Topic: 750K4 Not Starting After 2 Months Sitting

[Analysis]

Hi guys,

back in September I was riding my bike no problem - I did a complete overhaul on electronics, engine, carbs, etc. and everything was running fine - I put on around 800 km after the rebuild with zero problems. I went away for a few months and now it won't start. When I try starting it, it turns over fine but doesn't start. If it pull the throttle a bit while pushing the start button I eventually get a very loud backfire. I took the bowls off and they are all getting fuel, I redid the timing and changed the fuel. I'm about to check to make sure each plug is arcing (though they are brand new and the bike was stored in a garage). It must be the carbs? I don't have a carb sync readily available (bit of a hassle to get a hold of one again) so I'm hoping it is something else. Any ideas?

I should also note that the temperature dropped about 20 degrees since the last time she was running so maybe something about the cold weather?

Thanks!

[MoMo]

Make sure the spark advance is not frozen/seized...Larry

[Gordon]

It's very easy to flood an old sohc4 that hasn't been started in a while, even if it's otherwise in good condition.  The plugs get soaked quickly if it doesn't start right away and won't spark under compression.  Take them out, clean and dry them off, and try again.  Also, make sure the battery is fully charged.

[BeSeeingYou]

It's very easy to flood an old sohc4 that hasn't been started in a while, even if it's otherwise in good condition.  The plugs get soaked quickly if it doesn't start right away and won't spark under compression.  Take them out, clean and dry them off, and try again.  Also, make sure the battery is fully charged.

+1  don't be pulling on your throttle.  Be master of your domain.

[Analysis]

It's very easy to flood an old sohc4 that hasn't been started in a while, even if it's otherwise in good condition.  The plugs get soaked quickly if it doesn't start right away and won't spark under compression.  Take them out, clean and dry them off, and try again.  Also, make sure the battery is fully charged.

Thanks Gordon and Larry. The temperature is around 5 degrees Celsius right now. I took the spark plugs out and cleaned them and tested them for spark and found no problems. After putting them back in, I have nearly the same response though this time it sounds a bit better.

[petercb750]

Old fuel gumming up the jets? - it happens............
My bike can sit for several weeks between starts, and can be a pain...and as Gordon said, they are easy to flood. But one thing I do that seems to help is turn the fuel on, go inside and have a coffee, put the riding gear on, and then try to start it - weird, but it sure helps (on both the 750 and 400).

[Analysis]

I think that if I can't get it going I'm just going to take the carbs off and clean them out - kinda annoying as I cleaned them 3 months ago.

[Gordon]

Since this bike is relatively new to you, or at least newly rebuilt, it may be as simple as not knowing exactly what the bike needs to start in various temperatures.  What is the start-up routine and throttle/choke settings you're currently using? 

[Analysis]

Startup rountine involves me turning on the fuel, shaking the bike a bit to let the fuel move around and then I put the choke on and just hold down the button for around 3-5 seconds and then take a ltitle break. repeat the button and break. I haven't touched anything in regards to fuel mixture or throttle since the warmer weather.

[Analysis]

I just redid the timing and it didn't change anything.