[duc_duc]

So... I am taking my 2001 748's engine apart for an awesome built 853

I have:

SPS cams
MBP collets
MBP opener rockers
853 high comp domed pistons
Blue silicon hose kit
916 50mm throttle bodies
50mm Termi half system
Stock filters

Having done:

Blue print
Unshrouding heads
Polishing everything

I am sending it off to Mark Sutton at Ducshop in pieces to have him assemble and dial it in.
Any advice? (besides get ride of the 748 lump)
Any guesstimates on torque and power?

 

[ZDM]

Sounds cool! I wouldn't worry about figures, it most definately will run a heck of a lot better! I been thinking about doing the same kinda'. I have a 2003 999 base w/ PCIII and Termi 54mm titanium exhaust kit, so it is a good starting point. I'll either buy a used 999 motor and do a performance build myself and learn, send what I can't do to FBF. Then R and R my old w/ the new motor. Or just let FBF stroke, port/polish and blue print my present motor.
Never the less keep us informed on how your making out!

 

[tye1138]

116 rwhp
67 lb torq

One hell of a head ache once you see the bill...

LOL



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[mbevans]

116 rwhp
67 lb torq

One hell of a head ache once you see the bill...

LOL

Those numbers are quite close, I made the same torque with stock cams/853cc/half system/ airbox mods, yet using SPS cams with standard valves and with everything else you are installing should net 112-118 (real) . Enough to make you smile, for many miles to come......

 

[tye1138]

Funny thing is, a stock 848 motor puts out more power...

Thats evolution for ya!



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[amullo]

Tye! Yeah.. And so does a stock 749R engine. Your point?

duc duc!
What camtiming are you thinking of?
- I´m running my SPS at 109 centerlines and that seems pretty good for the SPS cams if your gonna run it on both street and track.

Have you looked into bigger valves?
- That would be the only logical missing step as i see it. Costly, but a good investment.

I´d look HARD at not using a 50mm exhaust. Talked alot about this with Tom at Hypertrick when i was going my old 748SP and he says that most of the old desmoquattro´s don´t really benefit from a large diameter exhaust (and several tuners seem to agree), so trying out a 45mm system might lose you one or two hp on the top, but drivability and midrange would probably be better with the smaller exhaust.

//amullo

 

[tye1138]

The 748 strada makes a pretty decent 853 bike because of the valve area. He could toss on a set of 748R heads, which is what I'd do. But at that point, why not start with a 748R block with all the light-weight components? I mean, there are better ways to waste a few grand.

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[duc_duc]

I dont know about the cam timing yet... When I talked to Mark Sutton, he pointed towards 107 -108. If 109 opened up the midrange then that would be the logical choice. I really dont run her hard past 9500-10k. Seriously.... I dont.

Now... I did figure out that the 50mm half system did lose some torque down low but I thought that the 853 kit with the cams and 50mm throttle bodies would work well... I have no Idea though.

I also have learned that tye with all his experience hates 2 things. the 748 desmo and spending money...

Mark said he had some older corse big valve 916 heads that he would not quite give to me... I didnt go into the details but I will know more when I talk to him next...

 

[John]

For fun check on the Moto-One site for similar build performance figures. Thats if the site is still there.

 

[paulmm600]

sounds like a great project.

i wouldn't mind seeing photos of all your parts, i'm thinking photos of the build as it progresses might be too much to ask

and definitely photos and a write up once it's all done and tuned


hope it all goes well


.

 

[amullo]

I talked to Tom at Hypertrick about tuning my bike as he´s a personal friend. The 107/107 that i had in mind is a good option if your running your bike at under 10k RPM and using normal SPS cams with normal or even slightly oversized valves.

He pointed out that we could probably run mine at 109/109 since i use it quite abit on the track and i was OK with sacrificing some midrange to NOT loose top end too much. And it looks like 109´s was a good number for it. But if it´s a street bike, then 107 is good enough since your not going to be spanking the engine that hard. I´m guessing that i could have had maybe 1 or 2 ft/lbs more in the midrange if we had hit 107 instead, but lost about the same in HP right at the end.

And the Moto-one site is no longer. Brad still has his reports up, but on his new site
http://www.bikeboy.org/

Also check out Hypertrick. The SPS in the reports section is mine.
http://www.hypertrick.net/


//amullo

 

[bradblack]

For fun check on the Moto-One site for similar build performance figures. Thats if the site is still there.

it's not there anymore, it's here - www.bikeboy.org

tye is right about the bill. how much have you budgeted for? you'd be better off buying a s/h 996 motor and just fitting that. stripping and rebuilding right is good fun (first time anyway) if you can do it all, but if you're paying someone to do it and it involves a cam swap you'd have to be looking around 40 hours or so. what hourly rate are you paying?

i did a 748R into 853 last year that made 122hp. didn't feel that fast, and you had to rev it to get it to move in a hurry. i'm not sure why some guys go on about the short stroke motors being a better engine - they're just smaller and don't make as much torque. i've built some 996 or bigger motors with the long stroke 900 crank that rev like crazy and go to match.

but don't let my pessimism discourage you. i not really one to be preaching about wasting money on lost causes. just know before you get into it exactly how much you're up for. well, worst case and best case, because once you get in there it all changes anyway. practise saying "faaaaarrk!" and "fuckin' how much!" with a tortured expression on your face.

