Topic: 836 Head Gasket Leaking 78 750K

[Bill K]

  I've got a head gasket leaking on my 836 I spent all my time and money on last winter. The surfaces were checked to be true both head and block. I did not however have either one machined. I used new HD studs torqued and retorqued the next day. I was worried this was going to happen and even talked to Ken a Cycle X about what technique to use. This SUCKS!
  So I'm thinkn of yanking the motor back out, tear it down and hopefully fix the issue. I want to do this quick, like in a couple of weeks. Should I have a little material removed frome both the head and block while out? If so how much? Adhesive no adhesive ? Any help appreciated. I actually hate to even pull the block as there is no leak at the bottom.

                                                                 Thanks
                                                                        Bill K.
Ain't it perty, leaks like hell !

[MRieck]

Make sure that head gasket sits flat. That particular gasket sometimes needs to have the dowel holes elongated a bit. I know Ken recommends spray Copper Kote on that gasket.

[solo 2]

+1 0n the copper coat, works well on the hi-po 2 stroke motors

[Bill K]

  Thanks for the advice. I think I'm gonna go ahead and pull the engine. I can't stand a oil leak. I can't help but wonder if I could have pulled that valve cover after running a bit and retorqued, if I would have had this issue. 

[HondaMan]

Where is the leak coming from? Oil passages at the back?

[Bill K]

 Seems to be in the front on the outer corners. It may also be leaking on the sides. When riding it blows back on my pant leg and side covers. I rode 300 miles in two days interstate with it like this and the oil level didn't even drop enough to notice. It's just annoying.

[JLeather]

I assume you replaced all the gaskets in the top end when you did this?  Especially the cam-tower pucks?  Spray copper is great for gaskets like this, and yes a re-torque after a good heat cycle or two also does a world of good.  Sometimes it's just bad luck, though.

Before yanking the motor you can just try a re-torque now and see if any are loose and if it stops the leak.

[Bill K]

 Yea, I did replace all gaskets including pucks. I'd LOVE to re-tourque if only I could remove the damn valve cover!

[JLeather]

Yea, I did replace all gaskets including pucks. I'd LOVE to re-tourque if only I could remove the damn valve cover!

Time for either a drill or a Gordon Frame Kit

[Mandic]

I just had to tear down my 77 750F 836 motor after 25 miles.  Yours sounds exactly like where mine is leaking.  What I discovered to be my issue was the knock pins that go on the oil return studs with the seals.  They were sitting up from the cylinder deck surface slightly which kept the head gasket from squishing properly.  My engine was pushing oil out all around the head but seemed to be primarily at the front corners.  And when I really went it would spray out on my pant legs. 

I'd say pop it apart, spray that head gasket with some copper coat, make sure the knock pins sit down in flush with the deck surface, and reassemble.  I just went over all of this with Ken at Cycle-X a few days ago. It sucks, but it happens.

[Bill K]

 Thanks for the further input. I was looking close with a flash light this evening and it's definitely the front. Looks to be more in the corners but its hard to tell once the wind blows it around. The back is dry.

                                                                         Bill K

[HondaMan]

Thanks for the further input. I was looking close with a flash light this evening and it's definitely the front. Looks to be more in the corners but its hard to tell once the wind blows it around. The back is dry.

                                                                         Bill K

This sounds suspiciously like the little rubber pucks are leaking under the cam bearings. 
When they do, the oil follows the slope of the fins and ends up on the front edges.
If it were a pressure leak from the feeder journals, it would be wet on the back side instead.

[Mandic]

When looking for an oil leak you usually want to look as high as you can find it.  It can of course blow up, especially in an air cooled open design like our bikes are.  But if it were the pucks wouldn't it leak back down the backside as well?

[Bill K]

  I replaced the pucks during the 836 build along with everything else. I was running lean and the motor got pretty damn hot untill I got that sorted. Maybe I fried those little puckers. When I tear it down I'm gonna replace the pucks, gaskets, o-rings and all.

[Mandic]

If you think you got it that hot, maybe you got it hot enough to warp the head a tiny bit?  I'd definitely recheck or have a machinist recheck your deck surfaces when you tear it down.

[bollingball]

What did you find that made it get so hot?

[Bill K]

 Just running lean. Took a lot of carb tinkering. Eventually shimming the needles and getting a good color on the plugs. Royal pain..

[cheapride]

I vote for the gordon frame kit.  Just buy a welder and install   Buy two and install one on my bike too.