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Restoring a 490

08 Apr 2020 07:18 08 Apr 2020 07:21 by webfluid. Reason: spelling
webfluid
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Restoring a 490 #51
Thought i would add my mock up of the ITs i have rebuilt in the last 3 years, finally got the 490 sorted out and its running pretty well now. The neighbours hate it. I found out what all the buzzing was coming through the handle bars basically every engine mount had come loose on the heat cycles so i have been right through the bike again and loctited everything, even though i have been using nylon nuts torqued to spec. Had a rough running problem at 3/4 throttle which had me stumped for a couple of days, tried rej-etting, different mixes, cleaned the carb so may times it was ridiculous. Turned the petcock to reserve and boom off it went. had 4 litres of fuel in it but forgot to factor in gravity and fuel slopping around in the tank.The exhaust is being a pig to seal at the cylinder head but i have re-jigged the angle of it now and hope a smear of silicone will fix that.
got a couple of people interested in it at the moment but with all this corona virus stuff going on i think ill hang on for a bit.

would also like to add it is alarming the rate of infections being confirmed in the US right now and i pray all of you stay safe.
best wishes and thanks again for all your help :unsure:

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08 Apr 2020 09:04
mdscott
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Restoring a 490 #52
Those IT bikes are really good looking. I finally after 6 months got excepted to join yamahait.com.au/forum/index.php .
Nice forum. I was looking for a IT200 near me, very hard to find, so ended up with a KDX.

Thanks Mark
Roseville, Ca.

'76 Bultaco 143 Frontera
'06 GL1800
'01 KDX220
'68 YG5T 80 Trailmaster
74 DT360
75 Norton
73 CB500K
63 C200
87 PW50
64 McClane Edger

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08 Apr 2020 16:55
Biknflyfisher
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Restoring a 490 #53
I have also had issues with getting the pipe to seal at its junction with the cylinder. I’ve tried varying the angle of the pipe by shimming the points where it attaches to the frame with some success. And, I used some high temp silicone seal which helped more, but I still get some blow-by.
I may try a thicker “ring” of sealant on the cylinder and see if that does the trick.
Brian

1983 IT490K; 2007 Yamaha FJR 1300,
2003 KTM 450exc
Too many fly rods,,,

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08 Apr 2020 23:16
webfluid
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Restoring a 490 #54
Getting the top exhaust hanger on the opposite side of the frame helps change the angle greatly, my biggest issue is the metal gasket drops straight into the mouth of the pipe and is not really sealing anything. fortunately my cylinder has a nice groove where the pipe is supposed to sit but cos of the age of the pipe nothing fits perfectly so it will always leak i think.

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