Hi guys, 

I want to try and repair a small crack in the bottom skirt of a Tiger Cub cylinder.

The bike will not be used on too much of a regular basis, so I hope that this repair can be successful. I am in two minds though as to how approach this repair. Do I braze it, Oxy/acetylene weld, CO2 or similar inert gas weld. Has anyone tried this? 

My head tells me to braze it from a joint aspect because it is flexible, but from a welding heat aspect, a quicker CO2 weld seems to be the way to go.

Obvioualy the crack will be prepared accordingly prior to repair.

Bruce

 

You got heat expansion and contraction to contend with on basically a tube, for reliability get it machined and fit a liner.

Can you send in a photo of the damage. Bye, Peter B.

if its below the piston rings you can drill a small hole at the top of the crack to stop if getting worse

I've done this on a few cylinders and its lasted years.

Not my preferred method, but it does seem to work.  

Edited February 24, 20206 yr by suzuki250

Hi Guys, 

I hope you,can see from the attached photo, that the hairline crack is in the very bottom part of the skirt, where the piston never gets to. 

The best solution is to re-sleeve it no doubt, but down here at the bottom of the African continent, that could be a greater risk than a repair. I have managed to buy a very good condition 2nd hand oversize piston.

I like the idea of drilling a small hole at the top of the crack to stop it propagating, then a bit of prep and brazing should hopefully do the trick from what you guys are saying. 

Hopefully the force is with me !!!

Bruce

I would suggest laser welding, that will insure that there is no thermal issue, the laser will only melt up what is in need.

I have had done that to the cylinder and cylinder head of one of my bikes too and there was no warp issue at all.

 

As this technoloy is now at hand I would use it, laser welding has spread and thus cost are not as high as a couple of years
ago.

Looking at picture close up crack climbing up , my exp with cracks , never same , will crack again upon freezing temp open up ,, upon hi temp will open up , find another , it’s junk  ,, good luck 

Cub barrels aren't exactly scarce,if machining is not an option in SA why not contact a supplier here in the UK to send you a replacement with matched piston ready to go ? If  the crack does open up and bits make a break for freedom you are going to trash alot more of the engine.Bottom end rebuilds are not cheap.