High Compression Pistons

[dlaing]

Moral of the story is, that higher compression pistons reduce engine's life and money of your pocket...

I don't think that Guzzi's mechanics were so stupid of instaling the pistons and making the motor as is now.

Every now and then I hear people messing their bikes with racing parts , well where you hear racing =less engine life, or much less engine life.

Few mods can actually make the engine work real better or last as long , one has to ask people that have made them and tested them for long,perhaps Dynotec or Daes have a good 'bag of tricks' (here in Europe)on the line for that purpose.

As far as I am concerned I am just into having a better fuel map suited to my needs and perhaps latter do that twin spark and some other essensial works done ,from a real specialist of the kind but there are another 40- 60k to go.

Guzzi engineers would have trouble going with higher compression, largely because of emission laws.

You can't just enrichen it and still pass emission testing.

Yet in 2003 or so they actually went with higher compression and got a fatter power band

I guess they improved the oil flow to make that happen, and presumably they changed the timing and fueling.

I am not sure how this did not mess up the emission testing. ...Did all bikes with the higher compression get a catalytic convertor?

The Early v11 six speeds and the v1100sporti have 9.5:1, the later six speed single plugs have 9.8:1 and the Breva has 9.6:1 and from the description of its smoothness, the Breva could easily go to a higher compression, if you are prepared to remap the ECU.

Going to High compression pistons like the FBFs is theoretically almost as easy to compensate for as aftermarket mufflers.

Yet, people fear it like some bad memory of a race bike in the 1970s that would not idle and needed race fuel.

Sure you can have the same problem here, but the majority of high compression upgrades are successful.

Or maybe we should start ordering extra gaskets to bring compression down to 9.0:1 so we can run on 86octane and ride for 200,000 miles!!! I don't see people lining up to go in that much cheaper and easier direction.

[helicopterjim R.I.P.]

Has anyone ever wanted to go to lower compression pistons?

[Pierre]

Has anyone ever wanted to go to lower compression pistons?

 

Oh I expect so , Jim. Same crowd that's never been comfortable with those new fangled poppet valve heads. Not many of those guys left, but a disproportionate number of them seem to hang out here. You can usually recognize them by their JAMES EARL JONES "direct from the lips of of god" Internet voice.

 

As for me - "give me higher compression, or give me a bicycle!"

[Alex-Corsa]

Guzzi engineers would have trouble going with higher compression, largely because of emission laws.

You can't just enrichen it and still pass emission testing.

Yet in 2003 or so they actually went with higher compression and got a fatter power band

I guess they improved the oil flow to make that happen, and presumably they changed the timing and fueling.

I am not sure how this did not mess up the emission testing. ...Did all bikes with the higher compression get a catalytic convertor?

The Early v11 six speeds and the v1100sporti have 9.5:1, the later six speed single plugs have 9.8:1 and the Breva has 9.6:1 and from the description of its smoothness, the Breva could easily go to a higher compression, if you are prepared to remap the ECU.

Sure you can have the same problem here, but the majority of high compression upgrades are successful.

Yep they know what to do when something is changed,so there is made a quite different motor than the one before that includes some changes.

Perhaps that's what the people who sell the pistons don't tell you.Do they say all the changes that you will be facing for a succesfull install?Do they tell you what's the success with the life expectancy on the perticular motor?Cause a factory usually does.. Even if they did tell some of that ,or do , you'll notice that this would be a project rather demanding on money.

So in order to be successfull ,and that can be done of cource,it gets quite pricey, doesn't it?

For the same reason I'd preffer something ready from the company than something from outside.(concerning such serious changes.)

 

 

 

 

Or maybe we should start ordering extra gaskets to bring compression down to 9.0:1 so we can run on 86octane and ride for 200,000 miles!!! I don't see people lining up to go in that much cheaper and easier direction.

 

200,000 miles is the official Guzzi estimation for the new Breva and Griso motors.

 

[Guzzirider]

Myself and Mal have fitted FBFs to our V11s in April and have both done several thousand miles on them, as have other members of this forum.

 

What difference do they make? Have a look at my chart in dyno gallery thread and you can see the main difference is increased torque and power throughout the mid range. You can feel this extra urge when riding the bike.

 

Important to run the bike on decent fuel once the change has made- there are plenty of stations selling 99 octane around here which is perfect. If I have to use 97 octane that is fine but if you use cheap fuel from a backwater station in the middle of nowhere it will pink, although V11s do that anyway on cheap petrol.

 

I guess logically it will reduce the engine life but what the heck, you only live once. Still waiting to hear a solid story of a FBF motor breaking or wearing out because of this conversion. I am not one of life's worriers and just tend to go out have fun.

 

I've thought about twin plugging but at the moment I can't be arsed because I am pretty happy with the Guzzi as it is and have been busy fettling my other baby.

