Blocked Carb

[mpower]

Hi,

The bike is a '03 gas gas pro 280 with a dellorto carb. For a while now I'm suffering with the fuel pilot jet blocking, to start with I was getting hunting revs then would clear with a blast so a fuel filter was added.

Now I'm having trouble starting from cold unless I blow out this jet, you can see through the centre that it's blocking, once running it's ok now. What would be the process to find and eliminate what's causing this to block up?

No signs of contaminants in float bowl or lines.

Thanks in advance

[mcman56]

A little water can do this and be very hard to see or find in the system. I have seen a little drop stuck in a pilot jet. On one bike I drained and air dryed the entire system but still had the problem. Finally a can of dry gas cleared the water. Dry gas has differferent names but is basically alcohol that would absorb the water and help pass it through the system. However, if you have ethanol in your gas it would probably be self clearing.

[laser1]

+1 on above. Also, Check that the carb gas inlet banjo filter (round mesh disk on side of PHBL carb body) isnt dirty (or missing). Also, make sure your air filter boot is correctly seated all the way around the carb air inlet. The Dellorto PHBL is not known for clogging, so it must be trapped water or ALOT of dirt is getting in. (Im assuming the air filter is cleaned and oiled)

If you have a VHST (came on some early 03's and easy to clog) then you need to keep the air filter very clean and use a good fuel filter and clean the pilot every 10 hrs or so.