philhill Posted June 8, 2009 Share Posted June 8, 2009 Sorry, more carb questions. I'm converting my DT125MX 1982 with the barrel, head, carb etc from a 1978 DT175MX. The bloke I bought them of swears that the carb is correct and original but I can't find it in the manuals! its a mikuni, stamped 4L100. The carb looks quite a bit bigger than the 125's and when I Googled the number it came up as a VM26. Right so here are my questions :- Have VM26's ever been fitted to the 175's ? Would they work on a 175 (overbored to + 1.50)? Could the 125 carb work on the 175 engine? Can I buy the correct carb anywhere if the answers to the above are negative? Also how do I check if it is a VM26 and confirm the Google info, I presume the '26' is a measurement in mm, but where is it measured? I got the lot for £51 so can't really complain if the carb is wrong, but don't want to wait 6 months for the correct one to turn up on ebay. Thanks Phil Link to comment Share on other sites More sharing options...
Moderator Cynic Posted June 9, 2009 Moderator Share Posted June 9, 2009 Sorry, more carb questions. I'm converting my DT125MX 1982 with the barrel, head, carb etc from a 1978 DT175MX. The bloke I bought them of swears that the carb is correct and original but I can't find it in the manuals! its a mikuni, stamped 4L100. The carb looks quite a bit bigger than the 125's and when I Googled the number it came up as a VM26. Right so here are my questions :- 1)Have VM26's ever been fitted to the 175's ? 2)Would they work on a 175 (overbored to + 1.50)? 3)Could the 125 carb work on the 175 engine? 4)Can I buy the correct carb anywhere if the answers to the above are negative? 5)Also how do I check if it is a VM26 and confirm the Google info, I presume the '26' is a measurement in mm, but where is it measured? I got the lot for £51 so can't really complain if the carb is wrong, but don't want to wait 6 months for the correct one to turn up on ebay. Thanks Phil RD 250LC VM26SS (4L100) Main jet=190 Needle jet=O-6 Jet needle=4N10 Needle jet position? idle jet=20 Slide cutout=2 Air screw(turns out=)1½ Float=21 ± 0.5 mm First question 1, no not by yamaha. 2) Yes if jetted properly and not like its original configuration above. 3) Yes if jetted properly, you may be VERY slightly down on power but the smaller carb will increace torque. 4) Yes i think a member called oldgitonabike could be very intrested in a swap. 5) Its the internal venturi diameter, its awquard to check accurately so prob best to trust to the id no for now. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted June 9, 2009 Moderator Share Posted June 9, 2009 Some carb info Here Whatever you do, do not but a repair kit unless you check its contents for sizes (jets etc). I nearly fell into this trap but was put right by the experts on the forum. Link to comment Share on other sites More sharing options...
philhill Posted June 9, 2009 Author Share Posted June 9, 2009 RD 250LC VM26SS (4L100) Main jet=190 Needle jet=O-6 Jet needle=4N10 Needle jet position? idle jet=20 Slide cutout=2 Air screw(turns out=)1½ Float=21 ± 0.5 mm First question 1, no not by yamaha. 2) Yes if jetted properly and not like its original configuration above. 3) Yes if jetted properly, you may be VERY slightly down on power but the smaller carb will increace torque. 4) Yes i think a member called oldgitonabike could be very intrested in a swap. 5) Its the internal venturi diameter, its awquard to check accurately so prob best to trust to the id no for now. Hi, thanks for the responses, this carb has a jet needle 4J13 and then 3or5 but is slightly bent and I think a 150 main jet, the slide cut out is 2, the carb is generally in good condition. I would do a swap if oldgitonabike wants it and has the right one to swap? More torque would also be good if you know where to start with the jetting for the VM22SS, torque is always better than power to my mind which is why my other bike is a Guzzi, when it got really twisty in the Pyrannies my mate on his brand new Tiger couldn't keep up and I left him for dead, and the Triumphs not short of torque! That said I also love the DT when it comes into the powerband and starts screaching !!!! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 9, 2009 Moderator Share Posted June 9, 2009 Hi Phil, I got fixed up and dont need the LC carb now. I do have a good DT175MX carb I might sell though. Link to comment Share on other sites More sharing options...
philhill Posted June 10, 2009 Author Share Posted June 10, 2009 Hi Phil, I got fixed up and dont need the LC carb now. I do have a good DT175MX carb I might sell though. Hi, yep I'm interested, Does anyone want an 250LC carb that just needs correct needle and jets? Phil Link to comment Share on other sites More sharing options...
Moderator Cynic Posted June 11, 2009 Moderator Share Posted June 11, 2009 Hi, yep I'm interested, Does anyone want an 250LC carb that just needs correct needle and jets? Phil Hello..... thank you....... Link to comment Share on other sites More sharing options...
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