ADVrider

Go Back   ADVrider > Bikes > Thumpers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 10-21-2010, 07:51 PM   #76
wrk2surf
on the gas or brakes
 
wrk2surf's Avatar
 
Joined: Dec 2007
Location: THE exact center of California/Bass lake/Yosemite
Oddometer: 6,113
tseta... my freind swears the lower cases are different as the model changed in the fron lower area.. can you inspect all 3 to see if there is any visible oil galley area?
__________________
Thanks for the 2014 support:BELL HELMETS, SCOTT USA, Kriega USA, Carbon-pro.com, GPR stabilzers, Renazco Racing, Sidi/Motonation, Masters paint and body, Magura , motolab , Tripy GPS, Loctite and Dunlop tires .
wrk2surf is offline   Reply With Quote
Old 10-21-2010, 07:57 PM   #77
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,736
Tseta, can you show a picture off the valve seals and comment if they are worn.

Your valves dont look so bad to me. I'd take them to an auto engine rebuilder if your KTM shop won't resurface them and recut the seats.
bill
__________________
'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
Bill Shockley
bmwktmbill is offline   Reply With Quote
Old 10-21-2010, 09:05 PM   #78
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Are these pictures of any help, regarding the valves and valve seats/seals?









-T
Tseta is offline   Reply With Quote
Old 10-22-2010, 09:55 AM   #79
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Well, I took the head and valves to a local mechanic. He immediately saw that the intake valves are done for. I then took the head and valves to the only (engine) machine shop in town that does any head work at all. Even though they have previously turned me down on even taking a look at motorcycle heads, I was able to convince them to get new valves for this head and grind the valves and seats to fit. I'll hear back from them in a few weeks.

I believe this will conclude the updates (that have actual new, engine rebuilding content) to this thread for a bit longer while. Many parts have been ordered and I will be waiting for their arrival. I don't know when I will have the time again to work on this bike, but once I get the ball rolling again, I'll be sure to update this thread.

I wish to thank everyone who has added positive comments or words of encouragement here, as well as those who gave me valuable advice regarding the rebuild of this engine.

Cheers,

Tseta
Tseta is offline   Reply With Quote
Old 10-22-2010, 11:29 AM   #80
DaBit
Gnarly Adventurer
 
Joined: Nov 2008
Location: Netherlands
Oddometer: 345
You have two more bikes waiting for you. Strip them too and get a volume discount on parts
DaBit is offline   Reply With Quote
Old 10-22-2010, 11:15 PM   #81
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,736
Tseta,
Thanks.
bill
__________________
'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
Bill Shockley
bmwktmbill is offline   Reply With Quote
Old 10-23-2010, 07:23 AM   #82
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,736
Tseta,
Another cylinder head question.
The valve sealing part I was asking about is KTM part #508 36 028 000.
It is called 'valve-stem sealing'.

I wonder if you can post a picture of this piece and the springs etc.
If the head is off at the rebuilders no problem.

I was wondering how it all works and if oil consumption could be connected to worn parts in this area or excessive oil in the airbox.
bill
__________________
'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
Bill Shockley
bmwktmbill is offline   Reply With Quote
Old 10-23-2010, 08:32 AM   #83
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Bill,

The head is at the machine shop at the moment.

I have one picture from last winter when I did my bike.



Never mind the red circle, it just shows where I loctited a small setscrew to prevent oil leaks from the exhaust flange mounting hole.

The brass colored pieces are the valve guides, the valve stem seals are just small shaft seal types of pieces (rubber lips, garter springs, etc.) that go on top of the valve guides. The springs and retainers go then on top/around these, with the valves obviously being in the middle, through the valve guide and the stem seals.

I will take better pictures for you of these components once I have the time to work on the bikes again.

