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Thinking Aloud
Posted: Wed Apr 08, 2020 2:33 pm
by Doom Patrol
Can you bore an original 175 barrel out to 185, and what size would that be? And what piston would you use?
Re: Thinking Aloud
Posted: Wed Apr 08, 2020 3:30 pm
by vegansydney
The most obvious choice if you want to keep the TV rod, or use an RD400 one, is the TS185-ER.
Re: Thinking Aloud
Posted: Wed Apr 08, 2020 6:11 pm
by Doom Patrol
Oh, it's one I found whilst poking about in the shed. The only reason I asked is because it's had a seize and there is a deep gouge. I think it's beyond a honing, which is why I asked about boring it out. I did think of the TS185 pistons.
Re: Thinking Aloud
Posted: Wed Apr 08, 2020 7:01 pm
by vegansydney
OEM TV pistons have a substantial number of oversizes. I’ve seen Borgo oversizes as large as 63.6mm and have a Hepolite on the shelf that is 63.0mm. IMHO I’d explore this option on an original cylinder before looking into the TS185ER pistons.
Re: Thinking Aloud
Posted: Wed Apr 08, 2020 11:36 pm
by Warkton Tornado No.1
These days, there are more & more manufacturers supplying Lambretta specific oversize pistons.
However, unless there is something 'special' about them (apart from the 'special' high price) then my default choice is to select a piston intended for a decent motorcycle engine producer.
The TS185 is a very good piston & can be had very cheaply (preferably genuine)