Engine smoking badly

[nubsey]

Hi all yes it's Nubsey again.

 Well we got the engine started, but my this thing smoke 200 hundred a day.

I have have my assistant run the engine for a while, but it sticks out smoke like they have just elected a new pope.. \please see my you tube video. A PICTURE IS WORTH A THOUSAND WORDS. Sorry for caps lock.

Any way as Max Bygraves would say. "Let me tell you a story".

 Bought the bike a gas gas 125 txt 2000 with the clutch side of the crankcase stripped down.

 He said it was to change a oilseal as it was bogging. Put bike back together with a new clutch etc. Finally got bike to start and smoke everywhere. No Bogging. I.E. revs up ok. So now the question is, where is the smoke coming from. I seriously suspect the oilseals on the crank case. Could drain the oil, from gear box and run it, but I suspect it would only prove my thoughts. It is quite an oily sort of smoke, there is oil coming fr5om the leak in the exaust system alsoo when he stared it for thre first time the plug was only put in hand tight and there was black burnt oil around the sparkplug.

 

 Now to the questions.

1 I take it that there are two oil seals on the crankshaft. One on the clutch side and one on the gearbox side.

 Are these oilseals the same, I have had a look in the parts pictures and I think the part number is,MT12944200. can someone confirm this. 

2 As the bike is a bit old, are there any other oilseal that are the same. Also possibly cheaper.

 3 When I go to start the job I will have to remove the big nut on the clutch side of the engine. This is the nut that connects to the crank shaft. Does anyone know what size the nut is. Nice to have a spanner or socket to hand.

 I think that is about all at the moment. I would love to take the grandson for his first trials, but could not bring myself to other competitors sitting behind a bike that smokes like that. He also still has a lot to learn. I never had that problem when I was his age.

 All the best Nubsey

PS the choke was on all the time he was riding the bike. He never listens to a word I say about starting procedures.

[bilks]

I should check your rear silencer first, drill the rivets out and check the packing is not saturated with oil because there looks like a lot of smoke from the rear silencer joint also.and running it with the choke on won't help.Oil Seal part no M1217001 size 25x40x8

Edited October 1, 2017 by bilks
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[billyt]

A smoking bike will be the least of problems if you don't get the lad to wear a helmet and some trials boots. His right leg is exposed to a VERY hot header pipe also.

 

 

 

 

[b40rt]

Worth cleaning / re-packing exhaust, but unless that engine was already pretty hot, I would go for crank seal.

[dan williams]

What oil/gas ratio are you running?

[huski]

Burning gear oil really stinks.Run it with the choke off first and see if it clears,it really needs a good blast to clear it out,not just in the garden.

[nubsey]

Well we had the bike not starting saga, So here comes the smokes like a chimney saga.

Thanks for that info chaps. Is this a particularly hard job to do. I think the clutch side should be ok, as we have reassembled the clutch etc. But am unsure as what lies behind the ignition cover. It looks like I will need a flywheel puller,or is there a trick you can use to save ones brass.

 Have looked on Trials and tribulations ltd and they seem to have all the parts I think I will need.

Gas Gas trials generator cover gasket (NOT PRO)

part number MO4431000G64.

Gas-Gas 93-2003 (edition) Main Bearing seal

Part Number  M01217001G55. 2 of

Gas-Gas JT, JTR TX, & TXT clutch cover gasket 92 to 03 Edition.

Part Number MO4430002G62

Flywheel Puller Gas-Gas Pro & earlier JT,JTR & TX

Part Number   BUZZETTIGG

Hope the puller is ok! here is a photo.

I would not worry to much about the lad not wearing a helmet etc. He is nearly 14 and knows it all. Well nearly all. Except when the bike is in gear, how to start it properly how to control it, how to ride it correctly, IE stand up when riding it. But yes that is a good idea, even if only to try to get him to do things correctly. But I do find a quick burn to the leg is a great way for them to learn and listen to what they are being told.

 The smoke does smell of oil. The young lad that we bought it off stated that he was going to change an oil seal as it was bogging, and there was an old oil seal in the box of bits. So he might have done the clutch side but he could not remember what he had done. It might just need the ignition side doing. 

If I do the ignition side first will I have to drain the oil out of the bike?

 Now what is this about packing the exhaust. Have never heard about that before. There is a leak where the pipe goes into the silencer.

 Ok on removing the pipe and letting it drip into a bucket, sounds like a good idea, as there is a lot of oil residue from the exhaust.

 The fuel oil ratio is 50/1 so should not smoke like that. With what I am spending for anothe 50p I coukd have bought a new bike.

[wheelieman14]

Repacking exhaust is removing old, oil-soaked (or blown out fiberglass) and replacing it with fresh fiberglass to absorb sound and help quiet bike down. 50:1 oil mix is going to smoke more than 80:1, but Choke should be turned off within a minute or so, for properly jetting carb. GasGas can also be made to start easier, but re-positioning the kick starter back a tooth. This helps to kick "down", instead of trying to kick "backwards" because kick starter is too far forward in rotation for starting point with boot on it.

