bog problem

[mintc]

i just shimmed my vales and put a new stock head pipe on and when i gas it hard from idle it will bog and die on me but when i ease into it it goes just fine i checked the pilot screw its ok do you think i could have one of the intake valves to tight i had 1 that felt kind of iffy with the new shim in it

[WALKINGWOUNDED]

Did it hesitate before the valve adjustment?

Don't rule out the possibility of a tight valve, but check other stuff for now.

Cam timing off a tooth?

Make sure you T.P.S. is plugged in.

Then make sure you accelerator pump is squirting when you twist the throttle.

[mintc]

no it worked perfectly before the valve shimming and new head pipe

[WALKINGWOUNDED]

I know you probably didn't touch the carb and TPS connector during the valve adjustment, but they can be suspect later if need be. I think I would check timing marks. You also mentioned that you put a stock head pipe back on there. Depending what you had on there before versus what you have now, you may have created a leaner condition with the different exhaust and may have to fatten it up at idle a little. Check those two items and keep us informed.

[mintc]

it had a stock head pipe on it before and ive tried the pilot screw in and out and different increments of quarter turns and it still done it

[Baron Von Beard]

Did you remove the cam sprocket from the cam chain when you reshimmed? You may have retarded the cam one tooth when you put it back together. Reshimming should not make the bike run noticeably different.

[ProMed]

i just shimmed my vales and put a new stock head pipe on and when i gas it hard from idle it will bog and die on me but when i ease into it it goes just fine i checked the pilot screw its ok do you think i could have one of the intake valves to tight i had 1 that felt kind of iffy with the new shim in it

Was the head pipe gasket in good shape or did you replace it with a new one?

[mintc]

set the clearences at .28 and .16 the gasket looked good would that make it bog and die, if it was a car i would say its like the accelerator pump is going out is what it acts like to me do they go out on these bikes just like that? and how do i check to c if its squirting gas?

[biketrdr]

Did you remove the cam sprocket from the cam chain when you reshimmed? You may have retarded the cam one tooth when you put it back together. Reshimming should not make the bike run noticeably different.

double check your cam timing!! then check the sticky ridiculous throttle response. you can't believe the diff ?

[Baron Von Beard]

Wait a second, you set the valve clearances to what!?!

[mintc]

.28 mm exhuast and .16 intake thats what my service manual said

[mintc]

.28mm exahuast and .16 intake is what my service manual called for on a 02 i dont think its the valves cuase it runs fine when u easy into it or u turn the idle up crazy high it dont do it i feel its not getting enuff gas i just took the float bowl off inspected the accelerator pump diaphramit was ok and took the jets out to make sure they wasnt stopped up they werent put it back together and still got the same problem these dang 4 strokes are a mofo to troubleshoot! my service manual troubleshooting section is no help eighter

[dav]

make sure the hot start cable is not sticking. this could be a easy oversight with the cable running on top of the valve cover. it is easy to pull it while taking the cover on and off.

[CRF450-RIDER]

mine did the same thing!!!! check the hot start and theres a Red over flow hose under the card.take of the cap and let the stuff cum out

[mintc]

i went out and drained the junk out of the red hose and checked out the hot start seen the end was out on the carb side so i was happy put it back in and tried it agaiun still got the bog and die i used the hot start several time tho with the end out could it have streched it or something do u adjust the hot start or should it have been ok when i slid it back in the cable hole?

[mintc]

well it aint the timing i tried moving it up a tooth and down a tooth on the cam sprocket didnt help itcoulp it be in the carb i was reading the ac pump artical on adjusting and the prob they were describing sounds like what mine is doing but my service manual doesnt have any specs on that or wear limits or say how to adjust it

[crf450r4u2nv]

that is just how mine acted after my rebuild

it turned out that it was my timing chain stretched

new chain and it runs great

funny thing is i didnt notice this bog untill i rebuilt it

i thought it was an ap problem too

worth a try anyways

timing chains are cheap

some say they are an regular maintinence item

i didnt see what year yours is or how manny hrs

mine was an 04

[mintc]

its a 02 i thought of the timing chain so i ordered 1 last week it should b n wednsday i prob got 40 hours since new crank if it was the chain wouldnt the moving it up a tooth fix the prob i wanted to try so i could c if the chain was the prob but that didnt work so could it still be the chain?

[mintc]

this souynd wewird or what?

[letmein]

I am assuming you RODE the bike? The bike will bog and or die on a stand, without a load. Go ride the thing and report back.

If you think you have check everything, then take off the left side crankcase cover and look for metal shavings on the ignition trigger.