2 Strokes Down Under

G'day, I need to get my hands on a top LC crank case to cut out the section above the sprocket/behind the engine number so I can weld it onto mine (chain damage, previous owner?). Bike has matching numbers, so better to repair than replace. The condition of the rest doesn't matter, cause it'll end up in the bin!
Cheers

Welcome to the forum is in order I guess...
Hmmm,a good welding shop (read tig) would be able to fix that for you.I have same prob with an RZ case but have been advised by someone known for his weld craft (thanks Pat) that it could be fixed easliy.
Give it ago first,if that fails I have a set of RDLC cases here doing nothing,Ill swap for a good LC tank lol.
Start a build thread,lots of great info & blokes here.

for me, welding cases is a big no-no as aluminium warps when welded so mating surfaces wont be flat anymore and the gearbox might start playing up etc.

easiest fix IMO would be to put a new top crank case on the bike and then get the numbers ground off, then stamp the new numbers in. easy!

The cases aren't machined as a pair?

Dave

If you were concerned about warping, you could bolt the cases together during the weld.

A good shop would also have quite a thick bench to take some of the heat out of the job.

Aside from that, you could also keep the casing cool enough with a wet rag or something over it.

Thanks for the welcome, and the replies... I have a guy in Gympie who reckons its not a problem to repair as long as he has the bottom, top and side all bolted together when he does it to stop the warping issue. If I can't get the bit off an old case he said he could improvise, and rather than fully welding it, put some small runs in stratigic places, and fill the rest. Sounds good enough to me.
L.B. I think I will start a build thread... I did spend a while trawling through the tech stuff on here, and it's a bloody mine of good info.
The crank case is the start... The tank has a slight leak, the plastics need a bit of welding, and don't get me started on the home made porting job some twat did on one of the barrels! Other than that, it's all pretty good.

Where the damage is will not cause any issues as its too far away from any gasket face. I have repaired a good few cases with the same damage.

DuncanB wrote:Thanks for the welcome, and the replies... I have a guy in Gympie who reckons its not a problem to repair as long as he has the bottom, top and side all bolted together when he does it to stop the warping issue. If I can't get the bit off an old case he said he could improvise, and rather than fully welding it, put some small runs in stratigic places, and fill the rest. Sounds good enough to me.
L.B. I think I will start a build thread... I did spend a while trawling through the tech stuff on here, and it's a bloody mine of good info.
The crank case is the start... The tank has a slight leak, the plastics need a bit of welding, and don't get me started on the home made porting job some twat did on one of the barrels! Other than that, it's all pretty good.

Bolting the cases together is not enough install the bearings and either the crank or a mandrel, pre heat the lot up weld then back into the oven and turn the oven off. Heat and cool slowly. They will walk on you otherwise

I'll pass all this info on to my welder... If all else fails, I'll be onto LB for his spare cases!

Come on... Someone out there must have a crappy old top casing that has the top section intact! PLEASE!!

It's very common for the chain to break that part of the casings.

dude, you didnt look very hard did you?

this should work a treat yes?

http://www.ebay.com.au/itm/YAMAHA-RD250 ... 500wt_1022

Doesn't look like I did, Jeram... Well done mate, that is just what I need for the patch up. I need a good quality tank while your on a roll.

LOL I was just coming back to add that for you as well LOL!

glad you took my comment as tongue in cheek

just decided whether you want to repair you cases by hacking up these ones, or whether you want to use these cases and stamp your numbers into it