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1000 2 valve Tonti Hot-Rodding Advice Needed

SuperEvil

SuperEvil

Just got it firing!
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So I have this CX100. I want to do what I can with this mill- knowing that I'm starting with a pretty restricted setup. I've already shaved a bunch of weight, developed a de-linked braking system with gsxr components, smaller battery, rewired then entire thing. Excel rims to lose unsprung weight. Time to turn to the engine.

My tentative plans:

2 into 1 headers with SuperTrapp Aluminum racing can (mostly for weight reduction over my Lafranconi setup with crossover)
Mikuni TM 38's with accel pumps and vel stacks
Air Intakes enlarged to match Mikuni's
Stock Valves (actually WANT the smaller valves... want my power low down, not up top!)
Lightened flywheel/clutch kit

What I need advice on is the rest of what makes the 850 mill snappier than my 1000SP lump:

Can I increase compression somehow with new pistons?
A mildly hotter cam?
Softer valve springs?
Oil cooler?

I can weld and fabricate and do my own engine work, so none of this stuff is out of consideration. Just out of my expertise range. I just need to see a list of what you guys would do to an SP in a perfect world. There HAS to be a way to make this engine faster than an 850, its a liter after all.
 
Might want to get a copy of the book Guzziology.

Making a Guzzi "Snappier" is usually a lesson in frustration as the bike was never designed to be "quick". The thrill of riding one comes from that wide power band & the superb handling. The sound of the exhaust is like no other bike, I can't tell you how many times I've been told my old girl sounded like a small block chevy coming down the road.

What you have done so far is probably just right to have a great performing older Guzzi. Get in too deep with changes to compression, cam, springs etc generally won't have good results for the time & money spent.

Put her on the road as is and tweak out all the bugs. Ride her for 300 or 400 miles on a Sunday on some back country roads. If you still want something "snappier" you might want to consider a different brand. Just my opinion for what it's worth. Trout
 
Supaevil, I can sort of understand what you're wanting here. Like yourself, Im an Engineer with 42 years up my sleeve with the same various skills as yourself, from what I gather .
I've never ridden an 850 Guzzi.So I cant comment about the performance of one .
My Guzzi is an '85 SP 11 /1000 which has been played with ,, fairly seriously I'd say .
I got it sight unseen , so didnt know what I was getting until it arrived from 1200 miles away.
Visually it appears to be a Cafe version of a Lemans 1000.Until I found this forum I had no idea that so much could be done to convert a Tonti framed bike to whatever you like. Mine is raw , sound is just sweet , handling is good with Marzocchi 38mm forks and Terozzi brace .
And it's red .
Im not sure what is inside the engine ,,,but ,, she flies . I know its got Mikuni TM 38 / 85 carbs and Hyperchargers fitted to each one , not everyone's choice of looks but . I have no idea what porting has been done , what size the valves are , what the compression ratio is , what rods and pistons are in there , or what the camshaft is if it is other than standard . ( It certainly does not idle or run like a stock engine ) There is a Dyna 111 ignition however.
This thing flies .
My conclusion here is that if I was needing a bike to go quicker and handle better , I'd go back to a '99 TL 1000 or something designed to do exactly that . My Guzzi is pretty maxed out for it's era , I reckon . I regularly thrash a section of mountain road , I dont think I'd want to go any quicker , this bike is awsome .( with exception of the rear brake which is pathetic )
As soon as I can figure how to load pics I'll post some for you all to see this beast .
Regards Supaflee
 
SupaFlea: Please do post pictures of the Red Beastie.

SupaEvil: The lighter flywheel, bigger carbs and better exhaust is what these Guzzi's respond well to. There is a mild street cam available. Go to www.mgcycle.com they do want the old cam back for a core. If you don't have a Dyna ignition system that may help although I still run points & condensor. I have found that once the valves and the points are set correctly and the timing is spot on these old 850's are pretty amazing even with stock carbs that have been jetted. Big bore kits will ad some low end power but do nothing for throttle response.

