I have a hellacious bog happening and i can't figure it out (08 crf450).... I've gone from the stock 42 pilot to a 45 to a 48 and back and it still bogs bad with out a huge change (to me). I put one of those fancy pants air screws and have adjusted from 1-2.5 and still bogs... I even put in a new plug. The old one looked a little rich so I moved the clip up one (from middle) and still the same result...

Anyone have any ideas on what to try next? Is it time to EFI?

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nts

quote:

I have a hellacious bog happening

Sounds interestings, please be specific.

1) Temps and Humidity
2) Idle speed
3) Mid-Throttle jets
4) Full-Throttle jets
5) Floats - low or high
6) Jet size (all)
7) Accelerator pump - stock or fixed

Leak jet?

quote:

Originally posted by MX516:
I have a hellacious bog happening and i can't figure it out (08 crf450).... I've gone from the stock 42 pilot to a 45 to a 48 and back and it still bogs bad with out a huge change (to me). I put one of those fancy pants air screws and have adjusted from 1-2.5 and still bogs... I even put in a new plug. The old one looked a little rich so I moved the clip up one (from middle) and still the same result...

Anyone have any ideas on what to try next? Is it time to EFI?

Pull the carb apart and clean, pull the accelarator pump off make sure the linkage hasn't been screwed up.

450 bog rather uncommon for us would agree with 061 if you are not seeing much differencs with changes you are making look at things you are not. Have had too much "play" with linkage. IF all this checks out replace gas completly,IF still not cured, look at valves and timming. Always want to think I am smarter than some stupid machine ,sometimes it takes awhile. JR

maybe try wireing the AP lingage????

Tone Show....did you remove the plug from the pipe??

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Originally posted by Ivest4:
Tone Show....did you remove the plug from the pipe??

good one Clarence I actually went through that.

516
Stupity on my part,sure you NEED a FI 450 AND we just happen to have one for sale!! How is all this info working with your problem? JR

Sorry for being late on the reply guys... I've been reading all the advise as it came in, just didn't have a chance get in the shop!

All of this info (and general frustration) lead me to just hunker down and start some over due maintenance that i am sure was causing my steed to give me fits... things like grease the linkage, clean the airbox and scotch brite the fame back to factory... after that was complete I yarded everything and gave my bike a nice hot water 'naked' bath (so glad i installed that hot water spicket)...

Heres what i found once I got into it... Valves: Check!; about .005+ and .010+, same as summer. (not sure thats the problem and way over due)

thoroughly cleaned the carb and everything looked good except under my QS2 Acc. cover... there was a touch of some grease stuff (airfilter oil?) and some sooty stuff under the little diaphragm. I am sure (and hope) thats the problem. No time tonight to find out... gotta watch the Tivo'd supercross at the neighbors.

Anyway, thanks for the advice (except for Clarence!) and the gentle shove to give my bike some much needed TLC. I will let you all know when I get it back together, how she works.

Oh-yeah KW...
5) Floats - low or high - Stock
6) Jet size (all)
- Pilot now 42 (stock) tried 45 and 48.
- Main 180 (manual says 178 is stock, don't recall changing it?)
- Needle moved up one clip from position 3 (middle) to pos. 4
7) Accelerator pump - stock or fixed? - i have the QS2 & and recently tried 'fixed'/tied mod (bog started before we tied it.

quote:

Originally posted by spin05:
maybe try wireing the AP lingage????

all the wireing does it make sure when you snap the thottle that the a/p arm follows the linkage with no delay but if the a/p timing is off it wont matter if you wire the thing

with all this ,.... HAS ANYONE CHECKed THE A/P timing ????? did you pull the air boot off and watch the pump spray ???? and make sure its on time it should start to spray as the slide is opening ... most bogs are caused by ether the spray is to early and hoses the slide before it opens or it doesnt spray intil after the slide is fully open .....


you can change jets adjust fuel screws...but if you havent checked accel pump timing you could be chasing your tail on this deal ....

and which leak jet is in it ???

and did the bog just start or has it always been there ??? if it just started it sounds like there might be dirt inside a air bleed passage which to clean you must take apart the the body of the carb apart ... whichs means you need to find a tamperproof torx bit and pull the main jet holder out and clean the air bleeds inside the carb body with shop air .. dont use contact cleaner on the rubber gasket it will grow and you cant buy that gasket ...

the other thing is how does the metal slide cover gasket look ? is it wrinkly and is the coating on the front side of the slide cover wearing ?? if that is the case replace it....

This message has been edited. Last edited by: wilcox,

quote:

Originally posted by wilcox:
and which leak jet is in it ???

and did the bog just start or has it always been there ???

Leak jet is Stock i guess?

The bog slowley got worse... no bog from when I put the QS2 (early 08) in till this Fall... and I adjusted the air screw a little and frankly just lived with it the last few months as it got worse. After a few close calls I've had enough! I hope to put it back together tonight and I will check the timing thing. thanks!

if you got it all apart right now your gonna have to fire it up for a minute and then jerk the subframe back off and watch the pump spray while turning the thottle with the motor off...

look that the metal slide cover. is the coating worn on the front side at all ????? if it is then its able to move in the bore of the carb when you bring the slide up ... it can cause all kind of lean/rich headaches ... and it sounds like you scoot has some time on it

Thanks! As I put it back together (hopefully tonight), I will check for the spray and report back. I am hopeing it all has to do with the sooty stuff I found on the rubber diapragm in the acc pump.

Yes, I have a few hours on it

here is a lesson I learned in vegas from the honda mechs. take off subframe, pull carb back from engine, twist throttle gas sould shoot almost across shop, if not clean ap orfice with small drillbit. any dirt that gets in carb will go into ap. ours was pluged this fix works just a thought

leak jet ! for sure go richer ! which means lowering the # 60 is richer than 70 it was the best change i did for my 07 crf 250

he doesnt ride one of those girls bikes like yours mike

While you have it apart, check the diaphragm itself for pin holes. It could just be wore out also from the use. We had one go bad and drove me nuts.

quote:

Originally posted by moderbike x:
leak jet ! for sure go richer ! which means lowering the # 60 is richer than 70 it was the best change i did for my 07 crf 250

moderbikez... did you do anything to your 450 when you had a mans bike?

I am on the look out for a new diaphragm since that seems to be a common theme and mine did appear to have some wear marks (didn't see any holes). Shops open tomorrow (got 3 to try) so hopefully they have it in stock...?

Hey Tone Show, hopefully you will have better luck than I had at the Kawy shops looking for a rear fender. 3 shops, not one had one in stock. Of course they probably don't stock much parts for the vintage bikes any more.