Venting fuel from float bowls : Yamaha R1 Forum

adowdell · 09-12-2006, 08:02 PM

I have a 1998 R1, that has ran awesome up until last week. It started puking fuel out of the vent tube from the right set of carbs. I pulled them, opened the bowls and clean them out, and found nothing. I put them back together and it work fine for about 20 min, then started puking again. But this time from the other set of carbs on the left. I pulled them and found nothing, but this time removed the needles, and seats, and looked through each tube, and carb cleaned them, even though they were spotless. Mind you it's a 1998 with whole 8,000 miles. Of which I've put 1,200 since I bought it early this summer and had no problems. So, after the last cleaning, the rubber o-rings were leaking since they're approx. 8 years old. So, I sourced some o-rings and put them back together agian. I rode into town and on the way home it started sputtering and leaking more fuel from the vents yet again. So obviously I have not fixed it. After having the carbs out and back in 6 times in 2 days, I'm getting a little frustrated. I have found no signs of varnish, or dirt, or anything that could obstruct passageways. Is there any passageways specifically to check.

Also does someone have a picture of the screw/plug that you take out to sync the carbs? I know it's down inside the top but am unsure as to which one it is.

I'm getting pretty frustrated as I took the day off of work, and missed a class and a half because of this, and I want to get it back on the road ASAP. Thanks for the help guys!!

JAYSTENSEC4CYL · 09-12-2006, 09:18 PM

sounds like the needle and seats are not sealing properly.

What does the inside of the fuel tank look like? Rusty?

Might need to replace the needle and seats. For sure check the float level setting.

William YZF-R1 · 09-13-2006, 03:18 AM

Quote:

Originally posted by JAYSTENSEC4CYL
sounds like the needle and seats are not sealing properly.

What does the inside of the fuel tank look like? Rusty?

Might need to replace the needle and seats. For sure check the float level setting.

Did you mix the parts up when you dismantled or keep them seperated ?

It does sound like the float bowl needles not sealing for whatever reason, or float heights.

To synch the carbs there are four small alan bolts with aluminum washers, situated below and in front the carbs. One on each inlet on the head.

Be very careful not to drop any of the bolts or washers as you could have to remove the starter motor to retrieve.

martinc · 09-13-2006, 04:01 AM

Erm...

To synch the carbs there are 3 flat head screws as a carb is fixed as its always been.

When you have the carbs in your hands,they are at a 45 degrees angle front/bottom of bodies when held upright and looking at the stacks.

Those screws are usually plugged by an aluminium plug which you got to drill carefully...its press-fit,but you drill a hole in it and put a metal sheet screw in the hole and pull it out...carefull,the adjusting screw is not far underneath,so I suggest a guide on your drill bit with masking tape (drill no more than 1/4 inch)

adowdell · 09-13-2006, 04:05 AM

New needles and seats are $24 a piece.... I bagged eich piece as i removed it and ensured that everything got back in the same bag.

No rust

I would suppose that it's bad needles and seats except that it changed sides... but i can't think of anywhere dirt would be to stick on open, if i can't see it. I'see about getting a rebuild set...

William YZF-R1 · 09-13-2006, 07:43 AM

Quote:

Originally posted by martinc
Erm...

To synch the carbs there are 3 flat head screws as a carb is fixed as its always been.

When you have the carbs in your hands,they are at a 45 degrees angle front/bottom of bodies when held upright and looking at the stacks.

Those screws are usually plugged by an aluminium plug which you got to drill carefully...its press-fit,but you drill a hole in it and put a metal sheet screw in the hole and pull it out...carefull,the adjusting screw is not far underneath,so I suggest a guide on your drill bit with masking tape (drill no more than 1/4 inch)

If the ERM is for me I thought the gentleman mean't the connections for the gauges - MY BAD.

But I guess you twigged that already

When I removed my carbs a while back I sort of noticed where the sync screws were on the throttle linkages while they were off the bike.

JAYSTENSEC4CYL · 09-13-2006, 07:59 AM

Adowdell try taking a sharp drill bit that is approx 3.4 the diameter of the seat and using only your fingers on the bit spin it a few times against the seat.

It wil cut a nice clean seat for the needle to sit against. If it does not work you have lost nothing as you will need to replace needle and seat anyways, but personally I have had good luck with this.

No rust in the tank, fuel filter is clean, float heights are set correctly, and clean seats for the needles to press against everything shoudl work.

adowdell · 09-13-2006, 03:03 PM

Quote:

Originally posted by martinc
Erm...

