Another eng swap thread:(Edit: no longer considering EFI, upgrading 750 engine

[LowercaseJake]

Not going to get into my mechanical woes but the lowdown is this: M600, swapped in 750 engine. Ran great. Swapped in a 900 motor, ran ok but the motor is problematic, and I want the shorter stroke of the smaller displacement motors back. So this time I'm going for an 800 with the open loop ECU or a DS1000. I already have a source for both engines complete with throttle bodies/injectors/wiring harness etc and already know I'll need to mill out the motor mounts, modify the frame crossmember, and I've already sorted what I'm doing about the exhaust system. Basically I'm confident in bolting everything up.

There seems to be a cluster F of information regarding how to overcome the immobilizer function, some of it conflicting and confusing. Easiest, straightforward way is to find matching ECU/Clocks/Key. Going rate for a full lockset with clocks and ECU on eBay seems to be the $500 range.

My preference: no immobilizer whatsoever, regular key that can be cut by any locksmith. Whatever set of clocks I want, preferably the old school type with a FWD speedometer and a tach that wires to one of the coils. Easy, if it can be done.

So I guess what I'm looking for here is multiple solutions from you experts incorporated into one thread. I'll also use this thread to document the swap. The only other hurdle I haven't fully figured out is where the fuel pump + pressure regulator will go. The tank is an aluminum Roadracing, and it was designed to be used for EFI. Theres a circular, removable plate at the bottom with an input and an output. But I see no provisions for wiring to exit this plate. Obviously you'll need pics which I'll provide later, but first things first: how do I make the infamous immobilizer a non factor in this project.

If this info is easily available via search I apologize, but it seems I may have more than a few options here. I'm leaning towards the 800 for the better tractability, simplicity, and wet clutch for day to day commuting but my source for the ds1000 engine is very tempting bc the price is right and he has EVERYTHING except the clocks and keys.

Appreciate your input as I begin the baby steps of this project.

- J

[LowercaseJake]

One thing here is, I see a lot of "oh just get the ECU flashed and kill the immobi for a couple hundred dollars". But who does this service? who's the most widely recommended? who's "The Guy"?

I know the turn signal flashers are contained within the dash of these Monsters. I'm pretty sure I can buy everything I need to get over that from either Bernard at Vizi Tec or Motogadget. That's the least of my concerns at the moment. Once the ECU is "flashed to kill the immobilizer" part is done, I guess my only question is can I bolt in the motor, throttle bodies, ECU, fuel plumbing, use any stock ignition keyset (they all appear to have the same pushlock connector) turn the key hit the switch and go vvroom?

Also, kinda wondering if I should have my machinist buddy mill a "sleeve" for the engine mounts. The early 10mm frame mounts are tapped, so I'm not sure if the newer 12mm studs would fit safely.

[koko64]

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I recently rode a modified M750. With a light flywheel, hi comp pistons, modified airbox and FCR 39 carbs; it spun up smoothly and quickly and had a sweet balance to it. I was very impressed despite my big bore bias.

You stateside? Then forun sponsor Motowheels will reflash your ecu. Send them the ecu and fill out the order form on their site which covers your tuning options or give them a call. They will remove the immobilizer and flash a tune to suit your mods.
Sponsor Monsterparts sells Powercommander units which can be dyno tuned to your mods.

Normally a large undertank plate allows for an internal fuel pump so maybe it allows the option of carbs or the use of the oem plate? Others here will know.

[LowercaseJake]

I do think it's designed to be replaced with the stock plate. Tho the presence of both output and backfeed is odd. Currently it's setup to run carbs.

Stuffing a DS1000 mill in there woukd be very cool. Tho I'm going to be honest - I've ridden both the 800 and 796. Loved both motors... They rev up fast and are just plain fun. Plus I like a wet clutch, to be perfectly honest.

[LowercaseJake]

I'm also very curious if the 900 headers could fit/ be installed into a DS1000 engine. Then I could run my banked FCR's. I believe a 99 M900 flywheel with its trigger would swap right in, and the cases are actually already drilled and tapped for the kokusan ignition pickup bracket. Looking at the motor, it seems possible.

[koko64]

It depends on the intake manifold stud spacing. I've never done it, but I'm aware of threads here when split FCRs were fitted and a custom Ignitech used. Worth a search here to see how much hassle it is. A hi comp 900 carbed or 900ie motor would be easier. I like the potential of 900ie motors with their hot oem cams. At least 900 pipes would fit. I dont know if a 900ie motor takes 900 carbed inlet manifolds as a straight bolt on but if it does you have a candidate there. An M900ie with hi comps, light flywheel, Ignitech and FCRS would be a wicked little street bike. A 1000DS more so but Im not sure if its much more hassle or not. The tricky part is the ignition, but Ignitech could build you a custom unit iirc.
The Ducati specialists here will know for sure.

[LowercaseJake]

In the meantime I may dust off this old 750 motor and bolt it in so I have something to ride. I'd either need to completely rejet my FCRs or pop the Mikunis back on. Not sure if the FCR41 can play nice with the little 750 or not.

[Howie]

750s like 39s.  If the 750 is a temporary install I recommend KIS and use the Mikunis.  An interesting combo is a 750 with 800 heads, not plugand play though.

[koko64]

The 1000DS is the longest stroke desmodue at 71.5mm so longer again than the 900 at 68mm.

[LowercaseJake]

I'm going to put my 750 mill back in while I aquire the parts for the 800 + EFI conversion. If it was ya'lls $ and time - would you rejet the FCR41's (not difficult since they're on my bench) and live with a little low speed hiccups, or get a jump on selling them and fit the Mikuni's? I actually still have a new in shrink wrap jet kit from Factory Pro for my Mikuni's, but my Domino throttle which I love is already setup for the FCR's.

I'm REALLY going to miss wheelies.

[LowercaseJake]

Maybe consider this an unofficial FS thread for the FCR's, haha...they're literally like new and still have the OG box.

[koko64]

Maybe an Ignitech ignition conversion to the 800 and run it with FCR41s? Or big bore hi comp 750 with 800 heads?
In the meantime use the Mikunis on the 750.

[ducpainter]

41's are too big for a street 800/750...maybe even a 900. A full on race bike, or an 1100, maybe.

Just one guys' thinking.

[koko64]

Try 'em and if they're too soft down low swap 'em for some 39's.

[ducpainter]

Try 'em and if they're too soft down low swap 'em for some 39's.

You, of all people, should know that I do have 41's on my bike.