4t @ The Scottish

[re500]

Howard Wallace

Good tip re the radiator, i dropped my engine in the frame to check mine and still had to unbolt the rad, though i didn't need to remove it. None of the valves were out of spec.

Jools

There are service tips specific to the 4T on the Sherco website. These cover all the usual service requirements. Sucks for those that dont have web access and really should have been supplied with the bike. Worth having a look even if you don't have the bike as they have plenty of detailed photo's.

RE500

[the artist formerly known as ish]

JM, I wonder if you could do me a favor and find the head bolt torque spec, and translate into inch pounds or Newton meters.

The tip sheet recomends you re torque head bolts, but I don't have the spec.

[howard wallace]

Ishy,

Yes we always seem to get the odd bit of tripe ,on these forums.Strange little quirk of human nature, to be negative and critical of anything ,other than what they ride !!

On a positive note, my shims didn`t need doing after several hours, and they`re a lovely setup ,especially the roller rockers, should last forever.

All up, took me a couple of hours,to theck clearances and have going again.

Cheers,

ShercoH

[marlintec]

Ishy, I would ask to Paxau or directly to information@sherco-moto.com (Andreu). I think is a 8 mm stud of high tension steel, so the nut should be tight to 32-33 Nm for the head. As comparison, Honda 4RT uses 9 mm studs that must be tighten to 39 Nm.

To convert Nm to inch-pound just multiply x 8.85

( to convert Nm to foot-pound multiply x 0.738)

( to convert Nm to kgm multiply x 0.102)

I'll post the information if I get before you.

Cheers, JM.

Edited June 16, 2005 by Marlintec

[the artist formerly known as ish]

Thank you JM, I did ask Paxau, and he said 3kg, it was the conversion I was looking for.

Now I find my Torque wrenches one in inch pounds only goes up to 2.5 kg and my bigger wrench doesn't start until 5.0

So I went out and bought a new one that has the kg scale and I can now set at 3kg without converting.

I also discovered that when I got the bike home the only straight fuel I had was for the lawn mower and that was only 87 octane, poor quality, this made the bike harder to start, the next day I bought race fuel high octane and more stable, the starting improved greatly with that one change.

Comparing the sherco to the Mont, I would say the Mont is higher tech and a bit of an hybrid, not like the old rtl but not far from a two stroke, where the Sherco gives me more of the old four stroke feel I got from my RTL.

Both bikes will do well and in my opinion 4 stroke machines will soon be the most common at events, and France will unveil yet a third full blown stroker to hit the market this year.

Last night in a mid week evening club event, the first five places in the expert class were all four stroke machines, all Mont except one sherco due to the availability at this time, but that will soon change and the 06 Sherco 4t will be a much sort after machine.

It is good we can transfer our findings over the forums like the very first batch of Sherco's in 1999 had the air breather tube inside the case and if overfilled with oil caused problems, the next batch of machines had this changed, little things like this will get sorted by the factory as the machine evolves, but there is something about testing ideas and theories that adds to the enjoyment of trials bikes.

[munch]

interesting ish,

here ive been the only 4t at most trials ive attended , occasionally one other

[bikespace]

Thank you JM, I did ask Paxau, and he said 3kg, it was the conversion I was looking for.

Now I find my Torque wrenches one in inch pounds only goes up to 2.5 kg and my bigger wrench doesn't start until 5.0

I reckon the 3Kg-m converts to about 29.5 N-m or 260 lb-in.

Does that sound about right?

[marlintec]

I remember the mag wheel oiled in those 1999 Bultacos... Well, it's a way to avoid rusting on coils ;-). Sherco has a very dynamic crew in trials and will get all these little things sorted. The carb item is the major problem, I think, and in some places, the hot running.

About the head torque, my 32-33 Nm were a guess based on the type of stud and kind of work. I see that the recommended tightness is about 10% less than my guess, so may be the big barrel needs a margin for dilatation. By the way, Bikespace is right: 3 kgm / 0.102 = 29.4 Nm x 8.85 = 260 lbsin.

