A bud of mine had the mag side connecting rod bearing go out on his Viper this winter and it cracked the base directly under where the rod swings so in order to rebuild the engine he had to buy a second hand base.Anyway we were talking about what to do with the old base today and the idea of having it welded came up but wanted some advise from guys that have done this or know of it being done successfully.Would yo guys do it?Would you trust a welded base?There is a very competent machine shop locally that I would trust to do this work but want to know what you guys think about doing this.The crank case is only cracked,not that that's good,rather than sitting with a chunk out of it and a gaping hole to be filled in.
A welded lower case is fine the machine shop, if competent, will "v" out where the case will need to be welded and lay a bead where "v"-ed groove was and can clean/flush off any extra material to make sure that the crank and rod clear while rotating. also weld the outside of the case basically to make the case as strong as before the mishap adn for cosmetic purposes.
Basically by welding you only need to assure that there is no leakage from the said crack so that that cylinder doesn't suck any unwanted air.
I have done it and would do it again.
Basically by welding you only need to assure that there is no leakage from the said crack so that that cylinder doesn't suck any unwanted air.
I have done it and would do it again.
I weld them all the time, its stronger then before, but I will warn you if its more then a pressure crack you better have it clamped down in a fixture table and weld VERY SLOWLY, or youll end up with a warped case half and its junk after that. yamaha has a precision machined surface between the case halfs and thats why they only use yamabond to prevent any air leaks.
fourbarrel said:
I had a crack welded on a case half from an RM250 and had no issues afterwards. The half was not available new, the crank journals were machined as a pair so you had to buy both halves. For $30.00 I figured I'd try it, (this was 25 years ago) it worked.
mopar1rules
Active member
I've welded cases before myself and have had success. When I did my ski-doo case, I bolted the 2 halves together and then welded. Another time I did not bolt the halves together. Instead I just welded the 1 half. When I did a viper bottom case half (mag side as well), I simply tig welded the crack and didn't bolt the case to a table or anything, and I didn't have any warpage issues. IMO, it takes more than you think to warp/twist them rigid castings and if they did get outta twist/warped like a few thousandths, I would say that it probably won't have issues flattening back out, when you bolt the 2 case halves back together, as the upper half is more rigid and w/all the bolts that hold the cases together, and w/yamabond in there, I don't think you'll have sealing issues. JMO.
Thanks for the replies fellas I'll pass on the info and see what my bud want's to do with the case.
mattyg1405
New member
weld it!!! any good welder could do it and not warp it... itll be stronger ... ive seen mercury v6 two strokes welded back together after it looked like a grenade went off inside...
ive welded a few engine cases and have never had an issuse... but ive also been careful not to overheat ..
ive welded a few engine cases and have never had an issuse... but ive also been careful not to overheat ..
rx1jim
New member
As everyone above stated, the cases can be welded successfully. I am about to repair a lower crankcase from an SRX 600 which has a hole the size of a nickel at the very bottom of cyclinder no. 3. I am fixing this case for NYSRX. I have welded many motorcycle engine cases in the past. MrViper is correct, you need to be careful not to overheat and warp the case. If you need to weld a small crack, you can do it without clamoing it to a flat surface. If you need to do a lot of welding then the best way is to clamp it to a flat surface and wled it slowly allowing it to cool between passes. I have had problems with warrping the clutch covers for small motorcycle engines because I got them too hot.
It isimprortant to get the area to be welded very clean before you start the welding process. Clean teh entire case half with a solvent then a strong detergent with hot water.
It isimprortant to get the area to be welded very clean before you start the welding process. Clean teh entire case half with a solvent then a strong detergent with hot water.
Its all about the welder...
Bob
Bob
mopar1rules
Active member
sideshowBob said:
right.....like using a lincoln instead of a POS miller.
all kidding aside, i know what you mean.
mattyg1405
New member
hahah you mean using a BLUE miller instead of a lincoln...mopar1rules said:right.....like using a lincoln instead of a POS miller.
all kidding aside, i know what you mean.
The case on my 02 viper was cracked when my mag bearing went 2 years ago and I sent to CVtech in Quebec. The charged me $80 to clean the inside and then the JB welded it on the outside and that was it. I kinda felt ripped off. But hey it is in the sled and works.
mattyg1405
New member
lolkirkswim said:
hey i guess it works.... i would have charged you about the same money to TIG weld it and pressure test it !!!
mopar1rules
Active member
kirkswim said:
OMG!! I would have asked for my money back, or for them to actually tig weld it, if no refund for the $6 value repair.
You only felt kind of ripped off?That kind of repair could have been done in your basement,I would most definitely have been demanding it be fixed right or at least about $60 back.Not to sound like I'm ragging on you but that is outrageous,$80 for a JB weld fix.Of all the companies to do that I would have least expected them for that,I've bought cylinders from them before and they are usually a stand up product.kirkswim said:
hmm even worse was UI sent them my crank after the road went and they told me non rebuildable. So I said okay send me it back since the rest of it was still good(find another one blown on a different cylinder and make one from 2) They didn't send me back the full crank I was missing the centre(it had blown mag side) and I kinda had to argue with the guy to get it back. He said "No rebiuldable we junk the crank..". I have a feeling my centre is in somone elses sled.....
WOW that is not the first time I've read about them screwing someone over a crank rebuild either.Makes you wonder about doing business with them.kirkswim said:
mattyg1405
New member
sounds like this place is a joke... i wouldnt let CVTECH do anything for me if this is the kind of work they do,,, jb welding and stealing cranks from people????