Carby Prep

[OzDamo]

Hi All

In my continuing efforts to get my 1992 FJ running the next concern is the carbies. It does start if I spray aero start into it.

Two problems...
1. My fuel tank looks HORRENDOUS inside. I'm concerned the carbies are full of muck.

2. The bike has been sat for about 3 years prior to me getting it the other week.

3. Uknown history before me

Is there some simple procedure to check them, or is it best to pull them all apart.

Is a rebuild very hard? I'm fairly good mechanically.

Should I just chuck fuel through them and try?

cheers
Damo

[Pat Conlon]

Yep, you need to go through your whole system, your idle and pilot circuits are plugged.
Clean your tank or it will happen again.
Flush out the fuel lines.
Replace the fuel filter http://rpmracingca.com/proddetail.asp?prod=M%2FC%3A1FK-24560-10
Get this $24 kit from RPM and replace the o rings http://rpmracingca.com/proddetail.asp?prod=carbkit
Read the instructions in the Files on carb cleaning.

Cheers

[OzDamo]

Read the instructions in the Files on carb cleaning.

Thanks Pat

I hadn't come across that in my searching. I'll have a good look in there.

cheers
Damo

[Flynt]

Is a rebuild very hard? I'm fairly good mechanically.

You'll see it's not super complicated and you can probably do it.  Two bits of advice however...

1. Be THOROUGH!  Most people underestimate how hard it is to get crap and varnish out of the carb's very small passages...  they clean 3-4 times before everything is actually clean and working well enough to tune them in.

2.  If you don't have access to a steam cleaning cabinet and an ultrasonic bath...  you probably will not be able to comply with #1. 

RPM will rebuild and balance for a very fair price in most people's opinion, then they are sorted.  Of course you're going to want to do the other stuff Pat mentions before you put it all back together and run it...  the carbs will be done and ready while you work your way through the tank.

my $0.02...

Frank

[fj1289]

Agree with Frank on getting RPM to go through the carbs.   It's not nearly as easy as it was 15 or 20 years ago.  Additives in gas now make for some VERY nasty and difficult cleaning of the small passages in the carb bodies.  Randy and Robert will also get it jetted for you and be pretty close to spot-on.  Plus they are extremely familiar with running these engines in a "heavy" chassis - legends and thunder roadsters. 

[Pat Conlon]

Hey guys, yep, Robert at RPM does great work, however, Perth is a long way to Oakdale.

Paging Robert.....What would you estimate the shipping costs to be?

[RPM - Robert]

UPS would likely be 120-150 usd each way.

I just a block, pistons, rings, prints etc etc. was around 24 lbs. was 210$

[OzDamo]

Thanks.

At the moment i just want this thing started and to blip the throttle. Take a quick video then done. Doesn't need to even run well.

My plan is to completely rebuild the engine at some point. But that will be down the track. I'm intending to put this engine in a custom trike frame. Once all the creating on that is done, then I'll rebuild the engine fresh.

I've got a very minimal exhaust on it at the moment. And it sounds awesome even when only popping to life for a brief second on starter fluid.

I'm so glad i got this bike. It seems way more suitable than I realized when I first got it for what I want to do, which is build a trike..

cheers
Damo

[ribbert]

There's no doubt Robert (RPM) does great work but $400-$500 AUD freight plus RPM labour/parts cost and delivery times return from the US running at 12-14 weeks, it just ain't worth it.

As I said, taking nothing away from Robert's excellent work, but these are just carbies. The most common carby in the world, made by everyone, fitted to everything and in constant use for nearly a 100 years, they are dead simple and with guidance from the forum experts, of which there are plenty, they can be set up easily, everyone knows the numbers. IMO the only tricky bit is getting them clean, this is perhaps best dealt with by experts when the time comes. Perth will have plenty of carby/FI shops that are well equipped for this. You just need to instruct them to make sure the orifices are clear and not just assume they are because they've been dipped.

Damo, you say you have reasonable mechanical skills, overhauling these carbies falls well within that spectrum and we are fortunate not to have shitty fuel here. Once set up you can forget about them other than for the occasional balance. I've literally done a couple of hundred thousand km's since I last cleaned mine maybe 10 years ago. I did re-jet them and raise the needles about 100k ago but the bowls were so spotless I didn't even clean them while I had them off. You have a '92 which has a fuel pump and lets you run a proper filter, keep that set-up on your build.

