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91 CBR250RR wont start; history of faulty vacuum pump and high idle

Discussion in 'Technical and Troubleshooting Torque' started by NoFearNick, Jul 3, 2011.

  1. Howdy all,
    I recently purchased a 1991 Honda CBR250RR with 46,000km from a dealership here in Sydney, since I bought it has been having problems (I've got another thread discussing DFT options, etc) and I thought I'd look at doing some work on it myself.

    First ride home, bike stalled and wouldn't start (faulty battery) - dealer replaced and delivered it the next day. I rode it that same day after they returned it and the engine cut out again after about 20 minutes of riding, left it for 5 minutes and started again. This process was repeated several times and eventually the bike shop I bought it from came, picked it up and repaired the vacuum pump (which apparently had a leak in the hose).

    It worked fine for a week or so, then the same problem started occurring again; after 20 minutes or so of riding the engine would idle very high and when taking off from the lights would need higher revs than normal or the engine would stall. Also the engine would occasionally just completely lose power and I'd have to pull over to the side of road and no amount of playing with the throttle, choke and starter would get it going - I'd usually have to wait several minutes.

    After riding home one day the bike would not start and it's presently in this condition; I turn the starter and it doesn't make the usual noise (of trying to start), even playing with the throttle doesn't change the note of the engine (as it usually would when working). Rolling starting it doesn't do anything and it's been in this state for a couple of weeks, the bike shop refuses to look at it so I'm planning on trying to fix it myself.

    So far we have opened it up and changed the spark plugs but that hasn't done anything. The bike had a minor service completed at the dealership prior to being sold to me (oil/air filters, oil change, spark plugs, carbies cleaned, etc). I'm just wondering if anyone has had a similar experience with their bike and knows what the potential problem could be?