hi there
i have a used 91' cbr 400 nc29 engine i am using in my off road buggy, i bought a new wiring loom but not 100% sure if i have wired the LT leads to the right places on the coil packs i have turned the engine over and it almost starts but back fires and wont run properly or on its own power without the starter motor

also the fuel pump doesnt work but have a funnel connected direct to the fuel junction on the carbs

i know which leads are which as i have the diagram of the loom and have them numbered 1-4 i just dont know where to connect them on the coils?

if you have any other tips for starting an old engine that has been in storage it'd help

any help would be apreciated

 

If it's the same as the 600 it's a waste spark system with two coils. The LH side coil fires cylinders 1&4 and the RH coil fires cylinders 2&3. Number one cylinder should be the left side and 4 the right side. The positioning of the two wires on the coil isn't important as long as they're routed to the correct spot as the coils fire both plugs at the same time.

Also may need the carburetors taken apart and cleaned if it's been sitting for a long time with fuel in the bowls.

 

thanks for the quick reply, today i done a compression test on it turns out one of the cylinders is at 70psi the rest are at 120psi...would this be enough to call it a dead engine? still have the reciept for it but its miles away!

 

Yeah thats pretty low. 120 is maybe bare minumum. 70 is toast. How is the oil? Might be worth squirting some oil in the plug holes and seeing if that brings the compression back up. If it doesn't, might just be tight valves, which is not a difficult thing to do.

 

It doesn't look good from those compression numbers, but I would also suggest checking it again with oil in the cylinders. If the one low cylinder doesn't improve much I would be looking for a valve adjustment problem or a burnt/bent valve. Might be worth getting your money back if it was sold as a good running engine.

 

tried a wet compression test today and the numbers shot up to 120psi so it must be the rings or the bores.

he told me it was taken from a running bike, i will have to take it back and either get another or my money back. another 60euro in petrol and a day wasted!

think ill be testing the next one on site

 

Yup. My money is on bad rings. Not a inexpensive fix either, with the rings and gasket kits costing a pretty penny. Sorry man... Hopefully you get all your cash back