What damage did I do?


34 replies to this topic
  • Wiz636

Posted October 21, 2007 - 05:11 PM

#1

Was racing my '06 this weekend in an area that became extremely silty as the race went on...much of it being ash from the eruption of Mt. St. Helens in 1980...and it mostly WFO running.

About 2 hours into it my bike began running poorly as the air filter was getting packed up but I did not want to pit to change it out as the race was almost over and I was leading my class. It was a bad decision and ultimately the filter became so packed up with silt that it just started sucking through into the carb. The bike started blowing some smoke and I began to hear a "not good" sound in the valve cover so I shut it down and took a DNF on the last lap.

Airboot was coated with silt, carb throat and slide were completely coated with silt...just getting ready to tear into the top end and assess the damage...what am I most likely to find? What should I be primarily looking for?

  • todds924

Posted October 21, 2007 - 05:26 PM

#2

Was racing my '06 this weekend in an area that became extremely silty as the race went on...much of it being ash from the eruption of Mt. St. Helens in 1980...and it mostly WFO running.

About 2 hours into it my bike began running poorly as the air filter was getting packed up but I did not want to pit to change it out as the race was almost over and I was leading my class. It was a bad decision and ultimately the filter became so packed up with silt that it just started sucking through into the carb. The bike started blowing some smoke and I began to hear a "not good" sound in the valve cover so I shut it down and took a DNF on the last lap.

Airboot was coated with silt, carb throat and slide were completely coated with silt...just getting ready to tear into the top end and assess the damage...what am I most likely to find? What should I be primarily looking for?

VALVES!!!! are toast. Rebuild the head and throw a new piston at it. Hopefully the crank and cylinder are ok.

  • steve_97060

Posted October 21, 2007 - 06:20 PM

#3

Was racing my '06 this weekend in an area that became extremely silty as the race went on...much of it being ash from the eruption of Mt. St. Helens in 1980...and it mostly WFO running.

About 2 hours into it my bike began running poorly as the air filter was getting packed up but I did not want to pit to change it out as the race was almost over and I was leading my class. It was a bad decision and ultimately the filter became so packed up with silt that it just started sucking through into the carb. The bike started blowing some smoke and I began to hear a "not good" sound in the valve cover so I shut it down and took a DNF on the last lap.

Airboot was coated with silt, carb throat and slide were completely coated with silt...just getting ready to tear into the top end and assess the damage...what am I most likely to find? What should I be primarily looking for?


that sounds brutal, where were you racing today?

  • grayracer513

Posted October 21, 2007 - 07:15 PM

#4

The valves might be toast. Check the clearance as you tear into it. If the clearances have not tightened up, there has been no wear. Volcanic ash is very abrasive, but titanium nitride is extraordinarily hard. If a significant change in clearance is found, then the valves will probably need replacement. The hard coating, as hard and durable as it is, is also extremely thin. The wear could also be to the seat only. You can visually inspect:

http://members.cox.n...yzer/valves.htm

The trouble is that the hard coating is so thin that even if you can't detect any wear to the valve face at all, you really have no idea how long it will be before it does wear through unless you start over with new ones. So, all you can do is see what you have to work with and make a judgment call as to whether to replace them or not.

The rest is a little more straightforward, and things like piston and cylinder wear will be a lot less arcane an issue. Examining the cams and lifters will tell you a lot about how badly the oil was contaminated, if at all.

  • Wiz636

Posted October 22, 2007 - 11:22 AM

#5

that sounds brutal, where were you racing today?


It was the White Knuckle HS in Odessa (but not the Dez100 site). There were tons of bikes that this happened to...I don't think anybody was expecting this kind of silt.

  • Wiz636

Posted October 22, 2007 - 11:24 AM

#6

The valves might be toast. Check the clearance as you tear into it. If the clearances have not tightened up, there has been no wear. Volcanic ash is very abrasive, but titanium nitride is extraordinarily hard. If a significant change in clearance is found, then the valves will probably need replacement. The hard coating, as hard and durable as it is, is also extremely thin. The wear could also be to the seat only. You can visually inspect:

http://members.cox.n...yzer/valves.htm

The trouble is that the hard coating is so thin that even if you can't detect any wear to the valve face at all, you really have no idea how long it will be before it does wear through unless you start over with new ones. So, all you can do is see what you have to work with and make a judgment call as to whether to replace them or not.

The rest is a little more straightforward, and things like piston and cylinder wear will be a lot less arcane an issue. Examining the cams and lifters will tell you a lot about how badly the oil was contaminated, if at all.


Thanks Gray...I'll post some pics later when I tear into it. I'm just going to borrow my buddy's KTM 300 XC for the 24 hour race coming up this weekend rather than rush through this.

  • dcoleh

Posted October 22, 2007 - 07:38 PM

#7

Valves and maybe top end.

  • blue9red9

Posted October 23, 2007 - 03:33 PM

#8

I want to know what you find too.

