Hey guys,

Well just some background. Full ninja 300 swap for my old 1990 pregen. It came with full harness and ecu, etc. Only problem I had to deal with is the fuel pump and regulator, which I solved it with one of ecotrons pumps and regulators.

I finally got everything together and ready to start and all it does is cranks. I did hear some noise at key on but it wasnt the pump. It was the sub throttle adjusting itself. Which sounds a bit odd..... It moves a bit and settles back.

But I took a multimeter to test to see if I was getting any power to the fuel pump at key on but nothing. The bike is showing a check engine light but since it has to deal with the fuel injection system it doesnt throw a code for me to check.

Only thing I can think of is a faulty Tilt sensor, or because I am missing the kick stand sensor. Any ideas? If I unplug the Tilt sensor will it not start if thats missing?

Also is the sub throttle moving and making noise normal?

I have no idea, but I guess that the tilt sensor should unable the sparks.
Did you check those?
I also believe that the tilt sensor is a normally open switch, but again, I am not familiar with the 300.

I have no idea, but I guess that the tilt sensor should unable the sparks.
Did you check those?
I also believe that the tilt sensor is a normally open switch, but again, I am not familiar with the 300.

yeah from what i read it disables the spark, fuel pump and injectors. But as of now I only know the pump isnt getting power. So I can assume the same with the others.

For the newgen bikes is the kick stand need to be plugged in? I took my kickstand off but i have the switch if i need to attach that back on. Thought if it was off it wouldnt need to be plugged in

.............For the newgen bikes is the kick stand need to be plugged in? I took my kickstand off but i have the switch if i need to attach that back on. Thought if it was off it wouldnt need to be plugged in

Check this article out:
http://faq.ninja250.org/wiki/Understanding/troubleshooting_the_safety_switches

Check this article out:
http://faq.ninja250.org/wiki/Understanding/troubleshooting_the_safety_switches

Thank you so if anything the sidestand is needed or needs to be grounded. Thank you. Ill ground it and see if it fixes anything. :D

Thank you so if anything the sidestand is needed or needs to be grounded. Thank you. Ill ground it and see if it fixes anything. :D

You are welcome :)

Please, let us know the results; what you are doing is very interesting.

You are welcome :)

Please, let us know the results; what you are doing is very interesting.

Well the kickstand switch wasnt the issue. I grounded that so it would assume the kickstand is up. That didnt fix anything.

From looking over the service manual, seems like if the down sensor is bad or thinks its on its side it wont run the fuel pump or anything. Just crank and flash the check engine like. Just like what it is doing.

So my question now is do I have to buy a new down sensor or anyways I can trick the ecu to run like it was there. Otherwise ill probably have to buy a new sensor since I know I dropped it once and I knew it would bite me in the butt......

Did you jump 12v to the pump to be sure it runs?

Did you jump 12v to the pump to be sure it runs?

yea i did that. The pump runs. I confirmed last night that injector 2 and fuel pump no power at all with key on. Supposed to have power for 3 seconds.

I need to take the tank off and find the down sensor and see if thats the one at fault

The vehicle down sensor was faulty. Need to get another one before i can see if anything else was wrong. So ill keep this thread posted

Glad you got that sorted :thumbup:

Well an update. I got a friends vehicle down sensor and swapped them and still didnt fix the problem.

Looked at a few forums about issues with other kawi's with this issue and came to one that might fit. There were only two things that I rewired to work for the motor swap. The pump and the ignition switch. My switch is from 1990 and I dont think it has that resistor the newer bikes have/need to run.

I read that the kawi bikes need 6 volts to come from the grey wire for the bike to run. Can anyone confirm this? I checked the bike today and was getting a full 12V coming from the battery and going to the ignition, which I read is wrong.

If anyone can please chime in that would be great. If not ill go get a 100 ohm resistor 1/2W from radioshack and solder it in the wire.

Well as an update:

All Kawasaki models that have digital fuel injection need 6-9 volts coming from the ignition switch (grey wire) so I sorted that out with two 100 ohm 1/2 watt resistors. I got the pump to turn on and run, spark was present but could not gauge how much since my battery went dead. I found out because the gauge was turning on and off on my while i was cranking the engine. But no check engine flashing. So hoping after a fully charged battery it will run.

