Topic: SOHC winter projects....

[Duanob]

What are ya'll working on this winter?

I am about ready to re-replace my head gasket. I just did the top end last winter. The after market HG didn't have a perfect fit around the left side oil gallery passage but thought with the o-ring and torquing the head down it should be OK.....wrong! It leaks like a seive so this sunday I am replacing it with an OEM HG I got from powersports. I think this time I am going to put a thin layer of sealant around the oil passage holes can anybody recommend a good one for the Hondas? It will have to be oil and heat resistant.

Also when I installed the head last time I think I put the cam chain guide in upside down. I don't know if it matters but I get a pretty noisey top end some times. Could be the way the cam chain hits the guide so I can fix that as well.
 
I'm going to time myself this time I can have the carbs off and back on in 40 minutes so we'll see if it all gets done in less than a day.

[Ryan66]

Need to finish plugging in my wiring and doing the 3,000 mile tune up on my 78 550. Hopefully by then it'll be rideable.

[jessezm]

What are ya'll working on this winter?

I am about ready to re-replace my head gasket. I just did the top end last winter. The after market HG didn't have a perfect fit around the left side oil gallery passage but thought with the o-ring and torquing the head down it should be OK.....wrong! It leaks like a seive so this sunday I am replacing it with an OEM HG I got from powersports. I think this time I am going to put a thin layer of sealant around the oil passage holes can anybody recommend a good one for the Hondas? It will have to be oil and heat resistant.

Also when I installed the head last time I think I put the cam chain guide in upside down. I don't know if it matters but I get a pretty noisey top end some times. Could be the way the cam chain hits the guide so I can fix that as well.
 
I'm going to time myself this time I can have the carbs off and back on in 40 minutes so we'll see if it all gets done in less than a day.

You'll get lots of opinions on the head gasket issue, but I'll share my recent experience.  I have rebuilt my top end 3 times in the last two years, and the first two times I used an aftermarket gasket that came with my big bore kit and had leaks at those oil passages (this is on a CB400f, but similar to yours).  The third time I used the same gasket from the same aftermarket kit and no leaks.  Here's what I did differently (aside from the obvious of making sure both surfaces are flat and true and clean as a whistle)

The first two times I used hondabond #4, which is the gray semi-drying formula, around the oil orifices only.  I don't know why this didn't work the first time it just didn't.  Many people recommend this and it works for them, but it didn't for me and I wont do it again.  On the second try, I don't know what happened but I think some of the sealant stuck to the rubber seals and instead of compressing and sealing the passageway when I torqued down the heads they got sandwiched between the head and the cylinders and prevented them from sealing properly.  It didn't leak a lot, but it was ugly.

Determined not to make the same mistake, this time, with all new rubber seals, I coated them in a very thin layer of silicone grease (oil might work just fine, but the grease stays put and I didn't want any getting on the gasket).  Then, I sprayed both sides of the gasket with Hylomar Blue (aerosol), which can be ordered online.  I did three light coats on both sides.  you have to be extremely gentle with the application because if you spray to much or too close, it will pool up and cause irregularities.   You should practice first.   I had this problem on the base gasket and it caused a very slight weep (which seems to have gone away with a re-torque).  Anyhow, this worked for me and for the first time I have no head gasket leak around those oil jets.

[Duanob]

Thanks for sharing your headgasket woes jess. I plan on doing this on sunday so ordering Hylomar blue online and getting it in time is out of the question. If I can find it locally in the tube I thought of just circling the oil passages with it and hope for the best. Or use the Permatex copper spray hi-temp gasket adhesive. Anybody had any experience with that?

[Tugboat]

Neck bearings, wheel bearings, fork seals & polish lowers, painting triples, new front tire, new LH switch. '76 750F

[Steve_K]

Wheel bearings, fork stem bearings, fork seals, new springs, polished lowers, new gators, new bars and rewire the 73 750. Good way for me to some time in the shop.  It feels good to get stuff done
Steve

[72500john]

I cant seem to get anything done as far as winter projects go.everytime i think about it we have a nice day and the bikes come out. strangely enough winter has not caught up with the mountains of va yet....now that i said that we will get 2 feet next week.

