95 mm cilinders and pistons

[luhbo]

Your findings will be interesting, you know.

I asked because I once ran into similar problems, but only at WOT, above 7800 and when trying to reach ARF 12.5, and, interesting enough, only with open race cans. In these regions those cans really make a difference. Compared to those my actual Ex-Box is delivering fuel

 

Hubert

[Mike Stewart]

Dynotec in Germany list an engine with 95mm jugs and with cam and headwork the output is 111PS at 7900 rpm with 105nm of torque. The german horse power is really close to the hp readings in the US. I do believe this to be measured at the flywheel. Figure at least 8-10 hp less at the rear wheel. http://www.dynotec.de/index.html First click on the english flag, then when the page comes up, scroll half way down this page and click on the link next to the hammered piston for the different cams and engines hp outputs.

 

Mike

[Murray]

Although the question has to be asked of the 111ps two valvers how much of them are engine and how much is nail bomb. I suspect they wouldn't be cheap. Not sure the sport is down a bit on compression but the only thing appears to be wrong with is rings I have noticed a slight loss in HP towards the top end too I think. Valves guides etc etc seem to be holding up ok and there is no detectable oil consumption blows a bit out the breather though. So weather I patch it up and get it to solider on till it seriously needs some work or I pull it down spend some money and try and make it a bit more fun.

[GuzziMoto]

There's no reason a 1100-1200cc air cooled two valve motor can reliably produce 100-110 Hp at the rear wheel. Even Harleys can do that. The question is how much modification will it take and how much money will it cost.

Modern Japanese engines are hard to make large improvements in their power output(it can be done but it costs big money). On the other hand, there is much room for improvement in a Guzzi motor due to the lower level of performance engineering applied to the motor from the factory. That tends to make larger improvements in power output easier and cheaper. And due to the overbuilt nature of the Guzzi, 100-110 Hp should be reliable.

I have raced against Guzzi's like the one ridden by Pete Johnson that could run with a Ducati 916 down the back straight at Road Atlanta(back in the gravity-cavity days when it was a mile long). Granted, at that power level reliability no doubt takes a hit(probably a pretty big one, although I never saw him break).I'm just saying there is lots of room for improvement and much of it will not have a serious effect on reliability.

[Pierre]

Your findings will be interesting, you know.

I asked because I once ran into similar problems, but only at WOT, above 7800 and when trying to reach ARF 12.5, and, interesting enough, only with open race cans. In these regions those cans really make a difference. Compared to those my actual Ex-Box is delivering fuel

 

Hubert

Got it back. Filter very plugged. Pump running extremely loud - so replaced it. On exmination, internal of pump filled with reddish "crud". Certainly appears the "crud" not only strangled fuel flow, but led to the death of the pump. This is the symptom I'd hoped to find, easy diagnosis and easy fix - though $260 for a new pump isn't exactly "easy" on the wallet.

 

Scheduling another dyno date as soon as I can. Will post charts when I have 'em.

[raz]

Got it back. Filter very plugged. Pump running extremely loud - so replaced it. On exmination, internal of pump filled with reddish "crud". Certainly appears the "crud" not only strangled fuel flow, but led to the death of the pump. This is the symptom I'd hoped to find, easy diagnosis and easy fix - though $260 for a new pump isn't exactly "easy" on the wallet.

 

Scheduling another dyno date as soon as I can. Will post charts when I have 'em.

I look forward to reading your results and that Guzzitech Article. You checked the inside of the tank and its mesh filter too, right? It would be a pity to clog the new gear immediately.

[Guzzirider]

I've decided that if I am going to bless my V11 with more poke, it is much easier to swap the motor for a Centauro unit with a big bore kit rather than throw £££££s at making a 2 valve motor go faster.

 

After seeing Bruce overtake me on the straight on the Raceco Daytona at Cadwell Park last summer, I got an appreciation of how fast a 4V Guzzi can be.

[Paul Minnaert]

well with the stelvio you get a part of that. And I suppose the new 8v engine is able to be tuned to at least the same power as the old engine. And with it's double oilpump better cooled

[Murray]

There's no reason a 1100-1200cc air cooled two valve motor can reliably produce 100-110 Hp at the rear wheel. Even Harleys can do that. The question is how much modification will it take and how much money will it cost.

Modern Japanese engines are hard to make large improvements in their power output(it can be done but it costs big money). On the other hand, there is much room for improvement in a Guzzi motor due to the lower level of performance engineering applied to the motor from the factory. That tends to make larger improvements in power output easier and cheaper. And due to the overbuilt nature of the Guzzi, 100-110 Hp should be reliable.

