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RASK CYCLE

SPECIALIZING IN:
HARLEY-TRIUMPH-BSA-NORTON  PARTS AND REPAIR

(724) 538-4123
(724) 538-9676 (fax)
 

 

UNLEADED VALVE SEAT CONVERSIONS

unleaded conversion

unleaded conversion

A. Seat with valve installed (before conversion)
B. Seat without valve (before conversion)

 

C. Seat with new valve seat installed
D. Seat with old valve seat machined out before
  new seat is installed..
 
There seems to be some confusion about what constitutes an unleaded valve seat conversion. We constantly get calls from customers who believe that unleaded conversion is done by changing the valves or valve guides. Worse yet, we have talked to people who have paid to have something of that nature done, and thought they were getting an unleaded conversion.

 We will try briefly to explain what an unleaded conversion really entails. In most British motorcycles, Harley Davidson Knuckleheads, Panheads, and Ironhead Sportsters, the valve seats are cast into the head and are made of a very soft material. These seats pit very easily when run with unleaded gas. To convert the head to use unleaded gasoline with no problems, the old valve seats need to be machined out and have new seats of a harder material pressed in at an interference fit. Valve seats may also need to be replaced when they have been reground many times or are severely worn.

 This leads to a condition where the valve recedes too far into the head. It impairs gas flow and you will lose spring tension. When this condition is apparent, valve seat replacement is necessary, and unleaded conversion would be automatic. There are many difference types of valves and guides that will work. If you don't you know which is best for your application, we will call and discuss it with you, when we receive your heads for machine work.
new valve seats installed
Knuckleheads, Ironheads XL'S, Panheads $90.00
Shovelheads, EVO, EVO XL'S $80.00
Triumph, BSA twins $90.00

Note:
  This price does NOT include valve job, which must be done after installation of seats.

(Priced per seat *includes seat and installation)

 

 

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08/09/13
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