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Hello from Germany

Karsten

Just got it firing!
Joined
Dec 20, 2014
Messages
7
Location
Germany
Hi,

My name is Karsten and this forum is new for me. Perhaps, I am posting in the wrong part but as I do racing with the little Guzzis I think it may be OK.

My wife, a friend of mine and me are racing with old V75 (started with V50), totally stripped for trac use. We had to do a lot of improvements just to get these little engines working and stable (valves, rocker screws, oil cooler) and the suspension doing what it should do, better braking and so on.

In our free time, we are organizing non-commercial trac days just for Guzzis and MZ (http://guzzi-mz-training.info) but that is just a (the) hobby.

Actually I try to improve the max. power of our engines because my wife Claudia needs more power. She don't want to be overtaken again after being faster in curves and braking better and then, on the next lane......
The little 2V-engines with the heron pistons are tricky. There is no possibility to increase the vale sizes a lot, so we have opened the channels (right word?) for the use of 34 mm carbs, we are using better cam shafts, higher compression, LM1-style (and weight) manifolds. The current power is somewhat in the area 55 to 60 hp at the clutch (the original V65 has 44 hp, a V50/3 has 37 hp measured) but in our racing class we have always the weakest engines (compared to DUC 750, Honda VF500F with about 70 hp). So, I will change the exhausts and open the channels a little bit more. In an other test bike I'll try the Lario engine (4V) with different valves (not larger but hopefully more reliable). I hope it'll work so that I can build a second engine.

so far....
Have nice holidays.

Karsten
 

john zibell

Moderator
Staff member
GT di Razza Pura
Joined
Oct 28, 2008
Messages
8,770
Location
Huntsville, AL
Hi Karsten and welcome to the forum. There are several racers on the forum that may be able to provide some guidance on the small block engines. I do know original Lario cams had issues but hopefully they have all been replaced by now. When you get into builds please do start a new thread on those topics. Porting the heads as well as building intake port ramps (these tend to increase velocity into the combustion chamber) may improve flow for you. However there are limits to what you can wring out of these engines. As for carb sizing, there is an Excel file that may help https://www.guzzitech.com/forums/resources/carb-sizer.188/
 

Karsten

Just got it firing!
Joined
Dec 20, 2014
Messages
7
Location
Germany
Hi John,

I opened the carb-sizer XLS-file but what does it show?
Here is a picture of the file:
carbsize.png


verwirrt....

Karsten
 

john zibell

Moderator
Staff member
GT di Razza Pura
Joined
Oct 28, 2008
Messages
8,770
Location
Huntsville, AL
In Excel, change the bore and stroke to match the figures for your engine. Then enter the carb size you want to use. It will then tell you the optimum RPM for that carb choice. Best operation is IK RPM above and below the optimum RPM
 

Karsten

Just got it firing!
Joined
Dec 20, 2014
Messages
7
Location
Germany
So the 34 mm carbs seem to to be fine. The optimum rpm is 6700 and that is the range of the max. power. Larger carbs are imho incompatible to the small intake channel. They had to be opened even for the 34 mm carbs. Series is 30 mm without accelation pump. I use 34 PHF with accelaration pump. The engine with the long stroke doesn't like rpms above 8000 (V65: 9000, V50: 11000).
So a friend tries actually to use larger bore with less stroke to have more rpms possible. But that is not yet simple.

FF.

Karsten
 

redwitch

Tuned and Synch'ed
Joined
Oct 9, 2015
Messages
36
Location
france
Hi,

My name is Karsten and this forum is new for me. Perhaps, I am posting in the wrong part but as I do racing with the little Guzzis I think it may be OK.

My wife, a friend of mine and me are racing with old V75 (started with V50), totally stripped for trac use. We had to do a lot of improvements just to get these little engines working and stable (valves, rocker screws, oil cooler) and the suspension doing what it should do, better braking and so on.

In our free time, we are organizing non-commercial trac days just for Guzzis and MZ (http://guzzi-mz-training.info) but that is just a (the) hobby.

Actually I try to improve the max. power of our engines because my wife Claudia needs more power. She don't want to be overtaken again after being faster in curves and braking better and then, on the next lane......
The little 2V-engines with the heron pistons are tricky. There is no possibility to increase the vale sizes a lot, so we have opened the channels (right word?) for the use of 34 mm carbs, we are using better cam shafts, higher compression, LM1-style (and weight) manifolds. The current power is somewhat in the area 55 to 60 hp at the clutch (the original V65 has 44 hp, a V50/3 has 37 hp measured) but in our racing class we have always the weakest engines (compared to DUC 750, Honda VF500F with about 70 hp). So, I will change the exhausts and open the channels a little bit more. In an other test bike I'll try the Lario engine (4V) with different valves (not larger but hopefully more reliable). I hope it'll work so that I can build a second engine.

so far....
Have nice holidays.

Karsten


Hello, Karsten. I live in france, am a old rider, , and just bought a nice V75, ( my first guzzi )that i intend to upgrade for some hillclimbing racing in the alps, where I live. it is interesting for me to find people who are familiar with tuning of these engines. would you accept to give me a few tips on preparing the bike? i would appreciate very much. also, for your trackdays, where is it, ad on which circuit? I might go over to germany and meet you one of these days. maybe even make a few laps on the track. ( i have been road racing in england and france for about 10 years, beetween 1975 and 1985;
Well.nice to hear from you best regards. Hervé.
 

Karsten

Just got it firing!
Joined
Dec 20, 2014
Messages
7
Location
Germany
Hi Hervé,

please send me an email. The address is written on my homepage (see in my first posting).

Et tu peu ecrire Francais :)

Au revoir,

Karsten
 
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