| Author | Message | ||
     Bclark |
I have suddenly developed a leaky head gasket on my rear head. How difficult is the replacement? Can I simply pull the head off, put a new gasket on, and replace the head? | ||
| Pammy |
It is best to replace head and base at the same time. When you release the pressure on the base(by removing the head)it will sometimes leak. Depending on the mileage, you might want to check other things for wear and tear(if you remove the cyl as well) | ||
| Bclark |
I thought about doing the base also, but I don't know about checking valve clearances and whatnot. If it is just replacing the gaskets and putting it back together, I'm capable. If it's more complicated, I'd rather take it to someone. The motor has approximately 18k on it. | ||
| Jayvee |
How sure are you that it's the head gasket and not the bottom rocker cover gasket? Is it oil, or is can you feel the puffs from the engine stroke? | ||
| Bclark |
No, it's not the rocker cover. I can see puffs of smoke from between the head and cylinder when I rev it and it's blowing oil onto my starter. | ||
| Steveshakeshaft |
On the ones I've done, it takes as long to scrape the old type paper gaskets off the rocker boxes and the cylinder base than it does to do the actual job! It's a piece of cake, just follow the manual. Rebuild with the upgraded HD or James or Cometic gaskets and it's fit and forget time. HTH. | ||
| Bclark |
So I can basically just pull the head off, replace the gaskets, and re-torque the bolts and I'm done? No need to do anything to the valves or anyting? | ||
| Puddlepirate |
Right, but if you go to replace the base gasket then the cylinder will have to come off. You'll have to use a ring compressor to get the piston back into the cylinder, then head gasket, head, retorque head, rocker boxes, carb, done. You will need a complete top-end gasket because the rocker gaskets, pushrod tube seals, and intake manifold gaskets should not be reused. No need to do anything to the valves, as there are no valve adjustments like on cars and whatnot. (Message edited by PuddlePirate on October 29, 2007) | ||
| Pammy |
...and cylinders. Check the rings. Base and head gaskets need to be done together. | ||
| Steveshakeshaft |
I really do recommend you pull the cylinder like Pammy suggests. Otherwise I give you odds of no more than 50/50 that you'll have to do the job again to replace the base gasket. (Besides, if you accidentally turn the motor at all with the head off, the base gasket seal will crack open). It really is easy once you beg, buy or borrow a ring compressor to refit the cylinder. Took me about 10 seconds to put the cylinders on one of my bikes 2 weeks ago. And it was a bonus knowing that everything in the cylinder was 100% as it should be. :-) | ||
| Bluzm2 |
You can get the piston back in the cylinder if you are VERY careful. Pammy, this is the part where you close your eyes, plug your ears and go "la la la la la" until I've finished the section below... The bottom of the cylinder has a chamfer. I used wooden chopsticks to push the rings back in the ring grove. A second set of hands is very useful to hold the cylinder as you VERY carefully compress each ring and push the piston up into the cylinder. The chopsticks keep you from nicking the rings like a screwdriver will do... Ok Pammy, you can open your eyes now..... Brad | ||
| Pammy |
I have used a bic pen before(and that was with an in-line 4)I have seen Wes do it with his bare hands. I have been thinking of doing a "Survivor man"/"CSI" kind of show...but for motorcycles. Yeah, that's the ticket... | ||
| Firemanjim |
You can leave the piston in the cylinder by pulling the circlip and taking the wristpin out, no ring compressor needed. | ||
| Bclark |
What type of things should I be looking for when I pull the cylinder? | ||
| Xldevil |
Hi. You should ask what causes your head gasket to be leaking suddenly. It isn´t leaking just because it likes to  I hope this isn´t only a symptom of some severe engine damage. If it´s not, you are to check the sealing surfaces of head and cylinder for flatness at the very least. You can measure and set a good squish once you are there.The factory set head to piston clearance is more or less useless. Ralph Btw.I can recommend Cometic gasket for heads.Easy to use and more easy to remove next time. I reuse 90% of my gaskets 2 to 3 times and never had any leaking issues.I clean the rubber gaskets of the rocker boxes and the manifold thoroughly in break cleaner.I do the same for the rocker base metal gasket and the pushrod tube seals. Since I´m not using a base gasket,there are not so many gaskets left to discard. But you got to be careful to the rubber gaskets.Don´t squeeze them between the rocker box parts during assembly. | ||
| Jimidan |
You can leave the piston in the cylinder by pulling the circlip and taking the wristpin out, no ring compressor needed. I like Fireman Jim's idea, as it seems that it would ruin the rings to slide them back through the chamfer again. I know of performance shops that would not think of pulling the piston out of the cylinder without re-honing and re-ringing. I am not a pro though, and I defer to the opinion of those that are about this. It just would not happen on one of my engines. Besides, like Pammy said, "Depending on the mileage, you might want to check other things for wear and tear(if you remove the cyl as well). With 18,000 miles on the clock, that seems to be the prudent and feasible thing to do. |
