2006 YZ 125 to 144

[wamxp1mp]

I know very well it's a forged piston not the first wiseco I've ever ran, just uploaded pic's to my photo album. This is after it's been wiped clean, you see the piston crown was turning black. I also inspected it after cleaning and the upper right exhaust port near the bridge a flake is missing. Notice the piston look at those cooling holes! The piston is starting to break n flake apart from catching on the cylinder edge on the exhuast port.

[Coopsvintageyz]

OK, from the looks of your piston, you are very hot, and lean! the oil is siring to the top of the piston, if it were rich, it would have been washed off on the crown of the piston, with just maybe a little bit of carbon in the center (about 25mm circle of carbon) also if you look real close, you can see discoloration (bluing) of the piston skirts. the piston got very hot!
I am still thinking a piston skirt clearance issue.

[wamxp1mp]

There is no blue colorations to the piston nor cylinder it's the camera flash maybe lighting reflection. When I look at the parts by eye there is no discoloration like that. The cylinder is on it's way back to get fixed shipped it back 2 day postal.

[kx_rider53]

Here's a link worth looking at from eric gorr about pistons.
[Only registered and activated users can see links. ]

[Coopsvintageyz]

You see all the black on the top of the piston, that shouldn't be like that, you should have some wash on the outer edges of the piston...( no carbon at all, around the piston edges about 10-15mm all the way around) The piston has gotten hot some how.

[wamxp1mp]

Well I asked steve125 and he said after looking at the pics (he has a yz 144 '05) done by eric. He thinks that the exhaust bridge wasn't relieved enough. But that it's fixable.

[wamxp1mp]

The YZ 144 is alive again and running much better oh yea!

[kx_rider53]

Glad to hear that. Bet your going to have a blast on it.

[Aus_Rider_22]

Originally Posted by wamxp1mp

The YZ 144 is alive again and running much better oh yea!

So what went wrong and how'd it get fixed?

[wamxp1mp]

I would say part of it was jetting I got told wrong that the stock jetting was okay just make sure you ran a good gas. Well the note I got back stated all they did was hone it for me but I know they did something to exhuast bridge cause the porting looked cleaned up and the edge's were much smoother. Well to make sure I didn't sieze it again I went up two on the pilot from #40 to a #50 I left the needle and air screw alone and went up 4 on the main jet to a #450. Well it's running alot better now I got alot more time on it today then last time before it seized. Remixed the gas at 24:1 for the first gallon for the initial break in the 32:1 for the rest of my gas I have. The plug electrode is black in color but it's not oily residue black so it wasn't fouling out but it wasn't as crisp as it could be. From what I can tell even with the mid/top porting I had done it still pulls/torque's better off the very bottom over the 125 even with this slightly rich jetting much better than the 125 did. All kinds of Midrange and it pulls all the way threw the top it freakin screams big time now. I'm gonna have to gear it taller cause first gear was nearly useless it torque's threw it much faster now more 200/250 like. Takes quite a bit less effort to pull it up into wheelie's. I can't wait to take it out on a track now! I rode it then swapped right away to my friends '06 CR 125 it made very similar power compared to my YZ when it was stock. Even with the FMF fatty and Vforce 3 reeds and the 13/53 gearing (my yz is 13/48!) the 144 was much more torquey quite a bit more power. It was worth every dollar! mad props also go out to EG cause I F'ed it up last time and I 2 day mailed it to him, he fixed it gave me a new top end parts and shipped it back next day air! All I have to say is 250F what?! I should have a Vforce 3 on the way for it soon, I really like the 144 so far it exceeded my expectations it's gonna be even sweeter when i get out on a good track next month weather premitting Washougal baby!

my friend with the CR was definetly jealous cause he wants to do that same thing to his CR.

[Aus_Rider_22]

Sounds like it's all sorted now which is always a good feeling!

[Dirtjump9]

Sounds great! Just remember that the more oil in your gas, the less gas there is so it will make it run leaner in that respect. But don't take my word on it:
Keep us informed... I might get my bike done before Eric closes....

[wamxp1mp]

oh yea I wanted to add that when I took apart the bike I know a few of you was saying it got real hot that's why it's all black looking on top colorwise. Just an FYI the new piston has a coating on the piston dome on the top side there is like a blusifide (spelling?) looks like what vertex does to thier skirts so it was this dark grey in color from new. That was different cause I havent' ever had a wiseco piston with this type of coating on it. Normally there the bare aluminum color with thier electra (sp) coating. I would say the piston reminded me alot like the GP piston I had in my '02 YZ 125.

