few questions about carbs

jam35 · Post by **jam35** » Thu Feb 06, 2014 10:09 am

Hi all

I know your probably sick to death of carb threads but have searched and searched and cant really find the answer im after

so, i have a 92 1000 exup ru, bike was running rough when i bought it, would idle like crap, clear after 3k, start with no choke whatever the weather so replaced the tubes.

when i stripped and cleaned the carbs it appears to have dynojet needles and 132 main jets. the float height seemed a little high too. put it all back together.

bike still starts and runs rough think the float heights were around 18mm and have since found that they should be 14mm

ive tried syncing with a manometer but is nea impossible to get the levels anywhere near where they need to be.

any one have any ideas if the float height should change with bigger jets?

thanks in advance

Post by **Stig** » Thu Feb 06, 2014 2:02 pm

the fact that you dont need the choke to start it suggests its running rich which may be the toobs. Were your replacement toobs new?
DJ needles are harder than the std items which are alloy. The DJ needles do wear the toobs much quicker partly due to the extra weight of the items against the soft brass

Post by **creedxup** » Thu Feb 06, 2014 7:01 pm

When you synchronise the carbs, don't worry about the values, just get all the heights (vacuums) the same

jam35 · Post by **jam35** » Thu Feb 06, 2014 7:10 pm

tubes are brand new, will take a look at idle screws, i presume that if i spray carb cleaner around them it will have some affect on the running of the engine?, does the float height remain the same regardless of main jet size?

Post by **Stig** » Thu Feb 06, 2014 7:18 pm

float height is the actual height of the fuel in the bowl when the carbs are the correct way up...this equates to 14mm when inverted and setting with the bowls off. The height should be the same irrelevant of jet size. If one of the float heights is wrong it'll make it run rough for the fact it may be starved of fuel on that particular carb...if its too high they'll flood and overflow

jam35 · Post by **jam35** » Thu Feb 06, 2014 7:20 pm

sweet will re adjust float height soon and see how it fairs and report back

itsnotagenesis · Post by **itsnotagenesis** » Sun Feb 09, 2014 3:45 pm

Not sure if I have this right or not as I done a few jobs at once and my problem of starting without the choke was fixed.
One job was the emulsion tubes and the other was the shims/ valve clearances.
Not sure what job fixed the problem.