Tuning a T4

[Simon_London]

Thought you might be interested in my T4 mods.

I fitted the 36-30mm reducer inlet manifolds from HMB Guzzi and some 36mm carbs. This alone gave a great improvement.

I was surprised at the further improvement with the Le Mans I+II exhaust system. Even without the crossover there is more power using Le Mans silencers. With the cross over down pipes there is more still.

The flywheel was swapped to the lighter Me Mans 3.3Kg one.

The bike really is transformed from the original strangled runt that left the factory.

Jetting (with bell mouths) 145 main 268 Atomiser K18 needle raised 1 notch and 60 idles.

Also swapped the standard PS13 front M/C to P11 giving loads more power and feel to the front disc.

simon







 

[oldbike54]

 Vroom vroom 

 Dusty

[frozengoose]

The flywheel was swapped to the lighter Me Mans 3.3Kg one.

The bike really is transformed from the original strangled runt that left the factory.


Also swapped the standard PS13 front M/C to P11 giving loads more power and feel to the front disc.

simon







 

Hi, couple of questions...

Did you notice more vibration with the lightened flywheel? A friend had the FW in his '03 Stone lightened and balanced and he said it seemed to vibrate more. I had thought about doing that with my T, but his experience with the FW seemed like it wasn't the way to go.

I just got done with a post on swapping out the stock 15 mm master cylinder with the REC Brembo 12/13 mm for better front braking. But you say the 11 mm is the way to go?

Thanks, Jon

[Simon_London]

Hi, couple of questions...

Did you notice more vibration with the lightened flywheel? A friend had the FW in his '03 Stone lightened and balanced and he said it seemed to vibrate more. I had thought about doing that with my T, but his experience with the FW seemed like it wasn't the way to go.

I just got done with a post on swapping out the stock 15 mm master cylinder with the REC Brembo 12/13 mm for better front braking. But you say the 11 mm is the way to go?

Thanks, Jon

Jon

Flywheel weight and Guzzis are interesting and divide opinion.

I actually have an 1100 sport flywheel (around 2Kg) on my G5 based Le Mans replica. Really makes the bike fly. It feels a bit lumpier at 3-4 thousand revs and decelerates quickly when you close the throttle. It doesn't vibrate more but if the carbs are not properly balanced it is more noticeable. It does change the feel of the bike quite a bit and isn't for everybody. The engine feels much more on/off and less classic lazy Guzzi.
 
The standard Le Mans flywheel is actually still quite heavy. My T4 has retained the lazy Guzzi feel and certainly doesn't vibrate more but pick up is  improved as is engine breaking and I actually find the bike safer as a result. I think the 3.3Kg Le Mans fly wheel is a good compromise. Perhaps a heavier flywheel can mask other causes of vibration? If you like to rev the bike then go lighter. If you prefer more gentle riding or do alot of urban riding then a heavier flywheel may suit you better.

I believe the standard front M/C is 13mm . In any case 11mm works best.

[frozengoose]

OK thanks, it's all food for thought.

[wirespokes]

Jon - We don't know Simon's configuration whether linked or not. At any rate, an 11mm (never tried one myself) or 12 works well for a single disc and 13mm for duals.

[Gliderjohn]

For awhile on my T-3 I tried about a 40% lightened flywheel and didn't really care for it. When I had to replace the clutch I went back to a stock one. Probably a matter of taste and riding style.
GliderJohn

[Furbo]

I did something similar when I build my hot rod Le Mans motor. I put a Cal II motor with the B10 Cam from the stock Le Mans engine and the 40mm carbs. Really woke that thing up!

[Simon_London]

Jon - We don't know Simon's configuration whether linked or not. At any rate, an 11mm (never tried one myself) or 12 works well for a single disc and 13mm for duals.

I still have linked brakes with the 11mm M/C to single front disc.

[frozengoose]

I still have linked brakes with the 11mm M/C to single front disc.

Do you know the Brembo part # for the 11 mm MC? Not familiar with that one.

The T comes stock with a 15 mm MC, so not sure if the 11 mm would work with the stock Caliper, IDN the model #.

[Simon_London]

Both my bikes come have standard linked brakes and F08 calipers. I sourced the later square reservoir 11mm  M/C  second hand from another bike.
Rear M/C is standard and I believe 15mm

[frozengoose]

OK, thanks Simon and all who commented, I'll be looking into this some more. Is there a listing somewhere of what Brembo parts fit which bikes. Tried their website, but it's less than helpful. The front brake has always been an issue on the T. It's why I learned to never tail gate!

[Antietam Classic Cycle]

Do you know the Brembo part # for the 11 mm MC? Not familiar with that one.

The T comes stock with a 15 mm MC, so not sure if the 11 mm would work with the stock Caliper, IDN the model #.

There are a "bunch" of different 11 mm Brembo master cylinders. Check out those that are designated as "PS11" here:
https://www.oppracing.com/category/1012-brembo-oe-oe-front-brake-master-cylinders/

Your stock caliper would be an F08 unless someone changed it already.

With an 11 mm master cylinder and F08 caliper (two 38 mm pistons) you'd get a 23.87:1 ratio which many people consider optimum.

http://vintagebrake.com/mastercylinder.htm

[frozengoose]

Thanks Charlie, always appreciate the input.