Heeeelp!!!! Just in the process of trying to dial in some carbs off a 1978 XS400.
So carbs have been cleaned inside and out, vapour blasted & compressed air through passages.
Running pods and shorty type free flowing mufflers. Pods are attached to the stock plastic pipes that the original air filters go in to, so they are not directly on the carbs.
Carbs synced with manometer.
Valve clearances, point gaps and timing done.
Plus don't look lean.
New mixture screws, turned out 2 turns.
Needle clips raised one notch towards pointy end.
Main jets were: 142.5, now running 150
Pilot jets were: 42.5, now running 47.5
Idles well maybe a tad high, around 1800 rpm, I would prefer around 1500rpm. Theres no hestitation on take off at all.
It runs really good up until around the higher rpm where it just doesn't rev any higher.
In 3rd gear it revs out to 8000 rpm real nice then no higher. In 4th gets to about 7500 rpm and in 5th gear it gets to about 7200 rpm. So as you go through the gears the point where it revs up to progressively gets lower.
Other than the higher rpm's as mentioned its running great. Not sure if my main jet is too big or too small?
Fuel seems to be flowing ok. Correct sprockets for that year are on. The back sprocket is a 38.
Could coils be faulty? Sorry I know this topic has been thrashed to death nut I did reads heaps and heaps of threads first
So carbs have been cleaned inside and out, vapour blasted & compressed air through passages.
Running pods and shorty type free flowing mufflers. Pods are attached to the stock plastic pipes that the original air filters go in to, so they are not directly on the carbs.
Carbs synced with manometer.
Valve clearances, point gaps and timing done.
Plus don't look lean.
New mixture screws, turned out 2 turns.
Needle clips raised one notch towards pointy end.
Main jets were: 142.5, now running 150
Pilot jets were: 42.5, now running 47.5
Idles well maybe a tad high, around 1800 rpm, I would prefer around 1500rpm. Theres no hestitation on take off at all.
It runs really good up until around the higher rpm where it just doesn't rev any higher.
In 3rd gear it revs out to 8000 rpm real nice then no higher. In 4th gets to about 7500 rpm and in 5th gear it gets to about 7200 rpm. So as you go through the gears the point where it revs up to progressively gets lower.
Other than the higher rpm's as mentioned its running great. Not sure if my main jet is too big or too small?
Fuel seems to be flowing ok. Correct sprockets for that year are on. The back sprocket is a 38.
Could coils be faulty? Sorry I know this topic has been thrashed to death nut I did reads heaps and heaps of threads first
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