Jump to content
Sign in to follow this  

Bogging and cutting out

Recommended Posts

First off, i'm on a 2005 yz85... I've noticed a problem, but just ignored it.. So, my bike starts after 50 kicks (2-3 if I rember to take the exaust plug out), but when I go from 1/4 throttle to wide open, it just cuts out.. I thought it was the pilot, but my bike still idols.. So it coudn't be the pilot..

I was thinking that I nead to lean it out? Also, i'm running 32:1 with HP2.. (93 octang).. I don't know, i've never jetted before in my life.. Any help is really appreciated..

Share this post


Link to post
Share on other sites

Has it always cut out from 1/4- full or is this something that just started happening?

If it used to run good before with the current jetting I would look at other things before I messed with the jetting.

Share this post


Link to post
Share on other sites
Has it always cut out from 1/4- full or is this something that just started happening?

If it used to run good before with the current jetting I would look at other things before I messed with the jetting.

I got it, and got a FMF Shorty within the week, and it ran great after that.. I'm almost sure it didn't bog there.. So it MUST be jetting.. (BTW: I no longer run the shorty due to neighborhood sound issues)..

I'm pretty sure since then it's ran fine.

Share this post


Link to post
Share on other sites

my bike was doing the samething tonight. It idled but right when i'd hit the powerband it would spit and sputter and eventually cut out. I checked the sparkplug and it was covered in oil, my bike bad been running well prior to this. If i were you i'd check/change the sparkplug and go from there. I'm going to jump from a 32/1 to a 36/1- 40/1 mix to see if that fixes it before i consider rejetting.

Share this post


Link to post
Share on other sites
First off, i'm on a 2005 yz85... I've noticed a problem, but just ignored it.. So, my bike starts after 50 kicks (2-3 if I rember to take the exaust plug out), but when I go from 1/4 throttle to wide open, it just cuts out.. I thought it was the pilot, but my bike still idols.. So it coudn't be the pilot..

I was thinking that I nead to lean it out? Also, i'm running 32:1 with HP2.. (93 octang).. I don't know, i've never jetted before in my life.. Any help is really appreciated..

What plug are you running? Stock they come with a BR10EG which is way too cold a plug. Most (including my son's) run a BR9EG plug. His jetting is stock except we turned the air screw out another 1/2 turn. We run Yamalube 2R in it at 32:1 with 93 Octane BP.

If you haven't changed it it sounds from your description your plug may the issue. Its a quick and easy check.

Share this post


Link to post
Share on other sites
my bike was doing the samething tonight. It idled but right when i'd hit the powerband it would spit and sputter and eventually cut out. I checked the sparkplug and it was covered in oil, my bike bad been running well prior to this. If i were you i'd check/change the sparkplug and go from there. I'm going to jump from a 32/1 to a 36/1- 40/1 mix to see if that fixes it before i consider rejetting.

It's not nessicarry when I get on the powerband.. But if I go from 1/4 to full throttle (Even when I start on the powerband), it will cut out, with NO power.. It kind of idles.. After I start, i'll just keep it at the slightest big of revs (always varrying the revs, never ideling), but when I let it sit for a while, it stalls..

I'll check out the plug tonight.. It seams to run like crap when its cold.. I'll just ride at 1/4 throttle untill it wars up, than it runs great.. It kind of sputters with I overrev (I'm not a squid either... I'm a rev-happy kid)..

Share this post


Link to post
Share on other sites
What plug are you running? Stock they come with a BR10EG which is way too cold a plug. Most (including my son's) run a BR9EG plug. His jetting is stock except we turned the air screw out another 1/2 turn. We run Yamalube 2R in it at 32:1 with 93 Octane BP.

If you haven't changed it it sounds from your description your plug may the issue. Its a quick and easy check.

I'll check it out tonight. Thanks for the help... :thumbsup:

Share this post


Link to post
Share on other sites

sounds like you need to warm it up. if you said it runs fine when its warmed up, then let it warm up. alot of bikes done have very much power when there not warmed.

Share this post


Link to post
Share on other sites

This sounds like something that happen to me it turned out to be that the float level was too low and the bike was starving for fuel. Take the carb off and pull the float bowl off and then turn it upside down and see when the tab on the floats grabs. if it grabs when you pull the floats fully up the bend the tab up so it grabs quicker. this should be you problem and doing this will make more fuel go into the carb when it is used. don't bend it too far otherwise fuel will be coming out of your overflow.

Share this post


Link to post
Share on other sites

Are the basics good...................compression, air filter, plug, fresh fuel, proper warm up and carb adjustments? Sounds like a worn piston to me. :thumbsup:

Share this post


Link to post
Share on other sites

It sounds like you have a lean condition, actually. Usually, when the bike dies from quick throttle openings it's lean (starving for fuel). High RPM stuttering is also a symptom of being lean.

Share this post


Link to post
Share on other sites

Be aware that the reed block is not symmetrical and can be put in upside down which can block off half of the fuel passage. This happened to me. I looked at everything trying to figure out the issue, turned the reed block around, everything good after that. If put in upside down, the reed and the carb boot do not match up.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×