05-01-2015, 01:48 AM #1
- Join Date
- Apr 2015
STX1100 TWISTED CRANK? Please help
If front two cylinders fire on or close to top dead but rear fires about 10 degrease after top dead, when you place front or middle on firing mark the other to are at the same hight but if you but rear on firing mark front two are not same hight in cylinder. Please help!,
05-03-2015, 05:08 PM #2
the ignition timing for a STX 1100 is : 17° @ 1250 rpm - 27° @ 3000 rpm
I'm not sure of the firing order/angles on this engine, but as you can see from my pics in http://www.greenhulk.net/forums/showthread.php?t=231360 , when the front is at TDC (or close to it), the rear 2 are definitely not at the same height. Its possible that when the centre piston is at TDC, the front on rear could be at the same height, one going up the other going down, but this is a guess based on my pic only.
All my experience has been motorbike related, but if you have a bike with weird firing angles its almost always a sheared woodruff key where the stator/flywheel attaches to the crank, I assume these engines use a similar method. Remember if this happened it would cause all firing angles on all cylinders to be out by the same amount.
05-03-2015, 10:29 PM #3
Well, being a triple it would need to fire every 120*. Which means if you are rotating it the right direction and you mark the PTO each time a piston comes to TDC, you should have marks at 4,8, and 12 o'clock. Now if you crank it with a timing light on each cylinder they should each fire a bit before that mark. I have seen several CDI's over the years with screwed up timing curves which would cause any sort of starting or running issues.
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