I'm not sure what I want to do on gearing for it yet, it just seemed like it was going threw 1st and 2nd gears faster it was able to torque threw them quicker. My friend was saying I should get a 14 up front and keep the 48 in the rear. I was concerned before but it doesn't sound like such a bad idea no more with how fast it was getting into 3rd. But it could be to much it worked awesome on the '01 YZ250F he had when it was big bored to a 290. Similar thing happened with it, it allowed for the gears to be ridden in longer and it still torque'd better off the bottom over stock.

No body ever said a big bore was going to be easy just wait till i turn it yellow.

[wamxp1mp]

I got my Vforce V3 for it going to install it this weekend and since it's been so nice and sunny all week finally gonna take it out to a track. The track is [Only registered and activated users can see links. ] it's decent length track little bit MX and SX in design on a river bed so it has sandy soil that robs power. Can't wait to take it out and really test it out on this track.

[Steve 125]

It wasnt the jetting, the exhaust bridge was not properly relieved. A bigger piston pulls more fuel through the carby than stock. So the stock 410 main would provide plenty of fuel for the 144. Just for comparasion I run a 370 main(summer)with the fuel I use. No exhaust bridge problems what so ever.

[wamxp1mp]

Well I don't think i'll get that lean on the main so fast this past weekend out on a local sand track I did a plug read and with the 450 main it came back nice n tan I still think it might be just alittle to rich off the very bottom I have a #50 pilot in it now stock air screw setting 2 1/4 turns out. I'm gonna try a #45 pilot and maybe turn the air screw back in to only maybe 1.5 turns out. Other wise it's running sweet.

I was waiting to track the bike out to the track before I gave a real opinion of it first. Went to local track called riverdale raceway it's down near mt. st helens! It's right near a river bed so the soil is a sandy/ash mixture, I figured it would really test out and show any power losses or if it was making more power.

Oh yea it was making more power all right! sections I used to rail in 3rd wide open on the 125 the 144 torque'd threw a gear higher little twist of the throttle an the front end came up. The section before it there is a big 180 sweeper turn that is really soft before I had to down shift into 2nd to get a good drive. Then you come up over a small table and there's a small mound about 5 feet afterwards. Before it was 3rd gear like wide open and just bounce threw the acceleration bumps maybe If I hooked up good enough before a I could wheelie. On the 144 (took me awhile to notice this cause it was pulling so well) on the 144 it was 3rd gear for the turn and then 4th gear alittle brap like a 250 up n over the table land get on the pipe and the bike would just wheelie right over the track garbage! It was quite a bit easier to do this on the 144.

My friend was out there on his '06 CR 125, I followed him dead on into this corner drifted wide way out into the soft stuff he went inside and we both got on the pipe hard bout the same time. The inside of the corner was more solid ground base and I was out in like 3 inches of loose sand normally it just killed the 125 unless you really clutched it. All I did on the 144 was twist the throttle it railed the corner no problem almost 250 like and I managed to pull past my friend and make the past stick cleanly! I pulled like a good bike length on him and I most of had to a traveled a good extra 20 feet more then him cause I was way outside of the corner. He was on the inside in the good fastest line. I pulled a similar feat later on down a very fast straight away after this double it wasn't smooth yesterday either all chopped up from all weekend of practice. The kid on a SXF 250 '06 even! bike looked new, I pulled up next to him we're dead even going over the jump. We land and get on the pipe/gas hard dude wasn't about to let me pass him either cause I really had to rail it. Freakin 144 not only pulled right with it dead even soon as I hit 5th gear I pulled a bike length and said see ya!!

Also had a guy who was ridding alittle bit faster than me in another session trying to get by me on a CRF 450 and wasn't able to. Especially when I pulled him coming out of this corner I held off behind for a few laps and then slowed down pulled over to the side of the track lookin for my friend, as the guy on the 450 rides by he was lookin at my bike I'm sure he thought it was a 250 at first I bet he did a double take when he saw the 125 pipe! With a gearing change so I can get alittle more out of each gear it will be faster!! you guys can keep your 250F's this is better!! I hope the weather is nice in a month can't wait to hit up washougal on it!!

[wamxp1mp]

I just ordered from motosportsoutlet a FMF factory fatty and the power core II shorty for it. Had to wait they was back ordered just got in the new batch like yesterday. When I called on tuesday they quoted me the regular fatty price for the combo normally it's more but i'm gonna get it for the regular fatty price they quoted me.

Next on the list will be some black boyesen ignition / clutch covers I hate the silver color they don't offer it in the aluminum color like my KX. Then I'll just have to slowly start pickin away online for the hinson clutch setup. At least the older '94 up inner hub and pressure plates work on the newer motor it's only the basket that is unique to model year.

[Satch0922]

excellent write ups...sounds like a blast to ride!

[wamxp1mp]

If the weather holds up i'll be able to get some more feed back on how I like it i'm going to one of my fav tracks tommorow washougal! I just hope it's not overly muddy.

[LoKi]

Doesn't look good for Washougal this weekend. Bring your rain gear.