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Choke used as cruise control..reduced power.

Discussion in 'Technical and Troubleshooting Torque' started by ol9fingers, Oct 22, 2011.

  1. Hi All,

    My RF900 has lost considerable power. Unfortunately the choke was being used as a cruise control. I pulled the spark plugs out, highly carbonised, put new ones in and it went great for a couple of hundred k's. I changed the oil (which reeked of petrol and the oil filter).The power reduction has now returned. My question is..what else should i be doing besides just changing the spark plugs?

    Hoping to get some help,


  2. strip down and rebuild,
    im no mechanic, but the choke would majorly effect the fuel air mixture, meaning it could be running rich or lean for a considerable time especially with it being used as a cruise control (dumbest thing ive hard of in a while) so everything is probably covered in carbon. the valves are most likely not seated properly and the injectors fouled....

    so id strip it down, clean it, flush all fluids, re-set all the clearances and check tolerances. which considering the age of the engine, doesn't seem like a bad thing to do anyway with-ought this problem.

    BUT I AM NOT MECHANICALLY MINDED, just my thoughts.....
  3. Well how far can you go? It all depends on your knowledge and skill and what you are willing to do.
    The sparkplugs arent the only part that will carbonise. Do a simple compression Check to ensure your exhaust valve is not leaking from a buildup of carbon not allowing it to reseat.
    When you changed the sparkplug, you may have disturbed carbon, causing it to fall into the cyl and subsiquently damaged a ring or the wall.
  4. can be caused by combination of not turning fuel off and sticking floats in carb
    (known issue with DR650's anyway)
  5. @spenaroo - that's a bit extreme. Change the oil, change the plugs. Don't stress about it. Don't do it again.

    @killbot88 - He didn't say it was him who did it! Cut the poor bugger some slack.

    @ol9fingers - You'll be fine. Change the oil and the plugs and don't keep doing it. If you really want cruise control on a motorcycle I can show you how to do it. Hand throttles and throttle locks and friction screws are not the answer. A properly designed, dedicated, cruise control device, suitable for a car or bike is available as an after-market part and simply needs to be installed and set up. Let me know if that's what you want and I'll duck the ball and point you at the SkipperAU, who told me all about it and he can explain it to you.
  6. Errm... sorry? I know he didn't do it. I haven't said anything about that or even had a go at him. My comment about "how far can you go" was in relation to what he is actually able to do. Heaps of people come into the technical area and ask what they can do about x, then after a few large posts from people who research it for them explaining what they can do, the OP comes back and essentually says they don't know what a spanner is.
    I was trying to understand his skill level. Taking the valves out and inspecting would be better than a compression test, but if he can't do a compression test there is no point advising him to take valves out.
  7. Ok - fair call.

    @ol9fingers - about the only other thing would be throw a bottle of injector cleaner / carb cleaner in the fuel tank, or if you feel all mechanical, take out the air filter and spray a sh1tload of carby cleaner down the intake ports, leave for an hour, then replace the filter and start the bike. Or perhaps do one pot at a time, and start for a couple of seconds to get it all into the cylinder. Or get an applicator tube like you get on chain lube or WD40 or something, and take the spark plugs out and spray it down the holes. ... All of which seems a bit over the top. Forget about it. Change the oil and the plugs and don't do it again.
  8. @ spenaroo '(dumbest thing i've hard of in a while)' lol, learn to spell

    Yep, I'll be changing the oil and pulling out the sparks again and checking the fuel filter.

    I drained the float chambers also. I'm reluctant to pull the carbies apart outright. If I take it to a mechanic and ask for a carby tune up, could they diagnose it thoroughly? Anyone know someone who'll take a look?

    Thanks for all the constructive advice.
  9. sad thing is thats after editing (usually post, see a lot of mistakes and proof read it) somehow that one slipped through

    as i said i'm not mechanically minded just thought of what could have caused it with my limited knowledge, nice to see its not as doom and gloom as i thought it would be
  10. Obviosly fuel related problem (duh)
    The power returned when the plugs were replaced & then diminished after a while.
    So the valves & bores should be ok.
    I'd be getting the carbs looked at.
  11. Should I stick another new oil filter in? (changed with the oil last time, 50kms ago)
    Also, can I clean the new plugs?
  12. This is my thought too. You could have gummed up the carbies.

    I'd be stripping those carbies and doing and overhaul.

    Compression check would be wise as a check, but I doubt that is the problem.
  13. No need to change the filter if its near new, even if you have had a bit of fuel in the oil. Any excess fuel in the oil will evaporate off pretty quickly, just keep an eye on the level.

    As others have said, its worth doing a compression check to put your mind at ease re. damaged valves, but it sounds to me like you have a carb issue.