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HPbikes YZ144 build and review.

By bboyce,
in Yamaha 2 Stroke

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bboyce

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I bought a 2009 YZ125 that had already been set up as a 144 by a reputable company. The bike was set up to run 50/50 C12/93 mix. I have no where around where I live to get C12 so I decided to contact the company for some input about the bike and asking if I can get the head redone for 100% race gas (prefer AVgas since I have an airport a mile away) and a spare pump gas head. Anyway long story short...they didn't want to give me any info since I wasn't the paying party, even though I had the guys name and all that jazz. They seemed like all they wanted was more money from me and very eager to get off the phone without giving me any info. 

 

So, I decided to contact Derek Harris at HPbikes since he has always been extremely helpful and a frequent poster on here. He told me he can do everything for me and was over the top with giving me info about what he can do. So I decided to sent the cylinder down to him and get a spare head to he can set it up. When he first received my cylinder he stated that it looked like the company merely bored the bike and didn't even match the porting or anything! I'm glad I wasn't the one who initially paid to have it done because I know they charge a lot more then Derek does and seems like they were more concerned about getting it done quickly without doing a good job. 

 

So HPbikes set me up with his porting and machined 2 heads for me like I wanted and I finally got to break it in today. Boy this thing hauls! The jetting he recommended was pretty close, just a little fiddling with the air screw and clip position is all it took. 

 

Now I have ridden a lot of new 250f's, my last bike was actually a 2013 KX250F, so I know what a good running 250F feels like. Also, this is my 4th 125, but first time I have ever had any motor work done to them, so I know pretty well how a stock 125 runs. I broke it in with the race gas head and have the timing advanced as far as it will go. 

 

Initial impressions are that it feels a lot torquier then a 125. Roll on power off the pipe is pretty dang good, which will be awesome for trails, but that's not where this thing shines. Once you hit the midrange, things start to happen quickly. Hit is hard, much harder then any 125 I've ridden, but it just keeps pulling and pulling producing more power as the revs rise. From what I can feel, there is at least double the usable spread of power over a stock 125. Rolling along in 3rd, I pegged it and flicked the clutch and it never even hesitated; could never do that on a 125. 

 

Overall so far I am extremely impressed how much power this baby pinger has. 

 

Keep in mind this is just my first impression, around my couple acre yard, will follow up after some track time soon. My buddy actually has a mildly built 2011 CRF250 that we plan to kind of do a mini-shootout with. I'm pretty certain he is going to wish he had done a 144 over his bike! 

 

 

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Grand Master

Hans Schmid

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I bought a 2009 YZ125 that had already been set up as a 144 by a reputable company. The bike was set up to run 50/50 C12/93 mix. I have no where around where I live to get C12 so I decided to contact the company for some input about the bike and asking if I can get the head redone for 100% race gas (prefer AVgas since I have an airport a mile away) and a spare pump gas head. Anyway long story short...they didn't want to give me any info since I wasn't the paying party, even though I had the guys name and all that jazz. They seemed like all they wanted was more money from me and very eager to get off the phone without giving me any info.

So, I decided to contact Derek Harris at HPbikes since he has always been extremely helpful and a frequent poster on here. He told me he can do everything for me and was over the top with giving me info about what he can do. So I decided to sent the cylinder down to him and get a spare head to he can set it up. When he first received my cylinder he stated that it looked like the company merely bored the bike and didn't even match the porting or anything! I'm glad I wasn't the one who initially paid to have it done because I know they charge a lot more then Derek does and seems like they were more concerned about getting it done quickly without doing a good job.

So HPbikes set me up with his porting and machined 2 heads for me like I wanted and I finally got to break it in today. Boy this thing hauls! The jetting he recommended was pretty close, just a little fiddling with the air screw and clip position is all it took.

Now I have ridden a lot of new 250f's, my last bike was actually a 2013 KX250F, so I know what a good running 250F feels like. Also, this is my 4th 125, but first time I have ever had any motor work done to them, so I know pretty well how a stock 125 runs. I broke it in with the race gas head and have the timing advanced as far as it will go.

Initial impressions are that it feels a lot torquier then a 125. Roll on power off the pipe is pretty dang good, which will be awesome for trails, but that's not where this thing shines. Once you hit the midrange, things start to happen quickly. Hit is hard, much harder then any 125 I've ridden, but it just keeps pulling and pulling producing more power as the revs rise. From what I can feel, there is at least double the usable spread of power over a stock 125. Rolling along in 3rd, I pegged it and flicked the clutch and it never even hesitated; could never do that on a 125.

Overall so far I am extremely impressed how much power this baby pinger has.

Keep in mind this is just my first impression, around my couple acre yard, will follow up after some track time soon. My buddy actually has a mildly built 2011 CRF250 that we plan to kind of do a mini-shootout with. I'm pretty certain he is going to wish he had done a 144 over his bike!

Sounds like a killer bike....