Anyway have fun with her. Guzzi's are the most fun & at the same time most serious bikes I have ever owned.
 
You guys are giving me just what I need. What the Guzzi responds well to- and what measures become a black pit of despair is exactly what I want to determine.

Im pretty happy with the old girl as is. I can appreciate what they bike was made to do. It's a thrill above 5000 rpm. I'm not looking to spend 10K making a bike that will get smoked by a stock 600 Monster. I just can't leave it restricted. If I've read correctly, this bike was strangled by the EPA. My friends Euro LMII is just a slightly more satisfying ride.

SupaFlee: Do you have a pic of your carb/manifold setup? I'm currently looking into how to get your exact carbs on my bike... keeping the intake diameter consistent and avoiding leaks. Some combo of stock sleeve and mikuni manifold, or?
 
SuperEvil said:
You guys are giving me just what I need. What the Guzzi responds well to- and what measures become a black pit of despair is exactly what I want to determine.

Im pretty happy with the old girl as is. I can appreciate what they bike was made to do. It's a thrill above 5000 rpm. I'm not looking to spend 10K making a bike that will get smoked by a stock 600 Monster. I just can't leave it restricted. If I've read correctly, this bike was strangled by the EPA. My friends Euro LMII is just a slightly more satisfying ride.

SupaFlee: Do you have a pic of your carb/manifold setup? I'm currently looking into how to get your exact carbs on my bike... keeping the intake diameter consistent and avoiding leaks. Some combo of stock sleeve and mikuni manifold, or?
Click to expand...

...a ducati monster WILL NEVER smoke a Guzzi , NEVER ....unless the rider is a Wussy...LOL
( talking about aircooled engines, of course..)
this being said :
the "usual " recipe for a daily drive is
Carbs
Cam
elec. ignition
bore cylinder
head work

Lighting the flywheel it depend of the rider's taste. But if you want more torque , you need heavy wheels.

Then, of course there are plenty of mods that can be done, but as someone said , love it for what it is, not for what it is not.

check this thread out... it may gives you some ideas....
https://www.guzzitech.com/forum/197/8758.html
Have fun !
Marco
 
Warmed over my last Mk111 Le Mans when it needed a new crank. Actually all I did was bump the compression up via copper head gaskets, and lightened the flywheel 25% by spending two days on a drill press. Having the entire engine balanced I ended up with a sweet ride.

Can't see the point of 38 carbs and small valves, you giveth and then you taketh away. Guzzi's aren't meant to be ridden like Harleys. You can idle around town under 3 grand if you like, but that Falcon emblem they use is for a reason. Guzzi's like to sore like an eagle, on the open road or mountain pass. Any Guzzi I have owned or ridden prefers 4 - 6000 rpm when playing with the option of another 2000rpm if you get serious.

My lightened flywheel engine accelerated quicker but didn't feel any lack in torque.
In recent years I've gone from a 1062cc Cali to a 936cc Bellagio, basically the same bike/engine but with a short stroke crank, twin plug heads and maybe a lighter flywheel. Both bikes have equivalent mods to pipes, air box and Power Commander. The little bike makes 1ft/lb less torque but 7hp more, it is smoother sweeter faster.

The Guzzi head is an ancient crossflow design and totally inefficient when compared to the latest technologies on offer, BUT .................... within its design parameters there are many improvements which can be made.
For the big block there are small, mid and large valve heads available from different models, but you will need the corresponding pistons to match the combustion chamber domes. Compression ratios and squish bands can be fiddled with from there.

I would recommend mid valve heads with at least a 3 angle valve seat, twin plugs, match ported to your new manifolds. Depending on local fuels at least 10.5:1 compression and a decent camshaft grind. Lighteneing the flywheel also helps the old 5 speed box shift smoother.
 
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