Jump to content
Sign in to follow this  

2005 400E low rpm bog...

Recommended Posts

I almost killed myself today blipping the throttle to get over a log when the front end dove instead of rising.

I've searched and it looks like my only cure is to play with the fuel screw, mj and pj. It appears that the O'ring mod won't work on my '05.

The bike has stock jetting, whatever that is.

It seems like while searching, I read that I need to turn the fuel screw in until it runs rough, then turn it back out until it's smooth again. If it's one turn out, then it's lean. If it's 2.5 turns or more, it's rich.

Am I correct? Thanks in advance!

Share this post


Link to post
Share on other sites

fuel screw is for idle.does your bike idle?

you need to wire the ap linakge arms together and shorten the stopper on the pump diaphram.

Share this post


Link to post
Share on other sites

The bike idles just fine Eddie, thanks.

I'm pretty sure I know what you're talking about by tying those together. Also, on the pump rod, which end do I shorten it on? Can I do this w/the carb on the bike?

I'm trying my first attempt posting a picture! If it posts, I just wanted to confirm that I'm in the right or wrong place...

The picture didn't work in this one - I figured it out below...

?action=view&current=carb1.jpg

Share this post


Link to post
Share on other sites

Got it.

Thanks for taking the time to help me on this - I appreciate it.

I'll post after the fix and let you know.

Share this post


Link to post
Share on other sites

Eddie,

Completed the mod and it really brought it to life. I mean, NO MORE bogging at all, you twist and it hits!

Thanks again. :bonk:

Share this post


Link to post
Share on other sites

Well, I'm envious - and confused a little.

Eddie, how does this relate to the Taffy mod (I have an '03 E model)? I was under the impression that substituting a Honda AP diaphram with a longer protrusion on the bottom side was an alternate method of dealing with a too-long AP squirt. Is the particular situation in this thread different? It sounds like your advice (that obviously worked great) was to shorten the protrusion on the bottom of the AP diaphram. Is that what you're calling the "stopper"? I did the Taffy mod on mine and it helped, but I still don't get a clean hit every time. I still get a bog every now and then (enough to keep me wondering if the front will go up or down). Can you clear me up? Thanks.

  • Like 1

Share this post


Link to post
Share on other sites

the taffy mod limits the stroke to keep the squirt duration from being 3+ seconds.this is the same as what the crf diaphram does.they do the same thing.

while cutting the duration via limiting travel is good the bad is it also limits the volume.

by wiring the arms together and shortneing the stopper you are forcing the fuel out early in the stroke and there by decreasing the duration.still delivers the high volume of fuel the drz need at quick throttle openings.

you shorten the stopper as much as possible to keep the ap linage from binding at full travel.

the inherent problem with the old style fcr is as the ap linage wears the duration will get longer and timing goes out of spec all on its own. look at the hole in the plastic arm where the pump rod sits in the pic.

they are not wallowed out like that when new.the higher the pump rod sits in the more duration and the more the timing is off.

my method also drastically increases the spray pressure.

it goes from being a "stream" to a "spray" because of the force being applied.

give it a shot.

all ive done in this deal is take what ive learned with the fcr-mx tuning and applied it back to the old style fcr.

Share this post


Link to post
Share on other sites

Thanks Eddie. I realize you took a lot longer to answer my question than you probably had. I sincerely appreciate it. I'm still unclear on what the "stopper" is and how to wire the linkage together. But, I'll be pulling the carb in 2-3weeks to change the jetting back to 600' from the 7500'+ jetting it presently has. At that time I'm going to study the carb a lot closer and see if I can see exactly what physical changes you're suggesting. I understand the theory and rationale of what you said, just not the exact physical changes needed to do it. If I still can't see what to do when I've got the carb laying in front of me I hope you'll be kind enough to take another stab at getting through this thick skull.

Thanks again.:bonk:

Share this post


Link to post
Share on other sites

the bottom side of the diaphram has a stopper on it that controls the pump stroke.it is longer on the crf diaphram.you want to make it shorter than stock.

here is the pic from this thread modded to show where to wrap the wire to connect the 2 arms.

the red circle shows the 2 arms you wire together tightly so that cant seperate.

the yellow circle shows the worn hole.

carb1.jpg

Share this post


Link to post
Share on other sites

Dang, almost an instant answer!

All I can say is I hope there were others out here that needed to hear the same answers 'cause I got way too much of your time today if I'm alone. You are unreal Eddie. I thank you sir. :bonk:

Share this post


Link to post
Share on other sites

i appreciate the acknowledgement on my available time.

let us know how it turns out.i think you will be pleased.

Share this post


Link to post
Share on other sites

This helped me. I timed my pump a while ago, but didn't wire the two arms together. The throttle response was really good, but lately has been getting worse. To the point where I was getting ready to pull the carb and re-time the pump.

Steve

Share this post


Link to post
Share on other sites

This sounds great I have had the same prob after the taffy mod. I was just curious what did you guys do to shorten the stopper? I have the rest figured I think but just can't remember the AP diapram stopper exactly.

Share this post


Link to post
Share on other sites

how much should i cut off the stopper? as much as possible, couple millimeters? thanks Eddie, you haved saved my ass countless times.

Share this post


Link to post
Share on other sites

walking outside to do it right now. thanks. i'll take another vid and post it on the other thread. thanks again.

ps my hole (hahahaha) is already wallowed out for the ap arm/rod. wouldn't this accelerate the wear?

Share this post


Link to post
Share on other sites
walking outside to do it right now. thanks. i'll take another vid and post it on the other thread. thanks again.

ps my hole (hahahaha) is already wallowed out for the ap arm/rod. wouldn't this accelerate the wear?

great take pics and post them up.

also, RE the "worn hole", would it be worth trying to rectify this and if you tried, you'd want the arm centred in the hole not up the top or on the bottom??

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  

×
×
  • Create New...