Base gasket and head gasket prep

[Downer]

Ok re-doing my head and base gasket again after two seasons of riding started to weep and look like crap so decided to put new ones in.

I just want everyone's thoughts on prep for base and head gasket surfaces? I did 5twins sealer on the head gasket around cam chain tunnel and four outer studs.

But i wanna know if laquor thinner or brake cleaner or something better to make sure these gaskets seal this time around I realize prep is everything I just wanna do it right.

I know your not saposed to use sealer on base gasket but Is anyone actually using sealer on the base and the head gasket with no leaks? If so what sealer?

I would really like everyone's opinion on sealers and prep thanx in advance

 

[5twins]

The base gasket would depend on the type. The latest from Mike's (and Athena) are chemically treated so require no additional sealer. Older ones and an O.E.M. replacement, well, that's up to you. I put sealer on my old untreated Athena like 6 or 7 years ago. So far, it's good. My head gasket is weeping across the front though. That's why I updated my recommendation for lines of sealer on the head gasket to include ones across the front.

Yes, wipe down all the surfaces with lacquer thinner before final assembly. And then, DO NOT EVEN TOUCH THEM with your fingers. Body oil can mess things up. People don't realize the importance of a totally clean assembly process when rebuilding a motor. This is like an operation on a human except the possibility of infection is replaced with that of an oil leak. Really, this shit matters.

 

[Downer]

How about touching the gaskets do oils from your fingers mess them up or should I wipe the gaskets too with thinner? Should it basically be sterile?

 

[hard_y_rd]

I thought you were supposed to soak yor paper gaskets in motor oil before assembly. Does this not apply for the base gasket?

 

[Downer]

What did you do hard y rd this is what I'm trying to figure out did you soak them in oil? And how long have they lasted?

 

[hard_y_rd]

Well ,I oiled them. My first engine rebuild. Never started the motor yet. Waiting to wire it over the winter to fire it up. Hope I didn't do something wrong here. I'm sure we'll find out here shortly.

 

[5twins]

The paper gaskets I oil are on other parts of the bike but not the head or base gaskets. Oiled gaskets include the sump and side oil filter cover, the right side cover, the electric start gear cover, breather housing, cam chain adjuster, and the points/advance housings. The base gaskets I've been using lately are those chemically treated ones and go on dry. The heat activates the sealer in them which probably wouldn't work very well if oiled. In this "Leakless XS Assembly" thread over at the 650 Garage from several years ago, gasket sealer was recommended for the older untreated base gaskets .....

http://xs650temp.proboards.com/thread/327/leakless-xs-assembly

 

[hard_y_rd]

I guess you got your answer, Downer. Looks like I'll be doing another base gasket in the near future.

 

[hard_y_rd]

So Downer now you got you answer, I'm going to hijack if you don't mind instead of starting another thread.
So i oiled my base gasket, Don't do this! I'll have to do another over the winter when i re-wire. My question is: Can i save the new head gasket? I did the whole cam tunnel threebond thing. (did't oil that one, HA HA) Will it be able to seal properly? I have oil in the motor but never started it.

 

[5twins]

I'm not saying an oiled base gasket can't work. Who knows, maybe it will seal up just fine. The fact that yours has set for a while is a plus. You can apply several re-torques before putting any running pressure on it. If you do replace it, you could leave the head and cylinder bolted together and lift them off as a unit so you don't disturb the head gasket.

 

[peanut]

it probably all depends on how clean and flat your mating surfaces are. if they were perfectly flat without scratches and deformaties you probably wouldn't need a gasket

I couldn't check the bottom of my jugs for mating surface straightness so I used threebond 1104 NEO on both sides on the base gasket. It certainly won't hurt anything . Any residue will simply squeeze out and I prefer the belt and braces approach myself .

I put the same cement on both sides of the head gasket also paying particular attention to areas around studs and where the mating surfaces were narrow. I made sure I skimmed both the head and the cover and checked they were level and flat which was lucky as the head was surprisingly warped. High spots at each end and low spots through the middle all around the cylinder liners and oil gallery which would definitely have caused a head gasket leak.

 

[hard_y_rd]

I'm not saying an oiled base gasket can't work. Who knows, maybe it will seal up just fine. The fact that yours has set for a while is a plus. You can apply several re-torques before putting any running pressure on it. If you do replace it, you could leave the head and cylinder bolted together and lift them off as a unit so you don't disturb the head gasket.

I just like doing things the proper way. I was thinking on leaving the head and cylinder bolted. I may do this as i want to check the cam chain. I had the cam a bit off center and had to loosen the top nuts and tapped the cam to center it. The cam chain sounds a bit "louder" now.
I did eye the chain when i installed it the first time. Hate doing everything twice. I usually research the shit out of things till i get the nerve to actually do it.

 

[peanut]

IHate doing everything twice. I usually research the shit out of things till i get the nerve to actually do it.

that could be why my engine has sat on the bench for the past 12 months lol