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Bent fin
- Fozzy500
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Bent fin was created by Fozzy500
So my CT3 recommissioning seems to be going pretty well but I recently noticed a slightly bent cooling fin on the head that I hadn't seen before. Looks like the head's been dropped. Now that I've seen it it shouts at me every time I approach to bike! I've got the engine out at the moment for a good clean and to paint between the fins but before I do that I was wondering if anyone had experience of /advice for straightening a fin with this relatively small amount of damage? Photo link below (I hope).
imgur.com/a/ga0eqld
Oh and did these bikes ever have any rubber dampers between the fins to stop them buzzing?
Thanks!
imgur.com/a/ga0eqld
Oh and did these bikes ever have any rubber dampers between the fins to stop them buzzing?
Thanks!
14 Nov 2023 11:41
#1
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- RT325
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Replied by RT325 on topic Bent fin
Brave man that straightens fins. Personally i'd leave it, except i don't do concours restoration but can understand how it draws your attention.
Maybe heat it lots then block it underneath & lever it down. Doubt i could be that lucky.
Someone will be along that has done it for sure.
Maybe heat it lots then block it underneath & lever it down. Doubt i could be that lucky.
Someone will be along that has done it for sure.
14 Nov 2023 12:41
#2
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- Schu
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Replied by Schu on topic Bent fin
Odds are it was a direct impact that bent it.
So maybe a reverse impact will straighten it out.
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So maybe a reverse impact will straighten it out.
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Schu
CT1B, CT1C, JT1, JT2, DT360A, GT80B, DT100B, DT125B,
DT175B, DT175C, DT250B, DT400B, Z50, SCR950
Someday, you'll own some Yamahas
CT1B, CT1C, JT1, JT2, DT360A, GT80B, DT100B, DT125B,
DT175B, DT175C, DT250B, DT400B, Z50, SCR950
Someday, you'll own some Yamahas
14 Nov 2023 15:07
#3
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- MarkT
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Replied by MarkT on topic Bent fin
Every fin I've tried to straighten has broken off.
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Some people have done it though... I just haven't been that lucky, last time I used quite a bit of heat too. (I will say the ones I tried to straighten were bent much worse though)
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Some people have done it though... I just haven't been that lucky, last time I used quite a bit of heat too. (I will say the ones I tried to straighten were bent much worse though)
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
14 Nov 2023 15:19
#4
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- Sneezles61
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Replied by Sneezles61 on topic Bent fin
A couple were bent on my RT2, I used a flat file… about 12” Long, 1/4”.. maybe 3/16”.. I pushed it in all the way to the cylinder… worked for me.
Sneezles61
Sneezles61
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14 Nov 2023 15:22
#5
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- Ht1kid
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Replied by Ht1kid on topic Bent fin
A friend told me he heats up the cylinder in the oven at 350 degrees for about 30 minutes and then uses a propane torch to heat the fin and uses a duckbill vice grip to straighten it I haven’t tried it. It doesn’t look to bad
The following user(s) Liked this Post: MarkT, shyted
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- Ht1kid
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Replied by Ht1kid on topic Bent fin
I tried calling him to see how many fins he broke using that method but he didn’t answer
14 Nov 2023 17:09
#7
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- asco
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Replied by asco on topic Bent fin
Quit looking at the bent fin on the cylinder and try to locate another suitable cylinder to use as a back up after it snaps.
AsHo, Yama-Psychologist
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1971 CT1-C (BRANDY)
1970 DT1-C (MONICA)
1972 AT2M (ZIFFLE)
1970 CT1-B (HULK)
1971 DT1E (GINA)
1970 CT1-B (CLIDE)
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1971 CT1-C (BRANDY)
1970 DT1-C (MONICA)
1972 AT2M (ZIFFLE)
1970 CT1-B (HULK)
1971 DT1E (GINA)
1970 CT1-B (CLIDE)
The following user(s) Liked this Post: Steve F, darinm, Sneezles61
14 Nov 2023 18:16
#8
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- Fozzy500
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Replied by Fozzy500 on topic Bent fin
Thanks for all the advice. I was worried about trying it. I think I'll try to ignore it for the time being....
All the Best
All the Best
15 Nov 2023 01:17
#9
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- Schu
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Replied by Schu on topic Bent fin
I like the taper wedge idea. I'm thinking a solid wedge of the correct fin space could be placed above the bent fin where the gap is now too large. The wedge could be tight fit at the base of the fin and slightly loose at the outer edge of the fin.
Then insert an opposing wedge under the bent fin and gently tap it into the gap and hopefully bend the fin back to its proper gap..
Then insert an opposing wedge under the bent fin and gently tap it into the gap and hopefully bend the fin back to its proper gap..
Schu
CT1B, CT1C, JT1, JT2, DT360A, GT80B, DT100B, DT125B,
DT175B, DT175C, DT250B, DT400B, Z50, SCR950
Someday, you'll own some Yamahas
CT1B, CT1C, JT1, JT2, DT360A, GT80B, DT100B, DT125B,
DT175B, DT175C, DT250B, DT400B, Z50, SCR950
Someday, you'll own some Yamahas
The following user(s) Liked this Post: Ht1kid
16 Nov 2023 04:05
#10
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