I have raced against Guzzi's like the one ridden by Pete Johnson that could run with a Ducati 916 down the back straight at Road Atlanta(back in the gravity-cavity days when it was a mile long). Granted, at that power level reliability no doubt takes a hit(probably a pretty big one, although I never saw him break).I'm just saying there is lots of room for improvement and much of it will not have a serious effect on reliability.

 

 

Intresting I take a slightly different view. The Guzzi motor orginally was a 700cc 34 hp twin, It is now a 90hp 1064 twin (as far as the v11's are concerned anyway) built on the same cases. The factory has pretty much done over the years what can be done and to make further improvements past what can be gained with exhaust and intake, involves serious engineering with what could be argued are marginal gains. But these are my observations and are not neascarily based on any fact. The Biggest big bore kit I have found for the v11's is a 94.6mm kit this lifts the capcity to around 1164. However its my understanding that there is no room between the cylinder studs for any further increases and possibly the 94.6 kit is a bit marginal as the cylinder walls are a bit thin in places. If anyone knowes that would be handy BTW. So the Guzzi two valver we are bombing up for fun not because we can turn it into a firebreathing powerhouse if we wanted to do that we would be turbo charging busa's and ZX14's.

[GuzziMoto]

Displacement wise that's true. You cant go much bigger. But it is still overbuilt for its size. But in terms of head flow, squish, compression, cams, weight of any spinning or reciprocating components, the Guzzi motor has a lot of room for improvement. It is not built with the same level of performance engineering as a Ducati or even a Harley.

[Ryland3210]

Displacement wise that's true. You cant go much bigger. But it is still overbuilt for its size. But in terms of head flow, squish, compression, cams, weight of any spinning or reciprocating components, the Guzzi motor has a lot of room for improvement. It is not built with the same level of performance engineering as a Ducati or even a Harley.

 

I've been under the impression that the air cooled Harleys produce far less HP per cube than my Cafe Sport. I haven't looked into the performance of the water cooled variety. Care to comment?

[GuzziMoto]

I don't know where they're at now, but a few years ago H-D 1200cc engines were making between 80 and101 rated Hp. at the crank(65-80 at the rear wheel) and they get 50-55 mpg(a good judge of combustion chamber eff.) Compare that to a stock V11 making 70 Hp at the rear wheel and getting 40 mpg.

And torque, not Hp , is H-D's bigger strength. They rev even less then M-G engines and make huge amounts of torque for their size.

The thing that gets me is how they are able to make as much or more power using so much less fuel. Max power is not the only measure of how well an engine is designed.

[Skeeve]

The thing that gets me is how they are able to make as much or more power using so much less fuel. Max power is not the only measure of how well an engine is designed.

 

Sorry to keep riding this same hobby horse, but it's all in the combustion chamber shape/design. The high numbers you're quoting are coming from the Sposta mill after Erik Buell got his hands on it, and dug up some old heads H-D had tucked away in their ex-development racing parts supply. Anyway, a little work on the porting [care of the old Jerry Branch heads] and some "modern" [only 50+ y.o. Ricardo concepts applied] combustion chambers, and hey presto: good power AND good mileage!

 

Have you noticed that Daimler-Chrysler trademarked the "Hemi" name, even tho' none of their motors actually have hemi heads anymore?

 

Piaggio has put a bunch of money into bringing out the new QV motor, but they could easily update the 2v heads w/ bathtub chambers, keep the dual plugs and get up into the 50mpg realm, w/ only a minor amount of redesign involved. Who knows, maybe they're already working on that?

[GuzziMoto]

Actually, the numbers I'm quoting include the Sportster and Buell versions, which are now almost the same engine. When they designed the Blast engine that became the basis for both the new Buell twins(not the Rotax motor but the XB's) as well as the new Sportster engines. Details like cam timing and compression ratio are the main differences. And the Sportster gets great mileage and power along with the Buells. I do agree that alot of it is in the combustion chamber. That's a big part of my point. If you improve the Guzzi head to whatever extent you can, there is lots of room for increased power output. The stock Guzzi head does not have a lot of engineering in it. There is a lot of room for improvement. Getting 20-30 more horsepower is much more doable then getting the same kind of increase out of say an SV1000 or a 1098.

Buell also puts much more engineering and resources into things like exhaust design. Modern Buells have exhaust systems that actually improve the power output. Many people put "free flowing" mufflers on their Buell only to find they lost a couple horses.