7 replies to this topic

[OZMINI]

Seeking advice from anyone who has put together a BMW K1100 head conversion.  I cannot get it to start!!  Brief build details, 1380 16V N/A (BMW throttle bodies) 11.1:1 CR, Australian "Microtech" ECU. 

 

It's not a Specialist Components kit.

 

I have had cams set between 1mm to 2.5mm lift on overlap.  I can fire the spark anywhere from 10 degree BTDC to 10 degree ATDC.  The only other issue is that I have a MED engine management pulley and pick up, which is non-adjustable. 

 

Information from anyone who has built a similar spec conversion would be greatly appreciated.  Matter of fact ANY opinion would be appreciated.

 

 

 

 

[JustSteve]

Backfiring through the carb.. atleast there's ignition

 

 

I'm not completely clued up on these modern electronic crap, but how do you set the ECU up for the fueling? I reckon it's running lean judging by the sound and backfiring through the carb. 

 

 

I don't think it's the ignition timing, im pretty sure too advance= engine trying to run backwards. too retarded=popping in the exhaust. I know there's no dizzy, but you could have it 180* out(wrong plug order)? 

 

 

After that it's only really going to be cam timing that's an issue.

[johnnyblaze]

i say timing , well thats what id say if it was a carbed car, sounds like its trying to start

[Frisco]

Yep timing

[mini13]

check the firing order, I know the k1100 is different to a normal mini, iirc you need 1243 rather than the usual 1342

[OZMINI]

Thanks for your input.  What has come up is the wrong tooth off on the trigger wheel.  Even though "Mircotech" advised taking the tooth out at 60 degrees before TDC (at the pick up)  That is, TDC the motor, turn it back (anti-clockwise) 60 degrees and take the tooth out that is under the pick up.  But,  everything I'm reading about trigger wheels and 4 cyclinders suggests taking the tooth out between 90-120 degrees. 

 

Any advice on trigger wheel set ups?

 

Firing order is diffinately 1243.

[mini13]

A lot of systems do use a 90 degree trigger angle, but usually there is a trim functiion that will allow you to get it bang on so the spark is xactly where the map says it should be.

 

have you checked the timing at cranking with a strobe? also be aware that if you are using an electronic strobe with the buttons on a wasted spark system they usually read double.

 

If spark is in the right kind of place (15deg btdc) and its poping back I would say its lean,

 

also from my dablings with the K convesions you want to be aiming for about 2mm overlap at tdc, maybe a bit more, but it should still run.

[OZMINI]

Thanks for the replys.  I'll let you know what the problem is, if and when I find it.