Jump to content
Sign in to follow this  

a few fcr questions???

Recommended Posts

1. When used to first start my bike with my stock carb, pulling the choke knob would increase the rpms quite a bit which was neccessary for starting (even in hot weather). I just installed my fcr and when I pull the choke it doesn't seem to have any effect on the idle. When I start my bike now I have to manually give it a little gas for the first few seconds to avoid stalling. Is this normal?

2. Also has anyone else noticed a loss of bottum end on there fcr's? Mine bogs on the bottum end just like the one on my z400 used to do. Its like I have to roll into the throttle, if I snap it, it bogs and/or dies. Maybe this is because I bought an older Fcr, off ebay, as opposed to the new "mx" style?

3. I definatley have noticed more power but I still can't really pull the front tire up (without a lot of body language) in 2nd gear. Is this normal with a Yosh, 3x3, Fcr, Hotcams and high comp? Seems like there should be more power there.

Share this post


Link to post
Share on other sites
When used to first start my bike with my stock carb, pulling the choke knob would increase the rpms quite a bit which was neccessary for starting (even in hot weather). I just installed my fcr and when I pull the choke it doesn't seem to have any effect on the idle. When I start my bike now I have to manually give it a little gas for the first few seconds to avoid stalling. Is this normal?

No

Also has anyone else noticed a loss of bottum end on there fcr's? Mine bogs on the bottum end just like the one on my z400 used to do. Its like I have to roll into the throttle, if I snap it, it bogs and/or dies. Maybe this is because I bought an older Fcr, off ebay, as opposed to the new "mx" style?

The fcr on my bike has tremendous snap to it and it is the "old" style

I definatley have noticed more power but I still can't really pull the front tire up (without a lot of body language) in 2nd gear. Is this normal with a Yosh, 3x3, Fcr, Hotcams and high comp? Seems like there should be more power there.

What is your final gearing? It sounds like you have a jetting issue, at least with the pilot circuit and most likely with the rest of it.

Share this post


Link to post
Share on other sites

My gearing is stock 400s. Im not sure what the front is but the rear is a 44t.

Perhaps the jetting does need to be tweaked a bit. I can't even remember for certain what I put in there. Im sure the main is a 160, I beleive I have the screw at 2 1/4 turns out. The needle is at the 3rd clip from the bottum and im not certain what the pilot is at, I think its a 45.

Also I unscrewed the choke knob to shorten it so it wouldn't hit my Clarke tank. It seemed very self explanitory on putting it back in but maybe I missed something and thats why it doens't seem to be working properly.

Share this post


Link to post
Share on other sites
here is the link to the carb. Says it came from a running drz400. But Im not sure if it was stock or aftermarket. Also I will remove the carb today and check all the exact jetting specs and hopefully get back to you this afternoon.

Share this post


Link to post
Share on other sites

open air box w/3x3, Yosh rs3, hotcams, high comp (13.5 to 1) about 550 or 600 ft. elevation and roughly 80 degrees out.

Emn 3rd clip from bottum

pilot jet 45

main jet 160

starter jet (next to main) 85

min air jet 200

slow air jet 100

taffy mod set to .025"

I was thinking about going to a 40 pilot jet and was wondering if I could go up to a 165 main.

And yes it looks warn out. I had to replace the float bowl gasket and float valve o-ring (they where shot). But aside from that what else could be warn out?

Share this post


Link to post
Share on other sites

Emn 3rd clip from bottum

pilot jet 45

main jet 160

starter jet (next to main) 85

min air jet 200

slow air jet 100

taffy mod set to .025"

I was thinking about going to a 40 pilot jet and was wondering if I could go up to a 165 main.

And yes it looks warn out. I had to replace the float bowl gasket and float valve o-ring (they where shot). But aside from that what else could be warn out?

you need a 60 starter jet.85 is to rich and thats why it requires throttle on choke.

as far as your taffy mod goes,how long is the squirt duration?

and to what else can be worn?

carb body,slide,slide plate,needle jet,etc etc.

that looks like a 98 yzf 400 carb.

coming up on 10 years of dirt bike use.............

Share this post


Link to post
Share on other sites
you need a 60 starter jet.85 is to rich and thats why it requires throttle on choke.

as far as your taffy mod goes,how long is the squirt duration?

and to what else can be worn?

carb body,slide,slide plate,needle jet,etc etc.

that looks like a 98 yzf 400 carb.

coming up on 10 years of dirt bike use.............

Im not sure what the duration of the squirt is or how to tell but, I set the gap at .025" as per a few threads I saw about the taffy mod.

Im not a carb expert but from the looks of it the slide is in good shape, im not sure what the slide plate is and the needle jet is new (if by that you mean the main jet).

But maybe Im just trying to make myslef feel better for being a tight wad and not dishing out for a new carb (maybe I'll keep my eye out for a newer one on Ebay). Anywho, Im gonna change the jetting slightly and see if that helps my bottum end.

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  

×