rolf j
Tuned and Synch'ed
- Joined
- Nov 2, 2008
- Messages
- 70
Hi,
I thrashed a piston at the race last weekend. The bike is originally a V7-Sport, but the PO has put in 88mm pistons, 78mm crank and a head that resembles LM1-2, surely using the LM1-2 size valves (44/37). Perhaps this is an old performance kit? No idea, I only know the job has been done a VERY long time ago.
The piston I found in there has the following measurements:
Diameter: 88mm
Deck height from top wristpin: 24,2mm which is near enough the 24,4mm that Guzziology states is the most common one in the Tontis (I may even have measured inaccurately). No problems so far.
The dome height is 6,5mm which according to Guzzilology is not found originally in any Guzzi engine.
The 88mm pistons come originally with the following dome heights: 1,8mm - 4,1mm - 15,0mm.
Any suggestions how and where to source a piston like this?
Would it be possible to mill off 8,5mm from the dome of a LM4 piston? (15,0mm originally). Is it enough material up there to do such a crude thing?
rolf j
I thrashed a piston at the race last weekend. The bike is originally a V7-Sport, but the PO has put in 88mm pistons, 78mm crank and a head that resembles LM1-2, surely using the LM1-2 size valves (44/37). Perhaps this is an old performance kit? No idea, I only know the job has been done a VERY long time ago.
The piston I found in there has the following measurements:
Diameter: 88mm
Deck height from top wristpin: 24,2mm which is near enough the 24,4mm that Guzziology states is the most common one in the Tontis (I may even have measured inaccurately). No problems so far.
The dome height is 6,5mm which according to Guzzilology is not found originally in any Guzzi engine.
The 88mm pistons come originally with the following dome heights: 1,8mm - 4,1mm - 15,0mm.
Any suggestions how and where to source a piston like this?
Would it be possible to mill off 8,5mm from the dome of a LM4 piston? (15,0mm originally). Is it enough material up there to do such a crude thing?
rolf j