not starting,but shoots fire balls!

[farmer250r]

i have a 06 trx450er,pulled the motor apart to check everything (bought it used and wasnt runing) so the piston and rings looked great,the bore still had the cross marks,the valves look good,i put it all back together with fresh gaskets,oil,filters.looked at the valve clerence and there in spec.it has spark,and its deffintaly getting fuel because as i crank it over,un-burnt gas builds up in the exhaust and then ignites into a big blue ball out the exhaust,im stumped,the motor is fresh,i mean everything looks great,the timing is dead on too,im going crazy,my 250r never gave me these many problems and it was a 2-stroke!:mad:
if Anyone has any idea what could be the problem,let me no,thanks

[dran714]

can u pull start it? only thing i can think is if you could swap known good parts off a known good quad.. good luck

[ridehonda400ex]

sounds like your running to rich if its shooting fire lol

[ridehonda400ex]

sounds like your running rich if its shooting fire balls lol

[farmer250r]

gonna try to pull start it asap,as soon as my pop gets his tractor out of the way so i can pull it out of the back of the shop.lol.but im gonna check the jeting soon,it does have a aftermarket exhaust so the kid could have jetted it to rich,but i think she just needs a good pull start.will see....thanks

[ridehonda400ex]

post when you find out the problem

[farmer250r]

tryed to pull start it today,and i got nothing,few spit ans spudders,but agian,nothing,anyone have any ideas?

[rubbersdown]

you 100% positive the timing is right? Sounds like a timing issue.

[ridehonda400ex]

if i were you. id re-check the timing, re adjust the valves, and put new plug in it. also maybe take the airbox lid off to compensate some for if its running rich.

[farmer250r]

thats what im gonna do,is there a firing timing? im new to the 450,but i guess i can read the manuel alittle better :confused:
but im gonna get the vavle shim kit,re-adjust everything,and see what she does,and the air box lid is off,use a k&n filter with the pre-filter.

[quad71]

You can change the main jet and piolt jet thru the opening in bottom of float bowl. also check the fuel screw the setting of the fuel screw helps it start and idle. if it was setting for a couple months the piolt is clogged. pull the main and piolt clean and tell us what numbers are on them. 45 piolt and 170 main is close with your set up. and 1-1/2 turns out on fuelscrew. also pull the neddle jet it should have 5 to 7 notches if not its stock and to lean. also the spark plugs are not like the 250r do not slide a gap checker in plug gap it will scratch off the coating just get a new plug get a number 8 ngk stock is 7.

[quad71]

There is alot of electrics on these too. you could do away with the throttle saftey system. or try a new throttle postion sensor. also may want to increase the gap on the decompression set up.

[rubbersdown]

Originally posted by quad71
There is alot of electrics on these too. you could do away with the throttle saftey system. or try a new throttle postion sensor.
Dont worry about the TPS. The TPS wont keep the bike from starting. If it goes bad it just automatically reverts to a "generic" ignition curve (I think the #2 curve (I believe there is 3 curves depending on the throttle position)). The bike will run slightly different and not be as responsive but the bike will still start and run like normal.

The ignition timing is not adjustable so dont worry about that. If you have spark, fuel, clean air and your valves are not zeroed out then it should start. If not then I still put my money on the timing being off, double and triple check it.

[farmer250r]

whats the best way to time the motor? i no the lil peephole on the side of the motor,but is there a firing timing,and a non firing timing?

[rubbersdown]

Originally posted by farmer250r
whats the best way to time the motor? i no the lil peephole on the side of the motor,but is there a firing timing,and a non firing timing?

The ignition on your bikes fires every revolution, so it fires on the compression and exhaust stroke so you dont have to time the ignition so dont even worry about that. The only thing you time is the valves.

As far as timing the valves, take the valvecover off, then the "peephole" cover as you put it. Then align the punch mark on the gear inside the peephole with the index mark on the crankcase cover. When those 2 are aligned the motor is at TDC. You need the motor at TDC on the compression stroke so look at your valves and make sure all of them are closed, if they are all closed then you are at TDC on the compression stroke. Once this is done make sure that the Index mark on the cam holder and the timing mark on the cam sprocket are lined up, if they are not lined up then your timing is off and you need to unbolt and rotate the sprocket on the cam chain so that they are aligned properly.

[quad71]

There is 2 marks in the peephole btdc and @tdc. you want it @tdc.

[farmer250r]

gonna try to time it tomarrow hopefully,ill post if i have any problems or questions,thanks guys! :D

[farmer250r]

pulled it apart today,timing was off,well i did the timing,and tryed to start it,nothing,but as i was pulling it apart,and rolling the quad back and forth to set the timing,i noticed a hard spot (spark plug was out) when i was moving it,my dad was helping mr,and he said its either a bent valve or my valve clearence is off,it was like .11 on the exshaust intead of .28 and didnt have the time to look at the intake,so whats your guys opinon? im about to cut this damn thing in half!

[quad71]

compression check sounds like may have bent valve when it was out of time. how much was it off ?

[rubbersdown]

sounds like a bent valve to me. Pull the head and inspect the damage. Probably not that bad sense the bike never actually started.

[farmer250r]

did a compreesion check but my tool is a piece of cr*p,it wouldnt read anything,but my dad tryed to shove it down in there and said he couldnt feel any air getting by,but still my guess is because of the tool being cheap,but when i inspected the head everything looked good,but i guess since i couldnt tell that it was,it realy cant be that bad,but bad enough to where it wont start,the timing was off maybe 3-4 teeth on the cam gear,fixed all of that,motor is complty timed right,but still not runing,anyone have any sugjustions on valves,ill be sending the head out to my local shop to put them in and seat them,but whats the best bang for my buck,im runing a stage 2 hotcam,stock pistion,nmotion exhaust,and open air box? whats good for my setup?
thanks everyone for the help! ;)

[quad71]

If you have head off spray wd40 in the intake and exhaust load it up good and look for fluid leak around valves. local shop? ask them if they have a serdi valve machine if not find one that has one, best bang for buck you may want to get stainless intake valves they last alot longer then ti.

[farmer250r]

okay,and what about oem valves? no good,the ti,not stainless,just dont wanna be spending a lotta cash

[quad71]

Steel valves go for 40.00 for one and titanium 120.00 for one. stock intake valves are titanium when you switch to steel you need new springs you can get kits for around 160.00 you get steel valves new springs and titanium retainers. thats all aftermarket. also i like uni foam air filters and i change it every 2 hours this helps extend life of valves.

[quad71]

This is the serdi valve seat cutting machinehttp://vimeo.com/12398173 via moto xperts.