MoTeC Global Forum

I'm using the m4 with a yamaha genesis 80fi. This is a 2 cylinder engine. I followed the guidelines regarding setting the crip, however it runs on one cylinder only. If I decrease the crip by 180 degrees, it runs on the other cylinder. I'm very new to the motec software and I'm wondering if there is a simple setting that I'm overlooking. Any help is much appreciated.

Is this the Paralell twin engine from the TDM?
If it is I think it may be oddfire but can't remember for sure. would be worth checking though.

it is a inline two cylinder.

Are you sure it is an even fire engine? If you can change the CRIP by 180 degrees and get the other cylinder firing it sounds like it is odd fire. I have seen a two cylinder, four stroke engine before that had both cylinders fire in one revolution and then nothing for the next revolution, this is odd fire and you would need to enter the odd fire TDCs into the ECU to make it work.

Pull the cam cover off and check the engines cycle first.

i have done this. i used a degree wheel to verify that the #2 cylinder intake valves close 180 degrees after the #1 cylinder. so in the m4, i went into the oddfire tdc's and entered: 0, 180. then i went into the firing order and entered: 1, 2. it still only runs on one cylinder. i pulled the spark plugs and coils (coil on plug) and verified that when i'm cranking, both spark plugs fire sequentially. the motec is setup for sequential. i don't get it! what am i missing here?

How have you determined your CRIP? I would say that you have started with a CRIP that is 360 degrees out. An in line 2 cylinder engine with 180 degree crank pins is actually an oddfire engine with TDCs at 0 and 180 degrees. If you have worked out your CRIP 360 degrees out the engine will not fire unless you correct the timing or CRIP to get a cylinder working. Then changing the CRIP by 180 degrees may get the other cylinder working. So it is possible that you are out by 540 degrees (not 180 degrees) with the CRIP.

What ref/sync mode are you using and how have you calculated the CRIP?

we calculated the CRip with a timing light. the pickup was placed on the #1 coil. we then went into the CRip setting interface, where you can set a test advance and change the CRip value. using the timing light and the timing marks on the crank, we cranked the motor over until our CRip was set so that the timing was on the TDC mark. the CRip ended up being 384 degrees. we then set the odd fire TDC's to 0, 180. i did notice something yesterday when i was getting ready to leave school: both fuel injectors squirt at exactly the same time.

boostein wrote:i have done this. i used a degree wheel to verify that the #2 cylinder intake valves close 180 degrees after the #1 cylinder.

Crank shaft angle or cam shaft angle?

I was a Yamaha XS-500 owner in late 70'. It was twin inline engine but not the same way like Triumph twins. When one piston was on the top the other was on the bottom. That means that you have ignition on 0 and 180 deg of first crank rotation and no ignition during second rotation. Engine looks like first two cylinders of four cylinders engine. Triumph style twins looks like four cylinders engine without first and fourth cylinder.

that's exactly what it is. odd fire tdc's are 0 and 180. just can't figure out why it won't run on two cylinders.

Did you try with TDC odd 0 and 540 or maybe first cylinder on 180 and second 0 deg?