Question about welding the engine

[thebottle]

I have a small crack just above the cam chain tensioner. I brought the engine to a welder and he said that he would rather have me pull it apart or other components on the engine like the rings could get messed up.

I would have to pull it completely apart because the crack is on the bottom half of the engine just below were the head splits. Has anyone welded in this area before? Do you think there is a risk of damaging the cylinders/rings?

[James England]

I have a small crack just above the cam chain tensioner. I brought the engine to a welder and he said that he would rather have me pull it apart or other components on the engine like the rings could get messed up.

I would have to pull it completely apart because the crack is on the bottom half of the engine just below were the head splits. Has anyone welded in this area before? Do you think there is a risk of damaging the cylinders/rings?

I'd post a pic. Just thinking... without seeing a pic.... couldn't you ensure that the piston concerned is fully up/down as required, when the welding is done?

[DGXSER]

I would think that you would be better off just getting a used engine case, and replacing the crank bearings while your at it. Might even be cheaper.

Welding aluminum is tricky, so I am sure the guy just wants to be sure he can get even heat and not screw up seals and such.

[TomB]

I think The Bottle means the barrels (jugs) are cracked at the camchain tunnel, sounds like the little lug where the M8 stud from the head is fastened down.

You'll need to take off the barrels to get it welded if it is where I think it is

[natemoen]

sounds like the little lug where the M8 stud from the head is fastened down.

I am guessing the same thing.

I am guessing the welder is worried about the small chance that there could be arcing between the cylinder walls and the rings/pistons and that is why he wants it disassemble. It is a semi reasonable concern.

[James England]

sounds like the little lug where the M8 stud from the head is fastened down.

If it's not actually leaking, I'd just leave it alone. The torque setting for that little M8 stud is a lot less than the cylinder head bolts and it's not particularly there for tightening the head gasket... more like keeping the CCT tunnel oiltight. Is it actually leaking?

[mharrington]

My bike has the same condition. I did have a pic but evidently I deleted it. A member here pointed out that someone overtightened the fastener above the cam chain tensioner during a cyl head install and thus cracked the area. The small nuts in that area do not get the same torque as the larger ones. First off- I know the proper fix is to replace the jugs/barrels. Here is what I did none the less.
I cleaned the area and crack. Then with my dremel rotary tool I took a bullet shaped carbide cutter and LIGHTLY grooved the entire crack. I then let the bike sit a few hours to let as much oil a possible drain thru the crack. Then I took compressed air and blew high psi air into and along the entire crack. (Blows the oil back up into the engine.) Then I scrubbed the grooved crack and surrounding area with laquer thinner and a clean rag. Finally I ran a bead of Permatex Black into the channeled crack. I did spread the silicone with my finger to extend out past both sides of the crack. I did this in sept of 2010 and it still does not leak. I have 2 extra jugs but dont FEEL like installing a different jug as the bike runs like new and does not leak. I chose Permatex Black over JB weld as its too hard to smear the JB in that area and the Permatex BLACK has great oil and heat resistence. (The highest of the Permatex line) Its also flexible and deals well with heat cycles. Good luck

[thebottle]

Where the red line is where the crack is on the bike... sorry I don't have an actual picture of it and I'm too lazy to go take one.

[mharrington]

Yes thats it. That ear cant take over tightening and cracks.
http://www.xs11.com/forum/showthread...848#post296848

[natemoen]

Are you sure it is leaking yet? If your cam chain tensioner is leaking it shows back around where you are pointing to.

[BA80]

The tensioner is just below that Nate. That is the stud in the head that points down.

Very easy to break.

If it's not leaking leave it alone or maybe try filling the crack with epoxy to try and stabilize it. If it is the only proper way to fix it is replace the jugs

[ddragon63]

the reason he the welder wants you to remove it and bring it in is for 2 reasons. #1 oil will catch fire @ a lower temp than it takes to melt the aluminum to create a weld puddle. and #2 Aluminum has to be SUPER clean to weld. Unlike steel where you can fudge it a bit, Aluminum needs to be contaminate free in order to correctly weld. I'm sure the welder doesn't want to be responsible for your bike burning to the ground or have the job come back because the weld broke due to contamination.

Looking @ the picture of where its @ I dont think there's any pressurized oil in that area so the RTV trick above would work. Personally if I was going to do a fix like that I would use a Cold weld Like JB weld or quick-crete and use a puddy knife to try and get it into the crack a little better.

Another way to do it would be to find someone who's familliar with brazing. They make a Material called "Aladdin" rod wich is a brazing rod designed to stick together any dis-similar metal. Most good welding supply shops should carry it. and usually you can buy it by the stick. You can also braze aluminum with aluminum filler rod and Harris stay clean aluminum flux. You will need to make sure you clean the crap out of it before doing any home type repair. If your handy with a torch (if you have one) a welding tip and some Aladdin rod and you'll be set. I've also sold some Aluminum stick welding electrodes to guys to use as brazing rod and they say it works great. Seeing as Stick electrode already has the flux on it its just getting your temp right and using it like flux coated bronze brazing rod.

Good luck I hope somewhere in all this I helped you out.

[natemoen]

The tensioner is just below that Nate. That is the stud in the head that points down.

Very easy to break.

If it's not leaking leave it alone or maybe try filling the crack with epoxy to try and stabilize it. If it is the only proper way to fix it is replace the jugs

That is the intake side, not the exhaust.

[BA80]

I....knew that.....I was.......just checking to see if you did.

Don't know what I was thinking. WAIT! maybe I wasn't thinking.

[natemoen]

I....knew that.....I was.......just checking to see if you did.

Don't know what I was thinking. WAIT! maybe I wasn't thinking.

It's ok Greg, it's ok....