Cracked Valve Cover

[schroedingersbaby]

I cracked the valve cover on one side due to over-torquing because of a crappy torque wrench. The crack is pretty thin, so I have a little question regarding fixing it. Would it be better to have someone do some aluminum welding on it and risk them ruining the rest of the cover with the prep work (what previous threads on the subject have mentioned) or would it be better for me to use some JBWeld on it and hope for the best. I might be a thin crack, but it was enough to lose oil through when I started the bike up. How much would an aluminum weld run me?

Oh and if you were wondering if a valve cover from a 1982 GS650GL would fit ok, not quite :lol: the right side was ok, but the left side was little off of where the holes are.

 

[7981GS]

One of our local motorcycle shops would do it for about $10.00 but, for the same $10.00 plus shipping, you can probably just buy another used cover.
It cracked most likely due to an uneven surface though.


Daniel

 

[schroedingersbaby]

The cheapest one I could find was 28 + shipping, and i already bought a replacement (for 20 bucks at a salvage yard), it just didn't end up lining up right, unless you guys are of the opinion that those two bolts won't end up mattering much.

 

[Dodik]

i'd cut a V grove in the crack and fill it w/ JB weld as a temp solution and try to find a new cover when i can.

 

[Flyboy]

I threw a shim once and it exited the motor through the valve cover, leaving a nice coin sized hole.
Had it welded up, no fuss, so it is also an option if you want to use your cover.

 

[tom203]

Sometime during model year 82, the valve cover was changed on the 650- the cam cover and cover gasket from a 81 and early 82 model is different.

 

[BassCliff]

Hi,

i'd cut a V grove in the crack and fill it w/ JB weld as a temp solution and try to find a new cover when i can.

I agree. There's not a lot of oil pressure and it's not a highly stressed part. It might be ugly but JB Weld should patch it up just fine. Maybe after some cleaning, sanding, and painting you could make it look like new.

I think it was late in '81 when a lot of the 16 bolt patterns changed to 19 or 20 bolts on the valve covers of the 8 valve engines. Too many oil leaks I guess.


Thank you for your indulgence,

BassCliff

 

[schroedingersbaby]

Well, I took it to two different aluminum welders and they both said the same thing, that where the crack is it's not going come out level on the gasket side when they weld it up. I found a new cover about an hour away, so I'm going to take a trip tomorrow and go pick it up, it'll be a nice break from studying for finals.

At least the topic is covered so anyone that keeps making dummy mistakes just like me knows what to do. :lol: Hopefully I should be riding after this, since it's the last maintenance thing to do. Just got to tune it up once I get it running, and hopefully the hanging idle is gone once I start it up again.

 

[schroedingersbaby]

Sounds like a good temp fix, but I think I'll go for the permanent one.

Sounds like a good temp fix, but I think I'll go for the permanent one.

Hi,



I agree. There's not a lot of oil pressure and it's not a highly stressed part. It might be ugly but JB Weld should patch it up just fine. Maybe after some cleaning, sanding, and painting you could make it look like new.

I think it was late in '81 when a lot of the 16 bolt patterns changed to 19 or 20 bolts on the valve covers of the 8 valve engines. Too many oil leaks I guess.


Thank you for your indulgence,

BassCliff

The leaks were fantastic, it smoked so much when it got on the exhaust I ran inside the house to grab a fire extinguisher.

 

[mike-s]

It looks as if it is a relatively simple fix and is achieveable with aluminium brazing, which is effectively high temperature soldering (380'c/780'F), so double the temp of lead soldering. if the entire peice was heated up evenly to near working temperature prior to the brazing (as opposed to using a tig or what ever it is you use for aluminium welding) then there is minimal chance of the peice warping. A lot of places aren't fans of doing aluminium brazing as opposed to welding as they think it just doesn't work. That is true if the peice is improperly prepared or poorly done, but it's just a good a fix if done correctly.

I fixed the sump thread on this and as i heated the entire thing up prior to performing the work (and continually kept it hot while continuing the work)

When i was done the warpage was about 0.5mm due to me keeping the temperatures consistent across the peice. However I couldn't tell exactly as i wasn't able to find a perfectly flat surface to check against with feeler guages & there was no windows near where i was working. This warpage was easily accounted for by both the gasket and the clampdown effect of the bolts.

The cost of brazing including the purchase of ALL the gear needed ended up being only a few dollars more than if i had gone and bought a new oil pan (due to the over-inflated cost of buying parts from a wrecker locally, and i wasn't going to have the bike sidelined while i wait for a part to come from half a world away).

The biggest expense for me in this exercise was to buy the MAPP torch as it was far overpriced at $140AU to buy (The same thing is about half of that when buying in the US). The brazing rods are pretty cheap, and both items can be purchased from any hardware stores that are "burnzomatic" stockists. And at the end of it, you have a blowtorch that can be used for many other things too, mine has already come in handy in other bike projects already.

 

[schroedingersbaby]

It looks as if it is a relatively simple fix and is achieveable with aluminium brazing, which is effectively high temperature soldering (380'c/780'F), so double the temp of lead soldering. if the entire peice was heated up evenly to near working temperature prior to the brazing (as opposed to using a tig or what ever it is you use for aluminium welding) then there is minimal chance of the peice warping.

