Oil leak: hard or easy fix?

[milktown]

i recently bought my 2nd GB400 from a retired mechanic. he said he had just gone through it pretty well and did a full service on the top end. about a week after buying the bike bike it started leaking oil from the head gasket. on closer inspection i noticed that it looks like he didnt actually use real oem gaskets and instead just used that red liquid gasket stuff. its gotten to the point where i have to wipe the oil off the engine every couple days. my question is, is putting a new head gasket on as simple as, un-bold head, put on gasket, re-assemble(using correct torque specifications)? or is it a process that entails a lot more fiddly thingys and complicated adjustments? iv done clutch plates, chain/sprockets that kinda stuff but never actually taken engine parts off before.

[neels]

Looking at your pic it's the valve cover gasket that's leaking, the head gasket is down below the exhausts.

Easy enough to replace without disturbing much of the engine, might need to adjust valve clearances when its done.

[Akzle]

Looking at your pic it's the valve cover gasket that's leaking, the head gasket is down below the exhausts.

Easy enough to replace without disturbing much of the engine, might need to adjust valve clearances when its done.

^ do what he said.

[AllanB]

As above reckon it is just the cam cover leaking. Buy a gasket and pop that sucker off - take care when removing the red seal that you don't drop any into the head.

[tri boy]

Also keep in mind, some 6mm helicoils may be needed.
It's common that people over tighten, and damage the light weight alloy threads in the head.
Hence the cover leaks.
Also remove the cover with the piston at TDC, with the cam lobes down. Install in the same position to guarantee correct torque.

[Drew]

A lot of those 80s Honda singles, don't run a rocker cover gasket from the factory. So lets not assume the last owner was less than thorough.

But it's a piece of piss to fix anyway....right up until some fuckwit thinks they'll try and just tighten up the bolts, and strips the thread out of half of them.

[fridayflash]

as said above, bit easier if at tdc, valves facing down saves extra tension on things when re-assembling.

[neels]

Also keep in mind, some 6mm helicoils may be needed.

Yep, bought a XL250 in bits like that, 3 helicoils later it did up tight again. :facepalm:

Do the GB motors run the oil gallery up one of the bolts like the dirt bikes? That's the one that usually strips from filling up with oil at the bottom of the hole, cotton buds are your friends when reassembling.


A lot of those 80s Honda singles, don't run a rocker cover gasket from the factory. So lets not assume the last owner was less than thorough.

Good point, in which case a bit of gasket eliminator and should be no need for valve clearance adjustment.

[milktown]

thanks for the help, im going to give it a go when i get my other bike back. i shall let you all know how bad i f**k it up and ruin EVERYTHING :niceone:

[unstuck]

thanks for the help, im going to give it a go when i get my other bike back. i shall let you all know how bad i f**k it up and ruin EVERYTHING :niceone:

Thats the spirit, start the job with a positive can do attitude.:shutup:

[merv]

Had to fix the same on our DR650SE a few years ago and its quite common that the cam covers don't have a gasket http://www.kiwibiker.co.nz/forums/showthread.php/47570-So-why-was-I-having-to-do-this

[tri boy]

I'm pretty certain that engine model had/needed a rocker cover gaskit.
They came in the OEM kits.
Required to stabilise the cam bearing clearances. Running an engine without it risks cooking the plain metal bearing surfaces.
Plasti gauge and a bit of time would confirm that.
I have been known to be wrong though..................

[pete-blen]

having a compressable gasket between 2 bearing mateing surfaces
is not the ideal way to maintain bearing surface clearances...
so I would say theres not a gasket there...
Honda have a gasket sealant that looks like silver paint..."Hondabond"
magic stuff never had a crank case leak useing it..

[Drew]

The rocker cover, doesn't saddle the cam directly anyway.

Why is this being made so hard?

Take off the rocker cover, ensure the holes the bolts go into are not stripped of their thread, clean the surfaces and reassemble with a decent sealant. Should take about an hour.

[merv]

The rocker cover, doesn't saddle the cam directly anyway.

Why is this being made so hard?


They usually do. See those pics of the DR650SE on that link of mine and you'll see the cam just sits in the head on machined surfaces and the top surface of the bearings are machined directly into the cam cover. The Honda singles are the same.

You are right though it is no big deal. Take the cover off - clean it nicely to make sure there's no shit got onto the bearings surfaces - apply the sealer, then bolt the cover back on. Don't overtighten - the correct torque on the bolts will have been figured out by the manufacturer to give the right bearing clearance.

[unstuck]

Should take about an hour.

For someone who knows there way around their bike, Id give it a couple otherwise.;)

[Drew]

They usually do. See those pics of the DR650SE on that link of mine and you'll see the cam just sits in the head on machined surfaces and the top surface of the bearings are machined directly into the cam cover. The Honda singles are the same.

You are right though it is no big deal. Take the cover off - clean it nicely to make sure there's no shit got onto the bearings surfaces - apply the sealer, then bolt the cover back on. Don't overtighten - the correct torque on the bolts will have been figured out by the manufacturer to give the right bearing clearance.I stand corrected. I see now where the can is located from teh picture provided.


For someone who knows there way around their bike, Id give it a couple otherwise.;)Long as he cleans the surfaces right, time matters little.


I'd also like to point out, that the gasket sealant shouldn't have fuck all excess. Smear it so thin it's transparent! Sealant squishing out the sides on the outside, is doing the same thing on the inside...Then falling off and trying to make a trip through your oil system. That is not the goal, and the shit will end up immeasurably thin between the surfaces once reassembled anyway. So long as the whole surface has a very thin layer, you're golden.

[milktown]

Why is this being made so hard?

Take off the rocker cover, ensure the holes the bolts go into are not stripped of their thread, clean the surfaces and reassemble with a decent sealant. Should take about an hour.

this is what i was hoping to hear