1981 RM250X

[Slow Pete]

Hi All,
          I'm about to put my cases back together and they are pretty good but not perfect.    I have new gaskets but I'm tempted to use gasket goo as well, just to make sure.   Is this a good idea and what is the best goo ?


Pete

[LWC82PE]

Threebond 1215 is excellent stuff. That's what i always use.

[Glen08]

Hylomar has never let me down

[bigk]

Yep, use some sort of sealer (Hylomar is good). A lot of people use the dry theory "in case" they have to pull it apart again & then the gasket won't get destroyed. This show's a lack of confidence in their engine assembly abilities IMO. Be confident & be sure the gasket won't leak, use a sealing compound.
K

[TTezza]

Been using it since the eighties, never let me down, tube last forever.

[OverTheHill]

Bit late for me to say this & i'm sure you would have been aware of any issues---but---had an X myself. Dad 'buy it' i want it i want it!!, the bearing rings cast into the case had been loose for ever & broken right up on one side. Oh it's buggered now so you own it DAD [thanks for nothing son lol]. Sold it in bits in the end but would have needed major surgery with cases machined & inserts made & fitted. Yamaha had it right with the old DT1 onwards & steel inserts, 45 years later & never a problem--well not in that area lol. My YZ125F back in it's heyday had alloy rings cast in & came loose so countersunk multiple grub screws around the edge & that fixed it [needs must]. seen mains fitted over the years & then the real cause has been discovered afterwards [like--oh it's still got up n down play--bugger. Hope all is well for you!!.

[SUZUKI311]

I'm with TTezza on this one, I have used Loctite 515 religiously for over 20 years with never a failure. It stays liquid outside of the join, so clean up is a snap. If you do have to dismantle again, it is easy to remove from the gasket. It can seal a gap up to .020" from memory, so its like an insurance policy, especially for old bikes where who knows who has had a go at dismantling the engines and possibly caused damage to sealing surfaces.

[LWC82PE]

515 is good but i tend to only use that on base gaskets. Hylomar is good on copper headgaskets but I dont use it anywhere else.  i have seen it cause problems on crankcase jointing. It does not seem to work in that area. I have had to rebuild quite a few engines that people have paid other 'mechanics' to rebuild which have soon after developed oil leaks so then I have had to totally strip them and then rejoin with Threebond and then that fixes it. I have also seen clear silicone not work well and there is some sort of brown sealant that a lot of the old guys use, i don't know what its called but it is also another one that does not work well and is a bit 'horrible' in my opinion and is quite hard to remove. I guess care in assembly also comes into play here as well. The Japanese factories use Threebond.

[TTezza]

Brown sealant is probably Stagg sealing compound. Used this on diesel flanges, bit gummy and harder to clean up. Loctite doesn't set hard making it easier when it comes to removing the gaskets next time and only sets once you exclude the air i.e. when you tighten the the part down.

[Glen08]

I wonder how many people don't follow the instructions with "hylomar".?
Plus dirty cases..

[DR500]

 Threebond.

[bishboy]

Have you or are you going to lap the cases?

[maxvmx]

Clean cases, no goo - never been a problem for me, my problem with sealers is how well the excess is digested by bearings. Never had a oil leak and never re-used old gakets.