  • Wiz636

Posted November 02, 2007 - 07:53 AM

#9

Finally got a chance to tear into my motor and it ain't pretty. I checked the valve clearances and they have tighted up a little bit but are still within spec. The oil is black, the cylinder needs to be replated but the piston didn't look bad but I will replace it also.

I have not disassembled the head/valves yet but I'm going to plan on replacing the valve seals and maybe the guides.

I will also have to flush the engine oil a few times...any ideas on how long I should run the engine between flushes? 5 minutes?

This is the engine side of the carb:

Posted Image

This is looking in towards the intake valves:

Posted Image

The black oil you see is Mobile 1 Racing 4T with about 3 hours on it:

Posted Image

My cylinder:

Posted Image

Nice looking oil...all the lifters were free and not sticking or scored up:

Posted Image

Intake cam...looks like some slight scoring, is it still okay to use??:

Posted Image

A little bit of wear on the camshaft cap:

Posted Image

Exhaust side:

Posted Image

Exhaust cam:

Posted Image

  • Wiz636

Posted November 02, 2007 - 08:17 AM

#10

Here's a question for you Gray...do you think I should put it all back together as is to do the flushing of the oil so that I'm not grinding up the new parts, or should I just get the new parts in and do it?

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  • grayracer513

Posted November 02, 2007 - 08:21 AM

#11

I would polish the cam journals (the bearing surface on the cams) by using wet (with oil or solvent) 600 grit emery cloth in narrow strips wound one full turn around the shaft.

The guides are probably OK, but have a machine shop evaluate them.

The valves, I will guess, are not happy.

I'm a little concerned with the scoring on the tops of the lifters that appears to be from dirt under the cam lobes. Check the lobes carefully, and consider replacing the lifters.

Compare replating/boring to a new cylinder from TT OEM

To be honest, since it's an '06, and the entire oil system is contained within the engine assembly, I'd pull it out, split the cases, and clean the whole thing up thoroughly. Then there won't be any question about it.

Even if it were a steel frame bike, I'd still pull the engine and cold flush the tank.

  • Wiz636

Posted November 02, 2007 - 09:00 AM

#12

Hmmm...I've never split cases before. Any special tools required for that?

Good idea on the cylinder...with the back and forth shipping to be replated I can get a brand new cylinder for about the same cost.

  • grayracer513

Posted November 02, 2007 - 09:12 AM

#13

Hmmm...I've never split cases before. Any special tools required for that?

A flywheel puller is about it, really.

  • eazrider

Posted November 02, 2007 - 09:40 AM

#14

If you are showing that sort of wear, it is time for a total overhaul....the abrasive particles imbed themelves in the softer metal, (piston, etc.) and act like sandpaper to accelerate wear. If it were my motor, and I intended to keep it, I would do the full Monty: valves, piston, replate cylinder, and would go as far as to rebuild the crank/rod assy. Now would be a good time to install a big bore kit of some sort, as you need to replace/replate the cyl and get a new piston/rings any way...Anything you don't rep[lace will show wear sooner than later. besure to flush the cases completely, as that volcanic ash is insisious and will contaminate the new parts unless it is all thoroughly away...good luck.

  • Wiz636

Posted November 02, 2007 - 10:01 AM

#15

Maybe I should throw in a WR crank...then I can light this thing up!

  • grayracer513

Posted November 02, 2007 - 02:14 PM

#16

That's a $6-700 experiment in swapping parts, you know.

  • Terrain Rider 4z

Posted November 02, 2007 - 03:09 PM

#17

Eh money is just money!!! Sorry to have been the bearer of bad news for you that day Pete. Looks like this is going to get expensive in a hurry. I might be dropping some coin myself after doing the night poker run through the silt :worthy:

  • Ronin 26

Posted November 02, 2007 - 03:10 PM

#18

I'd be tearing it completely down as well. I see similar failures when guys ingest river silt, rebuild it and soon after they are smoking again from the silt eating the rings. I have to flush the silt out of the cases, oil system, pump, and oil cooler if applicable (mostly ATV guys).

The marks on top of the buckets aren't terrible. I've seen them often, buckets rotate if you can't feel them I wouldn't worry about them. If they are really bad the bucket can break forcing the shim through, but that's pretty rare.

  • MX813

Posted November 03, 2007 - 09:59 PM

#19

Wow Wiz...didn't know the engine failure was that extensive, now the pics really show the truth.

Your cams look better than my 250f when I did my rebuild last spring thanks to much help from grayracer's input. The cylinder looks like it needs some work.

Interesting thought on throwing a WR crank and such in there for future lights but not sure what grayracer meant it being an expirement. Has this been done before w/o failure? Would be cool if you could (if $ allows) as now you know what real lights can do for you:thumbsup:

  • whipit1k

Posted November 04, 2007 - 04:58 PM

#20

Oh god.....if that was my bike I would die

Did you have any filter oil at all in your air filter???????

if so, USE MORE NEXT TIME


not crap air filter oil either. use a good sticky one like bel ray and dont be stingy with it!!! it is IMPOSSIBLE to suck dirt like that with a properly oiled filter





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