gemellocattivo.com

Which means "Evil Twin". Lets see your projects where you change boring into fun or create the fun from scratch.
It is currently Thu Dec 25, 2025 5:59 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 2777 posts ]  Go to page Previous  1 ... 274, 275, 276, 277, 278
Author Message
PostPosted: Thu Dec 18, 2025 11:35 am 
Offline

Joined: Sat Mar 26, 2022 1:39 pm
Posts: 162
mk e wrote:
I'll share this because it kind of broke my brain. The bike needs the lower fairing to be a catch pan to comply with the rules but that is where the muffler is on the V2 so it needs new exhaust. The primaries are 2 3/8"!

I don't think I've ever seen a header pipe that big. Its 478cc/cly vs my engine that is 458, but I only run 1 5/8" primaries, then 2" 1st collector and then 2 3/8" 2nd collector (6>2>1). There is no way my software would tell me that is the right thing to do so now I'm not exactly sure how to guide/help him designing the new system, I've just never seen anything like this ..oh, then the single muffler outlet is tiny...1 1/2"or maybe 1 3/4" (didn't measure) I don't understand that either.....its almost like there is no primary and the collector only? I just don't understand.

It is wild. IMO the breathing requirements aren't related to cc, but rather hp.

That bike is making about 80 hp per cylinder, which is a lot but not way more than something like an LS or BBC making 600 hp. That large primary necking down to a small muffler outlet will send positive pressure waves back up the exhaust - maybe that has benefits similar to the "stuffing" phase of a 2-stroke expansion chamber? I could see that working if the cam has an extra-long exhaust duration.


Top
 Profile Send private message  
 
PostPosted: Thu Dec 18, 2025 7:20 pm 
Offline

Joined: Thu Jan 01, 2015 6:47 pm
Posts: 4743
Valves are ordered and PennDOT delivered my Christmas present


Attachments:
20251218_181028.jpg
20251218_181028.jpg [ 3.66 MiB | Viewed 192 times ]
Top
 Profile Send private message  
 
PostPosted: Thu Dec 18, 2025 9:44 pm 
Offline

Joined: Thu Jan 01, 2015 6:47 pm
Posts: 4743
Syscrush wrote:
It is wild. IMO the breathing requirements aren't related to cc, but rather hp.

That bike is making about 80 hp per cylinder, which is a lot but not way more than something like an LS or BBC making 600 hp. That large primary necking down to a small muffler outlet will send positive pressure waves back up the exhaust - maybe that has benefits similar to the "stuffing" phase of a 2-stroke expansion chamber? I could see that working if the cam has an extra-long exhaust duration.


Yeah.....I was having similar thoughts

For all to enjoy the seer insanity...in Ti for only 3415 euro before tariffs
Attachment:
Ducati exhaust.JPG
Ducati exhaust.JPG [ 50.07 KiB | Viewed 189 times ]


We are thinking WAY simpler and probably also quite a bit lighter. It would end at about the tape lines
Attachment:
20251218_203442.jpg
20251218_203442.jpg [ 3.6 MiB | Viewed 188 times ]


But as I said the 2 pipe are quite different lengths and make different simulation graphs so I guess the truth is about in the middle if we do 1&1. Victor ordered the bits needed to build it so now that waits for parts and the sealed lower fairing and probably a composite or maybe aluminum rear tail section begin
For all to enjoy the seer insanity...in Ti for only 3415 euro before tariffs


Attachments:
Ducati shor and long pipes.JPG
Ducati shor and long pipes.JPG [ 360.24 KiB | Viewed 189 times ]
Top
 Profile Send private message  
 
PostPosted: Sat Dec 20, 2025 11:24 pm 
Offline

Joined: Thu Jan 01, 2015 6:47 pm
Posts: 4743
The bmw flywheel hit t5he mill today and is 1/2 done. it started at 24lbs and is now 17.4 with the plan to get it to 14.
Attachment:
20251220_124121.jpg
20251220_124121.jpg [ 3.58 MiB | Viewed 140 times ]

Attachment:
20251220_205958.jpg
20251220_205958.jpg [ 4.03 MiB | Viewed 140 times ]

Attachment:
20251220_211020.jpg
20251220_211020.jpg [ 4.71 MiB | Viewed 140 times ]


I got him setup up and he milled all day and did pretty nice job. I have to say I was a little disappointed when I was he left like 3/16 all the way around the clutch disc.
Attachment:
20251220_211114.jpg
20251220_211114.jpg [ 4.24 MiB | Viewed 140 times ]


