Hope someone can help me to get an idea of my problem

Hope someone can help me to get an idea of my problem.

When I accelerate there is a power loose at beginning to about 3 RPM, after that power increasing to normal and all works ok.

What can cause that, maybe someone had same issue out there?

It is clear that it looses power because of too much air - but can not find where it comes from. There should be another reason of such behavior, but I have no idea.

Other idea is that carb air valves opens too much at beginning - but is there any adjustment of that? When I disassembled I not touched valves, and carbs are syncked and vacuum is ok.

Other idea is that fuel leaks somewhere, but in this case why after 3K RPM throttle works good as supposed.

Recently I cleaned my carbs disassembling them, replaced parts with standard kit. All is set back,all works fine, idle speed, starting works like a charm.

I verified carb. fuel level, fuel hoses, pump, new air filter, new fuel filter, engine valve clearance, throttle sensor (on carb), carbs. syncked (vacuum is ok)...

I am out of any ideas, any idea is much appreciated.

18 comments
  • The same problem I am having. I've done the same as you. Runs fine for about a month.

    Spoke to a mate today who says the problem must be in side the tank. Fine particles breaking off maybe. He suggested emptying the tank and using a tank flush.

    Also, put a small hand full of new clean nuts in there to. Give it a good rattle to agitate any rubbish from inside.

    It's what I might try.

  • Thats a bit strange. Usually Bulldog had whole in power between 3-4k rpm but thats natural amd could be updated. My idea is it pump giving correct pressure?

  • Thanks Neil Hulse, that something new to try.

  • Yes, last year it was all ok, BT goes like electrocar )) full power from 0 to 4 rpm with no any problems and gaps that why this power loss is very annoying and noticible.

    I verified fuel pump, it operates and pumps the fuel, but how to check if it hss the correct pressure?

  • Pump fuel are verified usually that you will start on for let say a minute and you are collecting fuel and in the end you should get some number let say 400ml per min. But what is correct for Bulldog I dont know. I am not sure if this number even exict for this model. My idea what about to ask somebody for swaping parts? First fuel pump, then carbs...etc.

  • Sasha this might help...

    http://www.keihincarbs.com/tip s/gate.html

    I recently tuned my carbs because I was losing power/misfiring when at neutral throttle at 5-6k rpm, and this little guide helped me.

  • Thanks David Reynolds will read that and try.

  • Sounds nice! I did not found such test in manual, there was only a way to check the electrical part if fuel pump. But worth of trying in this way.

    There are not too much BT in my country (( I know only one person, very rare model here.

  • Perhaps it may seem irrelevant, however, I shall post it:

    Prior to Bulldog, I used to own a Suzuki XF 650 Freewind, for 7 1/2 years (great bike - i loved it!). When the engine began to...hesitate (!) or even stall, repeatedly, the reason was NOT the fuel system or the carburetion. The rectifier/regulator was to blame...

    I am not suggesting this is the problem, but, simply see to it.

    Here, it is No18 in the picture.

    http://www.manualslib.com/manu al/910785/Yamaha-2005-Bt1100.h tml?page=56#manual

  • Bulldog is rare almost everywhere! On the other hand, we are riding a...unique bike! :)

  • Thanks, any suggestion is good, checking is always a good idea.

  • Check the Spark plug gaps too.. when its small ,can give this simptoms.. must be above 0,7-0,8 mm

  • Thanks Dobó Tibor, I not checked that yet, so I am going to...

  • Good tips from everyone.

    Nice to see so much advice.

  • Thanks to all for all replies, really helps when you think you can do nothing more. Will post results for sure for all who will search something similar in the feature.

  • Keep us posted.

  • Unfortunetly did not found the cause of issue yet.

    Checked spark gaps, all normal.