450r running problem

[RAFFERTY1]

i dont know if anyone can help me on this but ive got a problem
on my trx450r.

sometimes the bike will ride fine and other times it just looses power when you try to give it any throttle, its almost like the rev limiter on a raptor when its in reverse. it will pop and bang but not move and then if i leave it to cool down it will be o.k. until it gets hot again.

i have had all the carb apart and cleaned it all out ive tryed adjusting the mixture but nothing works, trouble is that here the uk the bikes only been out for a week and i work at a honda dealer and we havent even got a workshop manual for it yet so i cant check the valve clearance or the throttle position sensor as i dont know what the settings are.

if anyone can help me on this i would be very grateful as its driving me crazy.:confused:

[Cody_300ex]

sounds like jetting to me.

[snow4fun]

I was just looking through my owner's manual that comes with the bike. Check out page 118. Valve clearance should be:
Intake: .006 in (.16 mm)
Exhaust: .011 in (.28 mm)
It says Excessive clearance will cause noise. Insufficient clearance will cause loss of power and possibly damage the valves. It does sound a lot like jetting. Have you checked the spark plug to see if it's okay? Maybe try a new plug. Good luck.

[lukester720]

Have you done any mods to your quad? Even as simple as removing the airbox lid or the baffle?

[RAFFERTY1]

NO ENGINE MODS.

I DID HAVE A PRO DESIGN PRO FLOW KIT IN IT BUT WHEN STARTED PLAYING AROUND I WENT BACK TO THE ORIGINAL FILTER

I DID TRY TAKING THE BAFFLE OUT TO SEE IF IT MADE A DIFFERENCE AND IT RAN GREAT FOR A WHILE BUT THEN STARTED MIS-FIRING AGAIN!

THE JETTING IS STANDARD.

[4fiddyR]

Dump your gas out in a jug and see if there is water in it. That gas cap vent hose is like 2 1/2 feet long, you can hold water in your steering stem, and if you wash it on the rear wheels you just unknowing dumped water in your tank.

Mine backfired like that and wouldn't run, and the fix was trimming my gas cap vent hose and now I pinch it off when I wash my bike.
Hope this helps!

[RAFFERTY1]

THANKS I'LL GIVE IT A TRY

I HAVE CUT THE VENT HOSE DOWN ALREADY BUT I'LL EMPTY THE PETROL OUT AND SEE WHAT HAPPENS

[Hammer trx450r]

i agree. sounds like a real good place to start. maybe alittle dirt got in on the filter transfer.

[86atc250r]

A friend had very simiar problems to what you describe with his 450R.

He disassembled the carb and found a black plastic shaving lodged in the mainjet. This shaving appeared to be of the same plastic the side cover is made from and was probably floating around in the bowl from day one.

It's a long shot, but something to check....

[4fiddyR]

Please let us know how ya make out!

[RAFFERTY1]

i think i may have found the problem.

if you touch the wires to the throttle position sensor it alters the reading.

so the vibration of the bike may be causing the this ive zip tied the wires to the frame to stop them moving and it seems to of cured it,

what does anyone think coincidence or the probable cause?