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Restoring a 490

17 Aug 2019 08:20 17 Aug 2019 08:22 by webfluid.
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Restoring a 490 #11
Have to say this engine is as awkward as it can get for me at this point. Having minimum tools no stand as such, its just a heavy old beast. Everything from putting bearings in to resetting the transmission. But today i managed to get it all put together internally. I have been staring at it all week psyching myself up to do it.

earlier in the week at the first case mating run i discovered that you really can't do it with the trans and crank in the right side.( even though the trans fits in there snug all assembled) The shift drum bearing in the left case needs heating so stub of drum fits. Its as tight as hell banging it with a hammer once lined up to get it , a pain in the backside, never had two cases fight so hard to go together. Once the case were together i discovered one of the crank bearings was not seated correctly but once that was done everything runs freely and the hard bit is done now and am now looking forward to building up the frame with the bottom end in whilst i wait for the barrel and a couple of other bits to come back from shot blasters.
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07 Sep 2019 11:39
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Restoring a 490 #12
Not much of an update but managed to put bottom end back in frame and after 9 weeks of waiting i have had the bits back from powder coasters so can start putting a few parts back on the bike
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08 Sep 2019 08:12
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Restoring a 490 #13
I have started a new post with a question if anyone can help

so i managed to put the spring back on the shock and install that enabling me to turn round the bike in my shed and work on the clutch side, i hoped to have this all buttoned up this weekend to protect it from the colder air in the uk at the moment. well my kick starter is not working properly and i assume i need a new spring as mine has a bit missing on the bit that seats in the nylon bush. i need to know if the end that is broken is to locate in the hole on the kick starter shaft. i assume it does to enable it to tension and return the kick starter. haven't come across this problem before .
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15 Sep 2019 06:27 15 Sep 2019 06:28 by webfluid. Reason: picture
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Restoring a 490 #14
So after a lot of fettling around with these used parts, i finally managed to get the kick starter repaired and installed , the outer clutch case now fits as it’s supposed to do after a bit of adjustment to the nylon bush. made it 10 times more difficult by not removing the clutch basket for the 3 rd time but it’s all sitting in there nice now so i can move into the barrel and piston.
which unfortunately looks like the piston is going to need replacing. which is another kick in balls really as it all looked really new . it has a .50 oversize wiseco. the ring gap isn’t even in the ball park area , there are some marks on the piston but nothing to bad but piston is out on every tolerance as are the rings. so it needs a re bore and top end kit.
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22 Sep 2019 13:51 22 Sep 2019 13:55 by bluntz465.
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Restoring a 490 #15
I have a set of 1st and 4th over rings if you go that route let me know,Also have a new kick spring if interested.

1957 Cushman Eagle 1969 Honda 90 ATC 1969 Honda CB250
1973 Yamaha AT3 1974 Kawasaki KH440 1974 Honda XR75
1975 Suzuki TS75 1975 Kawasaki GreenStreak 90 1975 Suzuki GT550
1975 Suzuki TS250 1976 Suzuki GT550 1976 Indian Chief
1976 Yamaha YZ80 1978 Yamaha IT175 1980 Suzuki GS550
1982 Yamaha IT465J

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23 Sep 2019 06:52
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Restoring a 490 #16
I managed to get to my engineer earlier in the week to have it measured for a new piston, i did think about just stuffing a set of rings on the piston and be done with it but it needs a rebore , only by .50 but it will certainly fit the new piston better, and although i am half expecting it to grenade itself first kick, ill take a gamble on the new piston.

so believe it or not there is a guy on eBay offering a 35% discount on a wiseco piston, rings, clips, pin, plug and filter package and threw in a little end too for a little extra and its still way cheaper to have that little lot sent over from U.S. than it is to buy a piston kit in the U.K.or import a yamaha piston in from wherever, although i would have preferred a yamaha piston personally

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14 Oct 2019 07:11 14 Oct 2019 07:51 by webfluid.
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Restoring a 490 #17
Not much of an update as the weather has gone bad over here to be working in damp sheds, but managed to pick up the Barrel from the engineers after a rebore of 1.00 (so still lots of life in the barrel), new piston , little end bearing and rings will go in as soon as i order a base gasket, which completely slipped my mind.
Had an absolute disaster with the piston being ordered from U.S.. managed to make it all the way to the U.K. only for the yodel delivery driver to toss it over my back gate and crack the skirt on the piston!
you couldn't make it up with the idiots we have delivering stuff in the U.K.. so ordered a new piston after getting a full refund from eBay and we move on to the next step.
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14 Oct 2019 07:31
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Restoring a 490 #18
here's a nice image of ring gap measured with a 0.40 feeler gauge. spec is between 0.35 and 0.50 so i would say that's about right. close up shot shows i might need to give the bore a good clean before assembling it ( just trying out my iPhone flash too!
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29 Oct 2019 09:01
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Restoring a 490 #19
Little update, piston is in , wiring loom is in position just awaiting arrival of some M8 washers to bolt the head down.
got to get some tyres fitted to the rims in the next month to get this bike rolling. but that takes money which is scarce at the moment. there is a big order to do for all the miscellaneous stuff but that will be after christmas.
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29 Oct 2019 12:15 29 Oct 2019 12:16 by shyted.
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Restoring a 490 #20
Hello webfluid.
Your bike looks brill. really nice job pal.
See the wiseco pistons,they are way better than stock. Thing is though,you have to let your bike warm up thoroughly before you give it any use. You can smack that piston crown with a hammer the quallity is that good.
Castrol 747 or XR 77 at 25 to 1 will give you a good ring seal on that nice bore.
I had an Aprilia 250 racing bike ( rotory disc valved in line Rotax twin ) with a factory race kit on it. very hard bike to ride ,very tempremental. very hard revving .With the Castrol,i never had a bore ,piston or crank failure.
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