 

[duc_duc]

Ok guys... Well I was going to do the break down and such.... Clean everything, then install it all and have the rest dialed in.

I am looking at most likely $2500 in total if I do it right. If I buy a 996 lug and punch it out or stroke it (which would be feckin sweet) I am looking at buying another $1500 engine and then spending 2k on it. Could I get anything for the 748 lug? Didnt think I could! Its mint by the way.

Now you guys got me doubting! shite! Im really not about tons of HP. I think any bike on the street with 100 or more is plenty. I just want to roll out of corners or do a little wheelie in second kind of power.

 

[mbevans]

Ok guys... Well I was going to do the break down and such.... Clean everything, then install it all and have the rest dialed in.

I am looking at most likely $2500 in total if I do it right. If I buy a 996 lug and punch it out or stroke it (which would be feckin sweet) I am looking at buying another $1500 engine and then spending 2k on it. Could I get anything for the 748 lug? Didnt think I could! Its mint by the way.

Now you guys got me doubting! shite! Im really not about tons of HP. I think any bike on the street with 100 or more is plenty. I just want to roll out of corners or do a little wheelie in second kind of power.

Relax, you're on the right track, especially since you got most of the parts already.
There is no way most of us that take the time to build a hot-rod Duc, ever see the $$$ again, except in smiles of knowing we have a special engine.

I rode my first 748 for a few thousand miles, enjoyed the bike but longed for more HP, then I installed a Nichols flywheel, Fox 890 kit and a few other bits, the thing was a night and day experience, that thing rocked!! Made for a fun track bike, fun Sunday morning ride bike. Really lifted that bike higher in HP.....Did I ever get my money out of it? No, but lots of pleasure..... I've done a few motors since and enjoyed using the results.

One of the nice parts of using the little 748 motor is you start with better gearbox ratio's than a standard 996 lug.....

Enjoy

 

[tye1138]

I also have learned that tye with all his experience hates 2 things. the 748 desmo and spending money...

I learned my lesson over the last two years living in desmoquattro hell.

Spending money is fine, but only on doing it right...

You can spend a bazillion dollars turning a base 748 motor into a 748R, but its cheaper and a more efficient expenditure of money to just buy a 748R motor and be done with it.

Its your choice though, but in the economic times, its a shocker people are willing to spend the money on such work to not have the anything near the optimal final result. If your gonna spend money, might as well go all the way.



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[amullo]

If your looking into a fast street engine I´d have to agree with Brad that there are better and more cost effective ways to get the bike to the "lift slowly in second" fast.

Get a nice used 996 engine, set the squish and fit som SPS cams, Map the engine and go with a 14/39 gearing. That will most probably give you about the power/torque as what i have and mine will lift the front in second at 6500 rpm if i hit it hard enough. The great thing about the SPS setup is that on the street you can exit a corner at 4k RPM, hit the throttle and the bike responds. My old 748 never did that, it was dead as a doornail under 6k.

One of the nice parts of using the little 748 motor is you start with better gearbox ratio's than a standard 996 lug.....

Enjoy

Have to agree with that statement. My SPS gearbox isn´t nearly as nice as my old 748SP gearing.. That bike had a gearbox that i still dream about. Short, distinct and very very well setup. Never did miss a gearchange with it that i can recall.


//amullo

 

[duc_duc]

hmmm

Did some more asking around.... I have decided not to go too crazy cause you guys are right... there is a glass ceiling here and it is my daily driver. No need for Mark sutton.... would definitely use him though if and when I build a hot rodded 998 some day. Bruce Meyers said there is no real reason to do port work unless bigger valves are going in. He stated that using the flat topped 853 pistons and skimming the heads along with CC reworking will be great and yield 12.5-1 comp. Sounds good to me. I am going to start tear down here in Seattle when the rain comes and I will post pics of my build. I think I will have Marty at Ducsea or Herb at Eastside motosports do the final dial in. I do appreciate the feed back and I think that I am going with 107 centerlines for the street. This bike will never be a power house and I realize this but I also didnt want to do a common 853 build. Will keep posted

 

[TomTom]

A well performed 853 job will be a treat, yes!

Cam timing will change the total feel of the engine, yes! (Talking advancing intakes at least)
In terms of response its day and night, imho.

With cam timing to what you are thinking of, no top will be lost.