Suzuki T250 smokes badly right side

finglish

Anyone had the same problem I think its the crankcase seal letting oil past and then being sucked up into the barrel but only a guess? I have never changed the seals before but reading the manual it says that there are 2 outer and a centre seal. But the centre seal can only be changed by having the crank rebuilt. So not sure if to change the outer seals only as there are no problems with the crank. Any one go any advice?

CaptCatFish · Posted: Sun Sep 05, 2010 4:45 pm Post subject:

I suspect the T250 is just about half the problems of the T500 which means you'll probably have to have the crankshaft rebuilt and inner seals replaced.

The good news is that if you are somewhat handy with tools, have a mechanically oriented brain and nerves of steel, there's nothing quite like doing your own work and it working!

The bad news is you'll have to do a complete tear-down of the engine, which leads you into other questions about having the cylinder bored to the next oversize (and finding the parts), new needle bearings, piston, rings, gaskets, 'ecetera, ecetera, ecetera", (as the dude said in the "King and I").

But do it. You'll be so proud of the final result. I know I'll be when I'm finally finished.

CaptCatFish

PS - If it has a crankcase drain bolt, pull it and see what comes out. That's the best evidence of the condition of the seals.

CaptCatFish · Posted: Mon Sep 06, 2010 4:00 am Post subject:

Sorry if my earlier response was a bit silly. It had been a long day..........

I do recommend checking the crankcase drainage bolts (and any residue from the crankcase) if your bike has the drainage bolts. You'll be able to see what color of oil comes out of the crankcase. If its conventional motoroil color, the inner seal is probably allowing tranny oil past it into the crankcase producing the excessive smoke.

If its diluted two stroke injector oil, it should smell strongly of gasoline and be very thin in viscosity. That would suggest incorrect float levels that is allowing too much gasoline into the combustion chamber, perhaps while it is sitting.

Lastly, what is the condition of the spark plug on that side after you run it for awhile? If its really shiny black on the center electrode, that suggests to me tranny oil is being burned. If it reeks of gasoline, back to the incorrect float or fouled jetting in the carb.

I'll be interested in your response. Good luck!

CaptCatFish

finglish · Posted: Mon Sep 06, 2010 9:23 am Post subject:

Thanks that was a top tip I removed the drainage bolts and the RH side out came the gearbox oil, The LHS was dry, the centre bot was already broken off so could not remove that another job for the teardown. Now what to do have the crank rebuilt cost Â£200 or just replace the outer seals the end bearings are good the bike runs well no rumbles or knocks.

CaptCatFish · Posted: Thu Sep 09, 2010 4:35 am Post subject:

I attempted the rebuild on my T500 by replacing the outer crankshaft seals (pretty easy actually) and keeping my fingers crossed about the inner seals. Unfortunately, they will have to be replaced as well so I'm in the same delimna.

The good news is that getting to the crankshaft (on the T500) is pretty straight forward and I suspect the same on the T250. I had the benefit of a practice motor (my donor motor) which has increased my confidence considerably.

Good luck and keep us posted on your journey.

CaptCatFish

finglish · Posted: Tue Sep 21, 2010 11:04 am Post subject:

Well I stripped it down at last and the 2 centre seals are knackered and the RH seal has been letting oil past. So it looks like a complete crank rebuild S.E.P kegworth in the UK have quoted Â£160 + vat all crank parts included. I guess this is the asking price? I also noticed that a couple of the gears are a sort of copper colour anyone know why all the rest are normal metal colour?

CaptCatFish · Posted: Wed Sep 22, 2010 3:23 am Post subject:

I'm certainly not an expert on transmissions but I think you are right to worry (just a little). The copper color suggest to me high heat conditions, perhaps from poor lubrication?

Just my opinion but if it were mine and I could find those two gears, I think I'd replace them while the engine was apart.

CaptCatFish

Tezza · Posted: Tue Oct 05, 2010 11:19 pm Post subject:

Just a tip on installing crank seals particularly the right hand seal. Make sure you install it the correct way around . The lip on the seal should face outwards which is the opposite way from the left hand seal. I know this because my right hand pipe was blowing copious amounts of smoke which turned out to be gearbox oil smoke. After I had another crank rebuilt with all new seals, I noticed that the old crank removed from the engine had the seal around the wrong way. Expensive error but at least I have a nice new setup and since switching to synthetic oil...almost no smoke at all.
Would not worry too much about that copper colour. The gears on the T250 have a couple like that as well. See the two gears behind the right hand flywheel. They also have that colour to them.

CaptCatFish · Posted: Wed Oct 06, 2010 3:10 am Post subject:

Hi Tezza,

Could you tell me a little more about making sure the right side seal is installed correctly? I've installed both outside seals on my T500 but now am second guessing if I did the right side correctly. The right side was where the tranny oil is getting by and I have proceeded on my engine teardown believing the center seals to be the culprit.

However, you've raised an interesting point. I sure would appreciate more info about how to check this before I split the engine casings.

Thanks!

CaptCatFish

Tezza · Posted: Thu Oct 07, 2010 4:21 am Post subject:

I will attach a breakdown of the crank assy and an image of the seal.

this is the side of the seal you should see on the clutch side.

dorT500 · Posted: Thu Oct 07, 2010 5:57 am Post subject:

Tezza, CaptCatFish is referring to his T500. The T/GT 500 seals/bearings are different. All the crank seals fit inside all the bearings. But the center seals on a T/GT500 have been known to be put in backwards.

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