Topic: Dammit!

[750Caferider]

Okay so I got my 78 750F back in April it ran like crap so I proceeded to fix it on my own...  Replaced the petcock, big improvement...  rebuilt my carbs, bigger improvement...  Last night I adjusted my valves @ .003 int/.004 ex and adjusted the timing back down/Thanks TwoTired!...  No shop manual for how to adjust the cam chain or do anything else... so I took her out for a spin...  Wow did that make a difference!!!  Got home and noticed oil on my left leg about mid shin... F**k ME!!!  I've already put $400.00 in it, so what next? I notice that the head gasket was leaking a little oil when I first got her but man it's on now!  I would really appreciate some advice form the some of the old timers regarding whether I should just go ahead and rebuild the whole damn thing or jerk the head and send it off to APE and find a place to re-surface my cylinders while also ordering new heavy duty head studs?  Anyone with some shop time fixing this would be greatly appreciated!

TwoTired I really appreciate all of your support over the past months!  If ya want to adopt a thirty-something noob that isn't scared to tear into anything lemme know!  And anytime anyone of you from the forum are in KC lemme know I'll buy the steaks or Bourbin!  Your choice!

Cheers to you!  Tears for me!

Anders

[750Caferider]

Oh and she's got 32441.7 miles on the ticker.  PO kept the bike up well but it was obvious some fools had worked on it before...  Damn the cold beer engineers!

[750Caferider]

Nobody?

[jcarthel]

REPLACE THE HEAD GASKET AND ENJOY THE BIKE!  32K IS NOTHING FOR THESE 100K MOTORS!

[jeepster]

Might not all be coming from the head gasket. Is your valve cover properly torqued? Did you replace the gasket on the valve cover?

[TwoTired]

I understand there are rubber pucks under the "towers" on the head.  Were all those replaced?  Are you certain they are sealing?

[KB02]

When you adjusted the valves, did to tighten down the access caps? It they're not tightened down properly, all kinds of oil can seep out and make a mess.

It might be time to replace the head gasket, too, but I'm trying to think of things to do so you don't have the pull the engine.

[Steve F]

I understand there are rubber pucks under the "towers" on the head.  Were all those replaced?  Are you certain they are sealing?

+1 on the rubber "pucks".  Those things are the most likely to give you grief.  You'll have to pull the cam and towers to get at them.

[Steve F]

It might be time to replace the head gasket, too, but I'm trying to think of things to do so you don't have the pull the engine.

If it's a 750, you'll have to pull the engine.  But you may not need to pull the head.

[eurban]

Anders-

You say you don't have a manual?  Download the factory manual here:

http://www.mediafire.com/?5ttzdg9yyuz

[Alan F.]

It might be time to replace the head gasket, too, but I'm trying to think of things to do so you don't have the pull the engine.

If it's a 750, you'll have to pull the engine.  But you may not need to pull the head.

I understand there are rubber pucks under the "towers" on the head.  Were all those replaced?  Are you certain they are sealing?

+1 on the rubber "pucks".  Those things are the most likely to give you grief.  You'll have to pull the cam and towers to get at them.

+1 on the pucks, you'll probably want to check compression and all, but the second you get the cam towers off the head, you'll know if it's the pucks or not.
-Alan

[Laminar]

Okay so I got my 78 750F back in April it ran like crap so I proceeded to fix it on my own...  Replaced the petcock, big improvement...  rebuilt my carbs, bigger improvement...  Last night I adjusted my valves @ .003 int/.004 ex and adjusted the timing back down/Thanks TwoTired!... 

Forgive me if I'm missing something, but here's what the Honda manual says about valve clearances:

[GammaFlat]

Forgive me if I'm missing something, but here's what the Honda manual says about valve clearances:

You're correct about the "factory spec".  Some folks have deviated from factory spec and recommend the valve lash be opened up a bit.  ...especially for the later SOHC4s. 

[Laminar]

Okay. I'd heard of opening the exhaust valves up to 0.10mm to provide it with a little bit more time to contact the head and dissipate heat, reducing the chance of detonation from an overheated exhaust valve, but I hadn't heard of doing the same for the intake.

[gregimotis]

Here's a trick I read here years ago, it worked brillantly for me:

Clean up you engine best you can, get all fresh oil off.  Spray all the areas it might be leaking with a can or two of athletes foot powder.  The powder is bright white, when even a drop of oil comes through, you'll be able to see it immediatly and you'll know where the leak is.

If it's leaking out the tappet covers, replace the o-rings.  Do not tighten those down much or the threads will shear off in the engine.

If it's leaking at the gasket, you'll see the oil there between the fins.  If it's the pucks, oil will drain down below the head gasket and out the fins on the cylinders.  Either of these require  an engine pull to repair and it's a common job - search head leak or head gasket or the like.

Here's mine:  http://forums.sohc4.net/index.php?topic=35937.0
note all my problems were the result of trying to cut corners.


Use the atheltes foot trick.  It works better than it sounds.

[Duke McDukiedook]

Only problem with a head gasket replacement means an engine pull on these bikes.

You might as well tear everything down when you decide to do this and replace all gaskets if you have the engine pulled by then.

[OldSchool_IsCool]

And replacing the head gasket means replacing the base gasket which means pulling the jugs which means inspecting the bores which means.......

It's a slippery slope.  Let's hope new pucks with a thin coat of 1099, HondaBond or Aviation Sealer will keep your pant leg dry. 

By the way, you can pinpoint the leak with some spray-on foot powder.  Clean the engine, let it dry, spray the foot powder over the suspect area(s), run the engine.  The powder will turn black wherever the oil seeps out.

Another trick to delay a tear down: if the leak is not too large, you can cram some rolled-up paper towel between the fins to sop up the oil.  Change the paper towel when saturated.

[750Caferider]

Thank you for all the advice guys!  Yes I've adjusted my valves a little loose...  I learned a thing or two on the five motors I built for my bug back 15 years ago...  I'm going to try the powder/spray route to locate the problem...  Valve cover area looks dry, the area between 1&2 looks suspect.  Took the tappet covers down finger tight plus and 1/8 to 1/4 turn.  This looks like a slow leak that has gotten worse so I'll be interested to see what happens.  If it's the head gasket I guess I'll go ahead and send it off to APE so they can make it bulletproof and as long as the cylinders seem okay after being checked at a local machine shop I guess I'll just re-gasket the engine and have the oil pump rebuilt while replacing the Cam chain with one from say Tsubaki?  Any suggestions other than that?  Great gasket kit?  Best manufacturer?
should I piece meal it with best from some? Oh and should I have to buy new head studs when the head be removed?  I'm not a racer but I do hit it hard at least 2 times(8/9k rpm) with each ride, I like the twisties!  Hey Dookieduke whatcha doing in say a few weeks?

Cheers and Thanks again!

Anders

[gregimotis]

If you decide to tear it down, look through my thread (link above).  All the common mistakes are there, and the right way to do it, also.  It isn't a particularly hard job if you have the funds and can follow directions.


Lots of threads here on that job, do some research on the best gaskets (Honda), Heavy Duty studs (APE), those pucks people keep talking about.] etc then take your time and don't try to be cheap.  Hone the cylinders and replace the cam chain+rollers while in there and you'll never have to do it again.

[andy750]

I'm going to try the powder/spray route to locate the problem...  Valve cover area looks dry, the area between 1&2 looks suspect. 

If its coming from between the 1 + 2 headers for example, its 99% the cam tower pucks....it was in mine...it got worse after my do-it-yourself rebuild as well and turned out to the problem.

good luck
Andy