HELP!! F**KED my LC4 cam

[laramie LC4]

Originally Posted by Alik

Hallo Laramie,

could You elaborate a little more - where is that space located?



Do You mind that spot in the middle near ((3))?
Have You got Your engine back yet? I didn’t find out by reading the latest posts.

yup that little, raised, round spot in the center. its a little different on my bike but same idea. if you drill and tap that out, then you can add the oil line w/ jet and have oil feed directly onto the top of your cam.

i have not done this yet but was looking at doing it sometime soon. i have all the parts on order and will dive in once they arrive. i finally got the pieces of my engine back (dont ask.... ) and will be doing this before i send it off again to have someone else fix all the fuck ups the first guy made.

when i get it done i will make a post and show what i have done.

laramie

[laramie LC4]

here is a pic of my rocker cover. you can see they are a little diff. i'm going to drill and tap into the center circle. i'm going to use the same size banjo bolt and jet that feeds the crank. i swear it looks like it was made for it. i cant imagine the rally guys not doing this if they could.



i hope to get this done soon. i have an appointment with another engine builder in 2 weeks. hopefully this one will be able to take care of all the issues the last one created....

laramie

[laramie LC4]

ok, did the deed....

used a 17/64 bit and a good drill press with a level table. then tapped it with a M8x1.0.

things to watch out for....make sure you center the bit, you only get one shot. i used a marker to mark a spot, then moved it, then moved it again until i was happy, then hit it with a punch.

like i said, it looks like it was made for it....



dumping straight down onto the cam. perfect length as well.



i used a 150 oil jet. the same size that is in the clutch cover and feeds the crank. ktm part # 58038130000

i still haven't chosen/had made the oil line that will feed it. i need to have my engine in the frame to finalize the placement/location of the line. im hoping i can use an OEM one and make life easy. if not i will have one made at a brake shop here in town.

worst case scenario, i put a bolt in it and pretend it never happened....

laramie

[rz35027]

Where is the oil line coming from? Will it divert too much oil from somewhere else?

[Tseta]

Good question by rz there. Also, I'm confused by the oil jet, I don't see it in the pictures?

-T

[gunnerbuck]

Yes, you do not want to divert any oil from the piston jet line unless it is going to a second piston jet....

The lobe pool ideally should perform a satisfactory job of lubing the cam/roller assembly unless for some reason it is not getting topped up... The cam chain usually brings up enough oil to keep this pool full and then the cam does the rest by splashing the oil onto the shafts, rollers and other moving parts... Whenever I have taken my valve cover off I have always noticed that the lobe pool contained a sufficient amount of oil and never worried about the cam parts not getting their share ...


Another worry with a oil jet in that location is that maybe some of that extra spray may make it's way up the vent tube, into the back bone and eventually the airbox... Something you'll have to monitor when you give her a go...

[Alik]

Hello Laramie, it looks very nice but I do have the same thoughts as Gunnerbuck and Tseta. Good point with the airbox etc. especially when you are doing a lot of offroad. There is allways some occassion to crash the bike and feed the oil up the line while the engine is still running.
Another thing... when there is too much oil in the pool on the top You are possibly runing the risk of "overfilling" the top and bring it down the valves? How about oil leaks ;)
I'm also worried about the engine that it will starve from oil lubrication in another important area.

[laramie LC4]

ok, i knew there would be questions...

1) the 2 oil pumps in the LC4 pump close to 8 quarts/min. WAY more than what we need, that is what the oil by-pass is for.

2) that banjo bolt is the "oil jet." it has a metered opening the exact same size as a 150 fuel jet would have. don't believe me, take yours out and look.

3) oil venting into the down tune wont happen in my bike. i run a krankvent on my vent lines which causes the bike to run at a vacuum. absolutely impossible for me to leak.

4) where am i going to get the oil from? i'm swapping the bottom single banjo bolt for a double (like the one on the side oil filter housing) and just piggy-backing off it. i know your gonna freak and say that it will rob oil from the crank, but it won't. once again it is controlled by a "oil jet" and there is NO possible way for it to flow that much oil. i promise there will be plenty left over.

5) over filling the top? maybe but any amount to much will simply drain back down into the case if it rises above the timing chain level. once again, we are not talking about a huge flow of oil here, just a small amount, well placed, to do some additional cooling and lubricating.

like i said, i've never seen this before but have to imagine that it has been done. if i don't like the way it seems to be working, like i said all i have to do is stick a bolt in it and forget about it.

laramie

[DaBit]

I don't have my LC4 anymore (replacement is same brand but had twice as many cylinders and valves), but I still enjoy reading these threads.

I am in the 'not necessary, but probably won't hurt either' camp. The cam chain transports quite a bit of oil to the head when the engine is making at least some RPM and the valve drive train is supported with needle- and roller bearings everywhere. I don't think this extra oil jet would increase the life of the smaller inlet rocker roller needle bearing which is about the only failure-prone component up there.

On the other hand: a healthy set of LC4 oil pumps produce more than enough oil to feed this extra jet.

[Tseta]

Thanks for clarifying. It sure seems like a sound concept. I suppose you've got nothing to really lose by trying, give it a go and please report back on your experiences. This may turn out to be a worthwhile mod for other LC4 owners as well.

Cheers,

Tseta

[tdreyer]

I will be waiting and watching closely. I am a firm believer that more oil up there is necessary.

[laramie LC4]

i will report back as soon as i can. hopefully i will actually have an engine sometime this year....cross your fingers. i hear it normally take at least 2 builders to get what you want. right?

laramie

[Alik]

I'll keep the fingers crossed anyway for the idea and for the engine in general. Some say that third time there's a charm, but I hope they're wrong :)

[rob748]

Originally Posted by laramie LC4

i will report back as soon as i can. hopefully i will actually have an engine sometime this year....cross your fingers. i hear it normally take at least 2 builders to get what you want. right?

laramie

at least your trying mines still in pieces staring at my while i ride the 300xc but im starting to miss the 640 so i will be looking to get the engine rebuilt soon

[jungbark]

So, any news laramie?

//Tobias Jungbark