Autonerdz forums

Hi James, what type of two stroke is this? What engine?  Myron

It is a 50cc 2 stroke with a 70cc Big Bore Kit...don't laugh. When it ran, it missed, fouled plugs and was low power.

So, I found the problem, actually 2 problems. I made a rookie mistake and overlooked something based on what the customer told me. He said he recently had the fuel pump replaced so I didn't initially check that. I also didn't go there as the spark plug was fuel fouling. I did get to finally after I was exhausting the other possibilities and it turns out the pressure and volume is way under spec. I am not sure how it ran as good as it did. I also checked the air compressor output and it is also under spec. It was aprox 50 psi on idle instead of 70 to 75 service spec. I think it was fouling plugs in spite of the low pressure as the fuel was probably not atomizing very well in the cylinder and just wetting the plug. Not sure if this will get fixed as the fuel pump alone is almost $600.00 Canadian and is a special low volume, high pressure, low amp design. Thanks for all the help guys, I learned a few things on this one.

James, like you, don't totally understand but would also like to see several operate.

I have no idea but the drop in amp and volts might actually change where the pentil is situated in the bore, just talking out loud here, can't validate it.

The on time is around 6Ms, have no idea what normal is?

Pasted below injectors @ idle on an 03 Dodge Cummins.  #4/5/6 all operate somewhat in concert, and only like this on 03-06.

They are convoluted but showing you this picture as the on and off time spans about 5MS,  and this is @ idle, just for a view of what they might look like, although not a bike like I stated GDI and diesel look very much alike.

For a ruin your whole day, these 3 are attached @ the hip like siamese twins. The fire of say 4, distributes some of it's energy over too say 5 or six, and that is stored there, then when it is excited with it's fire, it now has enough energy to actually complete it's job.

Many diesel techs get a misfire on 4, and when replacing #4 problem does not goe away, as actual problem is also partly because it did not get i'ts inductive kick from it's designated partner 5 or 6, who would have known.

The solution in the trade was they found that if they replaced all 6 injectors the problem went away. All this was brought to light to me in a class as of late, and nobody knew of this in total.  This only applies ot 03-06 and seems to show up no where else. 

On the rest say Ford or International, a miss fire in 4 is a missfire in 4, for what ever reason, electrical, or mechanical, or fuel.

Thought I would drop this in for fun, meaning the light @ the end of the tunnel maybe just somebody looking for survivors. LOL.