monsta rebuild

[monsta]

Is that 4130 for the gussets? 

nah, just a bit a mild steel that was lying around...

[MotoCreations]

A couple of notes based upon my experience:

- The frame x-area is the weak link.  Why is it the weak area?  Partly not due to a great design but primarily due to the HAZ area of the weld itself.  You will not see a frame bend -- it will crack adjacent to the weld itself through the tube on frames that do fail.

- Thus the gusset is a good thing -- it adds extra material.  But conversely you potentially add more HAZ area into the equation and can make the area more susceptible to cracking. 

- The composition of the steel frame that Ducati uses isn't 4130 chromoly -- but it isn't plain steel either.  It has a bunch of other materials added in and at times acts somewhat like 4130 in terms of welding.  Thus I recommend a small vent hole from the back side of the cover into the frame to vent (and especially if you back purge the weld itself with Argon).  I'm not going to get into TIG back purging but it does make a difference.

- Also make sure your frame / engine mounts are mounted to something solid ala engine case (or a frame jig like I use).  Do not remove the frame when hot -- wait until its cold to the touch. Make whomever is welding it aware that the frame can/will move very easily -- thus you can weld to minimize problems. Cold bending Ducati frames isn't hard to do but it's still a major PITA to get perfect alignment.  Thus don't cause a headache by welding the frame on the welding table without the frame mounted (via engine bolts) to something solid.

- Heat normalization.  95% of the people laugh about this.  I heat my TIG welds on a 4130 (and even factory modified frames) with a gas torch post welding and the surround tube area to correct temp and then slowly let it cool but still applying heat.  Eventually letting it cool completely.  All while being jigged.  Frames fit perfectly everytime and I've never had a Ducati (or my own custom 4130) frame crack.  I can't say that about some other repairs/custom frames I've seen from others.

- Another example of the heat normalization is the people re-welding Supersport and Monster aluminum swingarms.  TIG weld and inevitably it will crack again in the future.  TIG weld and then get the gas torch out and normalize the metal (and adjacent) -- and you will never have to re-weld that swingarm again in that area.  Most of the cracking of the aluminum swingarms is in the HAZ affect zone adjacent to the factory weld.

If you are adding gussets, etc to the frame -- best ones to add are immediately behind the steering tube and into the main frame tubes.  You will notice it almost immediately when you ride the bike.  Only problem is that it negates the fitment of an airbox to the area and thus why they were originally removed.

Now modify away!

[truckinduc]

Very good Info. I was told, many times, that the frame was 4130.  Its obviously no DOM so I doubt it is also 4130.

Mark, If you wouldnt mind taking a look at My thread I would appreciate it.  Im using 4130 tubing in my frame and ER70S-2 filler.

http://ducatimonsterforum.org/index.php?topic=6965.300

sorry not to thread jack Monsta.

[brad black]

monsta

what prep did you have to do to the cases and heads for powder and ceramic coating?

[Howie]

As I understand it, the first few Monsters were 4130, then they changed to an proprietary alloy somewhere between mild steel and 4130. 

[Monsterlover]

I've always heard it was ALS430, similar to 4130

[monsta]

A couple of notes based upon my experience:

- The frame x-area is the weak link.  Why is it the weak area?  Partly not due to a great design but primarily due to the HAZ area of the weld itself.  You will not see a frame bend -- it will crack adjacent to the weld itself through the tube on frames that do fail.

- Thus the gusset is a good thing -- it adds extra material.  But conversely you potentially add more HAZ area into the equation and can make the area more susceptible to cracking. 

- The composition of the steel frame that Ducati uses isn't 4130 chromoly -- but it isn't plain steel either.  It has a bunch of other materials added in and at times acts somewhat like 4130 in terms of welding.  Thus I recommend a small vent hole from the back side of the cover into the frame to vent (and especially if you back purge the weld itself with Argon).  I'm not going to get into TIG back purging but it does make a difference.