I know it would be great to hear it fire just once prior to the build but if the carbies are unserviceable you might have to wait, unless you know any locals with a spare rack of carbs (we have members over there) they could loan you, however you would need to use something other than your current fuel tank as a supply. If the tanks full of crud it's just going to end up in the carbies.

You could try a rudimentary carby clean and a temporary clean fuel source like a fuel can just to get it started. The fuel pump models will run without the pump and just a bit of head pressure.

You mention your delight in concluding the FJ mill was a better choice for your project than you'd initially imagined. There are many members here who also own more modern and powerful bikes and some for whom money is no object but still can't wean themselves off the unique qualities of the FJ engine. I for example (for whom money is an object), have another brand 1200 that is renowned for it's torque, but at 100kph I have to go back 3 gears to get the same roll on acceleration the FJ delivers in top gear! The engine mounting in a '92 also makes it one of the smoothest in line 4's you'll ever ride, the parts are cheap and plentiful and we even have places like RPM dedicated to preserving them through global parts acquisition and supply, FJ specific manufacture of critical parts and service with an actual shop front and world wide mail service.

The people I know personally who own FJ's collectively own a stable of enormously desirable bikes but still do the most km's on their FJ's, I get that. When we get together for a ride, it's almost always the FJ's they bring despite it not being an FJ themed outing. Haha, I just wish they'd bring the other bikes so I could ride them more!

Even by current day standards, the FJ engine is a beauty, you chose well and you won't be disappointed.

Noel (Melbourne)

[RPM - Robert]

The shipping to and from is a killer but we have been using UPS to ship to AU. It is the same cost as USPS , for the most part and it has been taking less than a week for orders from the US to get delivered in AU this way.

We only charge $200 to replace all the orings, clean, inspect, and bench synch the carbs, + the cost of worn/damaged parts or jets. After some people were quoted 3x that, we have had a few people, maybe a handful, shop their carbs over and back, from Japan, AU, and Europe.

That said Noel is correct. They are not difficult to do but you do need to make sure the internal ports are thoroughly cleaned or you might be chasing your tail

[fj1289]

I used to clean my carbs - and could get even the cruddiest set working well with very judicious use of cane cleaner and the nozzle - probably at least 2-3 spray cans of carb cleaner per rack.  This was fully disassembling each carb body to get to every nook and crevice and passage way (but leaving the rack intact).  Always wear eye pro by the way - the stuff burns like hell and clouds up your vision for a good while!

But lately this hasn't worked nearly as well for me - don't know if the chemicals in the carb cleaner aren't as effective now, or if the newer additives in the gas are that much nastier?  I think the gas is the issue - what used to turn into gooey varnish now turns into some kind of a hard shellac/epoxy/crap that is much more difficult to remove.  Another reason I prefer EFI now (I can just send the injectors out for servicing at $20 a pop!) .....

[Pat Conlon]

I only store my bikes with VP C-9 fuel....problem solved.

https://samscycle.net/storage-warning-local-gas

No more of this crap.....

[ribbert]

I only store my bikes with VP C-9 fuel....problem solved.

https://samscycle.net/storage-warning-local-gas

No more of this crap.....

Holy shit Pat, I was serious when I said my bowls were so clean after a 100k I didn't even bother cleaning them. In fact, I wiped the bottom with a tissue and there wasn't even a smudge. I know of former members who literally haven't had their carbies off in twenty years and there's nothing about the way they run that suggests they should.

We should be very grateful for our good fuel here.

Noel

[Pat Conlon]

Thanks to the corn lobby here in the US, the ethanol fuel problem will only get worse for our carbs.
The current E10 (10% ethanol) will soon be E15 or even E20 which is fine for fuel injection systems, only us carb'ed dinosaurs will be affected.

If you don't have access to non ethanol fuel, you better get used to moss growing in your fuel bowls.
............and no, I haven't (yet) found a fuel stabilizer that removes the effect's of ethanol.

[Motofun]

One trick to using pressurized cans of carb cleaner with those little red plastic straws is to "sharpen" the tip of the straw with some fine sand paper.  This way you can better shove the straw into those tiny carb ports.