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HONDARACER
03-17-2009, 07:22 PM
Riding along downhill at 60mph and all of a sudden the back tire locks solid. Bike goes into a wild skid and I am struggling to keep the bike upright. Finally gained enough control to pull the clutch. People behind almost ran over me as of course I had no brake light on and basically slamed my brakes on in front of them. Just very fortunate I didnt dump and skid down the road and get run over. Stopped on the side of the road and shook to poo out of my pants. Called the tow truck and waited. Bike was not siezed any more but had no compression.

Why did this happen? My theory is the carb iced. I had done a plug chop and found the jetting good so that the only thing I can think of. I will post pics of the barrel. I believe these barrels are CNC machined as the ports a very nice and tidy.

PJ ENGINEERING
03-17-2009, 09:09 PM
I believe these barrels are CNC machined as the ports a very nice and tidy.

They are not CNC machined in the ports, the faces bore, holes are but all the ports are cast.

why do you think carb Ice ? in all my years of working with 2 strokes i have never seen this.

I take it you were off the throttle when it siezed?

HONDARACER
03-17-2009, 09:25 PM
THe ports are CNC around the edges to chamfer the port. THey are doing that now to keep all the ports the same. You can definatly tell a vast difference between all the barrels I have and the 2009 model.
http://www3.telus.net/smokeskull/sieze1.jpg

http://www3.telus.net/smokeskull/sieze2.jpg

HONDARACER
03-17-2009, 09:27 PM
I am wondering if the oil pump didnt fail also. I dont recall any smoke when I started it this morning.
If the jug is marked with AB, what piston shold be installed? I have a 2007 barrel and piston AB with 53.98 and the 2009 AB and it has a 53.99 piston. Which one is correct?

PJ ENGINEERING
03-17-2009, 09:40 PM
I have 2 brand new 2009 cylinder on my desk and non of the ports are CNC worked, can you please post photos of what you think is CNC worked ?

Is that photo of the inlet side of the piston ? and was you on closed throttle when is locked up ?

HONDARACER
03-17-2009, 09:51 PM
Yes inlet side but there is also simular damage on the exhaust side but not as bad. Had a small throttle opening, but not closed.

random0082
03-18-2009, 07:34 AM
Karma. balances out the bad rep you left me on TJ forum eh.

And to keep it constructive - never heard of carb icing on the RS125 and oil pump failures can happen, but are relatively rare, esp on such a new bike.

Micah / AF1 Racing
03-18-2009, 09:49 AM
Was this the "fast" or "slow" of your two bikes?

HONDARACER
03-18-2009, 03:01 PM
Slow bike. I checked the oil pump and it seems fine as well as the drive gear. It was a fair bit out of adjustment. I advanved the pump with the cable adjuster.

I put the engine back together using a barrel and piston from a 2007 I bought off Ebay. I took the 09 cylider to a machine shop and he said the cylinder was not reuseable without getting an oversize piston and a good honing with a rigid hone.

Some tips for anyone doing an "INFRAME" on one of these. When installing the wrist pin circlip, install the clip with the opening facing up at slightly toward the rear and carefully push the clip into place. You probably wont be able to get it fully seated without a screwdriver or pick. Use a mirror to inspect the clip to ensure is seated proper.

THe rings I used had a lot of tension and I had to use a hose clamp to lightly compress the rings and then slid the barrel over the piston. The hose clamp will fall down and then you can just unscrew it and remove it. I also used a marker pen to mark where the pins are in the piston as an aid in correctly getting them aligned properly.
Another tip is to enlarge the holes in the crossmember a bit to ease reinstall of that piece. Mine was a real bear to get the screws all started as the holes are not large enough and theings seem to have shifted after I removed it. Better to make the holes a bit bigger than risk cross threading and damaging the frame.

Its about an 8 hour job to put in a piston with the motor in place.

Also I removed the hose from the bottom of the rad to drain the cooling system. I just used side cutters to remove the clamps that will need to be replaced.

random0082
03-18-2009, 03:56 PM
Some tips for anyone doing an "INFRAME" on one of these. When installing the wrist pin circlip, install the clip with the opening facing up at slightly toward the rear and carefully push the clip into place. You probably wont be able to get it fully seated without a screwdriver or pick. Use a mirror to inspect the clip to ensure is seated proper.

