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4t @ The Scottish


dixie
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Absolutely correct RE500 that's 100cc in one side and 700cc in the clutch side total 800cc. I was going to double check before doing the oil!

I guess that means fresh oil required every trial thenince 800cc is not a lot of oil?

One of the problems with the Husaberg/Husquvarna scrambles bikes which used a similar system to pump oil was that when the oil got dirty/contaminated - probably from clutch abuse the oiling was less than perfect & engine problems were more likely.

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g4321

Sherco state in their service tips for the 4T..

Change oil after the first 5 hrs and then every 30 hrs thereafter!!!

I think i'll play safe and change a little more regularly than that!

cheers

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Decompressor is centrifugal: when cam turns below certain rpm (I could remember about 600-800 rpm) a spring keeps pushing a lobe that lifts the exhaust valves (just a little fraction of mm). Just the minimum to allow you kick and also the maximum to allow the engine start without so much loss of compression. When you kick and engine starts, revs go up and a little weight, centrifugally moved, retracts the spring, leaving the lobe free and valves close completly. Honda 4RT works similarly. Sorry for this verbose explanation, its much better to see it (just quit the head cap).

About the 30 hours... It's not the same 30 hours of a hard spanish summer trials than 30 hours of greenlanning on Yorkshire woods. Figure yourself the effort realised and act in consequence. 30 hours should be the maximum delay, in any case. Ipone R4000 isn't a cheap oil and I would search for an equivalent, cheaper, that allow more frequent changes.

I would prefer separate oils, one for clutch-gearbox and other for engine (like 4RT), but Sherco uses the same 2stroke crankcases and, if oils were separate, mere 300 cc would rest for the engine. Insuficcient, clearly. Maybe in the future we'll see a new flywheel case to allow a truly oil pump and a little more oil...

Cheers, JM.

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Marlintec

Many thanks for explanation regarding the decompressor, seems like a neat solution, assuming its reliable !

Has anyone checked the valve clearances on the 4T yet?

Any tips for saving time..seems to me the engine needs to be dropped in the frame to remove the rocker cover! Must be a simpler way?

Cheers

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RE500, it's very very easy. Just remove tank and unscrew the two bolts of the cover (it cuold be good also to untight the bolts of the triangular cover that support the cam bearing). The cover will 'undercover' the rockers and you will a lot of space to check clearances. Much better than in Cota 4RT, that needs to remove fuel tank and injector, four bolts (for 2 covers) and there isn't so much space to check clearances in exhaust valves.

Anyway, Sherco 4T uses the vase/shim system, so may be you'll need a set of shims to do the adjustement. Cota 4RT use the old bolt/screw system... but you'll need a special wrenck to hold the screw (a little squared head).

If adjustemt is needed, remove the triangular cover of bearing cam and extract the rocker axes through the cam-wheel (very easy), then you can put o remove the shims.

In a talk with Josep Paxau, he said that after the first adjustement, valve clearances endured for long long time.

Anycase, it's a job for your dealer to keep the bike on warranty.

Cheers, JM.

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Marlintec

Again, thanks for the info'.

Unfortunately the top valve cover sits outside and under the frame rail so is

impossible(?) to remove without dropping engine. Just no clearance to lift the cover up and off.

Cheers

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Marlintec

Yes, did have a half hearted go, just to have a look at the decompressor!

See attached picture, cover is outside and under frame rail, it cant be lifted

and across as the plug tunnel stops it(?)

Cheers

post-11-1117705402.jpg

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Uh, really tight, it's true :lol: The prototype I tried had enough play to lift a little and save the 'plug tunnel' edge (it is an independent tube and remains free between head and cover). Maybe they have changed the chassis in the final series? Look at this photo of the early prototypes...

What says your dealer? Have you any manuals?

post-11-1117708181.jpg

Edited by Marlintec
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Marlintec

Yes, they have changed something, there is significantly more room

in your picture :lol:

Bike comes with a poster of last years 04 2 strokes. Only imformation on the 4T are the service tips on sherco.com.... and your posts!

Dealer hasn't done one yet!

RE500

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It's a pity that Sherco doesn't care about manuals or handbooks. When I bought the 2.5 '04 I did received absolutely nothing; I understand now. My handbook-poster was to be given with the '05 bikes... :lol:

On the other hand, there is a lot of information, tips, etc. on their web, developed by the US importer I think. But in this case, is evident that the bike arrived too soon or the instructions too late. Soon or later, your dealer must do some work to the bike and I wonder if he knows how to. Surely he do.

The first valve-check is after 5 hours... Maybe other Sherco4T could tell us about.

In anycase, I'm surprised to see the change in the chassis... Anyone has more information?

Cheers, JM.

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  • 2 weeks later...

I found by removing the radiator, which is much easier than the 2T, and comes out ,the front of the frame. You can remove the tappet cover and slide it forward over the cam gear in an arc towards the front wheel. This also leaves the front of the head wide open to check shim clearance.

ShercoH

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