weld a standard crank-anyone?

Taffy · Sep 23, 2008

just wondered if anyone has had cause to weld the big end pin of a standard crank? i've had a crankshaft twist and this seems the obvious solution. i trust anyone who has is talkinbg "sixfiddy" (patent stolen from bobzilla!).

regards

Taffy

sparks · Sep 23, 2008

Taffy said:
just wondered if anyone has had cause to weld the big end pin of a standard crank? i've had a crankshaft twist and this seems the obvious solution. i trust anyone who has is talkinbg "sixfiddy" (patent stolen from bobzilla!).

regards

Taffy

I'm sure this is the way to go even on a standard engine, I once quoted we used to weld up the crank pins on the GSX1100's back in the eighties, if you didn't they would take out the mains, flex and twist like made from marzipan.
I think some of the mains failures could be due to this especially with the roller bearing crank.

Regards

Sparks.

JoeUSA · Sep 23, 2008

Dale Lineaweaver welded mine when he removed the counter balancer and rebalanced my 05 550.

Regards,

Joe

fryguy · Sep 23, 2008

Taff

pm Nizzo, he has had some experience welding cranks, specifically what brand not sure, but he can tell you what you need to know

Enginehardware · Sep 23, 2008

Taffy said:
just wondered if anyone has had cause to weld the big end pin of a standard crank? i've had a crankshaft twist and this seems the obvious solution. i trust anyone who has is talkinbg "sixfiddy" (patent stolen from bobzilla!).

regards

Taffy

Taffy · Sep 23, 2008

RE: Re: weld a standard crank-anyone?

thomas

before you say a thing i said STANDARD!!!

i know you do yours as i have many fine photos.

regards

Taffy

Enginehardware · Sep 25, 2008

Re: RE: Re: weld a standard crank-anyone?

Taffy said:
thomas

before you say a thing i said STANDARD!!!

i know you do yours as i have many fine photos.

regards

Taffy

We weld the standard once on our own bikes and on customers when they demand it, but we do recomend it.
//Thomas

sparks · Sep 25, 2008

Re: RE: Re: weld a standard crank-anyone?

We weld the standard once on our own bikes and on customers when they demand it, but we do recomend it.
//Thomas[/quote]

Just as I thought Thomas, how many extra hours of reliability do you think you get by welding the pins.

Regards

Sparks.

The_Force · Sep 25, 2008

What kind of welding wire is best to use when welding the crank?
do you do it on both sides?
And if you have to change the bearing and rod after you weld is that possible or do you have to trash it?

Enginehardware · Sep 26, 2008

Re: RE: Re: weld a standard crank-anyone?

sparks said:
We weld the standard once on our own bikes and on customers when they demand it, but we do recomend it.
//Thomas

Just as I thought Thomas, how many extra hours of reliability do you think you get by welding the pins.

Regards

Sparks.[/quote]

Its hard to say due to most of our customer come back after approx 100 hrs, pre-maintenence, then we change the main bearings only, they have learned the lesson not to have a big break-down.
On the 650cc, specially the 82mm stroke we hade problems before, now we seldom see a break-down before 100hrs.
Since it dont twist when welded the stress on main berings is less and i belive that we could get 150hrs out of the mains now, but we dont take that chans any more.
This goes for a std engine, on our race engines we change more often.

//Thomas

Enginehardware · Sep 26, 2008

The_Force said:
What kind of welding wire is best to use when welding the crank?
do you do it on both sides?
And if you have to change the bearing and rod after you weld is that possible or do you have to trash it?

We use a TIG welder and we melt the pin and the crank together, no need to add much material.
we weld 2 lines on ea side.
To change the rod we just grind away the weld with a small "dremmel" and when a new pin is installed there is a groove to weld in.
If the rod is changed every 200-300hrs there will be a bigger groove in the crank, but with 3 changes the bike have 1000hrs then its time to scrap it anyway.
So i guess that 3-5 times it can be welded, before the groove is to big to be grind out, and the crank needs to be changed or welded up properly then machined to the correct size.
//Thomas

Dr_C · Sep 27, 2008

I just place a tack weld (TIG) in position ten o'clock and one at two o'clock (less than 10 mm long). The only thing to worry about concerning choice of filler material is that it needs to be "ductile". So stay away from high carbon content! Simple stainless (316L) has work out good for me during the years.

Enginehardware · Sep 27, 2008

welding photo

just a small photo of the weld.

/Thomas

oyk · Sep 28, 2008

hi, this the mx-composites connecting rod right?

could you give us any feedback concerning the difference in terms of performance?
say that you give a 200h life on the original rod, how about this one?

thanks in advance sir

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