I fixed the sump thread on this and as i heated the entire thing up prior to performing the work (and continually kept it hot while continuing the work)

When i was done the warpage was about 0.5mm due to me keeping the temperatures consistent across the peice. However I couldn't tell exactly as i wasn't able to find a perfectly flat surface to check against with feeler guages & there was no windows near where i was working. This warpage was easily accounted for by both the gasket and the clampdown effect of the bolts.

The cost of brazing including the purchase of ALL the gear needed ended up being only a few dollars more than if i had gone and bought a new oil pan (due to the over-inflated cost of buying parts from a wrecker locally, and i wasn't going to have the bike sidelined while i wait for a part to come from half a world away).

The biggest expense for me in this exercise was to buy the MAPP torch as it was far overpriced at $140AU to buy (The same thing is about half of that when buying in the US). The brazing rods are pretty cheap, and both items can be purchased from any hardware stores that are "burnzomatic" stockists. And at the end of it, you have a blowtorch that can be used for many other things too!

That's a thought...I always wanted an excuse to buy one of those:lol:. MAPP torches can be had for 22 USD plus the fuel tank. But I ended up finding the cover for 25 bucks relatively close by, so that's what I'll do to fix it..

Theoretically, would just lead soldering work? What's the operating temp of the valve cover? My cover literally has a hairline crack, so I wonder if just a regular cheap torch and some lead would work (the kind used for copper plumbing). If it works, then that would also solve the warping issue since the aluminum won't get hot enough to warp.

 

[mike-s]

I'll answer one bit at a time

That's a thought...I always wanted an excuse to buy one of those:lol:. MAPP torches can be had for 22 USD plus the fuel tank. But I ended up finding the cover for 25 bucks relatively close by, so that's what I'll do to fix it..

You could sill get the torch and practice fixing the damage for "next time", and the "next time" factor is what lead me to buy the torch as opposed to just junking the part and buying a-new.

Theoretically, would just lead soldering work?

Hell no, the metalurgy is all wrong. Lead solder would fill the gaps sure, but it wouldn't BOND effectively with the aluminium and ultimitely fix the problem. This is assuming you can get it to even work in the first place. I'd say the odds are that it'll come out, not next week, but sometime in the near future.

This applies to my needs more than yours, but plain solder is a totally different beast, it is softer, way softer and has not got any metal in there that is willing to bond with aluminium. Zinc readily bonds with aluminium if the surfaces are clean and prepared adequately. The stuff i used is a 3 way mix of aluminium, zinc & copper and is harder than aluminium, so there is little to no chance I'll strip that sump again.

What's the operating temp of the valve cover?

At a guess, if running super hot on a summers day i would say 180-250'c (300-500'f i think)

My cover literally has a hairline crack, so I wonder if just a regular cheap torch and some lead would work (the kind used for copper plumbing). If it works, then that would also solve the warping issue since the aluminum won't get hot enough to warp.

Well you may be able to get away with using a normal torch and the aluminium brazing material, as theoretically it is an extremely localised job. All you have to do is slightly open the crack out a little bit with a file & stainless steel brush to expose non ozidized/dirty parent metal, go over the whole item with a torch for a couple of minutes to get the thing nice and hot (its the extreme temp difference that is a problem, you don't have to get the whole thing up to working temp, just a couple hundred degrees is enough) and locally concentrate on the small worksite to get the crack up to operating temp and away you go filling. Then again iif you got the rods (they are easy to find, look for ALS-3 rods by bernzomatic) and a plain torch ( if you have it) with the right tip (a pencil tip will not work, you need the likes of a medium tip or a swirl tip to get enough heat output if your going propane) you may be able to heat it enough. If not, or you have a bigger workpeice/larger repair to do like i did, then maybe go for a MAPP torch. However if you need to buy a torch outright, i'd just go MAPP for starters.

Worst case scenario, if you make a mess of it, you only have to outlay $25 for a new rocker cover, AND you now have a torch.

But if you got lead solder to work, i would be impressed, very very very impressed.

 

[mike-s]

Oh and to clarify, by "soldering" i meant the technique used and the way the materials behave (a strong but surface bond into all the open metal pores), obviously i wasn't referring to the materials involved. Also the fluxes used in lead soldering are aggressive, and im not sure what they'd do to the part, the stuff i use requires nothing more than the surface be free of contaminants.

 

[schroedingersbaby]

Oh and to clarify, by "soldering" i meant the technique used and the way the materials behave (a strong but surface bond into all the open metal pores), obviously i wasn't referring to the materials involved. Also the fluxes used in lead soldering are aggressive, and im not sure what they'd do to the part, the stuff i use requires nothing more than the surface be free of contaminants.

I changed my mind and decided to fix it. Finances are a little tighter than I thought

For now, I'll just use some JBWeld since it's the cheapest and do your suggestion if it doesnt hold up, though I might try the lead soldering thing first, for science. It's always nice having extra tools.