FCR Weirdness

[JohnnyDude]

Hi All,

I wonder if any of you guru's out there can help me. ?

This afternoon I fitted the FCR39 that I've had sitting around for a while waiting for the bits from Suzuki to arrive. I had previously changed the jetting in the FCR to the "DRZ.INFO" settings without the coast enrichener.

1) Put in an EMM needle, on the 4th clip.

2) Put in a 38 pilot jet (PJ).

3) Put in a 70 pilot air jet (PAJ)

4) Put in a 160 main jet (MJ).

All went well with the fitting and the only surprises were the choke lever is just behind the petcock (Doh!), there is a hose from the black chamber on the right hand side that needed to be blanked off as the new velocity stack did not have a hole for it and the electrical connector from the bottom of the BSR36 is now not needed.

I used the "S" throttle cable to open the carb and removed the closing cable. Yes, I know I'm cheap! This was set so the slack was minimal and the carb would then open till the carb stop.

Upon firing it up it was fine. Ticks over superb and does not hunt. Blip the throttle and instant response. Carburation seems fine so at this point I'm v.happy.

So after reassemby I take it out for a test ride. Pulls away fine and throttle response is easy to control, not at all snatchy as I thought it might be. Time now to give it a handfull and see what happens.....

Well this is where the issue starts. From closed to full throttle is about 1/3 of the previous carb and while this is nice, I can't escape the fact that the bike does not seem to have the punch it had before. almost like the carb is not opening fully. I spend the next 20 mins riding around the area at full thottle thinking "summat wrong here", before I head home.

When I was looking at the carb before I fitted it, I noticed that when turning the throttle wheel on the side of the carb it only opened the slide about 1/2 way. Not ever having seen this carb before I thought this was normal, that perhaps it used vacuum to lift it further than halfway, and though nothing more of it.

Now I'm getting worried. Have I missed the hidden throttle stop that I need to adjust? or do I have a lemon?

Ideas please, I'm stumped.

[Dirtman13]

Don't block the hole from the black box thats your engine vent. It needs to breath. I reinstalled it into the new boot was easy. I had the same problem with the choke I ground of the tip pulled the black knob off drill out the hole shortened the shaft then pressed the knob back on. Choke now works. With great new carb I haven't used the choke but, it's there if I needed it. Last the slide should open all the way.

[JohnnyDude]

Hi Dirtman,

Thanks for this I'll remove the bung asap! I just looked at the exploded diagram on SUDCO and it seems that there is a stop "Number 18" on the diagram. I'll check this later as it's getting dark here and I've no light in the garage.

Anyone adjusted this, is there a procedure? I never noticed it before! ?

[pokey1]

I believe the Mikuni throttle cable doesn't have enough travel for the FCR.

[JohnnyDude]

Hi Pokey,

Thanks, you're correct but I don't think it's this in my case as the carb is stopping before the twistgrip is. This was the first thing I looked for.

I think I have a winner with the internal stop inside the carb. I just found it when looking at the diagram on SUDCO. I just expected this to be set at the factory! ?

You live and learn ?

[jsuhr]

160 seems pretty Rich???? what exhaust is it?

Whats you altitude?

I had to get new throttle as well as new cables but the cables came with. Otherwise mine didnt fully open

[JohnnyDude]

Hi jsuhr,

I'm at about 500ft ASL. So I followed the DRZ.INFO site to the letter. I've got the CRD Absolute Performance 2 fitted which is quite open. I've also removed the coast enrichener too so that might be the difference.

My jetting seems fine. No pops, glitches at all. Even tick over without hunting ? so I think this is not to far away. ?

[Noble]

Several questions:

What is the source of the carb? You mentioned SUDCO. Is it an aftermarket carb frm SUDCO with choke and throttle postion sensor?

