installed the thumpertalk fcr 39 kit to drz400sm, BUT....

[shift]

hey all, i'm setting up my friend's 07 drz400sm for our xc trip. he made it sound like the kit from thumpertalk was pretty much plug and play. i didn't check the jets, air fuel ratio screw or anything. i did take the clip up one notch on the needle since we will be doing all out riding above 4k feet. i did remove the pilot air jet, as the write up on TT said to. i don't see them saying that in the paper instructions that came with the carb though.

the bike hesitates, but starts, then quickly dies out. it backfires a lot when revved. seems like it's not getting enough fuel. he has a aftermarket yosh pipe on it. and the airbox is cut open at the top.

anyone here familiar with the fcr mod?

[shift]

ok, i realized i was missing the vacuum line tube from the petcock to the frame. but it's still running lean. it only wants to run with the choke on, and still bogs a bit.

without changes to jetting, i guess the nest step is to richen the air fuel mixture via the ratio screw? that and cover up some of the airbox mod the previous owner did for a jetting adjustment. he opened it up to abut 3" x 3".

[Wingfixer]

Why not just re-jet? Its not that hard and the 3x3 hole was made so the engine could breath easier and make more power

[Roadracer_Al]

You *must* do the 3x3 mod to run an FCR (in order to have the TT jetting even vaguely in the ballpark), so that is correct.

I have an older slant-body FCR, and it just plain wouldn't run right without the air bleed jet or screw (there are two options, one is a fixed-orifice jet, the other is a bullet-shaped needle that offers tunability). IMHO, put the air jet back in and try it again.

If that still doesn't work, post with the symptoms - exactly when does it have a problem, and exactly what is the problem, - i.e. stumbles at 1/8 throttle while cruising on the highway.

Also, hit the Sudco site and download the PDF for the FCR -- there are a couple charts that are absolutely invaluable for jetting - they tell you where each jet/adjustment affects in the throttle range.

[shift]

well, the plan was to be on the road sometime today. obtaining jets for the next few days is probably impossible. i was told the jet included should be fine. a friend who is great with carbs suggested the main fuel jet is clogged. i pulled the plug and it looked like the lip around the electrode was just a little white around the edges, indicating lean, no? if anything, the jet in there is too big, which should make it run rich, correct?

the airbox mod can easily be changed back. i simply riveted a plastic piece over part of it. easy fix...



i also had to overnight a internal oil filter cover for the ktm because the old one was stripping out. well the new one came and didn't have a rubber gasket indent around it. soooo, i applied a layer of high temp rtv silicone around the surface and hopefully that will do the trick.

i swear, anything that can cause a small problem, is. geez...

[restukey]

without changes to jetting, i guess the nest step is to richen the air fuel mixture via the ratio screw?

The FCR has a fuel screw, which isn't for adjusting the a/f ratio. It is for adjusting the pilot circuit, and opening it some might help the popping if it was from decel? A little white on the plug is normal with unleaded gasoline. I'd ride the bike for ten minutes before deciding it is lean, needs to warm up. If you are lean, you would need to change the main jet. Also, the clip position is for the first third of the throttle movement.

[Louge]

it only wants to run with the choke on, and still bogs a bit.

FCR AP setup tutorial: http://www.cafehusky.com/forums/showthread.php?t=6890
Be sure the cap is removed and set the linkage to 2.75mm. For additional Moab snap lower the linkage to 2.25mm.
(I ran mine at 3.5mm on the TAT to trade off bottom end snap for range.)

Reinstall the pilot air jet if for no other reason than to eliminate a variable.

Check the leak jet. It probably came with a blank, install a 70.