Topic: The highs and lows of K9

[H2Eric]

Having won the Bike of the Month for October with K9, which ranks pretty highly (thanks again guys for your votes), we now sink to the depths with a mechanical failure. It manifested itself miles away from home, about 120 miles in fact, with various rattles which got ever louder and could be heard very clearly despite the racket coming from the 4 into 1 pipe and wearing earplugs. There was nothing I could do about it so I pressed on for home. About 80 miles from home I felt something hit my right boot. I thought nothing of it initially, thinking that it was probably just a stone. Then I noticed the inlet tappet cover on No.4 cylinder was missing and worse, the tappet wasn't moving. Oh $h1t, a broken rocker! Whatever had happened the damage was done and as long as the engine continued to run I headed for home. Surprisingly little in the way of oil came out of the hole where the tappet cover should be. There's a hint there as to the problem. However, the engine kept going and even idled quite nicely when I got stuck in traffic, but more importantly it got me home.

I've had to wait a while for my good friend Graham to give me a helping hand to get the engine out of the frame. I can understand why some folk cut the top frame tubes and bolt a piece in to make attending to the top end a lot easier, but I don't think it's a good idea though. Anyway the engine is out and the rocker cover removed. Hmmm, not a pretty sight (pics below). No.4 inlet rocker broken and the exhaust very badly worn, likewise both rockers for Cylinder No.3 are very badly worn. The camshaft has had it. Oil was getting to the camshaft bearings, but it seems it wasn't getting to the cam lobes. I haven't checked yet, but an oil way within the cam tower must be blocked.

However, as autumn has arrived and the biking season draws to a close there is plenty of time to get things fixed.

Cheers
Eric

[Sam Green Racing]

Eric, been there....no t shirt tho!!!!! Yes, you lost oil to that side....hopefully you'll be able to tell what caused it, Good Luck, Bill

[Jerry Rxman Griffin aka MuthaF'er]

Sorry to hear that. Perhaps BOTM is a jinx.    I lost my bottom end due to an oil passage stopper ball coming out of the lightened balanced crank. Got the final parts last night and after I finish this I'm heading to the garage 

At least you now have an excuse to put a frame kit in along with a serious cam   

[brandEn]

Man what a bummer! I had that happen to my TAO build. What caused it was a blocked oil feed from installing my HD studs with Loctite. My own stupid mistake. You can send your cam to Delta Camshaft in Tacoma WA for repair.

[johno]

You mean one of these Eric ?     For the road I agree with you but when you spend time changing things like cams, valve timing, , head gaskets etc or evan just relieving the spring tension after each race meeting by backing off the rockers..............then these make good sense 
ciao johno

[johno]

PS ..... forgot to give my condolences Eric, you seem be in a positive frame of mind considering,  hope you find the blockage and let us know so we can avoid something simliar.     cheers johno

[H2Eric]

Hi Johno
That's exactly what I meant. Looks like a study piece of kit you have there and it must save you a great deal of time on a race bike.
I've taken another look at the cam tower on the left side and couldn't find any blockage, but there was some wear on the cam bearings with some excess play on the cam, so I guess that is how some oil managed to find its way in there. It now looks like a lack of oil getting through into the cam tower in the first place, hence finger now points to the oil control orifice in the cylinder head. It doesn't take much to bung one of those up. More damage to report in the form of the top of the inlet valve on No.4 cylinder (see pic below). Looks to have taken a real bashing before the rocker finally broke. It's also amazing that some of the other rockers didn't give up the struggle as well.

Cheers
Eric

[Sam Green Racing]

Eric, Billy has all the parts you need for your rebuild if you havn't already got them.

Sam.

[scottly]

Man, that's a sad sight to see.. I don't believe I've ever seen such wear on rockers before?

[Sam Green Racing]

I think riding the distance he did with a sick motor came down to the cost of more parts v cost of recovery vehicle.

Sam.

[scottly]

I suspect by the time he knew something was wrong, the damage was already done to the parts...

[Jerry Rxman Griffin aka MuthaF'er]

Wow. Amazing it still ran.

[H2Eric]

I think riding the distance he did with a sick motor came down to the cost of more parts v cost of recovery vehicle.

Sam.

I suspect by the time he knew something was wrong, the damage was already done to the parts...

Wow. Amazing it still ran.

Spot on guys
Not was it amazing it still ran considering the damage, but how well it ran.

Time now to take the head off and give it a jolly good clean and especially for Sam I may now consider replacing the rear rim, but before that, lunch.

Cheers
Eric

[Old Scrambler]

Sorry for your troubles...........I have several well oiled T-shirts as testimony of having been there

I acquired a complete K4 motor with very similar damage AND the cam was in two pieces. The motor still ran on 2 cylinders.  The oil feed line was blocked with gasket-sealing material.

[NickO]

Would it be possible to run the engine briefly on first start-up WITHOUT the cam cover fitted so correct "oiling" could be witnessed?

As our engine is going in a bespoke sidecar chassis, access to remove/replace the cover in-situ will not be an issue (for us at least). 

[scottly]

Yes, you can test run the motor without the cam cover, but it might be a bit messy. Most guys just remove the rocker covers on either end to verify oil is getting to the cam.

[Old Scrambler]

A friend without a clue about computers has been a motor mechanic for ever...............now retired and rebuilds CB750s that he acquired over time from city impound yards and garage sales. I don't think he paid more than $200 for the best of the 20 or so bikes in his shed.

He uses a cut-up frame to test-fire every motor without a valve cover. He checks the oil flow and compression. Then he re-torques the head and installs the motor in a restored frame.  No failures so far...........on more than a dozen bikes. 

[johno]

Yes Scottly thats my procedure,
 end tappet covers off on start up, then after running the engine for about 15 minutes I check again and check the tappet clearances as well just to be sure.

On the race motor I am going to buy a small Accusump one litre size so I can pressurise and check the outside oil flows everytime I start the old girl up.   I used to suffer paranoia about valve spring failure but after seeing Erics unique rockers I'll add top end oiling to the list.
johno

[MRieck]

You have to be careful when using Loctite on the cylinder studs. The 2 studs that deliver oil to the top end have to have the Loctite placed in the threaded stud hole...not on the stud. The problem is the Loctite up the thread of the stud and will block the oil feed holes. You already have squeezed the oil feeds with the larger OD of the HD studs...something else to consider.
 I blow compressed air through the main galley and oil jet holes to make sure they are clear.