In the picture you seem to have a hose that runs between 2 nipples on the side of the carb. The rear nipple originally fed air to the CE. The forward nipple is the nipple that feeds air from the CE to the pilot jet circuit. These should both be blanked off not connected to each other. Is there a jet in the fwd nipple? What size? Unless It is blanked off, you are feeding air to the pilot circuit from 2 places just like the CE does except there is no air cut-off for coast. Odd that it is working OK for you that way.

I take it you found a throttle stop in the carb. That is also odd for an aftermarket carb but easy to remove. Wonder why it was in there.

If you add a hose from one of the blank ports on the head just in front of the carb connector to the fuel valve, the vacuum operated fuel falve will work normal.

[JohnnyDude]

Hi Noble,

Well spotted! ?

I should have guessed that someone would notice this. The carb is a Suzuki DRZ-E model and it standard in everyway. I removed the CE and the hose you see is not linking but blanking both ports.

I could not bring myself to pay the 3.58 pounds each for the blanking plugs so made my own out of an unused hose. I placed a blanking bung into the middle of the hose so both ports are sealed. ?

The fuel valve. The UK version does not have a vacuum operated fuel valve. Ours is just a tap and nothing else. The two ports on the head are already blanked off. It just seems that the petcock on the "S" is about an inch further rearward than the petcock on the "E".

Thanks for the assistance.

[Wayward Son]

is it a yamaha wr carb?if so,they have a throttle stop.

you need to cap the fittings instead of looping a hose.

[JohnnyDude]

Hi Burned, ?

It's the carb you and a few of the other guys id'ed for me. It turned out to be a DRZ-E carb with the standard UK jetting. This I changed and junked the CE.

See the above post about the link pipe. For some reason, blanking plugs are like platinum in the UK. And when you find them they want stupid money for a blob of injection moulded plastic. Hence my improvisation.

[Wayward Son]

so does the slide go all the way up or not?have you looked in the carb while operating the throttle?

[JohnnyDude]

When I was changing the jets I noticed that the slide did not go all the way up when the wheel was turned but not knowing any better thought this was normal. ?

I cannot remmeber wether I saw the stop when I was changing the needle but I bet that's the cause. I noticed it on a diagram at SUDCO and that where I got the idea from.

I'll have to wait till next WE till I get enough time, with daylight to strip the panels off to get a look intot he top of the carb but I'm hoping to find a nice adjuster in there. Either way I need to get a look in the top to see what is going on.

Thanks again! ?

[Wayward Son]

the stop wont be under the cap.its on the out side by the throttle wheel.

i think the S cable is causing your issue.

[NateTheGreat]

You may also want to start trying different main jets once you get everything else figured.

I am at 1500ft or so and I started with a 162. I felt it was too lean so I went to the 165. So far seems to really rip hard from sea level to about 3k.

I was running an EMM and everything just like you.

Now I run a JD blue needle which has way better smoother power roll on.

[JohnnyDude]

Hi All,

Well after thinking about it all day I decided dark or not, the FCR had to be pulled. ?

Upon close inspect in the house it became clear what the problem was.

This offending spike was screwed into a position just behind the throttle wheels and limited the throttle to just less than half opening. "Why oh why" would anyone wanna do this!! ? :cry:

Still it's out now and the carb works WFO. As soon as I can get home with a little daylight around I'll refit the carb and give it a test run. ?

Thanks to all who helped and those that just pittied me! ?

[NateTheGreat]

Both FCR carbs I have had stops but they were like half the size of that monster and allowed full opening of the slide.

You may want to trim it to size instead of remove it. If you turn the linkage all the way with it out the little rollers on the slide go slightly beyond the slide groves and the slide could then fall down and be "unhooked" from the linkage. ?

[Wayward Son]

thats like what they do on yamaha wr's in the US.ive never seen one on a drz carb........ ?

[NateTheGreat]

My WR FCR and DRZ FCR both had one. ? They were both way smaller than that thing though. ?

[alophind]

Jhonny boy , the problem is that you bike is VERY CLEAN ?

please fix it ?