The 76 MC5 400 Penton that I just picked up has a Dell Orto 38MM carb on it. I'm disassembling and cleaning it and it looks good, but the bike acted like it ran out of gas both times I rode it for less than a minute, although it ran good up until that point, then acted like it ran out of gas, and since it sat for a while I thought maybe the float was gummed up. A new spark plug acted the same way. Does anyone have any experience or opinions about the Dell Orto carb, or should I just be putting a bing back on it?
It has a unique air boot in good shape, so it would be easier just to put it back on if opinions are favorable. Mike
Mike,
Is the fuel tank vent working? Maybe try riding around with the cap loose and see what it does? Odd it would run fine then starve for gas. Just a thought.
Bob, it's got a very nice plastic tank on it that is similar to a Clarke tank with a vent hose and a wide open vent. The fuel petcock flows freely. The carbs got a slightly different style choke without a tickler, so I would lean the bike over to overfill the fuel bowl when starting it, so I thought it might have just ran the fuel bowl dry then died. The needle has a rubber tip on it so I do need to order a new one.
Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
For what it's worth, I once had a 77 400 that would suck the float bowl dry on a long WFO straightaway...seems like we fiddled with the float bowl level to give it more fuel.
Steve Minor
I'm almost certain it's all just lack of fuel since the float level look to be low and the needle valve rubber tip questionable. I ordered a gasket set a needle and seat and a couple smaller pilot Jets today and have to wait for UK delivery. The only reason I ordered a couple different smaller pilot Jets is the previous owner said it ran great but it was a little rich on the low end. He raced it at Unadilla and Mid Ohio. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
I got the carb kit from Eurocarb in the UK within 9 to 10 days, which I think is great. I replaced all the gaskets and seals, the needle valve and seat and set the float a little higher, and changed the Pilot down from 60 to 58, per the previous owners comment about the low speed being a little rich. Once the carb was back on the bike it started with the choke on and after a short one minute warm up, the bike ran great pulled strong, and did not miss, falter or die. The idle mixture screw is now at 1-1/2-2 turns versus the 4-1/2 turns it was at previously. Thanks everyone for all of your comments and suggestions. Mike