Ducati.ms - The Ultimate Ducati Forum banner
  • Hey Everyone! Enter your bike HERE to be a part of this months Bike of the Month Challenge!

1 - 9 of 9 Posts

·
Mr Leakered
Joined
·
8,859 Posts
Discussion Starter #1
I've had four sets of headers on the ST. The original set was the only damage when I bought the bike at 21,000mi. I found a couple undamaged sets on eBay for $19.00 at different times. The second set got squished on speed bumps. The third set got mangled offroad last year. Afterward, I put the least damaged set back on.

I finally bought a fresh set off of eBay again. These were a bit more expensive at $60 and have a small ding. I noticed when unboxing that there was a glob of weld at the mounting flange inside the pipes. So, I decided to port them to full diameter, grinding the weld out. I'm pretty impressed with the change. I'd recommend having a look at yours. The weld added quite a restriction, IMHO. I could see how, from the carbon build up, that the gases flowed oddly around the weld in both the old set and new set.

Have a good one.
 

·
Registered
Joined
·
386 Posts
Yep, you have to be right. Polished mine with a Dremmel when I was modifying the exhaust. Didn't seem much point in doing the work if the gases weren't flowing well from the manifold.
 

·
Mr Leakered
Joined
·
8,859 Posts
Discussion Starter #3
There definitely something more to be felt at mid and high RPMs along with a slightly different sound both on the throttle and when engine braking.

It sort of makes me think that the typical dings on the horizontal header don't matter as much as the restriction from the weld?

Have a good one.
 

·
Registered
Joined
·
776 Posts
Jesus you guys are cruel.

Now I'm going to have to rip apart my bike, probably break a bunch of crap (I got skills) in the process, forcing me to spend half a day going back and forth to Harbor Freight, then another half a day going back and forth to the liquor store. Plus a weekend of downtime for the bike during riding season (like I'm going to be able to wait for winter).

All in an attempt to find and eradicate this potentially elusive, power-robbing 'glob of weld'.

Son of a...
 

·
Mr Leakered
Joined
·
8,859 Posts
Discussion Starter #5 (Edited)
Hahaha!

Okay, I'll break it down. This was for my ST4 with twin port headers. The ST2 and ST3 should be a bit easier?

I only needed to:
Lift the tank and slide the fuel lines up, away from the exhaust side
Pull the right side fairing
Remove the rear brake reservoir from the frame and slide it toward the rear
Disconnect the breather hose and move it out of the way

​I was able to wiggle out and wiggle in the vert header through the opening between the left rear passenger foot peg and frame. Pulling the ECU and oil separator might have eased some wiggling?

The header nuts are 10mm. Attacking the vert ones with a ratcheting box end wrench is the way to go. HF has a nice set.

I used a small Dremel grinding wheel to start and a bunch of the larger sanding drums to finish up.

I also used a wire wheel in a drill to weakly polish the pipes before installing. Wear leather gloves!

Duc, or their supplier, could have done this in about a minute with a real jig and equipment. This took me a couple hours and a few beers.

Have a good one.
 

·
Mr Leakered
Joined
·
8,859 Posts
Discussion Starter #6
I'll post a pic of the glob the next time I'm in the crawl space.

Have a good one.
 

·
Registered
Joined
·
386 Posts
I only had one problem getting them off. One of the nuts on the horizontal cylinder it seems had become welded on and the previous owner had rounded it off. I had to use grips and a lot of heat to move it and then it wound the stud out with it.
Got a new stud with a longer nut (tube nut) so hopefully the problem can not reoccur. Other than that quite straight forward : )
 

·
Mr Leakered
Joined
·
8,859 Posts
Discussion Starter #8
You can see the weld blob at the 5o'clock position on both ports. It is where the weld was started and finished. The pics are of the horizontal header. The vert wasn't as bad, but the new headers were wayyy worse on both cylinders. The eBay listing said these were from a 2002 ST4. I'm guessing it might have actually been an ST4s?

Around all the carbon build up, you can see in the second pic how the gas flow was disrupted by the blob. On the new headers, there was disturbance visible all around the weld.

It is interesting seeing all that carbon buildup because the plugs come out looking nicer on the ST than any other vehicle that I have seen, perfectly caramel with no build up. The piston and crown had some carbon when I swapped head gaskets last month, but it all came off very easy with just kerosene.

Have a good one.
 

Attachments

·
Premium Member
Joined
·
1,249 Posts
Jesus you guys are cruel.

Now I'm going to have to rip apart my bike, probably break a bunch of crap (I got skills) in the process, forcing me to spend half a day going back and forth to Harbor Freight, then another half a day going back and forth to the liquor store. Plus a weekend of downtime for the bike during riding season (like I'm going to be able to wait for winter).

All in an attempt to find and eradicate this potentially elusive, power-robbing 'glob of weld'.

Son of a...
All other members, this is a f*****g literary masterpiece. This is how one writes a retort to a first world problem. Short, succinct, and accurate except he left out the important component - a 3 pound mini-sledge. Extremely high marks awarded for mentioning the all important liquor store. Trust me, I know what I'm talking about because I'm pre-med, er I mean pre-law, and I know what I'm talking about.
 
1 - 9 of 9 Posts
Top