Vintage Dirt Bike Q & A

hi, me dt 175 mx yam uk bike (1979)carb problem? on tick over 1500 rpm engine speed drops cuts out so i start it up ajust idel speed then its to fast i do the same again ajust down seems ok then drops ,cuts out its a pain carbs been cleaned. ???

Sounds like a fuel issue. A thorough disassembly and cleaning of the carb, blowing out all the circuits with compressed air, with attention to the float needle and float height, when putting it back together, is a good start. Check you petcock as well. If I'm not mistaken you have the screen in the tank on the petcock inlet. Restricted fuel flow there could be a problem as well. An improperly venting fuel cap is another possibility. You should have a CDI ignition (MX175F for '79?), and the base plate should only fit in one position on your bike, so ignition doesn't sound like a likely problem. An exhaust restriction is also a possibility, according to the Clymer manual.

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Steve Amling

1976 CR 250M
1980 Yamaha DT100G
1980 XR 200
1981 CSR650

thanx m8, just done all that +blow back in 2tank vent, had some new reeds so fitted em.runs alot beter tick over good just been out on it( cut out once) fine tune it soon . it seems a littel harder 2 start than b 4 (winter here -5 may be that ?)


m-xmas phill.