So I am one of the lucky ones that got the W heads on my 98' 900. From all my research the W heads are good as a paper weight and not much more. I currently have 41mm FCRs, Leo Vinci slip-ons and dyna coils as my bolt-ons.
I am thinking the next thing I want to do is get a pair of V heads with valves and cam to switch out to my bike. Is this a worth while swap, and will the V heads bolt right up to my cylinders?
Thanks
I guess it depends on your ultimate goals. If you intend to stop here, then I don't think it's worth messing with. If you intend to get better cams (ST2 cams, for instance), and maybe bump compression and/or displacement a bit, then it's probably worthwhile.
You won't be able to tell the difference via the common "butt dyno".
They are a direct bolt-on replacement, though, if that helps you.
i've not done the swap, but i've been around a couple of w head bikes that performed somewhat dismally in comparison to v headed bikes when that was the only difference. i think it'd have to make a difference, i'd probably expect to see 10% on a dyno in peak power output. it made quite a difference to my 750, altho there was a little port work as well, but the valves were still a mm or so smaller than v valves.
i could be wrong , of course.
They will bolt right up, I`ve done that.
W my W, it sorta lost breath after 140 km/h, w V2 it just revs on. Biggest difference I think.
Worthwhile swap it IMHO.
If you install hicomp pistons at the same time I guarantee you`ll be happy!
i'm currently doing it.
from my reading you'll want the v-heads' cams too, not the cams in your w-heads (they are the 600/750 grind, and the valves are the 750 sized valves).
Brad's got some more info for ya:
Some info about the various 900 engines:
http://www.bikeboy.org/900equal.html (http://www.bikeboy.org/900equal.html)
Cam info:
http://www.bikeboy.org/duccamspec.html (http://www.bikeboy.org/duccamspec.html)
A Cagiva Gran Canyon mod, relevant as they've got the W heads:
http://www.bikeboy.org/grancanyon.html (http://www.bikeboy.org/grancanyon.html)
yes, the gran canyon was a real steaming turd. absolutely flumoxed me that one.
put some je's in it while the heads are off, it'll be a shitload faster. well, not exactly a shitload perhaps, but better. you have to remove the cylinders to redo the base gaskets so it's all apart anyway.
Thanks all. So the concensus is do the swap and hi-comp 944 kit.
yeah and port and polish the heads before you put them on.
You'd have a beast at that point. Kinda seems to me there are a few ways to go about it or lessons I've learned from my reading, and slow parts acquisitions (my shelves are populating with lots of noncurrent models stuff - don't know if that's the most prudent path - with the $$$ invested, I'd have a nice current DS motor in a bike by now, with some goodies on it):
If you have the W-heads, you can find a competent head shop* to put in the 900-size valves and whatever else you could afford while you are in there - port/polish, multi-angle valve cut, and a set of cams - like the actual 900's, or a set of the DP / VeeTwo torque cams - both are supposed to be suitable to your long manifolds and banked FCRs.
Kind of the same attack plan would be to swap the heads with the ones that already come with those goodies: Take the v-heads off a bike, which come with the bigger valves and v-cams, and put them on the bike - giving you the as-designed-on-paper 900SS motor, with long manifolds and banked carbs (yours obviously are the upgraded FCRs)
Putting in high compression pistons is apparently the difference maker - It seems my reading has lead me to believe that in replacing the pistons, the biggest factor in power gain is the high-compression element rather than the increase in compression. While the 944cc displacement is a boost, I seem to recall seeing ST2 power being unimpressive compared to the same displacement with high compression pistons, and other findings where 904cc (stock 92mm bore) motors fitted with the OEM bore 92mm pistons - but high compression pistons, also had the big (though less) bump up in power. So that's got me thinking, at this point a cost-analysis is pretty appropriate: Do high comp, but weigh cost difference of boring/plating OE cylinders with power-output and budget/time constraints, with 92mm HC pistons that don't require the cost of boring/plating.
That said - I do need to admit my lack of personal experience with this part of engine building - I'm just an impulsive consumer and lover of Ducs (especially the crappers in my garage). I would definitely be bothering the hell out of my local shop (and getting 2d and 3d opinions from other shops much to their annoyance) before fitting anything to my stuff. I do not know enough about looking at the existing cylinders' wear and knowing if they need reconditioning of any type, etc.
The next big jump from the v-valves/cams, with bigger displacement and higher compression, coupled with long manifolds and the banked FCRs seems to be going to the split-singles and shorter manifolds (the power gain coming from the shorter manifolds). This requires, from my reading, a bit of nuisance in making sure the 1-into-2 throttle cable and carbs are well harmonized, and apparently need synching with some regularity. I do not have sync-sticks, but I suppose one would not only need them for such a setup, but would have to become familiar with them, as they'd be used a lot.
Then there's the cams designed for shorter inlet manifolds, yielding bigger power - the 212 and 213 grinds from VeeTwo (all but gone nowadays since the company has changed businesses or focuses, I've read), and the OEM 900IE and ST2 cams - the Chris Kelley write up shows 100+hp with the ST2 cams in the setup.