Whatever way you do it, its best practice to have the open end of the circlip directly opposite the cut out in the piston, wherever that is on the piston in question as i believe it does differ between manufacturers

kanerdog1x1
03-18-2009, 04:01 PM
im suprised your engine builder says the barrell is scrap, after all its has only siezed. a builder with ALOT of aprilia experience should be able to or at least know a shop that can weld and replate to a very high standard. my barrell visits stan stevens, he does a fantastic job, there is no evidence of siezure after he has had his wicked way with it, good as new and not oversize.

nubus
03-18-2009, 05:02 PM
So, did you check the END GAP of those rings with "a lot of tension" before you assembled it?
Was it the bike with or without the painted chain?
Hope you don't wad this one too.

ThisEndUp
03-18-2009, 06:06 PM
So, did you check the END GAP of those rings with "a lot of tension" before you assembled it?
Was it the bike with or without the painted chain?
Hope you don't wad this one too.

All right now........easy does it over there.
Peace , love and cold beer.



Someone should create a sticky on how to properly replace a piston.
I'm sure there's plenty of people who could use that info.


:cheers:

HONDARACER
03-18-2009, 06:14 PM
So, did you check the END GAP of those rings with "a lot of tension" before you assembled it?
Was it the bike with or without the painted chain?
Hope you don't wad this one too.

Your a fuckin moron!

HONDARACER
03-18-2009, 06:55 PM
im suprised your engine builder says the barrell is scrap, after all its has only siezed. a builder with ALOT of aprilia experience should be able to or at least know a shop that can weld and replate to a very high standard. my barrell visits stan stevens, he does a fantastic job, there is no evidence of siezure after he has had his wicked way with it, good as new and not oversize.

Where did I say the barrel was scrap? It needed a good proper hone and an oversize [54mm] piston. I had the 2007 setup so I used that. I may buy a Polini BBK or just make some 144kits with my spare jugs.

frankd_nm
03-18-2009, 07:14 PM
Sorry to hear the bad news. I'm thinking it sounds like maybe some oil starvation. Since you said the pump was out of adjustment and you were riding at slightly open throttle. The two may have been enough when combined to cause the seize.

Is it all back together now (with the 2007 parts)? If so, how is it running? Are you still seeing the lack of power issue that you've been dealing with on that bike?

Just thinking that with a different jug on it you can now eliminate one more variable and maybe help track down the problem, if it still exists.

HONDARACER
03-18-2009, 08:24 PM
I ran it up and it sounds crispy and revs quick. I still need to put all the fairings back on and check the jetting.

FUERA.....1
03-19-2009, 03:57 AM
so, did you check the end gap of those rings with "a lot of tension" before you assembled it?
Was it the bike with or without the painted chain?
Hope you don't wad this one too.

lol...

HONDARACER
03-19-2009, 08:50 PM
Bike is running better and stronger than ever. Jetted the carb up to 170 main and installed a new Iridium spark plug. I think the heat must have damaged the old plug as it had a bit of a miss after.

Micah / AF1 Racing
03-20-2009, 09:05 AM
Heat did not directly cause the failure of the spark plug, it is vaporized alloy deposited onto the insulator and electrodes that caused it to cease functioning, in race conditions you often can feel the oncoming seizure with ignition irregularities....and also when racing or riding a two stroke, if the engine seems to be gaining friction or slowing down...pull in, over, or park it and examine it before it spits you off.

BTW, from your pics, it is obvious that the problem involved a stuck ring, which is the only real way the piston sheds heat to the cylinder walls...and it cannot do this function when stuck due to not touching the full circumference of the cylinder wall.

As long as you sized the pistons and rings correctly for the new cylinder it will run better provided the rings and piston are installed correctly.

This WAS NOT a jetting or lubrication failure IMHO.

Steve / AF1 Racing
03-20-2009, 09:28 AM
Your a fuckin moron!

This is worthy of a timeout.

The_Reaper
03-20-2009, 09:36 AM
pwned (:

random0082
03-21-2009, 12:33 PM
This is worthy of a timeout.

The guy never learns. thats 3 bans from 2 forums hes had now. in real life hes prob a little fat angry bald guy. lol

FUERA.....1
03-21-2009, 05:51 PM
The guy never learns. thats 3 bans from 2 forums hes had now. in real life hes prob a little fat angry bald guy. lol

lol :cheers:

nubus
03-21-2009, 09:58 PM
I like how he was offered NUMEROUS opportunities for help,
but just went ahead and siezed it anyway! Oh well!