201 V11 upgrade to higher compression

[helicopterjim R.I.P.]

Yes. And I followed the instructions from this website for break-in!

Break-in Secrets

I seem to have very good results and I enjoyed the process. It is very similar to factory instructions for break-in of aircraft piston engines.

[Enzo]

HJ,

 

I've read this guy's stuff before and like him. I did not hone the cylinders, but I did go out and put a load on the bike. I am continuing to do this. Fast accelerations. I see he says decelerations (engine breaking) is also very important. I probably only have 30 miles on the new pistons. I need to thrash them some more. So far so good. I do notice a stronger feel in the mid range area right off.

[dlaing]

Does anybody know anything about this kit from:

http://www.motorkit.it/

?

[helicopterjim R.I.P.]

No but it looks very interesting. Longer connecting rods and shorter pistons. I can't tell if the compression is different. I wonder what the cost is and what changes need to be done to the engine.

[Skeeve]

No but it looks very interesting. Longer connecting rods and shorter pistons. I can't tell if the compression is different. I wonder what the cost is and what changes need to be done to the engine.

47238[/snapback]

 

I wonder how the stock con-rods & stroke length compare to the established "sweet" ratios? [i'm not that up on this issue, just aware that there are some numbers that are recognized as being "good."]

 

Anyone know? Anyone? Bueller?

[big J]

Not sure if I have this right, butAFAIK longer rods promote torque due to increased length acting against the crankpin, lighter pistons allow higher rev ceiling ,rod angularity at mid stroke is reduced decreasing bore wear, piston spends more time at TDC so better fuel burn. Could of course be a load of nonsense, just my own observations from arsing about with engines. Anyone with any scientific info input please? Just a wee question; Al will you test your engine with both single and dual plugs? I reckon that a dual plug head will show the full benefit of hi-comp pistons by allowing the fuel to burn right across the chamber instead of being partially shrouded by the dome on the piston. Ignition timing should maybe be adjusted due to the flame burning faster. As I said, this could be a load of bollocks,any opinions/comments?

[emry]

In the auto world the long rod theory is always good for selling a new bottom end. In theory it make sense. The longer the rod longer the piston spends at TDC and the larger the angle of the rod verse the crank center line as the piston travels towards BDC. But I also read a very nice article including a excel spreadsheet demonstrating that the benifits were very small unless the rod was 3 miles long. Wish I new what I did with that doc.

[big J]

Thanks for the info emry,my opinion was only formed as I said from building engines and looking to see "how can I improve this?". Visual inspection and imagination are all welland good, but it's nice to have preconceptions proved or disproved. Would you be able to find the excel sheet? Be nice to see it. I still think that hi-comp pistons would really benefit from dual plugs but again this is only from previous experience of building engines and I have no direct measurable evidence. Anyone out there tried this or seen it done on a Guzzi? My old shovelhead made more power and torque and ran smoother with dual plugs. Started a lot easier too.

[al_roethlisberger]

Thanks for the info emry,my opinion was only formed as I said from building engines and looking to see "how can I improve this?". Visual inspection and imagination are all welland good, but it's nice to have preconceptions proved or disproved. Would you be able to find the excel sheet? Be nice to see it. I still think that hi-comp pistons would really benefit from dual plugs but again this is only from previous experience of building engines  and I have no direct measurable evidence. Anyone out there tried this or seen it done on a Guzzi? My old shovelhead made more power and torque and ran smoother with dual plugs. Started a lot easier too.

47299[/snapback]

 

 

Dual-plugging the Guzzi V-Twin is very popular in Europe, and has been for years, but not so much here in North America... for no particular rhyme or reason. Part of the reason may just be the market, as Guzzis in America are relatively rare as compared to Europe it seems.

 

That being said, the "global" experts on dual-plugging Guzzis is currently TLM(forum sponsor). They have a whole "kit" that they'll sell ya, but it's not cheap.

 

 

Now, the million $$ question: Is it worth doing?

 

 

.... I have dual-plugged heads, and can't really say unfortunately Part of my problem is that I changed so many things at once(or close) that is was relatively impossible to isolate the benefit of some of the individual changes.

 

Now I know this flies in the face of a scientific methodology of how one should do modifications, but keep in mind that my motivation was quite a bit influenced by the fun of tinkering, versus pure performance

 

 

That being said, here is the forum dual-plug FAQ put together by yours truly:

 

http://www.v11lemans.com/forums/index.php?showtopic=2355

 

 

And the original "anyone dual-plug..." thread, that is one of the oldest and longest running of the forum

 

http://www.v11lemans.com/forums/index.php?showtopic=320&st=0

 

 

 

Hope that helps.

al

[big J]

Thanks Al, just read the dual plug thread, you are to be congratulated for your determination to see this through. Did the head work raise compression to the same level [approx] as hi comp pistons? Was the squish band modified? Sorry for the dumb questions, I'm just fascinated by getting more power out of an engine, especially one that has been around as long as Guzzi's vee. Before buying mine, I would have assumed that development would have ceased to be an issue,that Guzzi would have this thing so refined it sips port.Moto Guzzi:dontya just love 'em!

[al_roethlisberger]

Mike Rich attempted to shave my heads, but in the end removed very very little as he didn't have much to work with before impacting the squish. His new pistons improve the squish from what I understand as well.

 

Because the heads can vary, and MG is notoriously liberal in their CR specs, based on past experience Mike suspects that my real CR will be closer to 10.25 -> 10.5 when all is said and done. He believes the same is true of the FBF "11:1" pistons, but is not certain.

 

As stock, he says the MG heads are a good bit below the CR they market.

 

 

...and yeah, you would think that MG would have indeed "refined" every aspect of these engines over the years ... but even though they perhaps haven't wrung every ounce of juice out of them, MG has to be given the credit taking the V11 engine as far as they have and keeping it reliable for the street

 

al

[big J]

Agreed, no disrespect to Guzzi's engineers. I'd imagine that with decent financial backing the quality control issues can be tackled; who knows maybe Piaggio can build MG into a major player like Ducati. Hope Luigi still has a place in the future tho, I'd kinda miss him and we'd have nothing to complain about!