I have oil seeping from the carb area, and found some in the air box. It starts slowly, like mist but it builds up and crawls down the hoses underneath the carb and onto the engine area. From my research on the HUBB I hope to have understood (please correct me if wrong) that it is called blow by and comes from either over filling oil, crankcase pressure building-up or worn rings. Now, my bike has got 14,200 kms (I bought it used @13K but everything seems the correct age) so I would like to rule out the rings and dipstick level shows half-way between min and max. If it helps I use it daily for my short 15 minutes commute, top speed around 80 kph (110 kph on closed road ) changing gears at 4000 rpm. I have been just once trail riding .

My questions are:

1) How can I stop the oil seeping down the carb?
2) If I can route the crankcase breather to a catch bottle?
3) If 2 is yes can someone point me to the exact hose?

Thanks in advance for any help.

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That's a leaking carb by the looks of it , most of my XT's get that same look after a while , one is a perpetual seeper so it always has that grime . Smell the drops to see if they smell like fuel. It would mean the carbs need a complete seal refurbishment.

Thank you for your reply jjrider, good call; your answer was spot on ....... the area smells strongly of fuel. However, I'm sure I wiped oil, how do you explain that?

When you say seal refurbishment, can you kindly indicate what parts I need? Do I need all this? KEDO - Performance Products

I never took out and apart a carb before but I'm willing to learn some wrenching. Any help is appreciated.

With these old bike sooner or later you'll probably need that whole catalog

There may be some oil seeping somewhere also , I can't tell with the pics , but I know with mine that leaking gas turn oil colored and viscocity wise from dissolving dirt and grime buildup plus evaporating some so it can look like oil , but the smell of any droplets should tell you which it is. Oil in the airbox may be from the breather hose that is attached to the front of airbox between the 2 intake boots right behind the shock. Technically it can be unplugged right there and put a breather filter on it so any oil vapors go to atmosphere rather than in the airbox . Plug the nipple on the airbox where it was plugged into though.

First we'll start with the carb .

The Kedo catalog isn't in english very good so I'll post another page to hopefully show what you'll need ,
I don't know which year your XT is but this should cover yours http://www.partzilla.com/parts/searc...TOR/parts.html

Parts that should be replaced are ,
#22 & #21 = drain screw and o-ring , they are generally pretty beat up so just get new
#16 (maybe #25) = pilot(idle)mixture screw ,may come as a set so #25 isn't needed , not sure how they come.
#10 =needle valve set , will have a small filter and o-ring
#56 = secondary carb main jet o-ring
#17 = float bowl gasket , I'm not impressed with the ones I get from partzilla , I don't think they truely are Yamaha seals , they're rather thin and barely seal plus leak in a few months usually, can't reuse ever without leaks. They get hard quick thus leak, maybe Kedo has better quality ones.
#6 = primary carb mainjet o-ring
#39 = fuel line between the 2 carbs ,mine have been hard and leaky , you can just use 6mm fuel lines and better clamps.

From your first picture it looks like some leaking is coming from up high , can you take a few more showing the tops af the carb and different angles?

If you start getting into disassembling I can help with pictures of my own so you can verify its done right. Once you learn it's nice not having to pay someone else.

Thank you very much for the detailed reply, I appreciate it a lot. I will order the parts this weekend and in the meantime try to source the manual / procedure to pull the carb out. Btw, mine is a 1999.

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Yamaha XT600E - 1999
Honda CBR600F1 - 2001

Undo all the bolts on the air intakebox, then you can pull it a little back. Undo the clamp screws on the carb, then pull airbox back and you can remove carb out at the left side, its tight but right angle and it will come out. Check the rubber beetween engine carb/carb airintake.

Thanks xtrock, will give it my best shot.

Out of curiosity, what is this screw used for:

Par No. 44: 3GV–1490K–10 (Stop Screw Set)

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Yamaha XT600E - 1999
Honda CBR600F1 - 2001

The idle screw. I dont know where you are looking, cant find anything on partzilla for 1999 mod. For the older models its the idle.

It's the screw that adjusts when the secondary carb starts opening.


Xtrock , does it look like there stuff coming out from the boot to carb joint or up higher ? One of mine has a cracked housing for the idle mixture screw so doesn't seal up real good and always drips a little or is always wet around the boss, it looks just like in that picture. Air swirling around the head mists the droplets up and all over so it's hard to tell exactly where it's coming from.

Ok, i was thinking 45 was the adjuster between carbs, where is the idle screw if its not the 44?

If you look in his top picture low and to the right of the petcock, right next to the chock knob, is the idle adjust screw , then up and to the right of the petcock you can see the stop screw , it silver with a nut on it .

Yes i know whats on hes picture, but hes asking about 44 and on my picture of parts its the idle, 45 is on the top between carbs.

I didn't have the time yet to inspect better the carb leak and take remedial action. However, I noticed that turning-off the petrol petcock stops the carb smelling of fuel. Turning it back on and leaving it on overnight gets the left hand side carb smelling of fuel in the morning.

The fuel leak must be very small as it doesn't actually seep out, but builds very gradually in the area of the left carb joint (I assume also called fuel intake boot?).

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Yamaha XT600E - 1999
Honda CBR600F1 - 2001

the fact that you dont see a "big fuel leak" doesnt mean that much. Seen cases that the leaking fuel past the float needle goes instead into the engine through the manifold, then seeps slowly down past the rings into the cranckase, diluting the oil. not good for bearings, etc...
so on xt's that dont have a vaccum petcock always good policy to close it.

if you still get oil in the airbox, you could simply disconnect the cranckase breather hose fron it, ad length and reroute towards the rear of the bike so any oil doesnt hit the tire.

So, I finally got the bike sorted ..... I cheated and took it to my mechanic as I just couldn't make enough time and space to take it apart myself. No more smelly, leaky carb now ..... after installing this:

Yamaha XT 600 E 99-03 Carburettor Gasket and Float Valve Kit Parts at Wemoto - The UK's No.1 On-Line Motorcycle Parts Retailer

Thanks everyone for your input, it is truly appreciated.

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Yamaha XT600E - 1999
Honda CBR600F1 - 2001