I have completed my 500 km (310 miles) break-in and now I am at over 2000 km (1234 miles). My overall conclusion is that my personal objective is almost met. Even though, at the moment, this conclusion review is for the bolt on only, Pinasco 177 cylinder kit, with a reconfigured stock SI 20/20 carburetor (the atomizer has been changed to BE3-160 jet and main jet to 112), Sito plus exhaust, 20 degree timing and NKG B8 spark plug. In about a year, I will fully complete the final phase of my modification; which will be a precut race crankshaft, a larger oil injector SI 24/24 or T5 carburetor, and an improved and match performance exhaust; thus achieving the potential Pinasco 177Au cylinder advertise and recommended specification.
Currently, I am very satisfied with my new ride. I personally feel that I made the right choice and purchase for my needs and wants. Keep in mind that this is a small displacement, a now increased to177cc two stroke, late 70s-early 80s technology scooter which had some minor improvement over the years. Also, I am a 5'10', 330lb over weight rider; so the results and objective is like comparing a two up ride, not a one person rider who may weigh up to 180lbs. Also my goal is not to achieve a top end, wheelie screamer, but an all round, long lasting scooter that will give me a satisfying, wider and useable torque and power in the low - mid rpm band, specifically for city riding and a little in the top end speed for my local freeway.
During my break-in, my speed was kept at a limited of 60 km/hr (37mph) and 40 km/hr (25mph) in the steep hills. I used a high grade, semi-synthetic oil in the oil injector tank, and added an additional 1% minimum, premix racing synthetic oil in the fuel tank; all from an identical single brand. Pinasco advises 3% for the first 500km break in period. For the first 150km (93 miles), I was a bit paranoid so I used 2% in the premix, which adds to 4% total oil/fuel mix. The motor was a bit rough in the first 100km (62 miles) and then after 200km (124miles), it began to unnoticeably smooth out. As recommended by the Pinasco installation manual, after 500 km mark, the cylinder head needed to be check and re-torque. All head bolts loosen up a bit and the re-torque was not a problem. We examined the spark plug and I am now moving the main jets up from 112 to 114, for sea level; the results were odd, one side of the spark plug had sighs of lean and the sign of other side of the plug as acceptable; I suspect and would consider this sign as border line. Even though Pinasco says the oil/fuel mix of 2% is acceptable after 500km, I have continued to using a 3% mix for another 800km-1000km or when I am going for a long distance day touring at continuous upper speed.
My first impressions are, "I really like the changes." From the touch of the throttle to slightly less than 1/8 turn, I had instantly noticed a stronger pull and power. The throttle feels like it has been reconfigured, something that feels new, tighter and more responsive. I find the lesser wrist movement is easier to too shift smoothly and faster; and also easier too calibrate speed and acceleration. Most of my city riding is within the first ¼ throttle rotation, and at freeway cruising speed it is between ½- 2/3 rotations. This change is positive and has made my ride more enjoyable and fun.
Even though I rode easy in the initial and throughout the duration of the break-in period, I notice that I shift less often and I usually maintained 60km/hr (37mph) city cruising speed, just above the local 50km/hr (31mph) limit. I often stayed in fourth gear, even during the usual city hill climbs that before would normally start bogging down my Vespa and needed to correctly shift down to third to compensate. Because I am in fourth gear often, I have gained gas mileage, but only if I take it easy and keep it below 80km/hr (50 mph). Thankfully, I blame the new and improved gain and a wider band range in the low-mid rpm power and torque. The vibration has noticeably increased at the bottom end; however, it begins to smooth out as the RPM increases. At the mid - upper RPM, the vibration, for a two stroke single, has surprisingly and very comfortably smoothed out; in fourth gear, the sweet spot is at about 70km/hr to 80km/hr. The sound of the Sito plus exhaust has change to a slightly deeper and smoother tone. The bike does feel more aggressive, tight and it sounded cooler; like a big, mature, horny wasp with a bit of attitude. Ok, that may be a stretch.
After the break in, I began to test and ride aggressively. So how did the bolt on only Pinasco 177 Au cylinder kit and new carburetion configuration performed. For take off and flowing with traffic, the acceleration has dramatically increased and is now very good and very acceptable for any comparable vehicle traveling up to 60km/hr (37 mph). To what use to be my wide open, fuel thirty, throttle speed at 90 km/hr (56 mph) is now y my top cruising speed, and my top end has now an additional 15km/hr (9.5mph). From 60km/hr-80km/hr (37 mph -50 mph), I still felt the acceleration and pull, not as strong, but acceptable enough for getting in and riding at my local freeway; from 80km/hr-90km/hr (50 mph - 56 mph), the acceleration pull is minimal to none, but is good enough for steady flat cruising; and from 90km-100km (56 mph - 62 mph), its acceleration crawls with no sensation of pull. At wide open throttle, the bike can't get passed 105km/hr (65 mph); the motor feels unbalance and sounds stressed, and becomes very thirsty for fuel. I found that if I roll back the throttle an 1/8 from wide open throttle, just enough to feel the rpm begins to slow down, I would be between 95km/hr-100km/hr (59 mph - 62 mph) max on the flats. When I rolled backed from wide open throttle, the fuel efficiency improves dramatically and the motor is running more smoothly and probably cooler. At the new steady 80km/hr - 85km/hr (50 mph -52 mph) cruising speed, I am not sure why, but my 2005 Vespa PX has gained up to about 15% fuel economy. I am guessing that my Vespa had a mismatch, improper and inefficient carburetor/ exhaust setup. My only criticism is that if I had a little more pull from the 80km/hr (50 mph) to top speed, my personal objectives for an all round performer, freeway riding and long distance day touring scooter would be completely met. Hmmm, what race pre-cut crankshaft and carburetor was I suppose to choose and use now???
During my ride, I kept thinking about one Gearheads saying, "Weight is horsepower." My wishful thinking that if I was the lighter rider of my idea weight of a 180lb, instead of 330lbs, the gain in acceleration and performance from this kit would have dramatically and greatly improved; thus my personal objective would have been easily met and most likely be exceeded. I also thought that a lighter rider would be able to ride faster at wide open throttle. However, that is until I discovered that when I rode down a 7% grade hill on the freeway, my Vespa had trouble getting pasted 110km/hr. I blame the stock crankshaft and the stock SI 20/20 carburetor for the choked and cut off, and reaching its absolute maximum rpm limit and speed. With a race precut crankshaft and 24mm carburetor, Pinasco claims that there sport/ touring tune 177Au cylinder kit set up can achieve an advertised specification of 12.5 hp and 125 km/hr (78 mph) top speed. Hmmm, looks like I will be needing performance shocks and tires very soon.
Whatever happens in my near future, right now my silvery metallic smoky grey 2005 Vespa PX 177 has become a sweeter, fun and more enjoyable ride. Can't wait to complete the second phase, shocks, tires...Oh no!!! Do I feel another addiction?
Average Mileage from an easy, fun and scenic 243 Km (151mile) day trip, traveling mostly between 60 km/h - 85 km/hr (37 mph - 53 mph); through an old highway back road route, with some town's in-between.
30 km/l (metric)
70.6 mpg (US)
84.7 mpg (Imperial)
Balance and matching is an engineering art
Best regards
⚠️ Last edited by rudy812 on UTC; edited 1 time