To synch the carbs there are 3 flat head screws as a carb is fixed as its always been.

When you have the carbs in your hands,they are at a 45 degrees angle front/bottom of bodies when held upright and looking at the stacks.

Those screws are usually plugged by an aluminium plug which you got to drill carefully...its press-fit,but you drill a hole in it and put a metal sheet screw in the hole and pull it out...carefull,the adjusting screw is not far underneath,so I suggest a guide on your drill bit with masking tape (drill no more than 1/4 inch)

So you have to drill a plug out, in order to sync the carbs? That sounds kind stupid for the factory to do that as syncing is fairly routine maintenance correct? I'll pull them apart one more time and if that doesn't work I'll try cleaing up the needle seat witha bit. Then if that fails I'll get new needles and seats. So only 3-5 more times of removing and installing carbs left....

JAYSTENSEC4CYL · 09-13-2006, 08:27 PM

not to sync the carbs you don't have to drill anything, but to set the idle mixture screws you do. And generally when syncing is the time to check set the idle mixture.

adowdell · 09-13-2006, 10:01 PM

I just want it running, and not puking gas all over the place... I've ordered float bowl gaskets, and I'll tear each one completley apart and put it back together as methodically as possible. Hopefully This last time will do.

As for the syncing, I was questioning which plug was the vaccuum port where you put the adaptors. Does anyone have a pic of it? It's the flat head plug when looking down on the stack in the hole behind the stack right? And it is a 5mm adapter tube right?

My buddies katana that we synced has the port built into the diaphram cap. Those stupid sync adjustment screws are going to be a pain to get to as well... any tips on that?

martinc · 09-14-2006, 03:11 AM

Doh...serve me well for writing help answers 5 minutes after waking up

JAYSTENSEC4CYL · 09-14-2006, 09:53 PM

The sync ports on an R1 are located under the Carbs. They are 8mm bolts that are directly under each carb, except the number 1 carb, it has an outlet built in if memory serves.

turd1 · 09-15-2006, 01:27 AM

98-99 r1's have 6 mm holes with plugs in the bikes head for attaching adaptors for synching the carbs.

the screws to actually adjust the synching are located on the carbs. just to clear up any confusion guys.

adowdell · 09-15-2006, 07:20 AM

Quote:

Originally posted by blur1
98-99 r1's have 6 mm holes with plugs in the bikes head for attaching adaptors for synching the carbs. the screws to actually adjust the synching are located on the carbs. just to clear up any confusion guys.

So the plugs, that have to be removed to attach the adaptors is in the head not in the carb? Does anyone have a pic of it? Is there a more accurate consistant reading there instead of from the carb or what? I've looked at the factory manual and where it circles the "plug" looks to be the exact same location as the float bowl drains.

And the screws are the adjustments in the linkages. I've got that covered. Just need to locate where to get the vac signal. Thanks guys!

JAYSTENSEC4CYL · 09-15-2006, 07:22 AM

The plugs are easy to find. They are on the intake ports, not the carbs.

Look directly under the rubber intake manifold and there will be a lonley 8mm bolt head starting at you. Thats what you need to hook up to.

turd1 · 09-15-2006, 07:31 AM

Quote:

Originally posted by adowdell
So the plugs, that have to be removed to attach the adaptors is in the head not in the carb? Does anyone have a pic of it? Is there a more accurate consistant reading there instead of from the carb or what? I've looked at the factory manual and where it circles the "plug" looks to be the exact same location as the float bowl drains.

And the screws are the adjustments in the linkages. I've got that covered. Just need to locate where to get the vac signal. Thanks guys!

yes the 4 plugs are in the head and need 6mm adaptors screwed in to them to do synching. the carbs only have the adjustment screws on them. heres a pic of the aftermarket adaptors i use.

turd1 · 09-15-2006, 07:34 AM

and here are my 4 hoses coming off the adaptors. they are the ones with the 2 white zipties around them and the rubber caps on the end ready to have the sync tool hooked up to them.

JAYSTENSEC4CYL · 09-15-2006, 07:45 AM

what have you done to your crankcase vent?

turd1 · 09-15-2006, 07:49 AM

Quote:

Originally posted by JAYSTENSEC4CYL
what have you done to your crankcase vent?

its got a www.krankvent.com on it.

turd1 · 09-15-2006, 07:51 AM

you can just see it here ( the aluminium part) above the filter on the end of the krankvent.