Routine maintenance (LC4 HOWDID)

[Tseta]

The carbon deposits are really stuck on there. I've spent the whole morning scrubbing the valves, the top of the piston and the cylinder head. Very slow progress.


-T

[makazica]

http://www.youtube.com/watch?v=Y2p8z...eature=channel

Very carefully not to take too much off if using rough grain sandpaper.
Maybe use only a cloth (or scotchbrite) and some solvent for starters.

[laramie LC4]

Originally Posted by Tseta

I have a 2003 LC4. The cylinder head is the high flow version already?

-T

OOOOOPSS!!! never mind. they could still port and polish it to ad some umph but the bigger valves are the real gain in power. sorry, ive just been planning to do this on my bike so i just had it in my mind.

laramie

[Tseta]

Thanks Mak, great video. I think I got enough of the carbon away already with just manual scrubbing and solvent.



The cylinder itself does not look to be too badly worn. Some light marks are visible.



Based on the suggestion of my friend, I took a closer look at the cylinder head. There has been some light porting work done to the head already at the factory, but there is still plenty of room to improve.



I don’t know much about porting, but I used a dremel rotary tool and various tool bits to try to remove the rough bumbs and such.



I lapped the valves lightly to the cylinder head, mainly to finalize the cleaning.



The cylinder head sealing surface was also checked for flatness with a straightedge and a feeler gauge, as described in the factory manual. The surface seemed to be completely flat.



I changed the valve stem seals and loctited a small setscrew onto the header flange bolt hole. That should end the oil leak from that area.



Then the valves were installed back to the cylinder head. Putting the collets/clips/valve holders (?) into place was quite fiddly.



This was the first time I did any actual valve work to any bike. It has been quite a learning experience.

Cheers,

Tseta

[makazica]

Sixth picture from the top, bolts that go inside the cyl head?

If yes, they need to be oiled on assembly.

May I ask you for some pics of your cam lobes and cam bearing seats in the head.....

[Tseta]

Originally Posted by makazica

Sixth picture from the top, bolts that go inside the cyl head?

If yes, they need to be oiled on assembly.

May I ask you for some pics of your cam lobes and cam bearing seats in the head.....

In this picture, the "bolt" that is visible is actually a stud. A nut threads on to it from outside the engine when the head is bolted on. There are total of two studs, one in the front and one in the back.

However, Mak, you are correct about needing to oil the head mounting bolts. I did just that.

Sorry, but I think I have already linked all the pictures I have of the cam lobes and cam bearing seats. Try this, this, this, this, this and this.

[makazica]

Thanks for the pics....anyway, I was talking about the bolts stuck in a piece of cardboard.

I think I'm gonna need a new cam next winter.

[Tseta]

Another long day at the garage. I started reassembling the engine.



I took a quick peek to the starter motor and changed the o-ring seals.



Gunnerbuck’s earlier post about the camshaft follower bearing pins holding made me worry and lose sleep. So I took the rocker arms out once more and punched 4 more marks onto the pins. Now they surely should hold?
(EDIT: It turns out that not even this might be enough... Better punch and flare the pins with more force, make deeper indentations!)



Earlier I mentioned that the subframe mounting threads had sheared off. Today I started to fix this problem. I chose to not just repair the damage, but also strengthen the assembly so that in the future the subframe will last better.











At the same time I also fixed the luggage racks. Earlier I had also reinforced the subframe as shown here. It seems that Russian roads take a heavy toll on the equipment.





Yours truly:



Makazica: Yeah, those bolts stuck through the cardboard are the head mounting bolts. Sorry for the mixup.

I’m feeling quite unsure about the porting work I have done. What does the jury think, have I done more harm than good?

Cheers,

Tseta

[gunnerbuck]

Out of curiosity what is your current mileage on the engine?

You have taken the time to make this thread very detailed and I would recommend it as one for the index...

Well done Tseta...

[Tseta]

30000 kilometers on the engine at the moment. I've owned the bike now for 10000 kilometers. I don't really know the previous service history, but I've learned that at least some work had been done around the camshaft area by some previous owner.

