2000 M900ie mods - HC pistons, big bore, or swap for 1100ds motor?

[M900GP]

I've been doing a lot of reading on these boards and following links to mod projects for older Monsters.  I've done a lot of mods to my 2000 M900ie EXCEPT the motor, so that's next.  I'm not out to make a dedicated performance track machine, but something that gives a bit more grunt on the streets and the occasional track day, sounds tough, and frankly is a fun project.  I'm decent mechanically and want to do as much of the work as possible, but want to work with a good machine shop and tuner.  I'm in the Seattle area, btw, in case you've got suggestions for either/both.

I like that I'm starting with a good base as I understand the cams, valves, and fuel injection unit on the 900ie are decent out of the box, though the heads could use some work.  At 9.2:1 compression and only 78 ponies, it's a bit anemic and sounds it - even with a custom short exhaust.  It seems the obvious culprit is cylinder pressure, so more compression is a must - how to get there is the question.  

Some of you like the big bore 944+ kits, yet others tout the drop-in 92mm pistons with higher compression, stating the gains by the overbore effort are minimal.  Clearly it's a bit more effort and $$ for the bore job and Nikasil.  I'm trying to locate the threads on this board of others considering similar mods where somebody mentioned just swapping out the whole motor for a 1000 or 1100 (ds) motor. I consider the swap since I've already mated a Multistrada SSS to my 900ie, so I have that to use for the 1100.  The 1100 bumps hp to 95 and compression to 10.5:1, and torque follows suit.    All of that said, a few questions...

1) The drop-in or big bore pistons bump compression to 11.5:1.  Seems great for a track bike running high-octane racing fuel, but how streetable is that, realistically, on 92 octane pump gas?  Just an ignition tweak to make it work?  PC-III?

2) Is it advisable to shave a bit off the top of those pistons and bring compression down to more easily run 92 octane?  If so, how much to shave?

3) What type of porting work is needed on the 900ie heads?

4) The alternative is the engine swap, and the 1100ds was suggested.  All new territory for me.  I'd also read that using the 900ie's throttle bodies with that motor is a good combo, yes?  I have a potential lead on a good/complete 1100s motor and it has the hyper "race" cams installed.  What do they add over the stock cams?  Are they out of a Hypermotard?  Anyway, 10.5:1 compression simply seems quite streetable and good middle ground between my current 9.2:1 and the 11.5:1 aftermarket jobs.  Price on that motor is unknown yet, btw.  I know the hyper cams aren't cheap additions.  The stock cams are available from what I understand, and could be used if the performance cams aren't a big improvement. Thanks for any input on those.

Total dollars required for doing HC pistons and head work on my 900ie vs. swapping out for the 1100s is a bit unknown until I know the price for the motor.  I can sell my 900 motor to at least recoup some of the cost of the 1100s motor, which helps.  Thanks for helping me sort out these options.  

Cheers.

[koko64]

How much of the work will you do yourself? That will have a big impact on costs. Check out sponsor California Cycleworks for high comp JE pistons. Quite affordable.

If the 1100 motor is compatible with your new swingarm and indeed has DP racing cams that would be pretty cool, but there may be conversion issues that require a bit of set up work on your part. There are forum members who have done this and have good knowledge re mix and matching swingarms, motors, chassis and running gear. Sounds like you have done a great job already. Obviously the 1100 motor is a better platform, but the comparative costs are not clear to me in our market compared to yours.

I am quite partial to my brother's M900Sie with high comp pistons, open airbox, a little porting and PCIII. Those bikes come stock with arguably the hottest oem cams and have an entertaining motor with those mods. I would add a Nichols light flywheel and consider porting with 44mm inlet valves.

[M900GP]

I can tear it down and put it back together, but I'd otherwise have a shop do the porting or anything with the heads, as well as the boring/Nikasil if I go the big-bore route.  I'd have a good tech either watch over my shoulder for the timing tweaks and setup, or just have them do it. 

[koko64]

If I went that way I would not bore it out, but put that money towards a good porting/valve job and light flywheel. Just my unqualified opinion. Maybe you know someone who could machine down your stock flywheel. The JE pistons are not much over $300 USD iirc.

[koko64]

Also noticed that you have a custom short exhaust. That may cost you a lot of power no matter which way you go and undo some of your good work. I would go back to oem headers and free flowing mufflers. Edit: Pardon me, you did that because of the SSS swingarm, I get it. Is it a performance oriented exhaust or more cosmetic?

[M900GP]

The exhaust is quite free-flowing, and yes to accommodate the SSS.  Stock header pipes for outlet from heads, then a custom collector configuration under the pivot arm and a handmade MotoGP-inspired stainless can.  I don't disagree that it may be costing me some performance (i.e. some lost back pressure), and that will be revisited with these mods anyway.

I picked up a light Nichols flywheel awhile ago and I've got an aluminum aftermarket clutch setup ready to go also.  I  have a DucaBike slipper I could put on, but that's for a track bike project.  Curious if anyone here has experience with those as I don't hear a of talk about them - but that's maybe best for another message post 

I've got my eye on the JE pistons - yes about $300 USD.  The question is the 11.5:1 compression and how that can work on the street.  I'd imagine somebody on here has shaved them down and reduced compression to the 10.5:1 to 11:1 range.  Wondering how much to machine off to get there.

It would be great to hear from anyone who's done the DS motor swap.

I'm also open to suggestions on machine shops that can do the type of head porting you mention.

Thanks!  

[M900GP]

What sort of performance figures is your brother getting out of his 900Sie with those mods?  Is he running 11.5:1 compression?  If less, how did he get there? 

All those mods make good sense.  Curious what they gained for him.

[kopfjäger]

A ton of info here from Brad.

http://www.bikeboy.org/performance.html

[koko64]

Me, I would reduce some comp via unshrouding the valves rather than skimmimg the pistons. Just my humble, unqualified opinion. If I was going to sacrifice some precious compression, I would want something in return.

Not sure, hasn't been dynoed. I've seen 90hp with the same mods, but his porting looked very basic and he is running stock size inlet valves and has not dialled in the cams. The cams are probably out from the factory as delivered. It is a satisfying bike to ride and while it doesn't have the grunt of my 1100, it spins up beautifully with a real surge. I really like these cams. A mate of mine has a hi comp 944 Superlight with light flywheel, FCR39s and 900ie cams. It also has a midrange to top end surge like my bros 900Sie. I used to think it was the injection, but realise it's the cams. If I build a hot 900SS  (dream project), I will use those cams.

[koko64]

A ton of info here from Brad.

http://www.bikeboy.org/performance.html

Yep, his article convinced my bro to go that way. Very entertaining motor once it has some compression.

[Speeddog]

I just did a set of heads for a 900SS, total refurbish with porting.

They always need exhaust guides, and sometimes exhaust valves.

It had the standard hi-comp JE pistons.
They seem to work fine with Premium fuel and retarding the ignition a bit, on the carbie bikes.

I did another 900SS with hi-comps, FCR41's, Nichols flywheel, refurbished heads (no porting) an Ignitech and light clutch assembly.
Customer loved it, until he got a 916.

[koko64]

GP must be off busy reading all the bikeboy articles.

[M900GP]

Koko is psychic!  Indeed I'd followed the path to the bikeboy articles.  I'd actually seen a few of them years ago but hadn't been through the broader list of posts.  Definitely helpful. 

Speeddog, we need to talk about that porting work!  Sounds like what I'm looking for.

[Speeddog]

Sure, give me a call or PM and we can work out the details.

Some pics of the ported heads:

[Howie]

OOO looks great Speeddog