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FCRs... So close, yet so far away....

5K views 40 replies 9 participants last post by  jbirdsaway2 
#1 · (Edited)
Before I completely destroy my 900 SS/FE, I thought I'd try the crowd again. Y'all helped me with the charcoal canister recently, and the other articles have been hugely helpful.

Got the FCRs in the 41 size. Pretty cool stuff. Instructions that came with the kit are only for pro users if at all. Junk, really. It's here at .ms that I learned how to get as far as I have. Anyway, got the old carbs out. Installed the new throttle. Routed the lines. Modified the airbox. Connected the fuel and vent hose. Connected and adjusted the throttle cables. Installed the FCRs after adding both adapters to each carb. Went for a meditative walk to contemplate how much support crap gets dumped by removing the stock carbs. Looks nice and clean. Ready to install the air box.

Then... HOLY FUCKING HELL. Give me a break. Attached are pictures of the end state... and by end state, I mean, I stopped before destroying my bike. I'll get back to it once I've heard from the group. I was warned by every string that the air box was a twat to get back in. Some even went as far as to suggest connecting the air box to the new carbs before installing. I tried EVERYTHING... once I noticed a fine sheen of blood on the edges of the new carbs, and noticed the glove had lacerated along with my finger, I tried a new approach.

I actually pulled the rubber boots out of the inside of the air box just to get an idea of how small the diameter was in relation to the outer edge of the carbs... Let me tell you something. The circumference is so much larger than the rubber air box boots that the actual clamps are too small when fully extended (you'll notice in the photos that the clamps are high and not in place... and dialed ALL the way out). And yes... I checked carefully before even starting to ensure I got the right box of stuff. This IS for (among other models) the 98 900 SS/FE.

Here's for the group... if you've read this far.... Should I just buy larger clamps for the rubber boot... clamp it in place, put the air box over the top (easier to manipulate those back into the air box as I just need to squish them and manipulate them into place), or should I stop and admit defeat, and reach out to Motowheels and buy the individual filters?

I literally just bought a K&N filter. This kit came with another brand new one.... at $60 to $80 a pop, I'm wasting money now. If it's safe to just buy the bigger clamps and clamp these boots in place, and call it a day, I'm game. I just don't want to fuck something up.

Thanks in advance... See photos of what I'm talking about.

Oh, and one photo to show some success so you see there're no hard feelings. It looks good and I can't wait to give it a whirl.

Scott, Vacaville, CA
 

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#3 ·
Hey Sean. Now I feel like a schmuck. Anyway, I'll probably need you to do a Technical Inspection before I try and start this thing anyway. You wanted to pop over tomorrow (Wednesday). I'll be at the gym after work until 17:30. You can pop over after that, or you can come earlier on Thursday... your choice. I know you're trying to get your act together for your trip Friday. Let me know. You can reply here, or, more simply, just text me and let me know what your preference is. Meanwhile, I'll get the larger clamps tomorrow and have them ready to look at by tomorrow evening. Cheers. Scott
 
#5 ·
Thanks, belter. The clamps are literally not large enough in diameter to fit around the carbs. I'll literally need a larger diameter clamp... maybe only a few mm.... but larger none the less.
 
#9 ·
I don't think the clamps in the pictures are the stock ones. They look different from the ones I've seen on my SS and my former Monster. The stock ones have a much bigger (infinite) adjustment rate I think.
So maybe a previous owner or mechanic replaced them and, although big enough for the stock carbs, it might be possible that they are just too small for Keihins.

So I would just be sure not to tear the rubbers and buy clamps that do actually fit.

On my bikes I've always had this kind of clamps:

 
#10 ·
ducvet, belter, RockAZ and BelgianDuc900SS, thanks a million! I was especially validated by Rock making his FCRs his blood brother like I now have. As I type this, each key stroke is like burning my finger tips as that's where the cuts are. Hahaha. Never fails. Once I get it all buttoned up, I'll drop a photo in. May be a day or two. Cheers. Scott
 
#19 ·
I don't think there's anyone who has FCR's and an airbox that HASN'T bled while fitting everything back together - so you now have your bloody badge of membership. ;).

FWIW, I used some liquid soap on the rubbers where they fit back into the airbox, and used some blunt nose pliers to grab the rubbers and pull them through the hole into place. Kept my hands well clear of those sharp edges. Mostly.
 
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#11 ·
Just to sorta' close this out (pic will still be posted when done), I found this tidbit by user sfyamr1 (which comports with what I'm currently doing to unscrew this light bulb):

"THE TRICK TO THE AIRBOX RUBBERS IS TO REMOVE THE RUBBERS FROM THE AIRBOX, INSTALL THEM ONTO THE CARBS, AND THEN INSTALL THE AIRBOX AFTER. ONCE YOU POSITION THE AIRBOX OVER THE RUBBERS, IT'S A VERY SIMPLE FEW SECONDS TO PULL THE SEALING LIP BACK INTO POSITION ON THE AIRBOX.