 

Guy

[Alex-Corsa]

Well , a real quality-performance upgrade would be the Ti Carillo rods.A bit pricey though.

I have chosen to upgrade my midragnge thrust with an exaust system & better chip map , it can get a bit better with some work anyways .

Don't know if it is more or less than having Hi Comp. pistons but for sure I have learned a lot in the process and the bike revs more lively now.

 

Dual spark is another story, it requires also some head porting and some other vavle parts i remember.

[pete roper]

Well , a real quality-performance upgrade would be the Ti Carillo rods.A bit pricey though.

 

Dual spark is another story, it requires also some head porting and some other vavle parts i remember.

 

Alex, Titanium is a vile substance to make something like a connecting rod out of. Don't believe me? Go and look at the Arrow site and look at the service schedule.

 

Twin plugging is easy enough althoughthere is more work required with squarefins than roundfins. Now that you can buy twin plugged heads off the shelf it is really quite a simple task though.

 

On the subject of increasing the CR? I don't have any problems with a high compression ratio, it's just that a wide combustion chambered 2 valve hemi with a single offset plug is NOT a particularly good spot for a high CR. I don't doubt that lots of people are running higher CR than standard with good results and no serious loss of reliability BUT it is highly unlikely that these gains have been made by a simple 'Drop in' piston swap. If people are happy to expend large amounts of time, money and effort chasing a little bit more out of their Guzzi motor? Fine! No skin off my nose, more than happy to try and help them and advise if I can. I'd still suggest that if you're after a lot *more* in terms of power and performance you're better off simply buying a different, more modern, machine

 

Pete

[Alex-Corsa]

Alex, Titanium is a vile substance to make something like a connecting rod out of. Don't believe me? Go and look at the Arrow site and look at the service schedule.

 

Pete

 

Carillo rods are concidered to be some of the best money can buy,for the job, Dynotec uses them in their 150PS Guzzis , MGS also has them and genarally Guzzi has used them for years in some 'special' bikes. They have better performance than the stock Guzzi rods.

And yet again about metal appart it's main qualities it is also how it is melted worked and get freezed again during the construction process.

Do you think lets say a 154CM steel or a softer like the 440A (i.e.AUS 6)from one company can be the same in roughness or toughness,or bending tollerances as the same steel worked in another one ?

[pete roper]

Alex, I don't know if Carilo are now making Ti rods but their *ordinary* ones are a steel alloy. They are very good, but they are a *performance* rod and as such have a more limited life than some. The last set I bought were also out of round by 1 thou on one rod big end and 1/2 a thou on the other. I used Carilos in my 10,000RPM hot rod and was maoer than happy but for our race bike I preffer locally made Argo's even though they are heavier. Horses for courses.

 

Pete

[luhbo]

Ti-rods are absolutely useless in terms of strength. I've never heard of any broken standard rods. The only usable advantage for street Guzzis is that Ti-rods could be remarkable lighter, especially at the big ends.

 

So in order to get some profit out of the money you've spent for them you should rebalance the crankshaft. Have you done this?

 

Hubert

[Guzzirider]

Hubert

 

Alex will have Carillo rods as they were fitted as standard to the Corsa version of the Sport Injection.

 

They do make the motor smoother with noticeably less vibration.

 

Guy

[dlaing]

 

200,000 miles is the official Guzzi estimation for the new Breva and Griso motors.

 

I think the valve train is the only real weak link, unless they improved that too.

The smoothness of the engine may also help with the life of everything else on the bike, too!

[Alex-Corsa]

So in order to get some profit out of the money you've spent for them you should rebalance the crankshaft. Have you done this?

Hubert

 

Moto Guzzi has done this for me since the Carillo came with the S.Corsa from the factory ,Daytonas also have them as well.

[luhbo]

....

 

They do make the motor smoother with noticeably less vibration.

 

Guy

 

Guy,

 

that's what I meant. Thank you for this information. Standard rods with heavy big ends make it difficult to find a proper balance. Compare the actual crankshaft shape with that of older versions and see what Guzzi has learned over the years.

 

Hubert

 

Moto Guzzi has done this for me since the Carillo came with the S.Corsa from the factory ,Daytonas also have them as well.

 

Alex,

 

sorry for missunderstanding you. I thought you've bought them.

 

Hubert

[Alex-Corsa]

Alex, I don't know if Carilo are now making Ti rods but their *ordinary* ones are a steel alloy. They are very good, but they are a *performance* rod and as such have a more limited life than some.

Pete

 

Excuse my false expression about it that they are Ti.I meant Carrillo ,Yes you are right they are not Ti but from a 'special' prepeared kind of steel., & they are performance rods. I don't remember how I had his false impression that they were Ti.

Accoding to MO magazine (German press) they score higher than the series rods in robustness and tension limmits according to the tests they did (MO 2/92 p.28).