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20 Posts
I would be grateful if i was offered some advice on this 5 month long problem.
I bought a crash damaged 1998 yzfr600r. Instead of replacing all panels i turned it into a street fighter. The only engine modification was to reconstruct the exhaust, (same internal design but slightly shorter) and removed the ram air ducts (which i imagine mostly comes into play when racing around). The existing vent for the carbs that used to connect to the ram air ducts terminates to open air.
It runs fine in the garage, revs as much as you want... perfect. When Starting to drive from a warm Idle, it initially accelerates quite well up to a few 1000 revs for the first few seconds, but having done so, it hangs for many seconds at about 3000rpm until i stop the bike, or leave the throttle long enough for the idle to come down to 1,100rpm. If i try to accelerate while it is hanging (reving high) its hopeless and hesitates so badly that it feels like it does not want to move forward. This happens until i stop the bike again. Its a continuous cycle.
I had the carbs professionally cleaned (ultrasonically?), changed the jets, the needles, the carb boots. Checked the float heights (fuel level 11 or 12mm below the mark), the diaphram, the sliders, the rubber seal. All carbs are syncronised. I tried to look for a vacumn leak... and even with the new boots i found one but think i managed to get rid of that problem by over-tightening them. But i still have this problem. Is it possible to have a vacumn leak from the shaft of the butterflies?
My mechanic could not figure it out and got fed up of me!
Help ???
I bought a crash damaged 1998 yzfr600r. Instead of replacing all panels i turned it into a street fighter. The only engine modification was to reconstruct the exhaust, (same internal design but slightly shorter) and removed the ram air ducts (which i imagine mostly comes into play when racing around). The existing vent for the carbs that used to connect to the ram air ducts terminates to open air.
It runs fine in the garage, revs as much as you want... perfect. When Starting to drive from a warm Idle, it initially accelerates quite well up to a few 1000 revs for the first few seconds, but having done so, it hangs for many seconds at about 3000rpm until i stop the bike, or leave the throttle long enough for the idle to come down to 1,100rpm. If i try to accelerate while it is hanging (reving high) its hopeless and hesitates so badly that it feels like it does not want to move forward. This happens until i stop the bike again. Its a continuous cycle.
I had the carbs professionally cleaned (ultrasonically?), changed the jets, the needles, the carb boots. Checked the float heights (fuel level 11 or 12mm below the mark), the diaphram, the sliders, the rubber seal. All carbs are syncronised. I tried to look for a vacumn leak... and even with the new boots i found one but think i managed to get rid of that problem by over-tightening them. But i still have this problem. Is it possible to have a vacumn leak from the shaft of the butterflies?
My mechanic could not figure it out and got fed up of me!
Help ???