Then there's going to 964cc (95mm) pistons, and for more extreme stuff there's the 984cc (96mm) pistons - but I believe this requires lotsa more work for it to work correctly, and may not work in some cylinders because of the oil passageways (and apparently the cases are milled? - I only briefly discussed this with Jeff Nash at AMS who had done this on some bikes in the 90's and was getting 100 rwhp out of them back in the day - apparently very unfriendly for the street).
Kinda seems like trying to get the last pair of the Mahle 95mm pistons from CA Cycleworks would be a pretty great way to go about it on the first go around, coupled with headwork.
From my reading, rereading, and rerereading of Brad's pages, and Doug Lofgens, I have concluded that the slightly bigger diameter headers / spaghetti headers / equal-length - (call it what you like) headers from Sil Moto or Spark really only help with more power once you are moving a whole lot more air - bigger intake and exhaust valves, ported heads, short manifolds, and bigger displacement. Their power graphs show little to no real gain in power with a motor that is only mildly modified. (That being said, they don't lose power and they weigh less while looking better, so still a win!).
So for me, that'd be kind of the hairiest of the beasts with the biggest results: Big pistons, Big Valves, Ported Heads, hot cams, short manifolds.
Lastly, the power graphs I've seen show the low pipe setups doing marginally/negligibly better than the high pipe systems - obviously less bends and a more direct path out. Similarly, the weight of the high pipes is marginally heavier than the low pipes. Kind of a win-some/lose-some arrangement: Better ground clearance, ever so slightly heavier and ever so slightly less flow.
* By head shop, I don't mean where people buy ceramic pipes to smoke weed from, I mean a shop that can do valve seats, has a flow-bench, etc. Not sure where you are, so suggesting MBP might be out of the question, but there are many shops that can port/polish correctly even if they don't specialize in Ducati - you just want to make sure they can show proof that they know what they are doing. The conversion of "W" heads to "V" style heads is possible, so I read. Here's a short writeup from Chris Kelley in describing the 100hp+ 2V projects, using MBP Ducati to do the headwork (link: http://www.ca-cycleworks.com/shop/heads/heads.html (http://www.ca-cycleworks.com/shop/heads/heads.html))
QuoteThe combustion conversion, however, is unique to MBP Ducati! This modification is to convert your "hemispherical" combustion chamber to the preferred "bathtub" style prevalent on the 900 2V heads. Some Monster 900s circa 1997 and 1998 have "W" stampings on the left side of the cylinder head. This conversion reshapes the combustion chamber to be similar to 900 heads with "V" stamps. Note that the 800 heads are able to match the final flow figures obtained with 900 heads. Also, 620, 750, and 800 heads are roughly interchangeable.
QuoteSo the concensus is do the swap and hi-comp 944 kit.
Yes but forget the 944 if you don`t find it dirt cheap.
HC pistons gives the far most power bump.
Of course a port job is good but costly.
V2 heads complete w their SS cams + HC = done!
IMHO.
Quote from: greenmonster on March 07, 2011, 10:54:31 AM
Yes but forget the 944 if you don`t find it dirt cheap.
HC pistons gives the far most power bump.
Of course a port job is good but costly.
V2 heads complete w their SS cams + HC = done!
IMHO.
I think this concisely sums up my opinions too without need for multi-paragraph rambling like I provided above
[laugh] [thumbsup]
[popcorn]
It's all about the bang for buck.
Like others, I have high comp pistons, FCRs and porting on V heads for a great street engine. A friend has similar mods but 944 high comp pistons. His bike has much more mid range torque. If you can afford the big bore option it would be worth it. The bigger piston has more squish area and is forcing more volume into the same sized combustion chamber for more compression again.
If you raise the compression, don't forget to retard the ignition timing by 2-3 degrees. You may also have to use higher octane fuel.
I would like to try big valves, more capacity and ST2 or IE cams one day.
Again, thanks for all the input. I'm looking around for V heads and cams (ST2, IE or the stock V). I'll see how the hi-comp or 944 kit works out also.
It's been said that Monsters are basically parts bin bikes, whatever is laying around that day gets bolted on. I was just out doing a little tweaking and thought, my 98 has the adjustable Showa forks and aluminum swinger, almost what I understand makes a 'S' model. Then Ducati threw on these small valve heads. Not sure what they were thinking.
[thumbsup]
They certainly used to be pre-2000. The fixer-upper M900 I have recently picked up similarly had the aluminum swingarm, and 3-way adjustable forks, but the W-heads (quickly evident from fins on the tops of each head). The frame's VIN indicates 1999.
Suspicious, I tell you, because my original Ducati - also an M900 is a 1999 according to frame's VIN as well. It too came with the aluminum swingarm, 3-way adj Showa's, but had the V-series heads! (No fins on tops of heads either).
Makes me wonder if one was an early 1999 build, getting the left-over W-heads, with finned tops, and the other was a late 1999 build, v-heads with no fins on top.
The 2002 900 motor I have (obviously an IE at that year) also has the "v" heads (though at this point, i suppose its proper to either call them IE heads due to cams, or simply the "SS" motor, since I haven't heard of any 900 SS's coming with the W-heads). The '02 heads do not have the fins on the top of the head either (making me think the v-heads on my '99 M900 could be late '99 assembly?).
best of luck to you!