Thanks for your kind words Gunnerbuck.

-T

[wrk2surf]

my valve job cost 90.00 for the exhaust/intakes and head...

Might be a wise idea as you have went that far..

[Tseta]

Originally Posted by wrk2surf

my valve job cost 90.00 for the exhaust/intakes and head...

Might be a wise idea as you have went that far..

There is only 1 local engine shop here that does that kind of work at all. I asked them about it and they turned me down without even taking a look at the head. "We don't know how to do KTM heads" was their reason.

Oh well, the head is bolted back on already anyway, and unless there is something horribly wrong with the work I've done, I'd rather not unbolt it (and have to change head gasket and valve stem seals) again until the next rebuild, 30k's from now.

Cheers,

Tseta

[makazica]

Tseta, one question.

As far as my rather limited knowledge goes, there are two kinds of valve work.
Lapping being the less aggressive, more of a cleaning method that's done on valves and seats and the other being valve and valve seat grinding - major work that should be done by someone who really knows what's he doing.

At 30k km, my limited knowledge says that lapping should be more than enough with new valve stem seals and the engine in a very good overall condition as yours is. Right?

About the head....sealing surfaces (cylinder/head and head/cover) can be gently - missing the english word so I'll translate from Croatian - "showered" ( taking off the least possible amount of material needed ) - head sealing surface rubbed in circular movements on a fine grit sand paper on a FLAT piece of, for ex. thick glass.....of course this could be done by machining.

Also, no machining for the rocker cover....we all know why!

The work on head sealing surfaces, I assume, could be done by any half decent shop with you standing by and not letting them get all aggressive and sloppy.

BTW, as you checked the flatness of your sealing surfaces....if you say they're flat and good to go.....I trust you!

[Tseta]

Originally Posted by makazica

Tseta, one question...

Umm, I'm not exactly sure what the question is.

However, yes, I agree with your view about the differences in valve grinding and valve lapping.

The manual says the following about checking the valve seats and valves:

Originally Posted by KTM LC4 Factory Manual

Valve seats
The valve seats must not be pocketed. Seat sealing width: intake max.
1.5 mm (0.059 in); exhaust max. 2.0 mm (0.079 in). Grind valves if
necessary.

Valves
Check valve heads for wear and run out. Max. run-out on valve heads
0.03 mm (0.001 in). Valve seats should not be pocketed. The sealing
area must be located in the center of the valve seat. The valve stem is
hard-chrome plated. Experience shows that wear appears primarily on
the valve guide

To me, the valves or seats did not look pocketed. Measuring the width of the sealing areas seemed to be difficult with the tools I have. So I just estimated, they looked good enough.

The lapping I did was very minor and light. The main point really was just to finalize the cleaning. To me it looks like the top end is in good condition, but I am no expert either.

Regarding the main sealing surface of the cylinder head, I am familiar with the good old trick of rubbing the surface on top of fine sandpaper on top of flat plate glass. I would have called this lapping as well, it is the same principle as with valve lapping.

I was concerned about the flatness of the cylinder head and I made sure to check it very carefully. I used a high-precision engineer's straight edge and measured all across the sealing surface as described in the manual (using a feeler gauge). I could not find any deviations from flatness at all.

So, all in all, I do believe the engine was/is in good condition, especially now that I've exchanged the worn camshaft follower bearings.

Hopefully I answered your question Makazica.

Cheers,

Tseta

[gunnerbuck]

...
Much better, it should hold...

Yesterday I was about ten minutes into a commute and I heard the engine change sound so I turned and headed back for home... Upon further listening I could hear a lot more clatter from the valve cover...

Tonight I pulled the cover and found the intake follower shaft had overcome the flare and slid out a bit as to where it slightly rubbed the case... This bearing has 70,000 km on it so I guess it was on borrowed time anyways.... I think the bearing must of locked up a time or 2 and spun the shaft... The shaft still has quite a flare on the end but still moved out of place.... Because I have 3 spare rocker assemblies there will be no down time waiting for parts.... The message in all this is "peen those shafts"...