Dies Out After 20 Minutes Of Riding?

4355 Views 17 Replies 8 Participants Last post by YFZER359, Mar 28, 2009

dmx434343

Discussion Starter · Mar 25, 2009

Hello everyone,

Ok so i don't own a yfz but my close friend/neighbor does.

Help us diagnose this issue.

Model/Mods: 2008 YFZ 450
Spark Arrestor Out

So the bike starts right up when not warm (cold start) and once warm will only have a slight pop on accell when in idle. But when under a load there is no pop, occasionally a bog when at slow speeds and stabbing the throttle.

THE PROBLEM

After riding for 20-30 minutes the bike will have a huge bog and eventually (5-10 seconds later) cut off.

Then it becomes extremely hard to start, only starting with the choke on.

So far we have changed the spark plug, and thats all. I plan to change his Pilot to 45 and up the main jet a bit (165 or 168). But do you think this issue is different then jetting?(current jetting is stock)

ALL input is greatly appreciated.

1 - 18 of 18 Posts

G

· #2 · Mar 25, 2009

QUOTE (Danny T @ Mar 25 2009, 08:55 AM) index.php?act=findpost&pid=761958

Hello everyone,

Ok so i don't own a yfz but my close friend/neighbor does.

Help us diagnose this issue.

Model/Mods: 2008 YFZ 450
Spark Arrestor Out

So the bike starts right up when not warm (cold start) and once warm will only have a slight pop on accell when in idle. But when under a load there is no pop, occasionally a bog when at slow speeds and stabbing the throttle.

THE PROBLEM

After riding for 20-30 minutes the bike will have a huge bog and eventually (5-10 seconds later) cut off.

Then it becomes extremely hard to start, only starting with the choke on.

So far we have changed the spark plug, and thats all. I plan to change his Pilot to 45 and up the main jet a bit (165 or 168). But do you think this issue is different then jetting?(current jetting is stock)

ALL input is greatly appreciated.[/b]

is there any gas in the tank?

dmx434343

Discussion Starter · #3 · Mar 25, 2009

yes the tank has fuel.

n.e.r.d

· #4 · Mar 26, 2009

Sounds like there is a clog in the fuel line or in tank fuel filter. check your fuel flows.

r1yfz

· #5 · Mar 26, 2009

chack the flow of radiator fluid! maybe its overheating

Joester

· #6 · Mar 26, 2009

check the vent tube coming off the gas cap for clogs. make sure you can freely blow though it.

ghglenn

· #7 · Mar 26, 2009

Fatten the jetting up for sure. Sounds like it is getting hot.

dmx434343

Discussion Starter · #8 · Mar 26, 2009

thanks for the replies, will check all of the above within the next few days. If you guys think it could be anything else let me know.

dmx434343

Discussion Starter · #9 · Mar 27, 2009

OK GUYS, found the problem.

When the fuel knob is in the ON position, no fuel is flowing. Fuel only flows when it is in the RESERVE position.

Can i just leave it in the RESERVE position or is this a bad bandaid.

How do i fix this and whats wrong???

Joester

· #10 · Mar 27, 2009

this is ALSO done in paint, lol. there is a little tube that is the on position that might be clogged, and running it on reserve means that once you run out, you're done. take the gas tank out and try to poke it through or something, or just take it out, put a little gas in there and shake it around upsidedown.

as you can OBVIOUSLY SEE in my illustration, the way it works is that once the fuel level gets down below the top of that tube, it cant get any more. you turn it to reserve and it flows through the bottom thing i labeled "reserve.

btw, im not sure that this is the system the YFZ uses. ive never actually looked in there, but i know alot of bikes use it.

See less See more

dmx434343

Discussion Starter · #11 · Mar 27, 2009

anyone else before i tare into this tomorrow?

thanks!

Junior82

· #12 · Mar 28, 2009

ok what you need to do is take your tank off the machine, where you turn your fuel on/off there will be 2 bolts/screws not sure that go into the tank, take it off the tank and inspect the inline fuel filters, the on position fuel filter will be the taller one.

also could check your oil, breather hose(s), spark plug

chickunfut

· #13 · Mar 28, 2009

QUOTE (Joester @ Mar 25 2009, 09:33 PM) index.php?act=findpost&pid=762300

check the vent tube coming off the gas cap for clogs. make sure you can freely blow though it.[/b]

My bike did the same thing and it was the little billet breather that was on the end of the gas cap vent tube. Some of those have a small ball bearing in them to keep gas from spilling out (even though the cap does that). The bearing will rust or get some dirt in the breather and eventually clog up...... It took me two races to figure that one out..

It only died when I would ride for awhile and catch a little air... After sitting for a few minutes it would start right up again.

YFZER359

· #14 · Mar 28, 2009

QUOTE (Joester @ Mar 26 2009, 05:27 PM) index.php?act=findpost&pid=762670

this is ALSO done in paint, lol. there is a little tube that is the on position that might be clogged, and running it on reserve means that once you run out, you're done. take the gas tank out and try to poke it through or something, or just take it out, put a little gas in there and shake it around upsidedown.

as you can OBVIOUSLY SEE in my illustration, the way it works is that once the fuel level gets down below the top of that tube, it cant get any more. you turn it to reserve and it flows through the bottom thing i labeled "reserve.

btw, im not sure that this is the system the YFZ uses. ive never actually looked in there, but i know alot of bikes use it.[/b]

yea it is like that. Im actually cool enough to look into my gas tank :mhihi: :neener:

But my guess would be that on thing is clogged. And richen the jetting, like said before.

Joester

· #15 · Mar 28, 2009

lol, ok. now i know, thanks.

btw, i wish i was as cool as you :neener: :neener:

YFZER359

· #16 · Mar 28, 2009

QUOTE (Joester @ Mar 28 2009, 08:52 AM) index.php?act=findpost&pid=763174

lol, ok. now i know, thanks.

btw, i wish i was as cool as you :neener: :neener:[/b]

lol

thats like the 5th of my post that you've replied too lol do you like look for my posts? lol

dmx434343

Discussion Starter · #17 · Mar 28, 2009

ok will take it off tomorrow thanks for the tips. and by the way the breather vent on the gas cap is clean i can blow freely through it. did change the spark plug and oil is fresh..

thanks again guys will update this thread tomorrow night

YFZER359

· #18 · Mar 28, 2009

QUOTE (Danny T @ Mar 28 2009, 11:00 AM) index.php?act=findpost&pid=763223

ok will take it off tomorrow thanks for the tips. and by the way the breather vent on the gas cap is clean i can blow freely through it. did change the spark plug and oil is fresh..

thanks again guys will update this thread tomorrow night[/b]

will do.

1 - 18 of 18 Posts

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