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 - 10 of 10 Posts

·
Registered
Joined
·
107 Posts
Discussion Starter · #1 ·
Hey guys,

Since it seems the super bike guys are more apt to rebuild an engine, figured i'd ask this here.

I'm building a franken 1200 engine after my MTS1200 crank failed. I'm curious what you guys go for in regards to:
Connecting rod big end to crankpin clearances. My MTS manual says 0 to .016mm which seems absurd.
Crankshaft main bearing shimming: is the 0.30mm the preferred preload?

Thanks!

Line from the crankshaft section of the tech specs (maybe i'm reading it wrong?):
Big-end bearing-to-crankpin clearancePin selectionØ 42.014 mm/
0 to 0.016 mm
 

·
Registered
Joined
·
284 Posts
Conrod big end bearings clearance should be between 0.030-0.051mm. If used on track, closer to 0.051mm. Usually they are too tight.
 

·
Registered
Joined
·
107 Posts
Discussion Starter · #3 ·
Awesome thanks! My monster 1200 with 2000miles showed .0018-.0019” which is .046 to .048mm so will probably go with the same color shells.

Found that Ben Fox was quoted as recommending .006” (.15mm) of main bearing preload on the 1098 platform, seems more reasonable.
 

·
Registered
Joined
·
107 Posts
Discussion Starter · #5 ·
Awesome, good to know, thanks for the input, definitely appreciated! Going for a bad ass street motor. Should be fun, basically mildly ported 12.5:1 CR mts 1200 engine with 1098 cams :D
 

·
Registered
Joined
·
107 Posts
Discussion Starter · #6 · (Edited)
When measuring the crankshaft clearances to determine which shims to use, I noticed that the left main bearing doesn't take any axial load, the web of the crank shaft rides on the bearing holder (bushing), is this correct? I don't see how it could work any other way since the inner race of the left bearing has no flange. Also strange that the workshop manual has you calculate the shim thickness based on the sum of both shims, even thought the left one contributes nothing to the preload. Thanks!
 

·
Premium Member
Joined
·
1,472 Posts
It very much changes the character of the MTS. I have HC pistons and 1098 cams in my MTS, with cleaned up heads. I also run a lightened flywheel and dry slipper in mine. You certainly need a way to remap, because it is drastically changed once the cams and pistons went in. Have fun!
 

·
Registered
Joined
·
107 Posts
Discussion Starter · #8 ·
It very much changes the character of the MTS. I have HC pistons and 1098 cams in my MTS, with cleaned up heads. I also run a lightened flywheel and dry slipper in mine. You certainly need a way to remap, because it is drastically changed once the cams and pistons went in. Have fun!
Thanks man, I'm definitely looking forward to it! Going to be running the monster flywheel with a spacer i machined to correctly space the alternator, so FW weight is just over 5lb vs the MTS's stock 9.5lb. Also planning to have Hudson Valley tune it when it's together. I have tuneboy so i plan to attempt to load a monster 1200/1198esque timing map and adding a decent amount of fuel just to get it running. Dry clutch would be cool but not going to happen at this point for me. Notes i found on your build definitely helped me figure out the direction I'm taking with mine!
 

·
Premium Member
Joined
·
1,472 Posts
My flywheel was 8.51 lbs total weight. Mine finished at1.12lbs. I love the change but it was prone to stalling. In Tuneboy config options if you enable FCE it pretty much eliminates the stalling. The lack of weight and higher compression make it noticeably more difficult to start. You need a good battery. It’s a great project.
 

·
Registered
Joined
·
107 Posts
Discussion Starter · #10 ·
My flywheel was 8.51 lbs total weight. Mine finished at1.12lbs. I love the change but it was prone to stalling. In Tuneboy config options if you enable FCE it pretty much eliminates the stalling. The lack of weight and higher compression make it noticeably more difficult to start. You need a good battery. It’s a great project.
That all makes sense. Mine won’t be a race bike so I think the monster FW will work just fine. If not, easy enough to play with later. Glad I bought upgraded battery/starter cables and a new battery for when the engine goes in!
 
1 - 10 of 10 Posts
Top