pipal1000

HOORAY IT NOW RUNS FINE !!! You guys are right on the button, it is a Delorto PHBH carb. Spent a pleasant afternoon on the patio furniture methodically stripping the carb .Had to argue this with the wife and explained I needed good light to do this work and the garage just isn't bright enough, that worked so I sat in the sun and got down to business. Unbeknown to me, seems this carb has 2 pilot jets. One is easily seen and unscrews, the other is behind this one right up inside the carb. The previous owner has obviously had a go at getting it this jet out and broke one half of the screw head off. So my only option was, in one way or another, to get it out. I opted to bang a sharpened flat blade screwdriver into it and with use of WD40 and by being very careful I got it out. Guess what I did then...... yeah... I gave it a blast. This little pilot jet seems to feed straight up into the main venturi and also branches off to a 'sloping' hole in the main venturi. I'm guessing but I bet there was a bit of swarf caught up and I've now got it out. Anyway after a most enjoyable carb blast I used a needle file to cut a slot into the wrecked jet and screwed it back in gently. I reassembled the carb and hey presto one running Cota 315R. I will order a new jet and replace it. My thanks to all you guys and I feel I have now joined the ranks of Delorto PHBH experts. By the way if you got a carb problem.... give it a blast.

I'm sure it's a delorto and have checked the owners manual and this small air filter is called a sub filter. It connects to a small spigot on the r/h side of the carb. Its about the same size circle as a 2p piece and about 25mm thick. It mounts to the frame on a rubber bush just next to the rear brake fluid reservoir. Ihave washed and oiled this and it seems to be clear. I do appreciate your help so will get the carb off again tomorrow and check the names/numbers on it. As you can image, I can now get the carb off in the dark with one hand tied behind my back. Whilst the carbs off I might even give it another blast. Cheers guys, keep the ideas coming.

It's the standard Delorto carb. I can see light through the pilot jet hole so assume it's OK. However, this is another job that will be done tomorrow. Thanks. I'm getting desperate so will try anything.......... well almost!!

Fellas - Tks V much. Have checked for possible trapped fuel pipe (again and again!!), have stripped carb to single items, used almost a full tin of carb cleaner and a high pressure air line. Have blasted every hole in the carb. Have checked and adjusted float heights, have blasted the carb. Have cleaned air filter and the little additional air filter and re oiled, have blasted the carb. Have adjusted the air mixture screw and tick over screw and blasted the carb. ave put in a new spark plug. Finally I blasted the carb. No change!!!!!. The bike just won't seem to run at low revs or tick over. Its like the whole of the lower rev range is a massive flat spot. I can keep the bike running by keeping the revs up and mechanically it sounds fine. Did I mentioned I blasted the carb. Have given up for today........not beaten, just recharging the enthusiasam batteries for tomorrow. Any other thoughts or ideas would be much appreciated............ should I blast the carb again???

I hope sombody can help me as this probelm is driving me mad !! Have just bought a 2001 315R Cota. Ths bike starts and runs on choke and revs up and settles down fine. When I turn the choke off this seems to starve the bike of fuel (I think?). If I don't touch the throttle the bike runs for a about 15 seconds then the revs climb and it just dies. I reckon this is fuel starvation and the revs are rising as the mixture gets weaker. I have had the carb apart, blown carb cleaner through all the holes and jets that I can see, have taken all the jets out and cleaned them. I also thought it might be an air leak so took of the carb stub and reed valve block. Have visually looked it over and checked the gaskets and applied gasket sealent to the faces and re assembeld (again!!). The last owner tells me that the bike has had a rebore and new piston and compression on the kick start seems fine. You guys seems to have answers for all types of weird and wonderful probelms and I hope somebody can help me here. Have just read on another link that the bike must have a BR6ES spark plug some am off now to check that and take the bl**dy carb off again...aaarrrgggghhhhh.