suicide bobb
XS400 Member
My bike has been plagued with issues for the longest time. Just got the most recent issue fixed by my mechanic, and now these issues present themselves.
In short, my bike feels like it's missing about half of its horsepower. Giving it throttle from idle, the throttle bogs for a good second before picking up, then slows its climb above 6k. It feels much of the same in operation, and improves slightly as it warms up. When cold, it basically requires a 3k rpm clutch roll-on to get going, and barely any pre-launch throttle after it's warm. When rolling, the throttle response feels great at around 1/4 throttle, but non-existent when you give it any more gas. Full throttle is almost completely useless as it provides so little gain over 1/4 throttle. As a result, the bike is usable around town but a turtle on the freeway. I am lucky to reach 55mph on the speedo (roughly 70-75mph). I remember reaching around 100mph once when I rode it last year.
Mechanic said the bike is completely in factory spec. The carbs are "spotless", valves adjusted properly, spark plugs gapped between suggested range, and timing set correctly. I also eliminated the gas tank/petcock as the source issue by using a waterbottle of gas directly into the carbs (no change in throttle response). He replaced the entire electrical system to cure the previous issue, essentially pulling it all off a parts bike that ran well but was bent up beyond repair. I'm at a loss as to what else could be causing this. Anyone have any clue what to check next?
In short, my bike feels like it's missing about half of its horsepower. Giving it throttle from idle, the throttle bogs for a good second before picking up, then slows its climb above 6k. It feels much of the same in operation, and improves slightly as it warms up. When cold, it basically requires a 3k rpm clutch roll-on to get going, and barely any pre-launch throttle after it's warm. When rolling, the throttle response feels great at around 1/4 throttle, but non-existent when you give it any more gas. Full throttle is almost completely useless as it provides so little gain over 1/4 throttle. As a result, the bike is usable around town but a turtle on the freeway. I am lucky to reach 55mph on the speedo (roughly 70-75mph). I remember reaching around 100mph once when I rode it last year.
Mechanic said the bike is completely in factory spec. The carbs are "spotless", valves adjusted properly, spark plugs gapped between suggested range, and timing set correctly. I also eliminated the gas tank/petcock as the source issue by using a waterbottle of gas directly into the carbs (no change in throttle response). He replaced the entire electrical system to cure the previous issue, essentially pulling it all off a parts bike that ran well but was bent up beyond repair. I'm at a loss as to what else could be causing this. Anyone have any clue what to check next?