[Greggo]

Workin' on a '76 750K with a Corbin Gunfighter seat.  Gotta get that one done and sold pretty soon here.  I've got a turbo 550 project getting shipped up in a few weeks from Carpy 

[jessezm]

Thanks for sharing your headgasket woes jess. I plan on doing this on sunday so ordering Hylomar blue online and getting it in time is out of the question. If I can find it locally in the tube I thought of just circling the oil passages with it and hope for the best. Or use the Permatex copper spray hi-temp gasket adhesive. Anybody had any experience with that?

I have used the copper spray before, too on head gaskets with no ill effects at all.  It just doesn't seal like the Hylomar, and I was taking no prisoners this last time...

[andrewk]

I've been using the copper coat on all kinds of air cooled engines (lots of sohc 4's too) for years with no problems.  It's good stuff- so is Hylomar Blue.

My winter projects are fierce this year.  I've got to tear down my K3 to fix second gear, and I am hoping to get all kinds of stuff done to it while it's apart, including a 915 kit, triple disc conversion w/ 16" rear wheel (have everything for the front, still sourcing the rear), solid state charging (going to rebuild whole harness), frame and wheel bearings, new final drive, and I have to rebuild my forks as well.  Should be awesome when it's done.  I'm betting that I will end up not doing the big bore this year, but I'm hoping to get the funds to do it all at once.

I've also got a 77 F frame  and a stuck f3 motor, and just about enough pieces to build a bike out of it.

It's damn near Feburary, I better get to work!   

[Freaky1]

Completely strip the motor down and resemble, new gaskets, paint, cam, cam chain, guide, new valves, retainers, springs and valve guides.
Install Gordon frame kit and powder coat, custom hand made seat, custom hand made rear fender, modern rear sets with modern master cylinder.
Modern front brake handle, modern master cylinder, modern clutch perch, custom headlight
Mount battery sideways, replace oil tank, re-wire with all electronics under the gas tank, mount coil to battery box, install remote RFI start kit.

Yea, I think that's about it. But seeing as how I started in April of last year does it really count as a "winter" project?

[rb550four]

Just assembled the cases on the first of 6 500 engines, they 're all out of the cradles and 2 are torn  down. Have 5 550's still in frame waiting on the completion of the for-mentioned. The act of sitting in front of a fume spewing salamander is a drag and hampers motivation. Hoping for  a little warmer evening temps then perhaps, I could get my ass in gear.

[apex_seeking]

New fork tubes, fork seals and bead blasted the lowers. Next up is the hondaman swing arm rebuild and I think I'll call it. At least until my "idle hands" get bored.

[cmonSTART]

Heck, I have a whole 750F project bike to do!  As spring gets closer I have some work to do on the Goldwing.  I have to rebuild the front forks and maybe redo the carbs again with a decent quality kit. 

[Duanob]

Just assembled the cases on the first of 6 500 engines, they 're all out of the cradles and 2 are torn  down. Have 5 550's still in frame waiting on the completion of the for-mentioned. The act of sitting in front of a fume spewing salamander is a drag and hampers motivation. Hoping for  a little warmer evening temps then perhaps, I could get my ass in gear.

You got 5 550's?!? I barely got time for one at a time. Way to go.

[toytuff]

Ride them!

Work on them in the Summer. To hot to ride. (for me)

tt

[Duanob]

BRAINFART! All this talk of leaking o-rings I forgot to order them. I've been driving all over town to hardware stores and auto parts stores and can't anything close to the Honda headgasket seals. Everything else was going smoothly and could have it back together by the end of the day except for a couple of 50 cent parts. Damn.

[tweakin]

915 engine build, new paint, rearsets, clip ons and controls, 530 conversion. I have almost wrapped everything up.  Now just need the weather to improve here in the PNW...

[Tews19]

Did some hunting for a 750 and was able to find one... Tore apart my 75 550. Frame powder coated. Polished plenty of parts, cleaned a set of carbs, started to reassemble the 550.

[Doggie]

Finishing up a '78 CB750K. New seat, short shocks, Carb rebuild, tank cleaning, header & exhaust finish??, not sure what to do on that.
                                          Doug

[grumpy]

Just completed my new motor install 10 mins ago.
Tomorrow after work I'll see if it starts