Everyone struggles with this, and if you try the other way, you'll never get it and likely damage something."

Wish I'd of found this before failing enough times to make my hands look like they've been in a wood chipper. Anyway, thought I'd share that old nugget of wisdom.
 
#13 ·
Well... I decided to end on a high note. Buttoned her up for the night and went and had a cold beer.

For the group: Got it assembled. Even using the technique I posted above, it was a nightmare. You can't fully install the carbs with the airbox boots connected (I used the clamps, by the way - ended up sourcing a longer screw from Lowe's as the clamp's diameter was too small with the existing screw to close), and then got the airbox in place. The airbox won't fit past the top of the rubber boots with the carbs installed. So you have to lay the carbs uninstalled in the vicinity of the intake manifold so it's lose and movable... then work the airbox into place over the rubber boots while slowly moving the carbs around to accommodate... then install the carbs.... then work the rubber airbox intake boots into the airbox. Helps to actually screw the airbox into place so it won't move. Work space is small. I had my lady reach in with her dainty hands and that did the trick. Anyway, got it all back together just as Iwannaduc pulled up to take some measurements on my solo seat for his Superlight project. He's my witness (Thanks Sean for your help getting the airbox clips in place!). It fired up pretty much right away. I mean, it chugged as the fuel lines and carbs filled with fuel... but after a few seconds of that, it fired right up, and immediately set into a nice idle. I let it warm for a minute or so, and gave it a tentative rev. Sounds good. I'll test ride it this afternoon. Thanks again to everyone who weighted in on this. I honestly think that when it's time to pull this apart and do the valves, I'll switch to the individual filters. Dealing with the airbox is too much trouble. Picture included of the installation. Cheers.
 

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#14 ·
I have an E900 Elefant with FCR 39's. The airbox connects to the carbs via a single piece 2 into 1 rubber boot type of affair. Like on the Ducati, everything is packed into a tight space between the frame and the cylinders. Getting it all lined up and knowing just where and when to push was a major frustration ..........until I discovered Red Rubber Grease! This stuff helps rubber slide easily over just about anything and with just a tiny smear, the boot now slides into place with minimal effort. Silicon spray works too but the grease is better. Maybe this'll help next time? (Also good for fitting rubber fuel lines in awkward places)
 
#15 ·
I honestly think that when it's time to pull this apart and do the valves, I'll switch to the individual filters. Dealing with the airbox is too much trouble.
Just to be clear you do not need to remove the airbox to adjust valves, and you will find after the rubbers on the carbs have been on for a while it gets much easier. The oval stuffed into a round hole gets easier when you have a oval hole.

Elefant rider

Any pictures of that arrangement?
 
#21 ·
Liquid soap, anal lube, it all ends in tears the first time - ...
Ah..hahahahahahahaha :laugh: I almost blew water out my nose when I read that....good thing it was only water :surprise:
 
#26 ·
Changed the plugs. Gapped them at .032 (a bit wider than factory manual calls for). Dialed down the extended adjuster knob on the idle to see if that would take care of the hanging idle. Went for a 30 mile ride opening it wide repeatedly throughout. Here's what happened:

Mile 1 to mile 20: Hanging idle pretty much gone. It doesn't drop to idle rapidly, but does drop steadily. I can live with that. As for the engine... no real changes.

Mile 21 to mile 30: Bike woke the fuck up.

Makes no sense to me. How is that possible? By the time I turned into my neighborhood, the bike felt completely alive. I have no clue how there could be such a change. I've read about crap clearing in old jets, but this is a brand new set of carbs. It was like one moment it felt a bit flat, taking effort to get it to move... the next, it's like wanting to jump off the ground when I gun it at 4 to 5k RPMs.

Oh well. I'm not complaining or anything. Just curious as hell. I could be saying that at mile 21 it died and left me stranded. So I'm happy. But WTF?
 
#27 · (Edited)
Glad its going well, as to the symptoms you described I would say either a sticky float bowl in one carb, maybe an air pocket in a passage or accelerator pump was sticking. Which also fits your previous symptoms as well. I forget - is that a new fuel pump? If not that little "sock/screen" intake on the pump could be falling apart, rotting, sending bits down the tube. Get a clear external filter put inline and you may as well put in a fuel shut off valve too if there is any reason to suspect a sticking float bowl. FCR's are notorious for filling your oil with a whole tank of gas while parked.

Less likely might have been a pinched fuel hose or clogged filter.

Least likely might be dragging brake pads?
 