Cheers,

Tseta
Tseta is offline   Reply With Quote
Old 10-23-2010, 10:25 PM   #84
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,736
Thanks Tseta.
You better sleep for a week.
bill
__________________
'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
Bill Shockley
bmwktmbill is offline   Reply With Quote
Old 10-24-2010, 06:39 PM   #85
rz35027
Gnarly Adventurer
 
rz35027's Avatar
 
Joined: Dec 2007
Location: Vancouver BC
Oddometer: 198
Thank you Tseta for all your explanation and photos... and illuminating thread.
rz35027 is offline   Reply With Quote
Old 10-30-2010, 03:12 AM   #86
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
I just received word from my KTM dealer that most of the parts have arrived. Now I will have to start planning and preparing for the reassembly. Unfortunately other commitments will keep me from getting to the bike for at least a few weeks still. In addition, the kickstarter parts bought from German E-bay have yet to arrive.

So, as mental preparation, I have been thinking about what has actually caused the most costly damage so far, the crank bearing's inner ring spinning on the crankshaft, and how to prevent something like this happening in the future.

Some pictures to recap the situation:









Obviously the bearing itself is somehow damaged. However, the actual rollers, the outer ring or the outer surface of the inner ring don't show any damage. When the removed inner ring is placed in the crank bearing (making it a complete unit again), no rough spots or other anomalies are found while turning the bearing by hand.

I've been doing some research into bearing failures, and this type of problem looks most like fretting corrosion.

http://www.cdcorrosion.com/mode_corr...n_fretting.htm

http://www.tribology-abc.com/poll/previous.htm

http://www.vibanalysis.co.uk/technic...corrosion.html

http://www.kittiwake.com/technical_article_fretting.htm

It is thought that this type of fretting corrosion is caused by too loose fits. Vibration then causes microscopic relative motion between the contact surfaces, which in this case are not intended to move against each other. Theory 1, thus, points towards a unfortunate stacking of tolerances where the resultant fit of the bearing inner ring against the crankshaft has been too loose.

However, the wear mechanism with fretting corrosion still relies on oxidation. As there should be plenty of oil to lubricate the crank bearings, the ideas turn towards the quality of the lubrication. Theory 2: perhaps the oil changes have not been done often enough, or poor quality oil has been used. Water and other contaminant (even solid, as in ground up pieces of gearwheels...) content of the oil may also be a factor.

Of course a combination effect of both theories could be just as likely. All in all, it remains that the crankshaft is toast, and I want to make sure it doesn't happen again. My plan is to measure the new bearing inner rings and the new crankshaft very carefully and calculate the resulting (theoretical) interference fit. This value can then be compared to many bearing manufacturer's recommendations.

I've also been contemplating about increasing the strength of the interference fit with anaerobic adhesives or retaining compounds. This includes a potential problem as the heat required to assemble the bearing inner rings onto crankshaft may affect the retaining properties of such a compound. Disassembly (doG forbid it would ever again be required... MUST get crankshaft shims right the first time!) could also be negatively affected.

I'd be extremely interested in some insight upon these theories and thoughts.

Cheers,

Tseta
Tseta is offline   Reply With Quote
Old 10-30-2010, 11:12 PM   #87
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,736
Quote:
Tseta, I won't quote the whole post but to me the culprit must be the vibration. I have never run into another shaker like the KTM 640.

As for the locking compounds, Dirty Sanchez should know or your auto machine shop. Try asking them what they do. I'll bet they know something.
bill
************************************************** ***************************


Tseta,
Dreamed about the crankshaft...
We have a bevel drive Ducati in the family, a '77 860, it has a ball bearing crank if I remember right, anyway all the smart guys said let the engine warm up for 5 minutes before you ride it, why I wondered, now I say let the LC4 640 engine warm up for 5 minutes also.

Do you follow my logic?
Once the engine is warm all the bearings tighten up in the cases but if you run the machine with cold oil and run it hard you could cause the bearings to spin especially if you couple the thrust with the vibration. The tolerances are greater when the engine is cold!!

From now on for me no riding a cold engine.

Just my idea.
bill
__________________
'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
Bill Shockley

bmwktmbill screwed with this post 11-01-2010 at 12:11 AM
bmwktmbill is offline   Reply With Quote
Old 11-02-2010, 12:57 AM   #88
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Bill, I agree with you about letting the bike warm up properly before flogging it. However, I'm not sure I follow your logic about the bearings tightening in the cases as the engine warms up. The case is aluminum which has a larger coefficient of thermal expansion than steel, that for example the bearings are made of. I have understood that this is why you need to warm up the case in an oven (or with a torch) if you wish to remove the case bearings.