[nubsey]

Wheelieman14 Many thanks and all taken on board. We have just got this bike, and we have a lot to learn. I use to do Banger racing so mechanics, are not to great a problem. It's just getting the right diagnostics.  It is always a  wonderful thing that people pick up on the little things. I have always said it's the little things that count in life. I thought that the kickstart lever was in the right place, but In could never get my foot up there to give it a kick. Thats just getting old I thought. But you have seen I have put it back in the wrong place.

 So will move it back a couple of notches. 

The Grandson just wants to ride the bike, and I want to get it right. I love learning about mechanical stuff.

 Still we will have a word with the people at the trials this Saturday, and perhaps we can get him in with a 200 a day ciggy machine. It will do him a power of good to see 6 year olds beating him.

 

 Now back to the repacking. I would need the size and length of the repacking material, to stick back in the exhaust pipe.

 I really need a workshop manuael on the bike, but they do not seem to exist.

[zippy]

My opinions:

Step one: switch to 80/1 for the fuel/oil mix

Step two: repack the muffler - Local motorcycle shop should have "exhaust packing" 

drill out rivets holding end cap, remove end cap. Pull perforated tube out of muffler along with all old packing.  Make sure holes in center tube are clear, they can fill up with carbon, gunk etc.., make sure inside of muffler is clean. Wrap center tube with new packing, may have to wrap it a little tight to get it to fit back in muffler, cut the excess length of packing off.

SHOVE the wrapped center tube back into the muffler, line up the tube with the hole at the end of the muffler, reinstall end cap making sure to line up the hole with the center tube. Rivet end cap back on.

Hanging exhaust center box over a pail wouldn't hurt either to let anything in there drip out that could drip out.

Step three: run bike

Step four: IF you are burning transmission oil it will be either the crankshaft seal on the clutch side, (that is where the oil is, Flywheel side would let air in and the bike would run lean and rev up a bunch) or the center gasket failed between transmission and Crankshaft area.

You stated "  I seriously suspect the oilseals on the crank case. Could drain the oil, from gear box and run it, but I suspect it would only prove my thoughts. "  NEVER run the bike without fluids in it for lubrication and cooling, BAD things will happen very fast.

 

Just my opinions.

[nubsey]

Hi Zippy, Many thanks for your opinions.

 When we got the bike, there was an old oil seal so wondering if it's already been changed, or perhaps there isn't one. Only a strip down will tell.Many thanks for saying it's only the clutch side, save me money on stuff I don't need, as I was going to do both sides. 

 How do I know how much packing to use, can I use the old packing as a pattern and cut off the correct length?

 

Oni Nou Thanks for the link for the videos. That was how I knew how to put back the clutch etc. But all tips most welcome. Jim Snell seems a really decent sort of chaps.

 All the best to all

 

 Nubsey

[aussiechris]

If it is a crank seal, you should notice the bike consuming gear box oil.  When my pro did crank seals recently, I was adding about 50ml of gear oil to bring the level back to half way up the sight glass for every tank of fuel.

New seals/bearings and it no longer smokes or uses gear oil.

[nubsey]

Thanks so far for your help chaps, Have just ordered a new oil seal and a new gasket. I know the old gasket has only been on for a week or so, but for a couple of quid it's not worth taking a chance. Will also have to try and move the engine forward a little bit as the clutch cover fouls the frame, but a 1/16" movement forward and it would most likely clear. Will do the exhaust next. There is a problem with a leak on the midbox, so perhaps it will need welding or something, but will know more when I take a good look. Just hope it is the seal and not the gasket thats gone.

 All the best

 Nubsey

[zippy]

23 hours ago, nubsey said:

Hi Zippy, Many thanks for your opinions.

 When we got the bike, there was an old oil seal so wondering if it's already been changed, or perhaps there isn't one. Only a strip down will tell.Many thanks for saying it's only the clutch side, save me money on stuff I don't need, as I was going to do both sides. 

 How do I know how much packing to use, can I use the old packing as a pattern and cut off the correct length?

 

 Nubsey

OH I have all kinds of opinions..... HAHAHAHAHA

What I do for the packing is just open the bag and wrap the center tube with all of the packing that is there.  The packing I get is one piece similar to a chunk of insulation.

Many different brands etc. but like this http://www.hrpowersports.com/product-p/270340.htm

then I use some masking tape (white papery type tape) to hold it in place/ compress enough to fit inside muffer

then cut the packing at the same length as the center tube or maybe quarter inch longer at each end.

then SHOVE it in the muffler, it is a tight fit.

 

Most likely the old packing will come apart in pieces, be soaked with oil etc.. not really easily used as a pattern.

[d2w]

Howdy. I just repacked the muffler on my son's TXT80 last night and thought I'd add my experience to this thread:

1) I choose to use the FMF Four-stroke packing rather than the two-stroke packing; the four-stroke packing is semi-rigid and I find it's easier to roll and form and it keeps its shape.

2) When pushing the packing into the canister and the pipe I use a sheet of thin plastic (Mylar) to form a "cone" so that it better slides; the cone helps to compress the packing so it doesn't get hung-up on the edges.

Dale