#28 ·
Only the carbs are new. I haven't gotten into the fuel pump at all. Could be the air pocket you suggested as the fuel lines were evacuated when I pulled the old carbs off. There's a good chance that with the new carbs in place, when the fuel lines filled and the carbs filled, could have gotten some air in there somewhere. I was hitting it pretty hard on the ride... it could have burped the system at some point. That would make sense to me. I'll take a look at the fuel pump and "sock/screen" intake on the pump and ensure it's clear. I've seen the posts on the FCRs filling the oil with gas. The shutoff valve with fuel filter is on my list of things to do. Thanks a million!
 
#29 ·
Is it possible the bike simply wasn't up to temperature until mile 21? If not fully warm and slightly lean it will be flat and when you get the engine temperature to where the jetting is close then it runs like it should.

know that it is normal to have fcr's hang when warming up, simply turn the idle down a bitr at a time until it drops normally. do not be surprised if the rpm's on the tach is close to 1000 rpms where the bike drops normally. The CV's do allow a higher idle the FCR's do not.

I start mine with the idle raised and let it warm until the idle jumps up.
Then lower the idle until the throttle takes opening with no issues and returns normally. At this point I drive off and know that in 1/2-1 mile I will turn the idle down more. After you learn the bike more you will know how much to turn it down and how many steps it will take. FCR's should never hang when fully warmed and the idle is set properly, thats why you didn't buy delorto's or mikuni's. :wink2:
 
#30 ·
Its been in the 90's where jbirdsaway2 lives, so I think 20 miles is a lot further than is needed to warm up, but our bikes with FCR's are cold blooded beasts that are a little slow to engage until warm. I find it gradually gets better in the winter, not suddenly as described.

I too have the idle adjuster where I can easily tweak it, usually two times, at the start of a days ride in cooler weather.
 
#32 ·
You said a mouthful regarding the temp. On the day I did that 30 mile ride as described, it was a withering 106 F. It's helpful to know that the FCRs make these a bit more cold blooded then they already were. I'll have to experiment with the adjuster knob on the idle. Like I mentioned, running it right out of the box, it hung at 2k when warm. I turned it down (left) about a full turn, and it slowly settles when off throttle now. And it idles at just a tic above 1k. It's also helpful to know that that's the normal idle trend for the FCRs. I'm fine with a 1k idle. If warming this up is what makes the difference, I can say that at around mile 20, I was out of the woods where the twisties and long straights peter out and sanity has to prevail as I come back in to town... that slows me down, which warms the engine more. My eyes are glued to the oil temp gauge. My 95' didn't have one, so I'm currently trending what the temperature does. And it really didn't get up to that 120 mark until around then. In fact, for 15 miles, it hung at around 100 and stayed there until a couple of high RPM runs just before coming out of the woods. I'll keep dicking around with it for a bit before committing to pulling the airbox (dread!) and doing something with the jetting. If it's just a matter of proper warm up, I can be more vigilant. The thing that boggles my mind is that with my 95', I lived in the same area, same environment, same altitude, same temps.... just different house nearby currently... and when I took that guy out, it was ready to go ballistic after just a few miles of warm up. And that was year round. It never took a shitload of warm up to come alive like this. Makes me a tad concerned about going to full synthetic oil. The dude I bought the bike from was a pure mineral oil guy for life (82 year old still racing vintage bikes). He put fresh oil when I bought the bike, so no hurry on changing it... but hell. If I go full synthetic, it may NEVER warm up. :think:
 
#33 ·
Jet size where? In the starter circuit or the mains? The extent of my carb knowledge is: I installed a stage II factory jet kit in my 95', and now just swapped out the carbs to FCRs from stock. I "dynoed" the 95' with the seat of my pants and plug analysis, which worked great at the time..........
 
#35 ·
I removed the airbox for this reason. It was worth losing a few horses at the top-end, and saving my sanity.

With that being said, I used to attach the FCR to the airbox first. With the airbox off it is much easier to position and attach the airbox boots. I might have also cut the grid in the airbox but I can't remember for sure.

With the carb body snugly attached to the airbox boots I'd screw them down, I'd positions the manifold boots on the bottom of the carbs and tighten only the top-half of it. Then I'd coat the carb-end of the intake manifolds with KY Jelly, and put either worm ring used for the bottom-half of the manifold rubber boot around a runner and let it slide and fall down to the head.

A few deep breaths and curse words toward Bologna later, I'd position the behemoth of airbox-carb assembly lightly and evenly across both runner openings such that both manifold rubber boots were as straight as I could get them. Then I would grab the FCRs and mostly put downward pressure on the FCRs themselves and a little downward pressure from the airbox to push the boots around the manifolds. I'd go a few millimeters a time per side. That KY Jelly really comes. In handy.

I'd then seal the bottom-half of the rubber boots by bringing the worm rings I let slide down back up and tightening them. I have a CR and it's easy to face the bolts such that they are accessible from directly under the fairings.

As a principle of therapy from the pain and suffering cause by that airbox I will one day set one on fire.
 
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