What I like very much of Sherco is that the 2stroke models are maintained on production. I have some doubt that the future of trials passes through 4strokes. It has been shown that 4S machines are suitable for some rides, whereas others do not enjoy the new engines. Sherco increases the ''bio-diversity'' of trials instead of reduce the possibilities, that's good!

I wonder if Scorpa will do the same or, like Honda, will bin the 2S bike... Hope they don't. Yamaha still produces very good 2S MX's.

Cheers, JM.

[jools]

On the Sherco 4T do you have to apply lots of heat-shielding?

Seems by reading these posts that if you do not do this then the bike becomes extremly hot and effects other parts?

I just want to find out as I am considering one for next year.

[boofont]

I wonder if Scorpa will do the same or, like Honda, will bin the 2S bike...  Hope they don't.  Yamaha still produces very good 2S MX's.

I think they're still going to be selling the SY, not 100% on this one though.

[the artist formerly known as ish]

Got a bit of a panic on yesterday, thought I had buggered it, was removing the valve cover and as posted in this forum it was too close to remove without removing the radiator and engine mounts.

Anyway when I was taking the side plate off that supports the cam it was a little tight and pulled the cam out of it's housing, "****" thought I would now need to remove the flywheel and start from scratch to re time the thing, so to the flywheel cover off only to find I had no flywheel puller to fit it, "*****" more"****"

What do I do know removed the cam chain tensioner and the job lot just slipped back into place, slapped her all back together and she fired up first kick

The didn't replace the shims has they have not arrived yet, the intake was fine but the exhaust was a couple of thou on the slack side, easy to check if you make sure the cam stays in place when removing the side cover, measure the valve clearance, then slide the rocker shaft out, remove shim measure and replace with new shim of correct thickness.

I would think the reason the auto valve lifter may not work in some cases is because it's need to move freely, taking the cover off and checking valves probably just frees it up enough to allow it to oporate properly, the cam cover is shimmed to allow correct clearence on the cam shaft without binding.

[g4321]

Been reading the discussion on the Sherco with interest.

Reading how the centrifugal decompressor/valve lifter works - or in some engines dosn't could the lack of a decompressor be related to wrong exhaust valve clearance

The amount the valve will open is going to be very small using a centrifugal system so if the clearance is out of tollerance the valve lifter may not open at all.

Could this be the case if the exhaust valve clearance is too slack?

[johnnysherco]

g4321 not a bad theory re the loose valve clearances and yes there is a relationship between the 2. I have just finished giving my 320 a full going over and servicing the engine. On checking my valves the exhausts were 6 and 8thou with 6 being the right clearance, after setting the clearances to 6 thou and finishing the engine service i can not believe the change in starting the 320. Last w/end at a trial the bike had heaps of compression and was hard to kick over to get started, now all it takes is a light push with your foot and it fires into life with no fuss, with no great feel of compression. I spent a lot of time looking and photographing every thing and i can not see what caused the decomp to not work from new. Sherco has done a great job in the engine and the quality of the internals and set up with the cam and valve gear and the whole engine is outstanding in my opinion. The bike is great to ride and has heaps of grunt and it is outstanding in hill climbs and it seems to find traction where the 2t does not. I think it will take a few trials to get used to the 4t and the torque of the engine. Also the sound makes everyone turn around to see what is making that fantastic note ah. johnnysherco

[atomant]

Johny Sherco, Thats real interesting what you found. Mine requires little effort with the kickstart to get it running so it cant be too far out.. But I will sure look at it when I do a full service!

Also, riding it today in the local trial, lots of peeps were commenting on it and how Sherco have done a good job on fitting the beast of an engine into the 2t frame.

I let a local expert (Jools) have a go and he loved it (Currently rides a GasGas 300 ) he said he tried the Mont and its crap in comparisson

And the sound does turn heads. The sound and feel of awesome power is unlike any other modern trials bike I have ever riden.

Edited June 19, 2005 by Webmonkey

[re500]

Very Interesting about valve clearance/decompressor effect

My 4T has always been hard to kickover, so, just measured the valve clearances and the exhaust clearance is miles out on both EX valves!

Both 0.35mm not 0.15mm seems so far out as to be very strange!

Anybody know what shims are available in the UK?

Cheers