josh975

hi
i have a very tempermental rex-x ive always stuggled getting it to run correct now i have managed to get it running ok at high speed but will not stay started unless flat out and low speed just cuts out idel seems too high the wheels just spin
any help would be much apreciated
cheers

RUNNINONMT

If it stalls when you put it on the ground then check you clutch.

josh975

hi9 mate thanks for that what would i be looking for when i take it apart
cheers

RUNNINONMT

Look for weak springs, broken springs, or bad bearings. my buggy would run fine for a couple of minutes and then from nowhere start stalling when i hit the breaks. It drove me crazy and then i got mad and was gonna throw the motor out and put in a new one and found that my bearings were blown.
i over looked it because i just changed them not long berfore this happened. Hope this helps.....

secretsg

iTrader: (7)

edit: found it..

liqfrce

what an article. would like to see someone post something better and more in depth than that. A must have for anyone new to nitro.

tony montana

iTrader: (76)

so If my ninja after it warms up it idles a little high then drops down after a few seconds, means my low speed is to rich?

Madbrad

iTrader: (30)

That means its too lean. Its take a couple seconds to load up on fuel to which then gives you a false normal idle. Another way to double check is the pinch test. Pinch your fuel ling going to the carb, is it runs for 3-4 second and slightly raises its idle your good. Runs for less, its too lean, if it runs longer its too rich. That gets you in the right area with the pinch test.

lowey79

It can mean that you're running slightly rich on the LSN and the idle gap is too wide... If it's a lean idle, generally it will idle high and the exhaust note will sound fluffy.

Best way to check LSN setting IMO is the punch test... Get it warmed up to running temp, drive a couple full throttle passes and then bring it to a stop and idle it for 10-15 seconds and then punch the throttle and observe how it responds...

If it takes off sluggish with a burbling sound and lots of smoke... It's too rich
If it bogs and hesitates on take off with little or no smoke... It's too lean
If it accelerates rapidly with a crisp clean sound and a good amount of smoke... It's spot on!

Once you've got the punch test right, then reset the idle speed using the idle stop screw and recheck the punch test... Fine tune again if neccessary...

The LSN and idle gap settings are a bit of a balancing act and can take a little bit to get right but once you find a method that works for you, it becomes quite easy!

Just my $0.02 But it works for me

tony montana

iTrader: (76)

I should have been a little more clear on whats going on. I was running my buggy in the yard a little yesterday and after making a few wide open passes it would idle up for about 3-5 seconds and then go to normal idle. But after a 5 minute qualifer before my pitguy can get to it soemtimes it cuts off like the idle is to low

Wrencher

iTrader: (11)

How it responds immediately after coming to idle after a high speed is related to the HSN,, It may be a tad lean on top, do the pinch test, if revs increase, your LSN is not too lean. If it is revving high after a high speed pass and then drops a few seconds later, the crankcase is loading itself up when it gets back to idle. It's a damn fine balancing act for sure, if it has excessive high revs, your gap is too wide on the idle setting.

lowey79

That sounds like it's rich on the LSN... Try leaning it a little and run it around your yard again... it should now idle up for a bit longer. If it does you're on the right track... keep leaning till it holds a high idle for 15-20 seconds, then reset your air gap till you get youe desired idle speed!
NOTE: You may need to richen the HSN slightly while doing this to maintain the balance?

If this doesn't work, then it'll be a HSN/LSN balance problem or an air leak or something like that? But it sounds to me like a rich LSN!

tony montana

iTrader: (76)

yeah I tried doing the paris tips for the low speed. But it seemed like it was running hot after I leaned it almost 3/4 turn, and it still idled up a little. the hsn is basically spot on. Good power with good smoke, so I know its the lsn. Its not real bad Im just being anal about it. Just want it to idle like it does when it first starts all the time

lowey79

Could be an air leak then?

Is it a GRP ninja or a OS ninja? If it's OS with a 3 needle carb You could try adjusting the mid needle... I'd try half a turn in to start with and no more than 1 turn! Just remember that what you do to the mid, you have to do exactly opposite to the LSN to keep it balanced! My Speed's have responded well to this adjustment and provided you move both the mid and the LSN together when making mid adjustments, it's nothing to be scared of!

mbx5rcr34

iTrader: (5)

guys i need your input here we went for practice yesterday & everything was fine new clutch shoe,spring & cleaned filter , except the jx motor flame-out (half-tank) ,so i tried to richen the top (hsn) & fill it up again after some passes same thing when it rich to half-tank it will flame-out ,i tried new p3 plug same thing,if not half-tank it will flame-out on 1/4 mark