18 replies to this topic

[BlueTwin]

Hi all,

hope you've made good use of the sunny bank holiday weekends!

I wondered if I could pick the collective brain about a 4TX fuel tap.  After stripping down last year to cure a failed pump I noticed there is a tap under the tank AND a tap on the side.  Seemed a bit wierd but I also found that there are some parts of a 4TX3 and it's a 1996 so all bets are off regarding it's pedigree... The under tank one works fine, just use it when the tank has to come off.  However the side OFF/ON/RES doesn't work as expected.  I haven't the bottle to check whether the reserve setting works right yet... because the bike seems to run fine with the tap set to OFF.  I noticed I'd not switched back to ON but only after around 25 miles - too much to be just draining the float chamber.  Tap looks like it's got everything connected sensibly... is there some clever function of the tap which I don't understand or is it kernackered?

cheers y'all

Dave

[RolfieB]

This is the diagram you need. But note that hose no 45 actually goes to the spigot for hose no 31 & vicci vercci.

http://www.yamahamot...FUEL TANK&uID=0

[BlueTwin]

Cheers guys.

 

Rolfie, sorry to be a bit of a thicky but can you just clarify about the item 31/45 switcharound...

 

 - the fuel comes from the tank along two hoses item 24 = "on" and 23 = "reserve" from the thingy with two different pipes under the tank

 - they both go into the tap (27) on two of its ports, and the third must be the output (31 on this drawing) to the pump

 - the end of 31 goes into the fuel pump which pumps fuel back down 45 into the carbs.

 

I guess you switch 45 and 31 at the pump because the drawing is wrong?

 

Are all of the fuel tap ports correctly identified on this drawing?  Top pipe = ON, Middle pipe = RES, Bottom pipe = OUT.

 

thanks

Dave

[Chris]

I'm watching this with interest as mine is the same.

 

I notice that the rate of flow is reduced when it is turned off but there's still enough fuel going through for sedate riding.

 

Reserve operation is still as you would expect - turn it on in a hurry if the engine stutters.

 

End result is that I don't turn the fuel off but this is a bit concerning as my carbs don't appear to have the extnded pipe in them that allows any excess fuel to drain out.

 

So, if the float valves weren't sealing properly I would end up with diluted oil!

[RolfieB]

I was worried that mine were not connected correctly, so in between looking at this drawing & looking at the service manual I noticed a discrepancy & posted on here my hose positions & the discrepancy. Studley had also picked up on the discrepancy & posted about it but a while ago, but also confirmed my hose positions.

 

So the top hose on the frame tap (No 24) is your main on (front spigot on tank tap). Middle hose (No 23) is reserve (rear spigot on tank tap), I believe this should have a plastic collar on it to denote reserve, not that it would make any difference if connected correctly. I think it's just for ease of identification.

Bottom hose (No 31) goes to the left spigot on the pump,  Where the diagram shows No 45 (it has an arrow on the pump by the spigot denoting flow).

The next hose attached to the pump (middle spigot) is No 45 which is the vacuum pick up from carbs. This hose is attached in front of the carbs. If you look in the intake section on the link it's No1 joint carb

The last hose on the pump No 48 is the supply to the carbs (attaches in the middle at the back of the carbs if you pull it off watch out for the little in line filter, position is correct in diagram).

 

If all is connected correctly Then my first guess would be a seal gone in the tap.

Edited by RolfieB, 28 May 2013 - 08:12 pm.

[RolfieB]

Never tried to be honest, wont have chance to try until Saturday as will be in Amsterdam for the rest of the week .

I was more concerned that reserve wasn't working as I'd covered 190 miles before bottling it & filling up, rather than finding out they were connected wrongly and running out of fuel. But found out on Saturday that reserve works as it should.

Will check on my return & let you know.

 

Looking at the diagram I would suspect it's no 28 (valve packing) if anything has gone amiss, not a lot else in the tap.

Edited by RolfieB, 28 May 2013 - 08:45 pm.

[BlueTwin]

Ho hum.. checked the oil level this morning, it's gone up again.  Now up to the top of the window and looking thinner than normal - although the apparent viscosity might be down to the outdoor temperature or my imagination.  Will do a sniff test of the filler cap, but I think I know the answer already.  I had the hydraulic lock and petrol in the sump only a few months ago - drained it down, changed the fuel pump, ran some cleaner through the carbs, vowed to leave tap in the off position whenever left for more than 5 minutes... and here we are again.  Looks like fuel tap isn't the only thing that's not playing ball... I love riding this bike, but it's doing my head in at the moment.  Hopefully stripping down the carbs and giving them a good spruce up will also cure the terrible misfire on mid throttle at motorway speeds too...

 

Thanks for the continued useful info.

[Studley Ramrod]

Was that a new fuel pump you fitted BT ?

[BlueTwin]

Brand spanking new in its Polythene from Weeemoto.  So now I have a part-used spare.  Which is handy.  I also have an old electric pump of a carbed R1, just in case I ever decide to do a conversion.  All the gear, no idea, as they say!

[BlueTwin]

cheers Prof,

 

had a rummage in the "cupboard of crap" last night and found the fuel tap repair kit which has the funny washer thingy and o-ring.  Away for a few days but will swap them out on my return and post the pics.  Bon weekend tout le monde.

[Sidarta]

Messrs. good day!

 

We can not forget that the carburetor float needle, is the principal to control the entry of fuel into the engine. If the needle tip is worn or the float is out of level, there will be excess fuel. In my 4TX 2001 I had the intake manifold cylinder No. 1 (left), totally flooded. The repair torneirinha is new and the fuel pump is in perfect condition. Raised to the level of the float 9 mm. Measuring the flat face of the bowl of the carburetor to the highest part of the float. That's because I could not determine what the water line on the outside of the tank. These references line level for 2001 are different from other models. Also installed new needles and needles headquarters. The carburetor is mounted, but not yet installed on the bike. I'm changing the chain of command and changing the valve shims. Everything is disassembled.

Excess fuel can cause: increased consumption, hydraulic lock and contaminate the oil damaging the engine lubrication. Leaking fuel, stay tuned and find the cause quickly.

 

Cheers!

 

Sidarta

[RolfieB]

Ok RolfieB.

 

Does your engine run with tap in off position?  Thanks for above info,

 

Prof.

Just ran my bike up with the tap in the off position & the results are as they should be, the bike ran for a few minutes then coughed, spluttered & farted then died.

Back to the on position & burst into life again.,

Yep, it only works this way round, to match the switch,      top =reserve,  middle =main,  bottom=pump with inlet arrow. so 23&24 need to be swopped over in the diagram.

 

Prof.

Bit confused by this post as in an earlier post you say that reserve works as it should, but now you're saying you need to swap the hoses going to the tank tap .