Cam Oil Seal

[Cy Welch]

I'm hoping someone can help. I have an oil leak from what appears to be the seal on the camshaft behind the electronic ignition module on the head on my 1980 XS400G. I'm hoping there is a way to replace this seal without breaking down the whole top end as this is the only leaking seal on the engine and if I can solve this leak I should expect to easily be able to get at least another year or two out of the engine before I take it out of service and refresh it. BTW this is the original engine with 45000 miles on the clock, compression still in spec and no apparent oil burning, just seeping (heaving seeping) from the cover over the igniter module. It's using about 1/2 cup of oil every 250 miles or so, all of it running down the side of the engine.

Can this be done without breaking it down? Can I take the ignition module from the end of the camshaft and get to the seal to replace it without pulling the head (and can I get this seal without a complete seal kit)?

Thanks in advance for any help you can give.

[drewpy]

I'm hoping someone can help. I have an oil leak from what appears to be the seal on the camshaft behind the electronic ignition module on the head on my 1980 XS400G. I'm hoping there is a way to replace this seal without breaking down the whole top end as this is the only leaking seal on the engine and if I can solve this leak I should expect to easily be able to get at least another year or two out of the engine before I take it out of service and refresh it. BTW this is the original engine with 45000 miles on the clock, compression still in spec and no apparent oil burning, just seeping (heaving seeping) from the cover over the igniter module. It's using about 1/2 cup of oil every 250 miles or so, all of it running down the side of the engine.

Can this be done without breaking it down? Can I take the ignition module from the end of the camshaft and get to the seal to replace it without pulling the head (and can I get this seal without a complete seal kit)?

Thanks in advance for any help you can give.

you only need to lift the cam cover off to do it. not a big job

[bralkan]

I'm hoping someone can help. I have an oil leak from what appears to be the seal on the camshaft behind the electronic ignition module on the head on my 1980 XS400G. I'm hoping there is a way to replace this seal without breaking down the whole top end as this is the only leaking seal on the engine and if I can solve this leak I should expect to easily be able to get at least another year or two out of the engine before I take it out of service and refresh it. BTW this is the original engine with 45000 miles on the clock, compression still in spec and no apparent oil burning, just seeping (heaving seeping) from the cover over the igniter module. It's using about 1/2 cup of oil every 250 miles or so, all of it running down the side of the engine.

Can this be done without breaking it down? Can I take the ignition module from the end of the camshaft and get to the seal to replace it without pulling the head (and can I get this seal without a complete seal kit)?

Thanks in advance for any help you can give.

Yep, just take the cam cover and ignition module off and you can get to that seal. Only really need to be sure you loosen and tighten the bolts in the right order. It is diagramed in the guide posted around on the forum. Should take you only an hour or less. You will need a torque wrench to re-tighten the cover back on.

[Cy Welch]

Yep, just take the cam cover and ignition module off and you can get to that seal. Only really need to be sure you loosen and tighten the bolts in the right order. It is diagramed in the guide posted around on the forum. Should take you only an hour or less. You will need a torque wrench to re-tighten the cover back on.

Ok, I attempted the job today and got the new seal installed and that leak seems fixed but I'm having a real problem. The manual calls for liguid gasket for reassembly, which I can't seem to find. I tried RTV gasket maker and it's not sealing (I've got leaks all over the place). Reading the instructions on the package for the RTV gasket maker I think I did it wrong so I'm going to try again tomorrow and follow the instructions (run the bead, place the part, finger tighten until the material starts to press out and then stop and wait 1 hour before tightening and torquing the bolts.)

I'm hoping this works properly since seeing how this is put together I'm pretty sure that the thickness needs to be pretty close to zero to give the right tolerances. My other option may be to try a product that is similar to what I've been trying but that says no wait is required, just apply, assemble and tighten and use right away.

Other than that, is there something else to look out for?

[drewpy]

Ok, I attempted the job today and got the new seal installed and that leak seems fixed but I'm having a real problem. The manual calls for liguid gasket for reassembly, which I can't seem to find. I tried RTV gasket maker and it's not sealing (I've got leaks all over the place). Reading the instructions on the package for the RTV gasket maker I think I did it wrong so I'm going to try again tomorrow and follow the instructions (run the bead, place the part, finger tighten until the material starts to press out and then stop and wait 1 hour before tightening and torquing the bolts.)

I'm hoping this works properly since seeing how this is put together I'm pretty sure that the thickness needs to be pretty close to zero to give the right tolerances. My other option may be to try a product that is similar to what I've been trying but that says no wait is required, just apply, assemble and tighten and use right away.

Other than that, is there something else to look out for?

MM... my haynes does say to use a non hardening gasket, but I have not done so as, you righly say, it changes the clearance on the camshaft bearings.

don't bead the gasket sealer, smear an absolute smattering on if you must, with a finger. goo WILL get into the oil ways if you bead it on.

on next oil change check the gauze filter from under the engine, even after I've smeared blue hermetite on it still got in the oil, luckily it has got trapped by the gauze filter.

[Cy Welch]

MM... my haynes does say to use a non hardening gasket, but I have not done so as, you righly say, it changes the clearance on the camshaft bearings.

don't bead the gasket sealer, smear an absolute smattering on if you must, with a finger. goo WILL get into the oil ways if you bead it on.

on next oil change check the gauze filter from under the engine, even after I've smeared blue hermetite on it still got in the oil, luckily it has got trapped by the gauze filter.

Well I tried again and followed the directions on the tube and it seems to have worked so far. I'll see how it goes over the next few days but it seems to be properly sealed without seeming to have affected the valve lash or other aspects. I will be keeping an eye on it of course as I'm a bit nervous about it.

