Topic: New perplexing conundrum of the weekend – K2 oil leak, fouled plug, carbs

[VTCBike750]

Ok so heres one for you guys  . 

So far Ive put 200 miles on my 750 Im rebuilding. Today I went out, hopped on the highway and put 100 miles on her.  See what she can do and how she handles it. Awesome 

Since Ive had the bike, I have noticed a little oil weeping from the left side of the head. Also, when I first ran the bike in Nov. #1 didn't fire.


However, on the ride back home I realized that she doesn't quite have the same power she normally does. Checked the exhausts at one point, all warm.  When I got home checked the exhausts, well guess what #1 is cold.  2, 3, 4 all HOT. #1 Cold 

Halfway through the ride I noticed the same weeping oil, but thought nothing of it its normal. Get home to find this.



First thing I noticed was a little bubbling of oil out of the nut next to the plug. 


Pull the plug and tada! Fouled with oil



I also pulled #4 plug, its solid black, but not oil fouled.  Just running rich.


Now I havent tried anything yet, Shes way too HOT to handle. Still have burn marks from last weekend
Ok, I did check and #1 is getting spark

Ive already decided that Im pulling the engine this winter, but would like to be able to ride it this summer without any major work.

Think there's anything I can do? Maybe check the torque on that nut?

Thanks guys

[jawntybull]

I've been rebuilding my first 750 over the last month and there are some similarities with your story, here is what I found.

Cold exhausts - if the plug has spark its due to blocked jets in the carbie for that cylinder. If cold after startup / idle its the pilot jet - very common problem. Pull the carbies, pull the jet (press fit) and clear out with fine copper wire. Check all of them as I had 3 blocked ones.

The left side of the engine was getting oiled up like yours; the bike leans on that side when on the sidestand and any leakage runs down that side. In my case the leakage was coming from the tacho cable hole; needed a new seal. This is also common and there is no alternative to buying the Honda seal for a few bucks. Remove the old seal with a wood screw and tap the new one home with a small socket.

Finally, check the crankcase breather hose. It has a low point that collects gunk and eventually blocks. If its blocked the crankcase pressurises and forces oil into the engine (smoke and fouled plugs) and also makes the valve cover leak. I actually could see the oil and air bubbling out around one screw after a ride once. To clear it, disconnect the end and blow hard... just get out of the way when the pressure comes back at you and blows crap in your face 

[VTCBike750]

Hmmmm, so #1 didnt eun when I got the bike, but this is the first time that its stopped. I dont think its the carbs. #1 was running hot earlier and they were cleaned 300 miles ago, including the little jets with wire and Ive been running seafoam in the gas.

Ive had the leaking tach seal, just replaced it with the DOHC seal with great results.

Im liking your thought on the breather hose. Ill have to check it out. It was bubbling and the plug was fouled. Ill check it out and let you know.

Thanks

[VTCBike750]

Well there are now a few issues. Swapped out #1 and ran bike. When it warms up it has all the symptoms of a rich running engine. All my air screws moved too !

1. Jawntybull - looks like Im pulling the carbs. Somethings just arent right.
    #1-Great spark, runs great at first, then goes cold, not oil fouled yesterday. Looks to be rich
    #2-running rich
    #3-Great, not rich not lean
    #4-Running rich

At first I just cleaned them and put them on the bike. Then synced them. Considering what Ive noticed on the bike and learned on the forum, I wouldnt be surprised if the small jets and clip positions are different.

2. Still need to look at the crankcase breather.

3. And my bike is lying to me. The other day the oil light was flickering and after running the bike its not showing up on dip stick. Ok so maybe it takes 3.7 quarts instead of 3 (I did change the filter, drop the oil pump. Primed it too). Add oil.
Ran the bike yesterday and it has WAY TOO MUCH OIL, take out almost a quart. Its a little low on the dipstick, but in the operational range. 

Well we will see what happens.

Thanks Jawntybull.

[ekpent]

Check the oil on the 750's after the engine has warmed up.The oil has a tendency to go past a check valve if they have been sitting into the crankcase and will give the impression that it is low.

[jawntybull]

Check the oil on the 750's after the engine has warmed up.The oil has a tendency to go past a check valve if they have been sitting into the crankcase and will give the impression that it is low.

+1 - mine drops to half way down the dipstick if left for a day or so

[VTCBike750]

So I tore into the carbs and well Its started a whole new posting.

I started CLEANING and going through the 72 cars and found a piece missing inside the #2 carb body


http://forums.sohc4.net/index.php?topic=93021.0

[VTCBike750]

Jawntybull, thanks for your suggestion.

I tore into the carbs and well, a lot of things were OFF!

Thanks again

[jawntybull]

You're welcome; I'm no expert but I've learnt a lot about these bikes in the last couple of months and it sounded like you had some similar issues with yours.

My engine needed carb overhaul, new tacho seal, clear blocked breather, valve clearances, plugs, point adjustment, timing, fuel tank clean, carb sync, new oil and filter, inlet tubes, airbox mods. It now runs like a dream.

BTW the other things that desperately needed attention on my bike were new cables for safety, new clutch lever and clutch adjustment (it gets hard to adjust when its worn and it slips or you can't get neutral), and overhaul of the front and rear suspension. Front needed new oil and seals and rear was locked solid with old dry grease; it still moved when you sat on the bike but comfort level was crap. The whole collar was rotating inside the frame rather than the swingarm riding on a layer of grease inside the bearing.

On the upside I now have a cracker of a ride; taking it to a rally this weekend with my uncle riding pillion.

[VTCBike750]

Nice, Im hoping to have a great running bike when this is all done.  Every step has been 2 steps forward and then one back. Making slow headway though.  Here I thought the carbs were good, but needs some attending too. Moved the needles to the middle as well.

Heres my build, its NO where near a restore.  But its my first attempt at working on any bike in depth.
http://forums.sohc4.net/index.php?topic=87951.0

So far Ive:
Rebuilt front forks
Rebuilt front caliper
Redone the electronics to stock specs
Set the valves
plugs and points
static timing (timing light broke in 23 seconds)
disassembled the rear wheel, getting ready to replace the shoes.  In spec, but hard rubber.
Remove liner and relined gas tank
New Tach seal, New o-rings for oil pump and countershaft bearing oiler
Modified clutch for easier shifting
Totally rebuilt the carbs now.
Currently soaking the airbox inlet tubes in wintergreen oil and boiling/hot water cycles.

To do list is replace all cables and new swing arm bushings.

Very cool. My uncle is coming to town in Sept and hope to go riding with him for the first time.  Hes sort of been one of the few who have gotten me into these old bikes.

Thanks again,
Happy riding.