OP
@afflictus avatar
UTC

Hooked
vespa 100 sport x2
Joined: UTC
Posts: 139
Location: Vancouver Island Canada
 
Hooked
@afflictus avatar
vespa 100 sport x2
Joined: UTC
Posts: 139
Location: Vancouver Island Canada
UTC quote
After my rebuild everything was going well. I was using the old top end DR 130 on my small frame. 25mm carb, leo vince with primavera primaries and 4 speeds.

I was on the highway after some city riding with out a hitch or problem. Then the next day I was on the highway for ten minutes and it seized. The plug was fine, everything torqued to spec, mixture was good. Main jet of 90 on the dellorto phbl 25mm.

After some pics, consultation with a friend the cause was an air leak on the intake side of the head cylinder causing blow by on the exhaust port side. I need a new top end.

After I install my Polini 135cc kit how would you recommend breaking it in or any other advice you have.

Thanks.
UTC

Banned
62vnb , 71 sprint ,1974 vespa90
Joined: UTC
Posts: 648
Location: Idaho falls
 
Banned
62vnb , 71 sprint ,1974 vespa90
Joined: UTC
Posts: 648
Location: Idaho falls
UTC quote
I have found how you break in your motor affects thru the life of you top end . I wait for a weekend find some back roads and don't go full throttle on any gears for at least 300 miles . This won't make you to popular on the road so early morning is best . Some kits will ask for a richer mix when breaking in , I have done this with nothing but good results . Have not had a sieze since I have used this method on a Mallosi 166 and two Pinnasco 177 .
UTC

Addicted
Joined: UTC
Posts: 920
Location: The Bank
 
Addicted
Joined: UTC
Posts: 920
Location: The Bank
UTC quote
I've heard of a pretty interesting way that is based on heat cycles, cooling time, and varying throttle range.
@brentscheffler avatar
UTC

Addicted
'78, '80 P125X, '80 100 Sport, '74 150 Super
Joined: UTC
Posts: 717
Location: Seattle
 
Addicted
@brentscheffler avatar
'78, '80 P125X, '80 100 Sport, '74 150 Super
Joined: UTC
Posts: 717
Location: Seattle
UTC quote
Re: How to break in a new Top end.
Afflictus wrote:
After I install my Polini 135cc kit how would you recommend breaking it in or any other advice you have.
You have just opened a can of worms.


Basically, there are 2 major schools of thought:

1) Conservative: Never go past half throttle in any gear. Vary the throttle as you ride. No two-up riding. No big uphill runs. For 300-miles-ish (?)

2) Ride it like you stole it.

I subscribe to somewhere in the middle of the two.
@drona avatar
UTC

Molto Verboso
59 Vespa, 65 Vespa, 66 Vespa, 57 Vespa
Joined: UTC
Posts: 1322
Location: Portland Oregon
 
Molto Verboso
@drona avatar
59 Vespa, 65 Vespa, 66 Vespa, 57 Vespa
Joined: UTC
Posts: 1322
Location: Portland Oregon
UTC quote
I'm with Brent on this one...
UTC

Veni, Vidi, Posti
Joined: UTC
Posts: 7646
Location: Tega Cay, SC
 
Veni, Vidi, Posti
Joined: UTC
Posts: 7646
Location: Tega Cay, SC
UTC quote
First start up , listen for anything bad, then shut off. Next, a short easy ride. I then very the speed and increase the duration of ride for the next 50 miles. Semi easy for the next 100. After that I do what I want.
OP
@afflictus avatar
UTC

Hooked
vespa 100 sport x2
Joined: UTC
Posts: 139
Location: Vancouver Island Canada
 
Hooked
@afflictus avatar
vespa 100 sport x2
Joined: UTC
Posts: 139
Location: Vancouver Island Canada
UTC quote
Advice taken, thank you all.

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