My Avanti started to run rough a few weeks ago but I put it down to needing to get the recently fitted Avanti Super Tourer exhaust dialled in. Got it on the dyno over at Lowestoft Lambretta Works today but after 4 hours, Sash admitted defeat and told be I'd need to take the barrel off and see what was wrong with it as although the compression was reading ok at 145lbs there seemed to be evidence of piston slap. Got it home and this is what I found
Racking my brains I think I know the moment when it went, I had ridden it hard for about 10 minutes between 60 and 70mph along a dual carriageway. I have one of Darryl's hand chokes and did several checks to make sure the mixture was fine. Stopped for a couple of hours and then rode back at about the same speed but after a minute or so it seemed to loose power so I pulled the hand choke and it didn't make any difference until I got the speed down to less than 50mph. Since then it has refused to tickover and been even more boggy than normal in the mid range hence my visit to Sash's dydno.
Anyone like to hazard a guess as to the cause? the plating is completely gone on the exhaust side bellow the port and that side of the piston is completely mashed with deep gouges, obvious metal to metal contact. There are also some patches above the inlet near the top of the barrel where the Nicacil appears to be missing. The rings, bearings and seals were replaced less than 2k miles ago and I have always run it on 3% (Groundsman for the last 2k).
I'm off on a mini tour of Europe next Friday so I'll have to borrow the TS1 engine in my other scoot which'll mean cutting the battery tray
Avanti woes
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Mines sucked a reed petal in last week, thought I'll strip it and check none of the petal got stuck in the ports etc. gave it a decoke then thought I'll measure the ring gap in the barrel before putting it back together it was about 3mm with bits of the liner missing much like yours. I've retired it for the time being.
how many miles total?
how many miles on rings?
Ring Gap?
Filter?
how many miles on rings?
Ring Gap?
Filter?
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Are you running opened mouth ? I wonder if you pulled something in through the carb' ?
The rings don't look too bad and I would have expected a heat seize to have more sign of damage round the rings........strange ?
My Avanti (after 10K miles) developed a lip on the top of the barrel due to wearing of the nicasil, piston slap and clearance issues were the problem, as has been asked how many miles as it done ?
The rings don't look too bad and I would have expected a heat seize to have more sign of damage round the rings........strange ?
My Avanti (after 10K miles) developed a lip on the top of the barrel due to wearing of the nicasil, piston slap and clearance issues were the problem, as has been asked how many miles as it done ?
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I was just this morning reading about the Hartley V8 in the Ariel Atom. (Made from two Suzuki Hyabusa heads on billet crank and crankcases).
http://www.h1v8.com/page/page/1562068.htm
Hartley reckons nicasil is very susceptible to dirty air.
Could be even worse in a 2t because of all the holes?
http://www.h1v8.com/page/page/1562068.htm
Hartley reckons nicasil is very susceptible to dirty air.
Could be even worse in a 2t because of all the holes?
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It's done around 4500 miles in total and I renewed the rings last year before heading off for the LCGB trip to Davos. That was about 1700 miles and I've probably done 200 or so since so around 2000 miles on the current rings. It was run in as per Ron's instructions using 4% but without any filter. At around 1500 miles I fitted a Breath Sweet and that has been on ever since so it wasn't anything sucked in.
I did gap the new rings, I'm not sure what gap I used but I have a feeling it was 8 thou? The old ones were around 25 thou.
Colin
I did gap the new rings, I'm not sure what gap I used but I have a feeling it was 8 thou? The old ones were around 25 thou.
Colin
minimum 11 thoucoaster wrote:It's done around 4500 miles in total and I renewed the rings last year before heading off for the LCGB trip to Davos. That was about 1700 miles and I've probably done 200 or so since so around 2000 miles on the current rings. It was run in as per Ron's instructions using 4% but without any filter. At around 1500 miles I fitted a Breath Sweet and that has been on ever since so it wasn't anything sucked in.
I did gap the new rings, I'm not sure what gap I used but I have a feeling it was 8 thou? The old ones were around 25 thou.
Colin
C’est la vie
Interesting!