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Brand0n

Sherco hunting!

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Hi everyone I've had my sherco for around 5 months now had abit of bother with the bike hunting and or reving right up after a touch of throttle and not coming back down to idle, also when the bikes set to a nice idle it just cuts out I've got fuel mix etc set to standard, ive recently cleaned the carb, new carb to air box inlet replaced, full cable etc.. it's slowly doing my head in and difficult to keep the bike at slow speed without it wanting to cut out or reving it's bollocks off! Just wondering what else there is to check or needing replaced on it? I've also tried the carb/ soapy water trick on the gaskets Also if the bike still fine to use with this issue? Lastly the bikes has a little white smoke coming out from a cold start then goes away is this normal? Any info to these questions would be greatly appreciated! Cheers, Brandon 

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Condensation is the white smoke, hot gases cool air. Crankcase main bearing oil seals leaking allowing air to be drawn into crankcase causing weak mixture and unstable idle or increased revs. Never safe to ride with engine in unpredictable state. Other leaks could be carb to manifold, over tighten securing nuts and carb face flange distorts creating extra air inlet point.👍🙂

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Will it just be a case of getting the crankshaft seals replaced, is this possible without splitting the engine down? Also roughly what would this likely cost if it's something you've ever had done or experience with?

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3 hours ago, Brand0n said:

Will it just be a case of getting the crankshaft seals replaced, is this possible without splitting the engine down? Also roughly what would this likely cost if it's something you've ever had done or experience with?

Not an expensive job. You can replace both seals without splitting the engine-halves. The clutch side is usually the one to go first.  You may well need a correct-sized flywheel puller. Around fifteen notes.  Use masking tape over the crank , to prevent damaging the new seals as you slide them on.  Two self-tappers and grips/pliers to remove the old ones - usually enough. Small woodruff key on the flywheel - I like to always get a fresh one , but not essential.

Replacing both seals is generally the last course of action for the symptoms you describe.  Much else you can do first.  Begin with fuelling and follow the fuel’s path all the way through the system (including tank-vent/filler cap , valve ,filters).   Remove the carburetor. Blow out and clean all jets. Set the float-height correctly ( very important).  Clean carb and jets thoroughly and check the reed-block and reeds. Pay attention to the reed-block gasket plate (this can crack).  When satisfied with condition of fuelling , and air-intake/filter - move on to the electrics , and check spark , plug-condition , timing and inspect all wiring for worn insulation and possible intermittent-shorting.   Make sure all fittings and connections are tight and free from leaks.  Ensure that the exhaust-silencer is not blocked or oil-bound.  Lastly , check throttle-cable action is fault-free and that you are using the correct fuel and oil-mix.

It has been suggested here , that a drain-hole drilled into the flywheel cover - will help condensation/moisture to exit the housing on that side , preserving the life of that seal. Check for excess water when removing the cover.

Overall cost is a puller , gaskets , seals and fresh fluids.  New woodruff key , spark plug and some sealant - optional. Good luck.

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6 hours ago, lineaway said:

 Nice post Neb, are you feeling ok? 

 What year Sherco and what carb?

now he is a sherco expert!

wonder if he figured in the cost of power tools, holders and torque wrenches? whats he gonna seal with sealant?

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14 hours ago, lineaway said:

 Nice post Neb, are you feeling ok? 

 What year Sherco and what carb?

2007 Sherco 250.

20180410_214449.jpg

Correct reed-fitting and float-height adjustment - very important.

Edited by Nebulous

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