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Tank Seating And Fan Motor.


badmarx
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hey lads, I just sold my wr250f and got a sherco 290 2002 model for free. i broke the bike down and rebuilt it the last two days. one of the problems i came across is the tank doesnt sit flat as it should even when emptied and the only thing that looks like its stopping it is the big brass looking fan motor. the motor is just shy of touching the spark plug cap. just wondering if anyone has a pic of a o.g. fan motor in situ to see the difference or if anyone bought an after market fan motor and found it caused this problem? il try posting a picture soon. post-17982-0-05603400-1360455261_thumb.jpgpost-17982-0-03137300-1360455279_thumb.jpg

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There is a lot of stuff behind the headstock and it should generally look like this:

I cannot tell on your fan motor.

Also, fuel tanks are bad about expanding with alcohol fuels and it may actually grow to the point it no longer fits the hole.

post-36-0-17655300-1360467673_thumb.jpg

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Hi , had a look on my Sherco. the HT lead runs round and under the fan from the left side of the bike. your fan looks about the right size to mine, but there is not alot of room for clearance.

It is quite a snugg fit any how, with cables from coil pack, throtle and clutch

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Hi, Not had this experience with a sherco but had a similar issue with my sons gas gas, I had to heat up the tank with a hot air gun and re shape it so it fitted around the fan, This was a reccomendation from gas gas uk, 2 years on and no problems still with the tank.

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Thanks Copemech, thats exactly what my motor looks like and its as close. air gun ! ah feck, I was even holding one in my hand while looking at the tank . . . great idea and worth a shot. thanks Steve. Bulto58 thanks very much for going to the trouble of looking at your own bike to compare.

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I think I read it on here in a previous post that if you drain the tank, give it a good rinse and then let it dry out properly that it will shrink back to its original shape.

Have done it in the past and it did sit much more comfortably when I refitted it. Need to do it again as my tank is definitely expanding again though.

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Thanks Copemech, thats exactly what my motor looks like and its as close. air gun ! ah feck, I was even holding one in my hand while looking at the tank . . . great idea and worth a shot. thanks Steve. Bulto58 thanks very much for going to the trouble of looking at your own bike to compare.

The reason I mentioned tank expansion it the fact that in your first pic it seems sth tank is soo far forward it will not line up with the front mount and is at the point of near hitting the steering head.

Need to get the front positioned then cram in the back if possible, otherwise you may have to shrink that tank! I have seen the tanks grow prolly 7-8 mm or more.

BTW, I understand the tank material is a Nylon, which does not conform well using heat.

Edited by copemech
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Yeah thanks lads. I decided to be a bit more insistant with the tank and it sat in a lot better. did what ye said by washing out the tank and started from the top. But still not in situ fully yet. I'm thinking this old girl might just need a new tank as iv found a fairly bad leak around the tap. I'd be grateful of any suggestions for this too. Dono if they can be fixed. the leak is where the main body of the tank meets da part that the tap mounts to. It looks like there should be a rubber gasket between plastic and tap too but that's just a guess. If so that's not there anymore. Cool little bike though can't get over how nice the general design and quality of it is.

Edited by badmarx
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Keep the questions coming, this is the TC brotherhood, in all my time on this site I've never seen anyone fail to get a reply to a request for advice (as for the quality of the reply...well...er.) The tanks do expand and they do leak but those faults should be manageable. When I went into semi-retirement and laid-up my bike for a few months I drained the tank dry and left it off the bike for a while. When I went to re-fit the tank it just fell in place, much easier than it had ever been !

The tap mount to the base of the tank does leak, some had an o-ring, some had a gasket and some had both; if you can get an imperial (larger than std) viton o-ring in there it seems to sort the problem, Copey might chime in with the exact dimensions?

Your carb might need rotating a touch to clear the tank when the choke is on but there isn't much room above the lever anyway, I drill the tip of the lever and put a tiny cable tie through the hole so I can easily just yank the choke down into the off position like flushing a miniature chain-pull toilet ! saves taking your glove off on a cold day (it's grim up North).

P.S.Watch oot:

I've just thought, if those two dome-head bolts that hold the tap to the bottom of the tank have corroded in place; be very careful when you unfasten them. The female threads are a brass nut insert, moulded into the nylon tank, if they rotate in their housing you're buggered.

Edited by ham2
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Also noticing that the closer I get the tank to where it should be, the more it impinges the little black choke Lever from reaching full upright position. I know these are pure newby questions sorry.

Like Ham2 says keep the questions coming, we were all newbies once.

Copemech does a great job of answering Sherco questions, seems to really know his stuff. Generally he is very nice and polite to the new guys, wait until he gets to know you :D

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Like Ham2 says keep the questions coming, we were all newbies once.

Copemech does a great job of answering Sherco questions, seems to really know his stuff. Generally he is very nice and polite to the new guys, wait until he gets to know you :D

He doesn't usually reply until night time...I think his coffin lid has a UV sensorsmileys-vampire-336457.gif

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You seem to be having the same issues I had a few months ago when I got my '03! My tank leaked at the tap also. I bought a replacement fuel tank gasket and fitted that. My tank had moved about over time however and even with the new gasket it still leaked. The part where the tap went through the tank had pulled up and so sat further in (so out of line) than the holes for the bolts. I managed to reuse the old gasket by chopping off the bolt holes and using it as a spacer to fill in the gap.

I'm not sure if that made any sense or is any help! The guys on here seem very knowledgeable and haven't shouted at me for my silly questions yet either! On the tank growing and shrinking, after the rinse I left mine out for about a week in an airing cupboard. Gave it a rinse and left it for a few hours today and it was still in its fat state. They must take a bit of time to shrink back down.

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Yeah thanks lads. I decided to be a bit more insistant with the tank and it sat in a lot better. did what ye said by washing out the tank and started from the top. But still not in situ fully yet. I'm thinking this old girl might just need a new tank as iv found a fairly bad leak around the tap. I'd be grateful of any suggestions for this too. Dono if they can be fixed. the leak is where the main body of the tank meets da part that the tap mounts to. It looks like there should be a rubber gasket between plastic and tap too but that's just a guess. If so that's not there anymore. Cool little bike though can't get over how nice the general design and quality of it is.

The expanding tank issue seemed a mystery to me for a long time. Yet it seems to be related to the alcohol in the fuels and the permiability of the nylon material. It does tike time for one to shrink, but they will it seems as time passes, not sure if one can accellerate the process of outgassing the material with minor heating or not.

My tank on the "07 had grown at least 8mm and would barely fit, and due to some long periods of inactivity, I put the bike back on 100% AVGAS(aviation fuel) with no alcohol as it is totally prohibited. To my surprize, it totally shrunk back to original size after a couple months when I noticed it. This entire situation started a long time ago, when we were not SUPPOSED to get alcohol in the fuel, as it was not posted anyway, so I thought it was possibly just autogas in general, yet I think differently now.

I have owned "01, "03,"05,"06,"07 and now "12 model, and within the timeline, seems they made changes to the petcock arrangement almost every year for a while there. Some had gaskets, others o-rings, and the cocks themselves were different. But long story made short, I had the best luck installing the slightly fatter imperial o-rings on those that would accept it. On my "07 the valve lever itself began to seep which is another story.

Yes, you may need to rotate the carb in its mount" just so" to get it right!

Ham2 must realize that I have to work you know, and by the time I get home and head to mancave, it is wee hours of the morn for you guys in the UK! :blush:

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