[Cy Welch]

Well I tried again and followed the directions on the tube and it seems to have worked so far. I'll see how it goes over the next few days but it seems to be properly sealed without seeming to have affected the valve lash or other aspects. I will be keeping an eye on it of course as I'm a bit nervous about it.

Ok, so what do you use? I'm still having seapage problems and I'm just about at my wits end. I'm going to try plain old thin brush on gasket sealer this weekend (the next point where I have time to work on it) and see if that helps.

Somewhat off topic, my idle seems almost perfect now, but I get just a bit of hesitation between idle and main circuit as a pass the 1/4 throttle point. I'm also pretty sure at this point that I'm a bit lean above idle so I'm thinking about raising the fuel level 1-2 mm (lowering the floats) which of course means I'll have to adjust the idle mix all over again. I just want to get everything working smoothly at the same time and then keep it going for a bit over a year, then I tear it down and go through it.

[drewpy]

Ok, so what do you use? I'm still having seapage problems and I'm just about at my wits end. I'm going to try plain old thin brush on gasket sealer this weekend (the next point where I have time to work on it) and see if that helps.

Somewhat off topic, my idle seems almost perfect now, but I get just a bit of hesitation between idle and main circuit as a pass the 1/4 throttle point. I'm also pretty sure at this point that I'm a bit lean above idle so I'm thinking about raising the fuel level 1-2 mm (lowering the floats) which of course means I'll have to adjust the idle mix all over again. I just want to get everything working smoothly at the same time and then keep it going for a bit over a year, then I tear it down and go through it.

lowering the floats, lowers the fuel level as it will shut off the fuel earlier. you need to lower the tab between the floats (effectivley raising them) then you will raise the fuel level. try it and see, if i run mine at constant 4k then is starts jerking around (its much better between 7 and 9.5 k )

[Cy Welch]

lowering the floats, lowers the fuel level as it will shut off the fuel earlier. you need to lower the tab between the floats (effectivley raising them) then you will raise the fuel level. try it and see, if i run mine at constant 4k then is starts jerking around (its much better between 7 and 9.5 k )

I think we have a confusion of terms. When I say lower, I mean as far as the measurement which is done with the barb upside down so IIRC decreasing that measurement which I am calling lowering actually raises them in operation. I'd say the confusion is all my fault though.

I found yesterday that while things seem pretty good at temps at or below about 70 degress ambient, that at around 80 it gets really baulky once off the idle circuit. Loss of power and such. So, cooler air runs good, warmer (hot?) air means not so good. So, lean or rich? The plugs are pretty white when I check them when I get home after getting off the freeway, but with the temp thing I'm not as sure now. I do get the same bit of jumpiness, but around 5-7 k and when it was hot it was trying to bog.

So, warmer thinner air means less opening of the vacuum slides right? So less fuel and leaner? Or do I have it backwards? I'm going to try raising the fuel level a bit as see if the problem gets worse or better and go from there I guess.

[drewpy]

I think we have a confusion of terms. When I say lower, I mean as far as the measurement which is done with the barb upside down so IIRC decreasing that measurement which I am calling lowering actually raises them in operation. I'd say the confusion is all my fault though.

I found yesterday that while things seem pretty good at temps at or below about 70 degress ambient, that at around 80 it gets really baulky once off the idle circuit. Loss of power and such. So, cooler air runs good, warmer (hot?) air means not so good. So, lean or rich? The plugs are pretty white when I check them when I get home after getting off the freeway, but with the temp thing I'm not as sure now. I do get the same bit of jumpiness, but around 5-7 k and when it was hot it was trying to bog.

So, warmer thinner air means less opening of the vacuum slides right? So less fuel and leaner? Or do I have it backwards? I'm going to try raising the fuel level a bit as see if the problem gets worse or better and go from there I guess.

air is denser when cold and the cold charge promotes combustion ( spitfire planes etc used water injection for that purpose)

the white plugs are a great indication that you are running lean, i would try your idle mix screw and richen it, as it does affect the rev range higher up. trouble is , the usa models are set really lean to pass emissions test.

I run rich on the bottom end of the rev scale to get my kicks at the top ( my bike hates slow traffic like me)

[Cy Welch]

air is denser when cold and the cold charge promotes combustion ( spitfire planes etc used water injection for that purpose)

the white plugs are a great indication that you are running lean, i would try your idle mix screw and richen it, as it does affect the rev range higher up. trouble is , the usa models are set really lean to pass emissions test.

I run rich on the bottom end of the rev scale to get my kicks at the top ( my bike hates slow traffic like me)

That will be my next project, to work on the lean issue. I got the leak fixed finally by using the recommended sealer (finally found it, and it specifically states it's used for mated machined surfaces as one of it's applications) and making sure that the cam seal was fully seated (found it was not fully seated and I think it was leaking around the edges) and it's looking good now. It's nice to have a dry engine (on the outside) for the first time in a while. Now to replace the tach cable (which is damaged and leaking) as I'm getting a slight leak there, but I knew that and expected that, and it's actually very minor, not wet, just kind of a slightly oily look just below it.

I have richened the idle mix a LOT and idle is quite good now, but it's had little to no affect on higher RPM running. I'm pulling the carbs this week sometime and when I do I'm going to raise the fuel level by a couple of mm's and see how that affects things. I guess worse yet is that the 1980's use the bs34-III's and they were intended to not be adjustable. No adjustment on the primary needle etc, so I'm hoping I can accomplish what I need by just raising the gas level slightly rather than having to change jets (I don't really want to go there at this point).