Next time you talk to Derek ask him where my powervalve spring is? Been like 2 months.....

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bboyce

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Go for it! The cost to do it is about the same as what a 4 stroke exhaust even costs. I'm a bigger guy (well that's relative for a 125- 175lbs) And after having a few 250f's I was a little hesitant going back to a small bore 2 stroke, but decided even if the bike is underpowered for me, there is nothing as much fun as a 125. So deciding to go full out 144 was never really planned but boy am I glad I did it. It feels nothing like a 125 (or144 for that matter) and more like a 175. Splits the 125 and 250 2t imo.

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DirtSmoker250

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That sounds really nice.  I've already put way more money in my RM125 then it is worth so I might as well hang on to it and try the 144kit.

 

The only problem is I just rebuilt the top end and bike has 5 hours on it.  Looks like it will be coming with me to the track/trails the next few weekends.  I have to get at least 25 hours out of it or it would of been a waste of money for my last top end job.

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bboyce

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That sounds really nice. I've already put way more money in my RM125 then it is worth so I might as well hang on to it and try the 144kit.

The only problem is I just rebuilt the top end and bike has 5 hours on it. Looks like it will be coming with me to the track/trails the next few weekends. I have to get at least 25 hours out of it or it would of been a waste of money for my last top end job.

I know what you mean. Hey ride it stock a lot so you can be even more excited for some major power increases!

Put 1.2 hours on it today in some muddy woods where we were breaking in some trails. Probably not the ideal place for the race gas head but it performed excellent. Hit was a bit much with the timing full advanced and my jetting needs a little more work, but all in all super happy. Bike still lugs down low pretty dang good but really gets up and rips when you twist it. I'm running stock gearing now and I desperately need to put a 14t sprocket on, it just pulls through the gears so fast.

Will update more after easter when I cam get out on a track.

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tnat1

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I bought a 2009 YZ125 that had already been set up as a 144 by a reputable company. The bike was set up to run 50/50 C12/93 mix. I have no where around where I live to get C12 so I decided to contact the company for some input about the bike and asking if I can get the head redone for 100% race gas (prefer AVgas since I have an airport a mile away) and a spare pump gas head. Anyway long story short...they didn't want to give me any info since I wasn't the paying party, even though I had the guys name and all that jazz. They seemed like all they wanted was more money from me and very eager to get off the phone without giving me any info. 

 

So, I decided to contact Derek Harris at HPbikes since he has always been extremely helpful and a frequent poster on here. He told me he can do everything for me and was over the top with giving me info about what he can do. So I decided to sent the cylinder down to him and get a spare head to he can set it up. When he first received my cylinder he stated that it looked like the company merely bored the bike and didn't even match the porting or anything! I'm glad I wasn't the one who initially paid to have it done because I know they charge a lot more then Derek does and seems like they were more concerned about getting it done quickly without doing a good job. 

 

So HPbikes set me up with his porting and machined 2 heads for me like I wanted and I finally got to break it in today. Boy this thing hauls! The jetting he recommended was pretty close, just a little fiddling with the air screw and clip position is all it took. 

 

Now I have ridden a lot of new 250f's, my last bike was actually a 2013 KX250F, so I know what a good running 250F feels like. Also, this is my 4th 125, but first time I have ever had any motor work done to them, so I know pretty well how a stock 125 runs. I broke it in with the race gas head and have the timing advanced as far as it will go. 

 

Initial impressions are that it feels a lot torquier then a 125. Roll on power off the pipe is pretty dang good, which will be awesome for trails, but that's not where this thing shines. Once you hit the midrange, things start to happen quickly. Hit is hard, much harder then any 125 I've ridden, but it just keeps pulling and pulling producing more power as the revs rise. From what I can feel, there is at least double the usable spread of power over a stock 125. Rolling along in 3rd, I pegged it and flicked the clutch and it never even hesitated; could never do that on a 125. 

 

Overall so far I am extremely impressed how much power this baby pinger has. 

 

Keep in mind this is just my first impression, around my couple acre yard, will follow up after some track time soon. My buddy actually has a mildly built 2011 CRF250 that we plan to kind of do a mini-shootout with. I'm pretty certain he is going to wish he had done a 144 over his bike! 

Great post, i have a feeling you went to the same guy my stuff was done by as i bought the motor off of a buddy and he used that one dude shop in wisconson, i just took it apart and brang it to my guy TZR Racing and he said the same thing that none of the ports were matched and all it was is a 125 bored out and wont make but a couple HP more than a 125 but with correct porting major gains will be had. There is a reason that dude sells his 144 kits for so cheap. FYI to all thinking about it go to a good shop that ports it also at the same time.

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harrperf

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Lol, he said he sent me one already. After a few weeks I called him and he said he would send me another..... Still waiting on either...

Still nothing?

 

I HAVE to have something wrong with the address...

I think other members have gotten theirs in canada, right?

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