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View Full Version : BF 750 Starting issue



slownlow
10-20-2009, 07:38 PM
Ok so here the back ground...

Bought a 05 BF while I was in Iraq. Had a friend look it over for me. Got home a few weeks ago and of course had to go ride. So I took it out to a local park. With all the rain we have had it was all a little deeper then it usually is and I ended up going in a puddle that was a little deeper then I thought. Although not so deep that would have thought water would have come into the intake. I now know this is a common problem. So I brought it home and of course it was hydro locked. Pulled both plugs and put new in. Water got in the oil so I changed it. Still can't get it to start. I have ran out of ideas.

Here's what I have done so far. I pulled the airbox. Found out that the guy before me didn't hook up the crank case vent so I'm guessing that's why I got so much water. There is also a small vent hole in front of that. I have no idea where that is supposed to go. So any help with that would be great. I have pulled the carbs and cleaned them out. Pulled the exhust off because I wasn't sure if it still had water in it.

I know I'm getting a spark. I also know the front carb is getting fuel. I'm not to sure about the back one but if it is I don't think it's getting much.

When I try to start it turns over just doesn't sound like it's firing. If i spray some starter fluid in the front carb it will back fire back up the carb.

I'm lost it shouldn't be this hard so I'm thinking I'm missing something. Or I have a more major problem. Possibly that smaller vacuum in the airbox goes to something that has sucked in water as well and needs to be flushed.

I really don't know so any ideas would be great. Thanks everyone that gives their two cents.

Bwild
10-21-2009, 02:17 PM
Sounds like a bent valve. Have a leakdown test done.The hole in the air box is a drain line. All that goes there is a rubber hose that runs down by the starter.keep us posted

slownlow
10-21-2009, 02:26 PM
Any idea what the compression should be?

Which 450?
11-21-2009, 07:18 AM
compression will be low, I think 80 psi. I will check me service manual monday.