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Discussion Starter · #1 ·
I am replacing the head gaskets on my 78 CB400 T2. I have everything apart but can't clean the old gasket off cylinder. The old gasket has essentially fused itself to the cylinder.

I have tried scraping (carefully), wire brush, carb cleaner but no luck.

Has anyone been in this situation? Any suggestions?

Also, a small cotter pin from the chain tensioner feel into the crankcase. How serious is this? Does this require crankcase disassembly or can I hope it will stay at the bottom?

Thanks
:(
 

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Head gasket - try paint stripper. Brush on in a small area and work it in. It should eat through the gasket, but it may take a little while. I'm sure there are other nasty liquids/solutions that you can try, but stripper has worked for me in the past.

Cotter pin - no, don't even think about leaving it in there. Chances are it'll get flushed around and could very well end up destroying the gears (or worse). Before you go tearing the engine down, try sticking a round magnet into the drain plug. Part fill the cases with thin oil and twist, turn 'n' shake the bottom end about. With any luck, the pin will stick to the magnet.

Come to think of it, if you've taken the head off, you might as well yank the cylinders off too. Whether you know it or not, you're likely to have disturbed the base gasket seal when separating the head from the cylinders . . . so you'll want to fit a new one of them anyways (and the cylinders being off will make the head gasket clean-up job a whole lot easier). Once you're down to just the bottom end, you should be able to turn the cases over and shake it out.

Hope that helps.
 

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I agree with the-chauffeur for the pin! Don't chance it... or else you will just have to rip it all apart again.

for the head gasket, a 3" wire brush on the end or a drill, thats what I always use for gaskets!
 

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Discussion Starter · #4 ·
Thanks for the tips. I'm going to try the magnet for the cotter pin since I have access to the crankcase.
Do I need any gasket sealer with the new gaskets or just the gasket?
 

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Hey Pheff.......TAKE IT FROM ME REMOVE THE Whole TOP End AND START FRESH AND CLEAN.... I tried just replacing my Head Gasket and Now MY MOTOR IS OUT OF THE BIKE IN THE BASEMent....

When u remove the Head Bolts all the Gunk falls into the holes in the Crank Case where the treads go...Well I unfortunaly ended up stripping one of my bolts beacuse when I was tourquing the bolts they were springing back a bit...... So i gave it a slightly harder push on the wrench and POP!!!!!!

Upon break down I noticed all holes filled with dirt and grime..

I have just finished drilling and tapping new threads...Not to bad but just sux when u want to Ride.....

Now I need to find the right spring compressor...Can Anyone help????? Can i get it a local parts store or is a special order????

I JUST WANT 2 RIDEEEEEEEE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Thanks George
 

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Discussion Starter · #7 ·
George et al.,

I thank my lucky stars I didn't have have trouble!

I was finally able to get everything apart and used razors, gasket remover and a wire wheel on my drill to get the old gasket off. I showed the cylinder to my local shop and some guy mentioned that it was probably original asbestos based gasket.

The cotter pin mentioned above never actually fell in the crankcase - after using a magnet for about 15 minutes I spotted it on the floor under the tire.

Anyway, after new gaskets and a little Honda gasket sealer she is running almost as good as new. I had to re-torque the engine bolts and re-adjust valves after some short riding but now she easily and smoothly gets up to about 85mph which, I think, is the max speed for that bike.

Good luck and get back to riding...

Thanks all for your help!

Paul
 
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