Case in point, KTM actually says the following about the balancer shaft bearings in the engine manual:

Quote:
If the balancer shaft is not installed also remove both grooved ball bearings (in the clutch cover and in the engine housing). Otherwise the grooved ball bearings would drop out of the bearing seats and cause engine damage as soon as the engine heats up.
Don't get me wrong, I do agree that the engine should be properly warmed up first. Perhaps I don't completely understand, and the tolerances do tighten up at some parts of the engine as it warms up i.e. the piston to cylinder clearance etc.



Relating to that, I've got this horrible feeling that I may have screwed up with the piston that I've ordered. Let's recap:

The cylinder measures as follows:

HeightDiameterRunout
-5 mm101.0205 mm0.0137 mm
-45 mm101.0181 mm0.0061 mm
-86 mm101.0196 mm0.0103 mm


So, about 101.02mm all around.



Now, I've ordered a Pro-X piston kit with a "B" piston, which, according to the manufacturer is 100.95mm.



With a simple calculation, the resulting assembly clearance between the piston and the cylinder should thus be 0.07mm.



For the 1998 LC4 engine, KTM specifies the maximum assembly clearance as 0.12mm. In light of these numbers, things look just fine, no?



Although Pro-X does not explicitly specify it, I got the impression from various sources that the piston I've ordered is a cast version. This is important because the later LC4 specifications start making a distinction between a cast and a forged piston, and give different assembly clearances for each.

For example, already the 1999 LC4 specifications state that assembly clearance should be max. 0.12mm for a forged piston and only max. 0.05mm for a cast piston.

In light of these numbers, things went pear-shaped, didn't they? Even if I would have ordered the "C" piston (which was not available...), measuring at 100.96mm, the resulting assembly clearance would still have been too large, at 0.06mm. The 2000 LC4 specifications then list that the maximum bore diameter of the cylinder is 101.04mm, so the cylinder should not be completely worn out yet.

Am I making this too difficult and complicated? Should I even be looking at and comparing the specifications for different year LC4s?

Cheers,

Tseta
Tseta is offline   Reply With Quote
Old 11-02-2010, 07:42 AM   #89
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,736
Bill, I agree with you about letting the bike warm up properly before flogging it. However, I'm not sure I follow your logic about the bearings tightening in the cases as the engine warms up. The case is aluminum which has a larger coefficient of thermal expansion than steel, that for example the bearings are made of. I have understood that this is why you need to warm up the case in an oven (or with a torch) if you wish to remove the case bearings.

Case in point, KTM actually says the following about the balancer shaft bearings in the engine manual:


Quote:
If the balancer shaft is not installed also remove both grooved ball bearings (in the clutch cover and in the engine housing). Otherwise the grooved ball bearings would drop out of the bearing seats and cause engine damage as soon as the engine heats up.


Don't get me wrong, I do agree that the engine should be properly warmed up first. Perhaps I don't completely understand, and the tolerances do tighten up at some parts of the engine as it warms up i.e. the piston to cylinder clearance etc.




Tseta,
You areright of course and I'd stick m head in a snow bank but it hasn't snowed here yet. I think my brain has a loose fit. I wish I knew the specific values for the expansion and contraction of steel and aluminum related to temperature.

Guess I'd go back to looking for a good glue to stick those bearing in the case.

I met a young engineer at the factory a couple of years ago.
If he is still there I will try to ask him by email what he knows.
bill
__________________
'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
Bill Shockley
bmwktmbill is offline   Reply With Quote
Old 11-02-2010, 08:38 AM   #90
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Quote:
Originally Posted by bmwktmbill
I'd stick m head in a snow bank but it hasn't snowed here yet. I think my brain has a loose fit.


Quote:
Originally Posted by bmwktmbill
I wish I knew the specific values for the expansion and contraction of steel and aluminum related to temperature.
Oh, you don't want to know that stuff. It's just boring physics/engineering data and the related calculations are difficult as well.

(Here's one table listing various coefficients of thermal expansion. Note that the value for aluminum is about double than that for steel.)



Now then, what to do about the Pro-X piston...

-T
Tseta is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 10:05 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014