neo

Another couple of lessons learned today....this is fun Firstly these Hi Temp sealed Nachi bearings are so new that no one has stock of C4's yet...had to opt for the C3 instead :-( Secondly, as HAM2 pointed out ...you can't believe all that you read in the Sherco parts book.... And it looks like the 06 and 07 manuals are wrong. 125's have 25mm bearings (not 30mm) so number 6205. Now for some questions.... Both casings have a small port hole (close the cylinder base) which allow the 2T oil to get to the outsides of the bearings. But now that I'm using sealed bearings should I plug these holes up and if so with what? I think it's good to do this as it will stop carbon deposits getting to the seals. But do the seals need a bit of oil too? Best of balance. Neo

Good point Ham2..... I'm learning more and more as I go on So it looks like the earlier bikes had rollers but then Sherco moved over to big balls That 6206 number is used by many bearing manufactures for this size of bearing. I'm told that Nachi do a rubber sealed bearing specificly for this type of application and they now handle up to 140 degrees centigrade....so this looks like the hot favourite Best of balance. Neo

If the coolant is topped up and the fan cycles on and off (and you've changed the thermostat) I can't see how you could have a problem. I few months ago I was convinced of the same thing on my 250....I ride most days and she's still going I concluded that the more I worried about it the hotter the engine was getting You can get stick on temperature strips that give the temp in real time. But if your really convinced it's to hot and it's under warranty why haven't you given it back to your dealer?? Best of balance. Neo

Now I'm really confused ...got the case open. These main bearings are "Cylindrical roller bearings" and not "Deep grove ball bearings" as the part numbers have been suggesting. I need to re-evaluate all this before anyone bother reply. Best of balance. Neo

According to the Sherco spare parts books and the SKF website you guys might both be right. The pre 2007 parts book shows.... 80/125/250/290 "CRANKSHAFT BEARING 6206.TN9 C3C3" - SKF have a 6206ETN9 as an Unsealed 30mm bearing. 2008 and 2009 shows.... 80/125 CRANK BEARING 6205 2RS.C4 - SKF have a 6205-2RSL as a 25mm Low friction Sealed 25mm bearing. 250/290 CRANK BEARING 6206 TN9/C3 - SKF have a 6206ETN9 as an Unsealed 30mm bearing So it looks like in 2008 Sherco fitted smaller 25mm Sealed bearing to their 80's and 125's but the the 250's and 290's still use 30mm unsealed. Maybe Sherco are testing out the sealed bearing concept in their smaller bikes first....smart move I think. So my 2006 125 should have 30mm unsealed bearings but I'd like to give the sealed concept a go. But my concern is SKF say that the sealed bearings..."should not be washed nor heated to temperatures above 80

Thanks Stork, In a way I'm looking forward to the challenge. I'm thinking of using a heat gun to get the case up to temp? This is the first time I've opened a gearbox but I knew it would happen one day Best of balance. Neo

I have concluded that this problem must be the main bearing on the flywheel side. I'm going to replace both main bearing and both seals a set of Silent Block (clutches shock absorbs) and maybe the piston rings too. So apart from gaskets what else do you guys reckon I should change while I'm in there? Best of balance. Neo

Hi, Does anyone have the answer to my questions above Also, I need to know the type of seals I should use for the main bearings and will I be able to get these from the bearing shop too??? Best of balance. Neo

Hi Jon, Thanks for your advice above. But on a Sherco when the primary drive or the Clutch Pinon is jammed (in any way) the clutch hub and nut still turn freely because the the clutch plates have tp be out to get to the clutch hub nut...."chicken and egg" really I thought about putting it into 5th gear and jamming the drive sprocket. But I'm unsure if I might damage something. Even though it should be able to take this stress because the engine drive take the same route....might try this as a last resort. Best of balance. Neo

Ok the cylinder is off.....and as suspected it's as clean a as a whistle. No scores anywhere piston or cylinder. The rings are smooth and move freely. It was also nice to see that it is still the "A" piston as the thin carbon deposit (on the top) sanded off with ease. There is no detectable movement in the big or small end bearings. And I can't feel any movement on right side main bearing too. Although there is less of a grip and/or leverage on this side. But my first concern is the amount of oil that appears to be in the crank case and coating the crankshaft flywheel. It feels like gearbox oil to me and if I wipe the crankshaft flywheel clean (at the top) then rotate it once, it's covered in oil again...Hmmm...am I seeing something bad or not? Next step was removing the side cover and clutch plates. Again it looks nice in there. There's a tiny amount of slack between the PRIMARY DRIVE CRANK PINON and the PRIMARY DRIVE CLUTCH PINON. But no noticeable wear on any of the gear teeth. So this looks fine to me. My concern is there's movement (2mm left/right slack) [correction (1mm left/right slack)] between the PRIMARY DRIVE CLUTCH PINON (the big gear) and CLUTCH BASKET. Is this bad or is it something to do with the SILENT BLOCKs (M358) shown in the spare parts book. I can't remove the clutch basket HEX NUT CLUTCH at this time as I don't have a Basket holding tool and I don't want to risk damaging the Aluminium CLUTCH HUB. Any ideas how I can safely get a the HEX NUT CLUTCH off without a basket holding tool? Also, when I go to refit the Cylinder is it best to fit new rings and do the rings need to be in a certain position before sliding the cylinder back over them?...I have not removed the piston or Pison Pin or Piston circlips so far. It's all come to a stop now but it would be good to know what parts I need to order by Monday....So advice at this state would be greatly appreciated. Best of balance. Neo

