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'09 Sherco 320 4T Rebuild Blog


proper
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Bugger. I should have bought yours....
From what I could find, the hot start could be improved with an OKO 24mm flatslide, 35-38 pilot jet, 100 main jet.

Doesn't break the bank either:

https://www.aliexpress.com/item/OKO-24mm-PWK-flat-slide-performance-carburetor-for-2-stroke-scooter-JOG-DIO-RTL250-CR80-CR85R/1774510926.html

Edited by proper
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  • 2 weeks later...

The OKO 24mm has been ordered, along with a bunch of main/pilot jets. The Sherco has the typical single piston 4T hesitation when cranking the throttle. Let's see if the OKO can work wonders. Will take a few weeks before it arrives.

What's next? I removed the flywheel nut with the air impact wrench. The flywheel has a M31x1 external thread. I did not find any after market flywheel puller that size. Impossible. Why, Sherco, why? To sell your own flywheel puller for top price? Not happy.

There are no other attachment points for a universal gear puller. The Flywheel can not be pried form the back, and I don't want to hit the crankshaft with a hammer either. Bugger.

Now what? I'll have to sleep on that one. You'll probably say: buy the Sherco puller from the money you saved on the OKO...

IMG_20170213_235204669_zpsw0opkvyj.jpg

The head will be removed tomorrow. Didn't want to wake the house with the air impact wrench. Not much room for normal 12mm sockets up there.

Exhaust has been blocked on both sides. One side has a clamped rubber grommet, the other side a flat plate with sponge rubber. Needs the gas burner at work the get it red hot. Let's see if those nasty dents can get sorted.

IMG_20170213_234820906_zps1dazg0ff.jpg

IMG_20170213_234732734_zpsaj7bozsw.jpg

IMG_20170213_234827860_zpse6ys0bln.jpg

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Noticed your crank does not have the 3rd bearing ''nub'' on the end which a 2009 3.2 should have...maybe a non-original motor in frame or actually an older model sold as a 2009?? If its actually a 2009 model it should also have the Sps carb already installed, easily identified by a round aluminum main jet access plug(its a modded keihin PWK28) . With this carb you will have Zero ''off idle hesitation/sputter at all...but you have to make sure there is no crap in Any of the jets or orifices.  That is a very interesting looking coffee can welded onto your header pipe there...very unique:mellow: Good luck on your build

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Thanks for that piece of information, Paul. Will check the carb tonight. That seems to be the best telltale.

Last night I was thinking: what if I could 3D print a M31 nut. That would give the gear puller something to pull at. Probably not strong enough, but worth a try.
Anyway, a M31x1 tap is on the way from China.

If there's any interest in an affordable 320 flywheel puller, let me know. I'll only produce one batch of them.

 

 

 

 

 

 

 

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If you unscrew the said float bowl nut, It will have a longer atomizer tube with a Dellorto mainjet on bottom (will have loose jet and spring and small end thing :huh:inside if its sps or converted) The 2008 came with a regular pwk with hotstart setup. I am thinking you may want to recheck your reg. papers as the crank indicates that it is not a 2009 model unless its been replaced or something..:popcorn:

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Oh..I just noticed both vent spigots one each side dont look like they or ''open''. If not, they are on a Sps...may be someones previous attempt to update/carb change, not sure about pwk 2t variations etc I know there are several...Guys at splat are one of the very best for info and parts. Enjoy your build

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O well, I don't really mind what year of build it is. No reg papers, no serial (should there be any?). I'll give the OKO 24mm carb a try, because I'm curious what it does. In a couple of months time the bike will be ready to ride some entry level club trial. Can't wait to hear that bark again. Thanks again for your help. Appreciate it. 

Vincent

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Popped the head off. Clear signs of threadlock on the camgear bolts. Must remember that. All looks well. Cam chain guides are like new. The cylinder head gasket looks fine too. Valves are next.

IMG_20170215_201347844_zpsuqzwrvmh.jpg

IMG_20170215_201359540_zpsurkkm5y6.jpg

Edited by proper
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3 hours ago, proper said:

O well, I don't really mind what year of build it is. No reg papers, no serial (should there be any?). I'll give the OKO 24mm carb a try, because I'm curious what it does. In a couple of months time the bike will be ready to ride some entry level club trial. Can't wait to hear that bark again. Thanks again for your help. Appreciate it. 

Vincent

Engine number should be above the swingarm pivot

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Story is that this particular Sherco has been used at expert level regional club championships. It's a Cabestany replica. The serial seems to point to a 2005 version?

Yeah, I know, the crankcase needs fresh paint.

 

 

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I re-read this great post by Vic: 

and realized I had skipped the step of checking the rocker arm bearing roller for deterioration. Indeed, the exhaust rocker roller has huge play, and can be twisted. This play probably accounts for the increased exhaust valve clearance.

I had a quick peek at splatshop, and wasn't disappointed. It's not a cheap part.

The rocker arm is fine, it's just the bearing roller needing replacement. So that's what I'm going to try. It isn't meant to be replaced, the bearing shaft is welded. (never seen such a perfect micro weld). I'll drill the shaft, and try sourcing a replacement roller, mounted on a precision 12.9 bolt.

At the inlet valves I measured the following:

Valve 1: gap 0,00mm   Shim 1.26

Valve 2: gap 0,05mm   Shim 1.26

Shim thickness was measured using a micrometer with a 6.34mm bearing ball in the shim recess. Double checked with the digital caliper. 

Here's the shim sitting on top of the valve stem. It took me a while to understand how to remove them. It turned out it only needs a magnet:

IMG_20170220_221345286_zpsxnbzjcan.jpg

IMG_20170220_221359451_zpskfmoxk9z.jpg

IMG_20170220_221451192_zpst0kxjzwg.jpg

Marked all the shims and valves postions:

IMG_20170220_221556355_zpswcqgybpg.jpg

Piece of wood to compress the valve spring:

IMG_20170220_221634089_zpsbvfgvd5i.jpg

I'm using a deep-throat bar clamp to compress the valve spring:

IMG_20170220_221754116_zps9wjt256d.jpg

But the spring will not compress. I'm afraid of giving it more pressure, as it feels pretty solid. Don't want to bend valves. Any ideas what's going wrong? The piece of wood is clear of the casing, the clamp sits directly on the valve. The stem doesn't move up in the cap.  

 

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