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Restoring a 490

30 Oct 2019 20:37
bluntz465
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Restoring a 490 #21
The advice to slowly warm up a wiseco piston is exactly what we followed back in the day but not sure if it is needed today as the tech has changed a bit.However it won't hurt and since that advice is pointed out,I would give the other as well and that is to slowly ease out as well and let it slowly cool down when done riding her. but this is race conditions obviously.Very few guys will push a 490 to that level.

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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05 Nov 2019 12:16 14 Nov 2019 08:12 by webfluid.
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Restoring a 490 #22
I will heed the advice with the piston, had a hell of a job getting it to bed in on the 250 and swore i’d never use another!
But availability is the main reason for using one this time. and affordability.
Had a day fettling with lots of
little things on the bike once
the nuts had turned up. managed to get the forks on, engine buttoned up and carb cleaned up.
have a jetting question in the main forum if
anyone can help?
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14 Nov 2019 08:08 14 Nov 2019 08:09 by webfluid.
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Restoring a 490 #23
Managed to get the plastics back to some sort of condition, can't do nothing with the stretch mark on the rear fender that's gone right through, the crack around the rear lense has been wired and super glued. ideally it could do with a replacement for cosmetics.
The tanks i have one is original yamaha the other is a clarke tank. i planned on keeping the yamaha one for another project because it is as good colour wise as any i have had. The clarke one has a broken cap, i have since discovered the clarke thread is different to the yamaha one and to replace the cap it would need to be imported from the U.S. as they are specific to clarke tanks.
so it looks like i will use the yamaha one as i am not paying silly money for a cap and will sell the clarke one on once completed.
Managed to get my tyres fitted today, the rims have been stored outside and the spokes have tarnished slightly, but that can be sorted quickly.
I shall get this bike rolling if its nice the weekend and get it to my friends workshop to finish off after christmas
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16 Nov 2019 08:40
webfluid
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Restoring a 490 #24
Managed to get a few things done today, got the wheels on discovered an issue with the tank fitment that needs attention, damn thing is absolutely massive and the extra weight of the engine compared to the 250 i had makes me want to find out the weight difference between the two. wheels went on without a hitch, and since this pic was taken i have removed a link from the chain, and it might need another yet.
it gets dark early and only managed an hour on it may have another look later in the week.
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16 Nov 2019 12:50
RT325
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Restoring a 490 #25
When we sold them new in NZ they had a restrictor washer in the inlet in front of the carb. only found it by acident so removed it & the customer came back complaining of too much power haha. Washer pretty much halved the carb size. There was probably a yamaha thing telling us what to do & remove it but can't remember now. was the bosses sons bike come to think. he became a bit of a wheelie expert after that. Great bike. Don't suppose yours still has the restrictor?.
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17 Nov 2019 03:55
webfluid
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Restoring a 490 #26
remember having a suzuki RG 125 brand new in my youth that had the same thing, fortunately i knew this before i bought it and had it removed also before i had put a mile on it.
This 490 has nothing restricting it, there is a full DG system and boyesen reeds. i am not going to speculate what it will do
as i have never ridden one yet. just hope it starts, runs and i don’t fall off the thing setting it up

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17 Nov 2019 09:46
mdscott
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Restoring a 490 #27
Sure is looking good, :OnFire

Thanks Mark
Roseville, Ca.

'76 Bultaco 143 Frontera
'06 GL1800
07 DL650
74 DT360
75 Norton
73 CB500K
63 C200
87 PW50
64 McClane Edger

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17 Nov 2019 13:40
webfluid
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Restoring a 490 #28
Added a mudguard, rear chain guard, sorted the brakes out and managed to get a spark from the ignition system. Still waiting for exhaust spring tensioner new exhaust mounts but couldn't resist fitting them today .....just to see what it looked at. i also noticed the rear shock is lacking resistance and although it is not leaking i thing could do with a re gas.
Also discovered there is only 4kg difference in weight compared to the 250 which surprised me as it feels a lot more, but i guess most of it is the engine barrel.
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17 Nov 2019 14:51
Biknflyfisher
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Restoring a 490 #29
The black chainguard on the top of the swing arm is virtually impossible to replace over on this side of the pond.
I noticed that your cylinder and head are not the factory black - did you have them bead blasted?.
Brian the biknflyfisher

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

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17 Nov 2019 21:44
webfluid
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Restoring a 490 #30
yes had the barrel and head bead blasted, am in two minds weather to paint it, will probably leave it as is. have seen a few like this. likewise i will leave the exhaust matt black , i didn’t like the finish initially but it seems to have lost the bbq paint look as it’s dried. still lots to do.
with the work that’s been done on the engine i am reluctant to try and turn this into a showpiece and am happy for it to keep all the parts it came with. The chain guard is a rare item and the first i have come across. and did toy with the idea of selling it but didn’t get the interest i hoped for so decided to keep it and put it on the bike but did sell the pair of NOS hand guards i had to pay for the tyres

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