Ride up some bumpy, rocky or steep hills and you'll leave them all for dust And remember your bike is a ballerina compare to their diesel trucks on two wheels Best of balance. Neo

Sorry to take this thread off the subject.....but looking at the 3 guys at the back in orange. The one in the middle. There's something very odd about the look of his pants. My wife reckons this new GasGas has got him going....But alias I don't know what she means Best of balance (and try to stay out of Lycra suits). Neo

I just noticed this on the GasGas forum.....This is interesting but do you reckon it's plausible? Best of balance. Neo

I think you might need to put that question to 1shercohe1..... But either way I think "Keihin" has been mentioned enough times in this thread to come up in a search. Thanks for the tips on the jetting. Oh and the Oz kit will not stop it being fiddly...The ports (Intake and Airbox) are too poorly aligned to stop that. Best of balance. Neo

Sorry Cope, I'm currently on a business trip. Might not be able to try the 24mm for a couple of weeks or so. What jets should I start with....same ones as the 28mm? Best of balance. Neo

Sure does....I'll check it out...many thanks. Best of balance. Neo

Hi Gents (Cope and all), Yes I could not see/feel any up/down play when the flywheel was off. But I tried again with the flywheel on and I can move it (up/down) maybe 0.1mm (0.2 max). And the whole thing turns so smoothly without sound it's hard to see that this a the cause of the Strange Rattle. I'm going to take the clutch cover and basket off and see what it all like from that side too. But recalling that it does not make a sound while it's cold does this give an extra clue? I can see the areas above the intake ports through the exhaust port and they look smooth. But would it be OK if I lift the barrel up (with the head still on) just below the piston rings and rotate the barrel 180 degrees so I can inspect the intake side of the piston through the exhaust port?...or would this be a crazy thing to do? Best of balance. Neo

I've just been doing some research on the SKF website...... Are you guys talking about a Sealed Bearing or Shielded Bearing? According to the SKF information..... "Sealed bearings The bearings with shields or seals on both sides are lubricated for life and are maintenance-free. They should not be washed nor heated to temperatures above 80

Hi Cope, There is no up and down moment that I can detect. So what your saying is there should be NO side-way moment at all ? Will this only get worse?....Ridden every day how long have I got? If I open the case I may as well do all bearings "crank and upwards" and all seals (and gaskets)...but what's that going to cost me? Are there any other checks you think I could do before drawing a conclusion? Best of balance. Neo

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Hi Cope, The 24mm is exactly the same physical size as the 26mm, 28mm. 30mm and the PWK. The bowls and even the slides are OKO interchange able (but the slides don't fit in the Kiehin). I know the bevelled intake spacer you mean as I've seen these on the GasGas's. So without it all the carb bowls rub on the gearbox case, even with the Sherco 5mm manifold spacer. Although I think it is a fairly light rub. I use and 5 cent piece wedged between the carb bowl and the case. It doesn't move so the case is not damaged in any way. Also I have a clear plastic bowl on this carb so if there was a lot pressure it would have cracked or leaked by now. Best of balance. Neo

Hi Have an OKO 24mm (Keihin copy) on my sons 06 125 and it's awesome. Better low end power. Revs up cleaner, never drips and since fitting it 6 months ago it's NEVER missed a beat or needed adjusting. This in total contrast the Keihin 28mm, then OKO 30mm (then back to the Keihin 28mm) I fitted to my own 06 250. I've only recently been able to get it running next to perfect....but it's taken me a year of on-&-off tinkering to get it that way. My recommendation is the OKO 24mm for the 125. Sorry I don't mean to contradict Cope....as he really knows his stuff. Best of balance. Neo

Hi Cope, Interesting information on the fuel and starting. I generally ride everyday and she starts 1st or 2nd kick every time. So I don't think the fuel is lacking anything. Can you think of any simple tests I can do to confirm the "fuel in the crankcases" theory? Best of balance. Neo

This is exactly what I originally thought was casing it this problem (and this theory's supported by the grey exhaust smoke that clears when the engine does)...But because the choke only stays on for no more than 5 seconds But it takes so long to clear (10 to 20 seconds) I was concerned there was something else go on Could a build up of fuel in the crankcases happen in just 5 seconds of cold running on choke? If this diagnoses is correct, just to confirm it, should it run Fluffy again if I use the choke for 5 seconds when the bike is warm? Thanks for your feedback so far gents. Best of balance. Neo

Hi All, My bike is running like a dream at the moment ....but there just one problem that's got me wondering.... After (and only after) a cold start the engine runs fluffy (poppy) and will not rev clean until revved right up for 20 seconds and cleaned out. After that she runs almost prefect. It happens every time now and is still apparent no matter how long a spend working the bike up. I'm using Castrol TT synthetic but it was the same with the previous synthetic two stoke oil too. Does anyone have any idea what could be causing this? Best of balance. Neo