old trials fanatic Posted November 29, 2007 Report Share Posted November 29, 2007 I've bought an alloy square barrel which is apparently off a Dot which is in god nick and on std piston size. The exhaust port is bridged but above the transfer ports both sides are three holes about 5mm in diameter. Dont know anything about the barrel but just wondering if anybody knew why they were there? Quote Link to comment Share on other sites More sharing options...
peterb Posted December 8, 2007 Report Share Posted December 8, 2007 Hi there OTF, Can't help with this one but the barrel may be a Marcelle item. Holes above the transfer ports - never heard of before, do the holes link up to the actual port? With a bridge on the exhaust port, it could be that the barrel is from a moto cross/road race motor - possibly a wide exhaust port. The extra holes above the transfer port would only serve to allow a greater volume of compressed fuel/air onto the top of the piston but then this would affect the port timing for closing off on the compression stroke, also increase the open duration and improve scavenging from the crankcase - hmmmmm..... best to consult the Tuning for Speed book! Well worth a try on a bike. Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted December 8, 2007 Author Report Share Posted December 8, 2007 Thanks. The barrel is aparently a Dot one but after ringing the Dot factory they dont know about the holes either. It's on std bore in good nick with very little if any wear on the bore or the piston. Oh well will keep trying. Interesting connundrum though. Quote Link to comment Share on other sites More sharing options...
vinnied Posted December 10, 2007 Report Share Posted December 10, 2007 Thanks. The barrel is aparently a Dot one but after ringing the Dot factory they dont know about the holes either. It's on std bore in good nick with very little if any wear on the bore or the piston.Oh well will keep trying. Interesting connundrum though. Would it be possible to post a pic. OTF vinnie Quote Link to comment Share on other sites More sharing options...
subira Posted March 28, 2008 Report Share Posted March 28, 2008 Think this little fella is going to go for really silly money ! http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...A:IT&ih=013 Fortunately I found one a few months ago, probably not in as good condition, but was very affordable (but let's just say its a project) With lots of interest in the 'right bits' on Ebay and at the Jumbles, it looks like there's going to be a new wave of beautiful bikes out there very soon!! Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted March 29, 2008 Author Report Share Posted March 29, 2008 Think this little fella is going to go for really silly money !http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...A:IT&ih=013 Fortunately I found one a few months ago, probably not in as good condition, but was very affordable (but let's just say its a project) With lots of interest in the 'right bits' on Ebay and at the Jumbles, it looks like there's going to be a new wave of beautiful bikes out there very soon!! Or even this one http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...E:IT&ih=011 Seems after the one on e bay which fetched over Quote Link to comment Share on other sites More sharing options...
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