2006 YZ 125 to 144

[Red Rider 943]

Originally Posted by wamxp1mp

according to ups my motor is suppose to be delivered today!
should have the 144 together by this weekend!!

Sweet. I bet you're excited!

[wamxp1mp]

I have my motor back oh yea and it's definetly a 144 now I wanted to take pics and show the difference etc but I got the motor back completely together from what I can see threw the spark plug hole and exhaust port. Nice shiny new wiseco 144 piston in there and alittle bit of the porting, I can't wait to take this baby out plus i'm dying to see how it sounds. Will have to start it up and run it next to my friend who still has a stocker. RMC sunday for a break in ride and break in the new retro yamaha gear

[Aus_Rider_22]

Sweet!

Let us know how she goes, and sounds!

[Joshtee]

Ya, I am very intrested in how it turns out. Just sent my KX125 cylinder off to EG for the 144 kit.

[Red Rider 943]

Make sure all the bolts are torqued down to spec, and are not just snug...

[wamxp1mp]

Well yea I have to go get some 110 race gas also not a big deal if you saw how nice and clean I keep my bikes you'd probably want me to work on your's for ya

[wamxp1mp]

Taking it down to the local indoor tommorow RMC this is more break in ride won't really tell how much more power it has. At least it's together and running now the exhaust note no judgement yet really I do notice it has a bit more of crack to it's braps sounds alittle more throaty reminds me of a works bike sound. It got a bit more of that 250 ping towards the end I only got like 30 mins of ridding on it putting down the drive way in 1st 2nd can't tell really anything to much this was just more a make sure it's running okay before spending money to go ride some where. Should be able to get alittle bit more of an idea after tommorow - more then.

[Red Rider 943]

Can't wait to here you're report.

After my porting from moto814.com... My bike sounds like a works bike. A real nice deep sound to it.

[wamxp1mp]

The worst has happened!! 10 mins into my first practice session (the bike was nice and warm before I rode it) it was running fine and I was taking it easy on it. It then just siezed!! I've torn it apart and the was just on the exhaust bridge side and just the lower part of the piston over the cooling holes it's all scratched up and there's piece's stuck to the cylinder wall. It wasn't from a lack or lubrication or fuel I think the plating was bad it's only up to the exhuast port bridge there's a few bits stuck to the clyinder. I want to cry I don't know anyone else who'd had this happen this is way wierd. I only have like 40 mins on it this shouldn't of happened. Everything else looks fine and it wasn't running lean doesn't make any sense to me.

[Aus_Rider_22]

Definetly not good news. Not what we wanted to hear!

Can you take some pics? A very similiar thing happened to my YZ just 10 minutes after being rebuilt. We put it down to the bridge of the port being no good. IMO that mechanic should have let me know it wasn't up to scratch before he rebuilt it.

Since then I've changed dealerships and rebuild them myself

[Satch0922]

Contact Eric and I bet he makes good on it. I feel for you though.

[wamxp1mp]

I went and looked at it again and I'm certain it's the plating it lifted and basically bubbled (looks like someone welded it almost) you can feel the ridge's. I don't blame eric I blame us chrome for this I'm thinking maybe a bad cleaning before plating or something. Being that it was the exhaust port bridge area the hardest area I'm not overly shocked.

There's a 3 mm area concentrated right in one area where it's raised up all uneven cause of the bubbling you can see the scrape/rub on the wall where it deformed the piston but there is still cross hatch bout 10 mm's up leading up from the low exhuast bridge port area more bubbling the and some more scraping up the rest of the cylinder wall but not all the way up that looks not that bad really still cross hatching looks cleanable via scotchbrite pad.

The scatches on the piston are confrined to one area lower skirt the rest of the cylinder and other parts are okay the plug was actually reading a light grey (rich conditon) the ring is almost perfect cept a minor nick indent. It was the plating that caused this this happen once before to someone a few years back on an RM. Eric wasn't happen about it fixed it for free. I have to get a hold of him tommorow I'm sure i'll have to be shipping it back. This hardly ever happens I have this black cloud following me normally my bikes don't break unless I crash started in '04 with the KX 125 blowing a tranny bearing now this one. Looks like I'll be back out on the 250 again.

[Coopsvintageyz]

Grey plug color is not rich in my book?... it means lean
Go up on the pilot, and richen up the needle, and main, break the motor in, and then start jetting the bike in.

