I've been away a while (long story, but it involves a house and weekends eclipsed with it), but I have been looking to dig into the M900 again and get her roadworthy again.
To summarize, I have some mild engine work done. Displacement is still 904, though JC High Comp pistons. Dyna coils, stock cam, matched intake headers which now have FCR 41s on them and I'd replaced the stock ignition boxes with the programmable white box. Much of this is not tuned, though the bike runs okay.
I was looking for help from a local mechanic I trust, though he's since passed. I was looking to really get the bike to shine this winter and was considering a full engine refresh along with some of the suspension bits.
So. A general question might be who to consult in any engine work? I'm not opposed to sending the engine out, but someone in the upper midwest / Detroit area would be a great start. I would be considering a balance job, and looking at proper tuning from jetting through exhaust.
On that topic, the bike retains the stock header, though I'd always wanted to upgrade the breathing. I understand the fundamentals of the upgrade path (larger diameter pipe would likely equal the higher revs), and I favor the punchy midrange more than high revs / power. Given the work and FCRs on the bike, would a 45mm header be out of line?
As always, thanks for any pointers or help. The S2R is still in the garage keeping the M900 company. More on the S2R later.
The JE pistons need premium fuel and the ignition remapped to reduce the peak advance about 2-3 deg and the curve more graduated and progressive. I'll pm you a baseline hi comp map for you to try as the canned map is usually for a stock motor. The stock headers are surprisingly good and the cost of fancy headers could be put towards head work and 44mm intake valves with a nice multi angle valve job and porting to suit. Machine 700g to 1kg off the flywheel and dyno tune the FCR's to perfection.
Never even spoken with him, so I have no idea what his availability is, but JD Hord is down in Bucyrus.
Not very far from Detroit.
Maybe Stu knows?
S4 can make 100HP with 40mm pipes.
I'm not convinced even a big 2-valver need bigger than 40mm.
Quote from: Speeddog on September 29, 2019, 11:58:06 PM
S4 can make 100HP with 40mm pipes.
I'm not convinced even a big 2-valver need bigger than 40mm.
That was what I thought. Lots of philosophy there, as the 2v bikes seemed to be at 4m, 4vs at 45 then 50mm with the 996 and up. Some guys and a local tuner even recommend 39mm FCRs unless you’re doing the 944 upgrade. Likely a flow thing. I haven’t dialed anything in but since I had high comps, I got the 41s. I’m only assuming these would work well. My assumption was the 39mm FCRs were for M750 and 41mm for M900s.
I'm running FCR39s on my 750.
Even without the accelerator pump, they work fine.
39 vs 41 depends on who you talk to, I imagine.
Did 41s on a customer 900SS, those were good too.
Keep the FCR41's since you have them [thumbsup]
How many miles on the motor?
Remove cylinders and check that the alu plug on crank isn`t loose and therefore backing out.
If loose, split engine.
If not, you have the most bangforbuck mods already, Overhaul heads and get get a good ignition box,
like Ignitech.
Quote.the programmable white box
What is that?
I have opened the stamped part of pipes, did`nt do much.
Quote from: Speeddog on September 29, 2019, 10:20:22 PM
Never even spoken with him, so I have no idea what his availability is, but JD Hord is down in Bucyrus.
Not very far from Detroit.
Maybe Stu knows?
Nope. No idea. Mods sound reasonable. Cylinder head ports are shyte. Almost all power for 900 engines can be found there.
http://www.ducatimonsterforum.org/index.php?topic=77343.0
Just a thought.
Check out JD Hords site and you'll see he has done split single FCRs on a Monster without modifying the frame. From his explanation to me years ago he uses a hybrid set up. From the Dyno chart they must be a medium length longer than Malossi, but shorter than oem, adding top end without robbing much from the bottom. I'll look for it.
https://www.hordpower.com/gallery3/index.php/Dyno-Charts/album07/manifolds
Any progress?