Over the last few weeks my ST1300 ('08)
was finding it hard to wake up, both morning and evening. The bike would start, but idle was very rough or it would stall. Once it warmed up a little idle was 1000 rpm
+100. Good as gold once the gates opened.
I read everything I could find on the internet and the service manual. It all pointed to syncing the starter valves.
I don't own a manometer and I can't justify the price of buying one. I do however have 10 metres of clear tube, blue food colouring and water.
The manual says valve 1 (the non adjustable one) has a vacuum of 20 mm hg. Back of the envelope calculations I need ~300 mm H2O have the same reading. I used a 2 metre stick a meter rule and set up a simple vacuum gauge. This isn't the first time I've made one of these. It was the full length of the stick.
I found the five way valve and followed multiple sets of instructions on recording the vacuum.
But this is where my problems started. To "calibrate" my gauge I connected it to valve 1 with the bike running at 1000 rpm. I maxed the gauge and needed to disconnect before sucking the water into the valve. Valve 3 (the one next to valve 1) was the same. It's very quick, I ran out of tube before it looked like slowing down. Putting my finger over the tube it sucks my skin in and leaves a red mark. My calculations put this suction at ~150mmhg+.
Does anyone have an idea on what could be wrong? Is this normal even though it doesnt agree with the calculations? I think my gauge setup is true, but I can't explain the crazy high readings.
Thank you in advance,
Bernard.