davdeborg Posted July 27, 2013 Report Share Posted July 27, 2013 hi got a amal carb on my 151 and in all fairness its not too bad I was going to service it with new jets gaskets the full works or would you go down the route of fitting a mikuni carb ? also anyone know the size of the needle and main jet as standard ? I think needle on mine is a bit worn any help advice appreciated . cheers Quote Link to comment Share on other sites More sharing options...
bondy Posted July 27, 2013 Report Share Posted July 27, 2013 hi if it runs ok on the Amal i would leave it on. but i had a good bing on my 199B but since puting a new mikuni on it runs so much beter. all 3 off my bultacos have mikuni on and all run sweet. its personal choice really but if the Amal is in good condtion why do you need to change it? Quote Link to comment Share on other sites More sharing options...
bondy Posted July 27, 2013 Report Share Posted July 27, 2013 just to add i service my bing and didnt really make any diffrance. the mikunis are good i payed £106 for mine and it cane with spare jets. Quote Link to comment Share on other sites More sharing options...
davdeborg Posted July 27, 2013 Author Report Share Posted July 27, 2013 I know there expensive its just me I cant leave anything alone bike starts first kick just not sure its set up right its approx. 1 3/4 turns out the mixture screw. sometimes idle increases and you have to keep adjusting idle screw etc one day its fine next its a bit quick next its slower. I got bike hot screwed mixture screw right in then un screwed it slowly until revs increased kept turning until revs fell a fraction then turned back to where it was at highest and left it there . its just needle looks a bit worn so me being me was going to mess with it cheers Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted July 27, 2013 Report Share Posted July 27, 2013 I've got a mikuni on mine but I intend to change to a dellorto fwiw. Quote Link to comment Share on other sites More sharing options...
davdeborg Posted July 27, 2013 Author Report Share Posted July 27, 2013 I've got a mikuni on mine but I intend to change to a dellorto fwiw. why the change you have probs with mikuni ? cheers Quote Link to comment Share on other sites More sharing options...
bondy Posted July 27, 2013 Report Share Posted July 27, 2013 theres nothing wrong with mikunis there a good carb. some guys just like to try diffrant carbs. Quote Link to comment Share on other sites More sharing options...
boghopper350 Posted July 27, 2013 Report Share Posted July 27, 2013 I like the idea of trying to keep these bikes as standard as possible. But I have found that no matter what you do to an old amal you are up against it trying to keep them running nicely, as you say they need constant adjustment when they get worn (and they do wear quickly) I thought that my 199a was running quite well but I had a mikuni sitting in the box of bits in my garage. I had to try it. I havn't touched it since. It runs so much better, all day, every day. This would be the case with any decent carb, jetted correctly. Quote Link to comment Share on other sites More sharing options...
p@ul250 Posted July 27, 2013 Report Share Posted July 27, 2013 (edited) Mikuni on mine. Good carb, A brand new Amal carb would be £109.99 + VAT. But would come fully jetted for your bike. have a look at http://www.amalcarb.co.uk Got one for a Montesa I'm restoring. Took a few weeks to arrive as they build to order. But was kept informed all the time. For a 72>74 sherpa 350 you should have the following Carb type - 625/414 Main jet- 150 Needle jet - 2 stroke-size 106 Pilot jet - 20cc Slide MK 1.5 No 3 cutaway Needle on position 2 Hope this helps Edited July 27, 2013 by p@ul250 1 Quote Link to comment Share on other sites More sharing options...
bondy Posted July 27, 2013 Report Share Posted July 27, 2013 hi agree boghopper i had 2 Amals on a 199A and my 198B both was hard work. Quote Link to comment Share on other sites More sharing options...
bondy Posted July 27, 2013 Report Share Posted July 27, 2013 i also got a brand new bing carb from spain that was good but i sold the bike. its your own choice at the end of the day Quote Link to comment Share on other sites More sharing options...
boghopper350 Posted July 27, 2013 Report Share Posted July 27, 2013 Sorry, I forgot to mention that my 199a had a bing on it that was standard. Bings are supposed to be slightly better than amal, but the point is they do run nicely on a good well set up carb and it's less agg with something like a mikuni, dellorto or even oko. Quote Link to comment Share on other sites More sharing options...
davdeborg Posted July 27, 2013 Author Report Share Posted July 27, 2013 Mikuni on mine. Good carb, A brand new Amal carb would be £109.99 + VAT. But would come fully jetted for your bike. have a look at http://www.amalcarb.co.uk Got one for a Montesa I'm restoring. Took a few weeks to arrive as they build to order. But was kept informed all the time. For a 72>74 sherpa 350 you should have the following Carb type - 625/414 Main jet- 150 Needle jet - 2 stroke-size 106 Pilot jet - 20cc Slide MK 1.5 No 3 cutaway Needle on position 2 Hope this helps thanks mate perfect cheers Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted July 27, 2013 Report Share Posted July 27, 2013 why the change you have probs with mikuni ? cheers Got Mikuni on the Bultaco and on the OSSA. To be honest both bikes run ok on them however especially on the OSSA I am fed up with it flooding when going down steep inclines etc. Worse on the OSSA as the carb is already mounted about 10 degrees from the horizontal. I've spoken to Motocarb and Allens and they both said you can get flooding problem when more than 20 degrees inclined. No such probs with Dellortos however they are more expensive. Just an explanation of why I am thinking of changing. Quote Link to comment Share on other sites More sharing options...
mrb505 Posted July 27, 2013 Report Share Posted July 27, 2013 Replace the needle U and needle jet 106 they are the parts that wear in these carbies fairly regularly The other jetting in your carb Amal 627 should be pilot 20 main 150 and slide 3.5 When adjusting the air screw I adjust it out till it runs fastest then scew it in a touch just where it starts to slow down I like it a bit rich on the pilot I wouldn't buy a new Amal they are rubbish the old ones are better, well the one I bought for my M49 is Quote Link to comment Share on other sites More sharing options...
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