- Also make sure your frame / engine mounts are mounted to something solid ala engine case (or a frame jig like I use).  Do not remove the frame when hot -- wait until its cold to the touch. Make whomever is welding it aware that the frame can/will move very easily -- thus you can weld to minimize problems. Cold bending Ducati frames isn't hard to do but it's still a major PITA to get perfect alignment.  Thus don't cause a headache by welding the frame on the welding table without the frame mounted (via engine bolts) to something solid.

- Heat normalization.  95% of the people laugh about this.  I heat my TIG welds on a 4130 (and even factory modified frames) with a gas torch post welding and the surround tube area to correct temp and then slowly let it cool but still applying heat.  Eventually letting it cool completely.  All while being jigged.  Frames fit perfectly everytime and I've never had a Ducati (or my own custom 4130) frame crack.  I can't say that about some other repairs/custom frames I've seen from others.

- Another example of the heat normalization is the people re-welding Supersport and Monster aluminum swingarms.  TIG weld and inevitably it will crack again in the future.  TIG weld and then get the gas torch out and normalize the metal (and adjacent) -- and you will never have to re-weld that swingarm again in that area.  Most of the cracking of the aluminum swingarms is in the HAZ affect zone adjacent to the factory weld.

If you are adding gussets, etc to the frame -- best ones to add are immediately behind the steering tube and into the main frame tubes.  You will notice it almost immediately when you ride the bike.  Only problem is that it negates the fitment of an airbox to the area and thus why they were originally removed.

Now modify away!

great info, thanks Mark.

a couple of questions if you dont mind...
1.what temp do you recommend I heat the frame to for normalization?
2. I was thinking of bracing around the steering tube, but there is no cracking there so I wasn't sure if I should worry...
   If I did I was going to do the same as the pic below.. is that what you would recommend?



Brad,
the cases were cleaned and masked on all sealing faces as well as faces that would have things mounted to (frame). I stuffed rags behind the larger cavities to support the masking tape so it wouldnt rip. I screwed bolts in all threads and also masked bearing holes and remove all seals.  The powder coater doesn't do media blasting so I sent it to someone that does lots of engines, he uses garnet.
Then take straight to powdercoaters making sure not to get oily or dirty.

The head were taken to the ceramic coaters and he did all the prep work...

[Ducatl]

Wait wait wait, you masked an engine for powdercoat with rags and regular masking tape?

I'm...confused

[greenmonster]

Ducati did the similar bracing on their Corse/factory bikes:

[monsta]

Wait wait wait, you masked an engine for powdercoat with rags and regular masking tape?

I'm...confused

about what?

green monster..  I saw you posted that pic in truckinducs thread, I've never seen it before. I guess that whoever made the frame in the pic I posted (I dont know its history, just seen a few pics of it)  got the idea from Corsa?? 
anyhow.. good find! 

[DucHead]

For the cases, did you use "normal" powder or the high-temperature stuff?

about what?

Probably because "special" (feels like cellophane) tape is used for masking during powdercoating and rags might ignite when put in the oven.

[Monsterlover]

Sounds like my coater does things way different.

They blast everything and mask everything.

Threaded holes are plugged with these little rubber stoppers, gasket surfaces are masked with this thick tape.  It's far from cellophane, think 2x thickness duct tape and 3x the stiffness.

Ovens are 400-450* depending on the material that needs coated.

The downside to all that is the cost is higher when they do it all.  It's nice to drop off a box of stuff, though, and have it just come back all done

[monsta]

For the cases, did you use "normal" powder or the high-temperature stuff?

Probably because "special" (feels like cellophane) tape is used for masking during powdercoating and rags might ignite when put in the oven.

I didn't know there was normal and hi temp stuff..
they heat to 200deg C  (392deg F)

I've done quiet a few other things and never had a problem with masking tape... 
and about the rag, I rang the powdercoaters first to see if it would be ok, they actually suggested that I could stuff the cavities with newspaper.
I guess the spontaneous combustion temp is a lot higher than 200deg..

[dbran1949]

Fahrenheit 451

[Travman]

Fahrenheit 451