[wamxp1mp]

haha you only wish it was that simple sorry trick 110 is a leaded race gas that burns at a good 103 the plug I can't use as a diagnostic it could be coated with possible metal flakes from the piston. I called and spoke with him this morning and yea I have to send it back in he told me the plating has a warranty and that he does have another cylinder. He asked me if it was running lean I said no I was using trick 110 with stock jetting you can clearly see the buildup is from the cylinder wall you can see where it dug INTO the piston. I have been taking pics with my digital cam each step along the way I've been tearing it down I haven't taken any yet of the cylinder but I will before I ship it. I feel this is more pain in the *** cause of the hassle of having to ship it back and wait to get it back. From what I can tell the bike was gonna be sweet but I never got it on the pipe I was being gentle on it trying to just break it in I never really got it past 1/4 throttle. I just want it fixed cause this shouldn't of happened at all not with such little time on it. None of the piston flakes melted, the piston on the lower skirt looks like someone took a sharp pin edge and went up in down on it digging into it with lots of pressure over the cooling holes like the bubbling caught the edge of the hole. The bike sized on the up stroke so it should of had alot of lubrication. It stopped about midway up the plating flaking / bubbling became to much and the tolerence closed up the piston just stopped. The bubbling looks like casting slag.

[wamxp1mp]

I went and checked tricks site and I was wrong it's not trick 110 it's trick 114! this is what I lifted from thier site about the fuel I was running for the type of fuel I don't think it was fuel related.

Typical Properties

Research Octane (R.O.N.) 114
Motor Octane (M.O.N.) 106
Anti-Knock Index (R+M/2) 110
Reid Vapor Pressure 6.9
Distillation Curve (ºF)
-Initial Boiling Point 97
-10% 147
-50% 211
-90% 232
-End Point 291
Specific Gravity .72
Color Blue - yup it was blue untill I mixed it at 40:1 with klotz super techni plate.

[Faded]

Originally Posted by wamxp1mp

10 mins into my first practice session (the bike was nice and warm before I rode it) it was running fine and I was taking it easy on it. It then just siezed!!

How warm is 'nice and warm'? Did you heat cycle it at all?

[wamxp1mp]

1 inital very easy warm up 15 min heat cycle barely cracked the throttle it was jsut barely running under it's owner power, let it totally cooled did another for 10 mins road it around on payment/driveway very lightly in first gear talking nothing above 1/4 throttle here avoid any chopping of the throttle everything was rolled on and off. Let it cool before I rode it yesterday warmed it up. first time of the day for 5 mins then again before I took it out on the track had been warming it up again for 10 mins. Plus when I start my bikes from a dead cold I use the choke and avoid any use of throttle for at least a good 30 seconds but since I was breaking it in I was more like a min before I turned it off. When I did ride it on the track I wasn't revving it up either I mean it never really got on the pipe it just about to then I'd back it off to shut it down I think towards the end I got up to close 1/2 throttle but it was maybe for a second or two at most nothing like an over rev far from it. It was running sweet then it felt like it was fouling the plug out (this was mid turn and I was like off the gas I told ya I was babying it) it just went boooog boooooogggg and stopped I was barely moving. I wasn't planning on really starting to rev it for at least another practice session. I felt like I was going about everything right, fresh oil change fresh air fliter cleaned the carb/airboot richened up my jetting back to stock before stock was alittle bit on the rich side. Swapped out the antifreeze for some engine ice fresh high octane race gas premix new plug nothing old was reused. Don't blame me for anything with reasembly related I got the motor back complete but I did check to make sure the head/cylinder was torqued and they was. I even made sure it was stroking threw the motor looking threw the exhuast port before mounting it back into the frame. The last time I siezed a motor due to my error was in '99 when I failed to install a circlip properly.

[Coopsvintageyz]

I would still run the bike rich!, ... I mean blubbery rich.
And then back down the jetting.
When you go back together with the bike, start the bike, and spray contact cleaner around the intake, and base gasket area, you might have a air leak?
I would measure the piston skirt, 10mm up from the bottom, and measure the cylinder bore... piston skirt clearance for a wiseco should be around .002 to .003 thousands (std piston skirt clearance is .04mm to .045mm)
I is very possible that the piston skirt clearance is too tight for the expanding piston, that is why the bridge is peeled off. Wiseco pistons need a little more piston skirt clearance than oem. at least check it out, before you send it back.

[wamxp1mp]

I hear what you saying and I was wonder this myself but the piston is a special one gorr has wiseco make for him.

[Aus_Rider_22]

Originally Posted by wamxp1mp

I hear what you saying and I was wonder this myself but the piston is a special one gorr has wiseco make for him.

It would still be a forged one that expands and could require this checking