old trials fanatic Posted June 18, 2007 Report Share Posted June 18, 2007 So the road to Robregordo starts here and now. Dug the old 199b out and started to begin fettling ready for Robregordo next year. Now as previously mentioned somebody in the dim and distant past fitted an Amal Mk2 to her and i've never liked the running with it fitted. So going to fit a new carb but which? Ruled out the Bing as too many people say it's crap. The Mikuni or the Dellorto seems the way to go. A lot of the Spanish lads had them fitted i noticed at Robregordo this year then again i've also heard good reports about the Mikuni. I had one fitted to a Bultaco a long long time ago and seem to remember it worked well. They are both roughly the same price so what is the view of the "panel" ? Preferably if you have had experience of both or one of them i would appreciate your comments along with jetting suggestions. Looking to order one in the next couple of weeks so which do i fit? Thanks in anticipation Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 18, 2007 Report Share Posted June 18, 2007 Go with the bing if you can, they run well on the bike are easy to set up and once done are easy to fettle. dave renham will advise as to set up I'm sure, if ness. Quote Link to comment Share on other sites More sharing options...
rcgods Posted June 19, 2007 Report Share Posted June 19, 2007 One of my M91s runs a Mikuni carb and all seems good with it can't tell a difference between it and my Amal carbed M91 though. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 19, 2007 Report Share Posted June 19, 2007 Vesty never used a mikuni. Quote Link to comment Share on other sites More sharing options...
scotty Posted June 19, 2007 Report Share Posted June 19, 2007 I'd go with the bing too! my 199A runs perfect with it! dont forget bultaco rarely got it wrong! Quote Link to comment Share on other sites More sharing options...
brian h Posted June 21, 2007 Report Share Posted June 21, 2007 OTF - I am also an OTF too!! I would recommend you stay with Bing - fit a new slide , needle and jet (from Dave Renham) and set the ignition to 3.75 BTDC this setting was provided by SHM on one of his trips this way several years ago, I can assure you my engine runs smooth and very responsive. I am pleased I decided to stay with Bing, rather than spend up large on a Dell Orto or Mikuni - after all I believe Mart used Bings on his works Bultacos. Brian H Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 21, 2007 Report Share Posted June 21, 2007 (edited) 3.75 is wrong I'm sure. I've got 2.8 in my mind as what we used to set them at, quicker off the bottom? Not 100% sure as its been a while. Edited June 21, 2007 by Nigel Dabster Quote Link to comment Share on other sites More sharing options...
dabdab Posted June 26, 2007 Report Share Posted June 26, 2007 Never seen 3.75 recommended for a 325 or 340 Sherpa T I have my M199A set at 2.4 BTDC which was recommended to me by Reg May in a letter. He was talking about a M199, but everything I have seen since indicates its the same for the 340. Reg believed that 2.4 was the smoothest for average riders, and that anything more advanced would be to sharp off the bottom. I can say at 2.4, with a Sherco ignition and a Keihn flat slide carby, the old girl is as smooth as a butter As to the fact that Vesty never used a Mikuni, I will bet Reg May slipped on a brand new Bing every six or so weeks, because he could, just to keep it sharp. I`d do that to if there was no cost. Out here in Oz, for a bike ridden every weekend in the seventies, old Amals used to last 6 months and Bings went off after a year. The problem was, Bing parts were hard to get as the Bultaco importers of the time ( 1975 on ) claimed they could not get slides, and particularly, jets, and every one burbled around on too rich carbies. Thats why Mikunis were popular - easily available, low cost, harder slides and slide bores. Why the Keihn ? Simple, Mikuni no longer make a 28mm spigot mount carby, and the Keihn, and its parts, are readily available as an optional carby for Sherco et al. And a Keihn is emminently tunable - small changes really make a difference. Quote Link to comment Share on other sites More sharing options...
peterb Posted June 29, 2007 Report Share Posted June 29, 2007 Hmmm, lots of things to say. I used to ride 325's in the UK in Nationals in the late 70's, always had a fair bit of ign advance and a thinner head gasket, around 3.5mm BTDC. Yes it was a bit sharp off the bottom, not very good in the wet but that was how I liked it. Used to like the 28mm Bing too, back then. I still have a 325 - sort of, it is a 352cc Alpina motor with the port timing modified, running a PRO reed v/v block with a 28mm Kehin flat slide. The Keihin worked the best from trying a 26mm Mikuni, and a 26mm DellOrto, the PHBL 26BS DellOrto was better than the Mikuni and can be used straight off a PRO with just a change to the main jet, to 95. Rest is just fine. The DellOrto and Mikuni were trialled without the reed block fitted. The bike is used for decent sized rocks and hills. If you are riding in some specific series, you may have to fit a period carb, in this case the DellOrto PHBH could be used - not my favourite carb as the mixture varies a lot with altitude, but fine otherwise and I think these are used a lot in Espana. Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
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