Ninja 250 jetting and wiring.

[StewieeeG]

Hey all. I am starting to work on my engine atm as I currently do not have a welder to work on my buggy with.

I fired it up again today and it has some issues we'll say.

It doesn't enjoy starting. (I need start ya bastard to get it to fire)
And when it does start it will die on throttle input, but once it does start for a few seconds it will rev without dying. It has a slight delay in revving and then once it starts to rev it will backfire loudly and constantly while flaming out. (pretty spectacular) and when the throttle is let off it will delay when revving down and not fully drop down to idle.

I'm thinking that it is flowing way to much air into the engine and really lean which would explain the fact that it backfires and hangs and doesn't want to start. I thought the valves may also be a little out?

Any idea?

Sent from my GT-I9100

 

[fowler]

Do u have the filters on

If u are running open carbs then of course it will run like crap

If u are running filters then it may be dirty carbs

While the engine is on the bench I'd definitely be doing
Carb clean
Valve set
Pull the sump off and do a bottom end check

While its out u may as well
No point putting it in the buggy to find it ****s its self in 5 hrs

U will require a service manual
Just google it
There should be a free one kicking around

 

[firemanjim]

Sounds like you're running RICH to me..... find the fuel mixture screw and screw it all the way in(GENTLY counting turns so you know where you started from) . Then back out 1&1/2 turns.... good starting point. Too lean and you'll fry the motor. Too rich, pops n backfires cause you have excess fuel. You probably see white smoke too, huh? Add a working spark plug to exhuast and you can shoot flames on demand.... lol but true

 

[StewieeeG]

I don't actually know if there is a fuel mixture screw on it :/ I have looked and can't find one. Websites don't mention it.

I shall buy a k and n filter for it from work and then rip the head off and get to work on the valves.

I found a service manual in 2 minutes

Yeah there's a bit of white smoke. And I like that idea of shooting flames on demand <

Would you be able to explain what a bottom end check is?

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[firemanjim]

He is referring to checking out the bottom end. Crank bearings , con rod , ect.....
Post a pic of carb. Whats the make n model? I can tell ya if and where the mixture screw is if i knew what ya got....

 

[fowler]

U don't have to take the head off

U just take off the rocker/can cover to get to the tapets

I wouldn't actually pull the bottom end down
Just remove the sump

Then u can do a visual inspection
Just move stuff around
If u can feel any "up down" movement in the crank or big ends then they're no good

If u had a dial gauge then use that

If look for a foam filter
Those k&n filters are rubbish
Pod filters rarely flow better than stock one on a bike
If u think
The filters are way smaller than the stock one
So the way to get equal flow is to make the holes in it bigger

Long story short
I put pod filters on my first buggy for a space issue

After a few hours of fun in the gravel out I can remove the k&n filters and wipe the fist out the carbs

If u can, get some oiled foam filters
Much better if u can't fit the stock box on

 

[StewieeeG]

I shall look into checking the bottom end and I shall check the oil for shavings Etc Etc.

How about uni filter? They seem to be fairly good, yet cheaper than 150 rrp k and n's

Is anyone able to help me with the starter relay?

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[fowler]

What's wring with the starter relay

Uni filters are ok

 

[StewieeeG]

I have a custom loom which just does enough to run the engine. And I do not know how to power the relay to make it trip so I can crank the motor over. I can get a photo of the loom diagram if it will help?

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[fowler]

The pic would help

It's not very hard to wire a relay
U just give it system voltage
Then run a ground wire though a momentary switch

How are u currently cranking it?

 

[StewieeeG]

I shall post a photo of both diagram and loom in about 30 minutes when I get to the shed.

It doesn't seem hard. It's just I don't know how

Current I'm just bypassing it by using jumper leads attached to the engine and starter motor. With the other wires (coils, earth) plugged in the battery terminals

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[StewieeeG]

Here are the photos of the loom

Sent from my GT-I9100