But that forced me to be in the shop most of the day and after clearing the bench
Attachment:
20251220_163114.jpg
20251220_163114.jpg [ 3.51 MiB | Viewed 140 times ]


I got the 1st head out and starter working to seal it so I can leak test the intake ports. The little plugs I bought for the valve guides turned out to be a bugger to install and after getting 1 in place after 30 minutes I decided to trim them
Attachment:
20251220_172731.jpg
20251220_172731.jpg [ 3.92 MiB | Viewed 140 times ]


then clean and install the covers
Attachment:
20251220_204914.jpg
20251220_204914.jpg [ 3.98 MiB | Viewed 140 times ]


I still need to figure out how to seal up the cam drive end and the oil return holes but tomorrow is a new day.
Attachment:
20251220_204923.jpg
20251220_204923.jpg [ 3.19 MiB | Viewed 140 times ]


Top
 Profile Send private message  
 
PostPosted: Sun Dec 21, 2025 10:35 pm 
Offline

Joined: Thu Jan 01, 2015 6:47 pm
Posts: 4743
Attachment:
20251221_181223.jpg
20251221_181223.jpg [ 3.96 MiB | Viewed 115 times ]
To close the look on the flywheel:
Attachment:
20251221_130126.jpg
20251221_130126.jpg [ 2.89 MiB | Viewed 115 times ]

Attachment:
20251221_192805.jpg
20251221_192805.jpg [ 3.24 MiB | Viewed 115 times ]

Attachment:
20251221_193221.jpg
20251221_193221.jpg [ 3.4 MiB | Viewed 115 times ]


24lb to 14lb so he was pretty happy....happy enough that as we were chatting engines and I mentioned my piston rings were not loose, they are nitous safe he told me he's got a couple nitous tanks he's be happy to donate to the project....I'm nlot sure that's the kind of help I need :lol:

I realized twice today that I'm an idiot. First I made a couple covers to bolt on and seal up the oil return holes....hmmm...I already put the cam cover on so no way to bolt on the new return hole cover but maybe RTV will hold them. Then I made a fancy wood cover for the cam end since the mill was busy, I figured at least give it a try. Once that was on I was kind of looking at it and realized the head bold holes need to be sealed but the cam cover is still already on so more rtv and see what happens I guess. Oh, and i forgot I also need 2 exhaust valves...3 times an idiot.

Attachment:
20251221_181223.jpg
20251221_181223.jpg [ 3.96 MiB | Viewed 115 times ]


Top
 Profile Send private message  
 
PostPosted: Tue Dec 23, 2025 10:07 am 
Offline

Joined: Thu Jan 01, 2015 6:47 pm
Posts: 4743
The wood wasn't a great ide. It turned out there was or it developed a large crank
Attachment:
20251222_105200.jpg
20251222_105200.jpg [ 3.66 MiB | Viewed 72 times ]


That should be fixed now
Attachment:
20251222_114121.jpg
20251222_114121.jpg [ 4.64 MiB | Viewed 72 times ]


But the RTV needed 24 hours and Victor was waiting for fairing help so we jumped on that so its on the bench not the head at least though today. The plan is make a 1 piece copy then Frankenstein that until it looks right and is a catch pan, then probably make a nice light copy. Working on the 1 piece mold now. I think this should all be considered practice for the lightweight 30-8 deck lid and targa top projects.
Attachment:
20251222_152841.jpg
20251222_152841.jpg [ 4.48 MiB | Viewed 72 times ]

Attachment:
20251222_170632.jpg
20251222_170632.jpg [ 4.08 MiB | Viewed 72 times ]


Top
 Profile Send private message  
 
PostPosted: Wed Dec 24, 2025 10:42 pm 
Offline

Joined: Mon Jan 05, 2015 9:16 pm
Posts: 90
mk e wrote:
The wood wasn't a great ide. It turned out there was or it developed a large crank
Attachment:
20251222_105200.jpg


That should be fixed now
Attachment:
20251222_114121.jpg


But the RTV needed 24 hours and Victor was waiting for fairing help so we jumped on that so its on the bench not the head at least though today. The plan is make a 1 piece copy then Frankenstein that until it looks right and is a catch pan, then probably make a nice light copy. Working on the 1 piece mold now. I think this should all be considered practice for the lightweight 30-8 deck lid and targa top projects.
Attachment:
20251222_152841.jpg

Attachment:
20251222_170632.jpg

We need a dedicated Ducati thread!

Merry Christmas Mark. I hope you and the family have a great day!


Top
 Profile Send private message  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 2777 posts ]  Go to page Previous  1 ... 274, 275, 276, 277, 278

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group