FCR + Merger spring - Still bogs

[Flint]

Greetings all,

when i bought my TT 39mm FCR kit I installed the Merge spring right from the beginning. However, the bike bogs off idle and seems to misfire a lot when riding. Seems to be when applying the throttle. it sounds similar to the symptoms requiring the O'Ring mod - however, i have the Merge spring installed.

Any ideas what i need to do to fix this ?

Thanks for your assistance.

Flint

[hinksy]

If you have done just this mod without adjusting the timing of the carb`s pumper , then I would start by adjusting the AP screw at half turn incriments . It sounds like you either have too long a duration on the squirt or maybe too short . Fuel mixture can also help too , greg

[Craigo]

What needle and pipe?

Is the bogging at low throttle settings

Edited June 12, 2012 by CraigoDRZ485sm

[fish_bate]

If the squirt is coming on too soon, the fuel hits the back of the slide and pools in the carb throat. This can cause a bog issue as well.

[Flint]

I followed the FCR jetting precisely - The bogging is right off idle and also when applying throttle on and off when in the trails.

I have the 3 x 3 with stock pipe and followed the recommended jetting for this.

I presumed that the AP was set up correctly and would not need adjusting - was that a bad assumption ?

If i need to set up the AP properly, how should i do that ?

Thanks for your assistance.

Flint

[Craigo]

What needle is installed and what is your altitude?

[Flint]

The needle is the recommended EMN with clip 3rd position. Riding altitude about 650 - 1000 feet above sea level.

[Wayward Son]

turn the timing screw in a half turn at a time will it clears up.

[Flint]

Hi Eddie,

when you say "timing Screw" is this for the Accelerator pump or the fuel air screw ?

With reference to the Fuel Air Screw, I have tried it a half turn out and up to 3 turns out but it does not resolve the issue.

Also, I bought the reommended after market one with the little T bar on the bottom. The problem is that it is very loose and vibrates out and drops onto the casing below. What kind of product should i use to stop this happening.

Thanks for all of your help over the years - very very much appreciate !!!!!

?

[William1]

Yes, he meant the AP timing screw.Take your time, make notes of how far you turn it. Often, 1/2 turn CW cures it. Do not test by having the bike sitting in the driveway. Ride it normally.

Set the fuel screw on the bottom of the carb for a perfect idle and then leav it alone.

Fuel Screw/Pilot Jet

Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.

Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.

*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***

Turn the screw in until the idle becomes rough or the bike stalls.

if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.

If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.

Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.

If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.

If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.

If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,850 rpm, but go by the spec in your manual.

As far as the fuel screw coming loose you can insall a second oring on the groove midshaft or use safety wire to 'tie it' in place.

[Flint]

Great descriptive post - thanks !!

Can i get to the AP screw without taking the carb off ?

[William1]

Yup, as long as the throttle wheel cover is off, the screw is fairly easily accessible. A 90 degree driver makes things easier though. Take your time, think and keep good notes. Turn the timing screw CW 1/2 turn and go for a nice ride. Do not try to force it to bog. Just ride normally.

Edited August 12, 2012 by William1
Stupidity! Thanks for the cath CraigO

[Craigo]

Please excuse, but isn't "Turning in" clockwise..CW.....Not CCW...(counter clock wise).... ?

[Mad Dogg W]

Flint, are you sure you got the Merge spring mounted right ?

I used an R&D Racing AP return spring and it took me about 10 attempts to get it mounted properly. If it wasn't mounted clean it didn't return the pump drive shaft properly....

[William1]

Craig....err, yes, you are completely correct. Dooh! I'll edit my mistake out...... Thanks for the catch. However.... if you move the screw one direction and it gets no better or even worse, try the other direction. Just be careful and keep good notes.

Mad Dogg makes a good point. Ensure the plastic cam firmly presses agains the timing screw. Watch the linkage as you rapidly twist the throttle (engine off). Confirm the cam and screw stay together and do not seperate (the springs job).

[Flint]

Hi guys,

thanks for the tips. I am pretty good with this stuff but new to APs and to this carb.

All the assistance is much apreciated !!

?

Thanks

Flint