

Posted September 30, 2006 - 05:48 PM

#3

Does Athena have a kit for the 05 yet? A link would be nice.

Thanks

  • pamatt

Posted September 30, 2006 - 06:09 PM

#4

Check with the local dealer. If you can not find it email me.

  • qwert321

Posted September 30, 2006 - 06:44 PM

#5

do a search on ebay there on there for just over 600 and the kits come with new cylinder, piston , head , and power valve quite hte deal if you ask me

  • dtkiko

Posted September 30, 2006 - 08:33 PM

#6

looks like a very enticing deal you got there, mate!

how much horsepower and torque will the new bore to 144-cc gives to the bike, any idea? in no way do the 250Fs could compete given this new size, i bet :thumbsup:

thanks for your advice.

kind regards.

  • burgunder

Posted October 01, 2006 - 07:25 AM

#7

Contact and search Eric Gorr. (144 kit, port, polish, case mods) After all my research, I believe that is the route I am going to take when I am ready.

  • kevin204

Posted October 01, 2006 - 07:26 AM

#8

The 250F's are still smoother and easier to ride, but the 144's have more peak power, and if you can keep it in the meat will easily be competitive with them, while having 2 stroke simplicity.

  • dirtkid

Posted October 01, 2006 - 09:32 AM

#9

i heard 144s have some diffulty with the exhaust ports.. ihave no idea what that means tho... i just got mine bored to a 137.. i like.. ALOT!!!

  • Kibles

Posted October 01, 2006 - 02:51 PM

#10

i heard 144s have some diffulty with the exhaust ports.. ihave no idea what that means tho... i just got mine bored to a 137.. i like.. ALOT!!!


Who did the work? And if you don't mind me asking, how much did it cost?

Thanks :thumbsup:

  • dirtkid

Posted October 01, 2006 - 03:44 PM

#11

i love my 137 bore.. it really pulls on top.. and its just all around more power
i dont know how much it cost for the bore.. ill check my receipt.. cause i walked out of the dealer spending about 1500 for just about an entire new engine... bearings, gaskets, piston, wrings, tranny, shifting forks, bore out.. etc.. i would say more than a hundred.. i konw you can get a 2mm bore for like 40 bucks.. ill give you name of it when i think of it...

  • Zenith

Posted October 03, 2006 - 10:13 AM

#12

I think you'll be disappointed if you think a YZ144 is going to smoke a 250f. You will have a bit more peak power (and only a bit because 250fs are making more and more power each year, just look at the 250SXF) but in terms of area under the curve the 250f still be superior, and peak power means very little to the average guy riding on slippy dirt. It will certainly go some way to evening things up, just don't expect to be blown away.

I think the problems with the exhaust ports you're talking about are where the porter has to widen them considerably. The piston ring will tend to bluge out into the port slightly as it goes by, over time it causes the ring to wear faster then normal. Hence the reason you see tuners suggest replacing the ring(s) sooner on overbores. The same thing can apply to the transfer ports...

  • mcdrz

Posted October 04, 2006 - 07:17 AM

#13

I think you'll be disappointed if you think a YZ144 is going to smoke a 250f. You will have a bit more peak power (and only a bit because 250fs are making more and more power each year, just look at the 250SXF) but in terms of area under the curve the 250f still be superior, and peak power means very little to the average guy riding on slippy dirt. It will certainly go some way to evening things up, just don't expect to be blown away.


This is actually a pretty accurate depiction of the situation. The 125, if built properly can not only make a bit more peak hp, but can be made to have several more peak hp, but that does not necessarily equate to good rideability for most people.

More peak hp and lowered rideability certainly does not equate to a more competitive bike in most cases for most riders (maybe the special few that can keep it in the small zone). There is no cheap fix to the 125/250F battle. I think any 144cc conversion needs to be a well thought out and integrated attack on power band width and torque characteristics to make it more like the 250F. The reality is that the 125's still spin up faster and have a decided advantage in many areas...torque and hp delivery width is the true weak point though.

My philosophy is that you don't worry so much about peak hp, but focus on using the mods to get the modified 125 to the best it can be on power band width, torque and hp delivery characteristics for your use/want.

With that said, even if you double the power band width...you still can't match the 250F for width, but you still get the other benefits of the 125 (weight, faster revving, little gyroscopic effecting handling, less expensive maintenance, ease of maintenance, etc)

The best 144 is one that has been given planning, professional installation, and a integrated system (BB piston, head mods, porting, pipe, reeds/reed block, carburation, etc) to meet your goals.

  • gyd

Posted October 04, 2006 - 10:25 AM

#14

Picking up 144 built for my son to test today, will be testing it tommorow. Dyno numbers are:

1. Stock YZ 125: 29-30hp 15-16 lbft torque

2. YZ 144, FMF Factory Fatty, Shorty Silencer, VForce 3, Extensive Power valve modification along with port configuration and head work.

37 hp 20 lbft torgue, pulls past 12,000.

Engine builder tuned in chasis and said would pull 3rd gear starts with 48t rear sprocket and he weighs 165lb.

  • mcdrz

Posted October 04, 2006 - 02:07 PM

#15

That is exactly my point, a professional tuner with goals. 37 hp isn't setting any good 250F's on fire, but I'll bet that the 144 pulls through a much broader range then previously and the 20 ft lbs of torque aren't giving anything to the 250F's. The benefit with this configuration is still revving quicker than the 250F's and reduced bike weight.

Try some well thought out gearing changes to maximize delivery width as it revs quicker still. Make it deliver the forward momentum like a 250F does. Try a light FWW and/or gearing like 14/50.





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