Well as an update:

All Kawasaki models that have digital fuel injection need 6-9 volts coming from the ignition switch (grey wire) so I sorted that out with two 100 ohm 1/2 watt resistors..........

:thumbup: :thumbup: :thumbup:

Last update. Got everything running with the battery charged. Its running but havent tested it on the streets bc of the weather but looks sound to run strong. Only thing that isnt oem on the bike is the fuel pump i got from ecotrons and seems to be working very well. Happy with the swap and how easy it was.

Any more updates on this or more details on the swap? I would be curious how everything fits under the stock bodywork and/or mounting issues you encountered

Any more updates on this or more details on the swap? I would be curious how everything fits under the stock bodywork and/or mounting issues you encountered


I did a swap with 300 engine and got the wiring harness with it plus ecu, and the stock header. Everything was just modified to fit around everything but only thing that really needed modifying was the front mounts needed to be 1/4 inch wider on each side (kept pregen radiator). And shorted the end of the header since the pregen is a bit slimmer than the 300. It fits under stock bodywork, only a bit bigger than the pregen motor. Works fine, put over 3k miles on it since the swap.

And the pump from Ecotrons worked fantastic.

I have a few more questions.

Would you do it again?

Did it gain any weight?

Was it a night and day difference to ride?

Did you happen to gather any performance data?

I have a few more questions.

Would you do it again?
My pregen engine was from 1990 so it was in good shape but I just wanted a change. Plus I got the engine, ecu, harness, header, etc for 500 bucks so wasnt that expensive. I did the machine work on the mounts and did the work myself installing. Took me about a week doing about hour or so a day.

Did it gain any weight?

Probably 10 lbs, then again some stuff that was needed on the pregen wasnt needed on the 300 but still probably around 10lbs if that.

Was it a night and day difference to ride?

Torque is more linear. 0-60 is greatly improved. More power, can get up to 90 mph a ton easier (pretty much getting up to speed when getting on the freeway was easier). MPG stayed the same, around 65-75 mpg. Some of the gearing is different so some of the gears can be stayed in, and a better final gear.

Did you happen to gather any performance data?
Nope lol. Just know what a stock 250 carb engine got and a 300 FI got hp and tq wise. But for 500 bucks it was a good jump in performance. Especially since full exhaust system is around 300-500 on the bikes.


Let me know if you need any more info

Let me know if you need any more info

I would like some...
did you use the 300 TBs ?
what final gearing are you using ?
does the chassis feel a bit less stiff ?
any feel of difference of the center of gravity or balance on straight or out of corners ?
can you give us any other feedback ?

I would like some...
did you use the 300 TBs ? Yes. I pretty much got the engine from a salvaged 300
what final gearing are you using ? 15/ 42 I need to change up my tires 110/90 and 140/90. I would rather go skinnier tire and save on weight than have stability.
does the chassis feel a bit less stiff ? Not more than stock 250. Suspension was tweaked for the extra weight but it was only a bit. I got a bit more weight on the front.
any feel of difference of the center of gravity or balance on straight or out of corners ? The front has a bit more weight now. My cornering is a lot sharper bc of the added weight. But since the motor is in the same place as the old the center of gravity should be close to the same.
can you give us any other feedback ? Feedback to if I liked it. Heck yes i did. I got more power and reliablity out of the motor swap. EFI. No more carbs. Digital stock 300 guages. Pretty nice.

this thread has blown my mind, now if i can find the same engine, wiring harness ecu and exhaust headers ill be set!!! can you post a picture of the machine work you did on the front engine mounts for some reference for me. im looking into doing this swap and your thread is as beautiful as ms america in her bikini

this thread has blown my mind, now if i can find the same engine, wiring harness ecu and exhaust headers ill be set!!! can you post a picture of the machine work you did on the front engine mounts for some reference for me. im looking into doing this swap and your thread is as beautiful as ms america in her bikini

i just took off 1/4 inch on both sides. Just took a grinder to them and everything fit. No pics sorry but you will see that you can take that much from each side easily. There is a bushing thats welded on that gives you plenty of room to work with.

And your last comment is funny. lol. Good luck :rotflmao: