Vilike's Carb Diaphragm topic

[Vilike]

Yesterday i had to order four diaphragms from a bike-breaker here in Hungary. Im waiting those things for tomorrow, so if they arrive i'll report !   

[Vilike]

Hi there,
so i had to get those diaphragms from the breaker.
The results : 2 from the four are cracked, and all the four slides are a different type.
The bottoms of the slides are totally flat.
On my FJ 1200 the bottoms are have curves on them. So now i have to get them back to the breaker. He's buying them back, no problem.

I think i'm going insane guys...   

Okay, there is another alternative here : a carbs-set from an '1990-er FJ 1200. Here i go again... 

I will check in guys !

   

[Vilike]

Hey, i just bought a carbs-set from a 3CV. I take it in and a few hours later i will tell you guys whats happened .

[flyingbanana]

These dont seem too bad

http://www.nrp-carbs.co.uk/index.htm

[Vilike]

Thanx.

Well, i had to replace only the diaphragms in the carbs-set. It works not better. 

I think it was not the only trouble of my bike.
The engine starts fine. At 1000-1500 rpm it runs fine too without acceleration. But as i give a minimal acceleration, the engine drowns to stop, and bangs.
Sometimes i can run it up to 3-4000 rpm, then it banging too but it runs a bit smoothly.
And sometimes not all the four cylinder runs.

I have no idea...Maybe ignition ?

[ren-dog]

I think it was not the only trouble of my bike.
The engine starts fine. At 1000-1500 rpm it runs fine too without acceleration. But as i give a minimal acceleration, the engine drowns to stop, and bangs.

If engine won't rev, the following possible issues come to mind:
1) Fuel starvation.
2) Poor dwell angle. As FJ's don't have points it becomes a coil issue.
3) Plug gap too big.
If by bang you mean backfire then this would again suggest:
4) Overfuelling
5) Ignition missfire

Sometimes i can run it up to 3-4000 rpm, then it banging too but it runs a bit smoothly.
And sometimes not all the four cylinder runs.

Sometimes is more indicative of electrical problems, the banging and runs smoothly points to:
6) crossfire between ignition leads or
7) faulty coils.
But could also be:
sticking valves.

If the choke is off and it doesn't blow black smoke at idle we could likely rule out 4).
If bang is backfire we can rule out 1).
Now check spark plug resistance and gap.
Then check resistance on coil windings.
Run it in the dark and look for sparks jumping everywhere, or get mate to stick his hand on leads whilst reving engine.
If bang is mechanical noise check


Hope that helps

[Vilike]

Thanx ren-dog ! I will check on your ideas !   

[Vilike]

Okay. I had to change the entire carbs-set on the FJ. But here is a question : On the "new" 3CV carbs set, there is a pipe with a snag beetween the second and third carbs. What is it for ?

On my 1TX FJ, there is no pipe like this. Is this the place for the rubber tube from the tank

http://www.imagebam.com/image/6e28ae62315158

[TRoy]

wait.. isn't that the fuel inlet?

..you're trying to use the carbs from a fuel-pump'd FJ on an FJ that is gravity feed...

read the previous posts in this topic.. Randy explains how to take the carburetors apart and install the correct dual inlet system that your FJ uses.

it never ends

[indyblue]

Please excuse the noobness, but is there a reason you can't use these (I am surely missing something, no mention of year)?

http://www.carbkitscapital.com/carb_kit_list_part.php?make=Yamaha&cat=Carb_Slide

FJ1100 1100cc FJ1100 (1985) (50H) Carb Slide Diaphragm
FJ1100 (1985) (50H) Carb Slide Diaphragm OEM Quality, Complete Mikuni Slide Assembly replaces OEM#50H-14940-00.   
$93.95 USD
   
FJ1100 1100cc FJ1100 (1984-1985) (47E) Carb Slide Diaphragm
FJ1100 (1984-1985) (47E) Carb Slide Diaphragm OEM Quality, Complete Mikuni Slide Assembly replaces OEM#36Y-14940-00.
$78.00 USD


I seen 3CV mentioned so there are these too:

http://www.wemoto.com/bikes/Yamaha/FJ_1200_3CV_Type/88-90/picture/Carburettor_Diaphragm/
Yamaha FJ 1200 (3CV Type) 88-90 Carburettor Diaphragm £ 60.14

[ren-dog]

Okay. I had to change the entire carbs-set on the FJ. But here is a question : On the "new" 3CV carbs set, there is a pipe with a snag beetween the second and third carbs. What is it for ?

On my 1TX FJ, there is no pipe like this. Is this the place for the rubber tube from the tank

Ahhh. I see now.
Your bike has fuelling issues because
the fuel metering is different inside these different model carbs.
The fuel feeds are in different places,
The needle and seats inside the carbs are different,
You will also have to check the float heights
etc, etc, etc.
Do like TRoy says and look for posts on changing carb internals from fuel pump to gravity fed. 

[SlowOldGuy]

Please excuse the noobness, but is there a reason you can't use these (I am surely missing something, no mention of year)?

http://www.carbkitscapital.com/carb_kit_list_part.php?make=Yamaha&cat=Carb_Slide

FJ1100 1100cc FJ1100 (1985) (50H) Carb Slide Diaphragm
FJ1100 (1985) (50H) Carb Slide Diaphragm OEM Quality, Complete Mikuni Slide Assembly replaces OEM#50H-14940-00.   
$93.95 USD
   
FJ1100 1100cc FJ1100 (1984-1985) (47E) Carb Slide Diaphragm
FJ1100 (1984-1985) (47E) Carb Slide Diaphragm OEM Quality, Complete Mikuni Slide Assembly replaces OEM#36Y-14940-00.
$78.00 USD

Are these prices for EACH diaphragm??

If so, then simply contact Randy and pay a mere $400 for a COMPLETE, BRAND NEW SET OF CARBS!!!!
(that's a set of 4 complete carbs!!!!)

DavidR.

[Vilike]

Hi guys !

The FJ runs great ! We had to fix the problem with the replacing of the carbs-set.The last trouble was that the 1TX carbs-set has two fuel-inlets, the 3CV set has only one. And we accidentally confused the inlet snags with the overflowing snags. Now the bike has a 3CV carbs-set and runs very smoothly.

Thank you for all your help guys !   

[ren-dog]

Congrats and well done

[Kopfjaeger]

betas my idea s .... i sued the thumb out of a rubber glove and some non hardening aviation gasket goo on the carbs of the honda vt500e that i HATED. didnt work to good but was better than the holes.... cut the thumb off slipped it over the carb slide..(round ) and then hel it in place by using the groove around the top of the slide and some fine copper wire... painted the inside with gasket goo and slid back into throttle body, put top on and cut away excess like a pie in a pie tin... never to be opened again..... still wouldnt pull more than 110k's downhill with me tucked down so far it looked like i was being obscene .... and yes it did need a tail wiind, head wind washed off ten kays an hour. hence why i hate honda's.( with the exception of the bol'dor)