Author Topic: 10mm bolt on fork tube  (Read 277 times)

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Offline Terryb

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10mm bolt on fork tube
« on: August 18, 2022, 10:30:13 AM »
Hi I am correct in thinking that the Bolts on my RD200DX fork tubes and most Japanese bikes are 1.25 fine thread,as just bought some and not the same size thread as what’s come out?

Please advise before I have a rant at supplier

Regards Terry

Offline Gr8uncleal

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Re: 10mm bolt on fork tube
« Reply #1 on: August 18, 2022, 10:53:46 AM »
Which bolts are we talking about, Terry?
Yam RD200DX
Yam FZX700 Fazer
Yam RD400C
Yam RD350B
Yam RD350
Yam RT2
Yam DT360A
Suzi GT550J
Suzi 1250 Bandit
Yam RD125A
Yam R5
Yam DT3
Yam CT1C
Yam RD200B

Offline Terryb

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Re: 10mm bolt on fork tube
« Reply #2 on: August 18, 2022, 11:29:53 AM »
Hi the bolts are the hex 10mm ones which go in bottom of fork legs inside and hold the fork tube in

Online pidjones

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Re: 10mm bolt on fork tube
« Reply #3 on: August 18, 2022, 11:55:24 AM »
Most that I've seen have been 8mm Allen head (don't remember the socket size) with a copper flat gasket under them.
"Love 'em all... Let GOD sort 'em out!"

Offline NivagRD

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Re: 10mm bolt on fork tube
« Reply #4 on: August 18, 2022, 12:04:57 PM »
I think I have a couple old spare ones in the workshop. I will have a look and a measure. When I put new ones in, I put a bit of thread sealant on the threads and copper washers. Gavin
1973 LS2, 1980 RD200DX, 2019 CB650R.

Offline NivagRD

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Re: 10mm bolt on fork tube
« Reply #5 on: August 18, 2022, 12:48:40 PM »
I no longer have them but I think the new ones came from Fowlers (2R7 model - original part number for the bolts is 278-23181-50, replaced by 3D82318100). The washers are 509-23158-LO and Fowlers have them. From memory, the bolts were Metric fine but I have no way of checking now. Gavin
« Last Edit: August 21, 2022, 06:27:01 AM by NivagRD »
1973 LS2, 1980 RD200DX, 2019 CB650R.

Offline Yamahaar

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Re: 10mm bolt on fork tube
« Reply #6 on: August 18, 2022, 04:31:59 PM »
Not sure if thie helps but the RD125DX bolts are M8 x 1.25

Offline Terryb

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Re: 10mm bolt on fork tube
« Reply #7 on: August 19, 2022, 09:16:12 AM »
Thanks for input guys I was correct 10mm fine thread 1.25 ,company sent wrong ones I ordered and going to send the correct ones  :P :P

Offline Terryb

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Re: 10mm bolt fine pitch confused
« Reply #8 on: August 20, 2022, 09:10:59 AM »
Morning the saga goes on about the bolt,I’ve just received so called size 10mm 1.25 fine thread bolt but it’s not the same as what came out so what’s right me or them .I’ve attached pic right hand is what came out which is a finer thread Any help guys :-\ :-\ :-\ :-\

Offline Astute Greaser

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Re: 10mm bolt on fork tube
« Reply #9 on: August 20, 2022, 10:01:20 AM »
Sorry Terry but have you not got a thread gauge to confirm what you have and what's been sent. If not treat yourself as only 5 quid
https://www.ebay.co.uk/itm/233467141569?epid=1958746083&hash=item365bb9ddc1:g:~CUAAOSwQrNg8dAB&amdata=enc%3AAQAHAAAAsF3%2FgnvVFWRLaVQ9A7A9Dzn4u4besWtBX1vzJscmyxgOFHloBWyFjawEHW4OZ9aDMgGUTQjphb%2FmWDg627Qrb8Y%2BUAuT%2FgA49zcIcJ4zQjl31eHQZkqcyvQorBUn%2Fgmln%2BGpeaYuVg4gOkKlU%2BLhRzrofvxesASDK2O%2BACcIDDlvbSkSHskY0PUWR%2FMpVycNj1wX3zox8Z0LiavJRCFkVV6QEjNx9NFd3GWOFwnvMOjk%7Ctkp%3ABk9SR-j03qbXYA

You are right as general rule M10 and larger are fine thread on Japanese. But there are exceptions !!
Clearly you're original needs replacing judging by the damage to the threads under the head. Is the matching seat in the fork okay?
Are you're forks the 2R7 type with caliper behind forks instead of front like the 1E8.
Sticks in my head that I ordered the copper washers for 2R7, thinking they would be same as 1E8 but they were too large. I had struggle searching to find those washers as slightly smaller o/d than standard to fit in the hole. Also check the head diameter of the new screw is not to large! Your originals look turned down.


Offline Terryb

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Re: 10mm bolt on fork tube
« Reply #10 on: August 20, 2022, 10:09:45 AM »
Hi yes I did damage the head getting it out,but thread in the tube is ok checked the other tube and it’s fine.the model of my bike is a RD200DX 1983 with caliper behind the leg.The bolts what come out are a finer thread than what been sent to me which say 1.25 on packet and yes I would have smoothed out head and cut to correct length so I will buy a gauge but who’s right the new bolt being a 1.25 bolt pitch or the ones in my bike :-\

Offline Astute Greaser

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Re: 10mm bolt on fork tube
« Reply #11 on: August 20, 2022, 11:42:37 AM »
2R7 explains why most were wrong in thinking M8
M10 x 1 extra fine is probably what your originals are. This thread was also used on the master cylinder banjo as well, which seems in conflict with the caliper M10 x 1.25 fine ::) M6 coarse is 1 pitch. So if you push the the thread of an M6 screw on top of your original M10 this will confirm. De facto thread gauge  :D Oh and an M8 coarse is 1.25 pitch  ;)
You can get replacement screws from eBay but do checkout the head o/dia. Stainless will have to come via china but standard high tensile couple days
https://www.ebay.co.uk/itm/113100739946?hash=item1a5554556a:g:fUkAAOSwZb5bMLou&amdata=enc%3AAQAHAAAAoDPhn1vIYv2%2FBWcYWcX1GPIPxzx6ctXH%2Fojj04LFA7iVHO4%2FvaZF4OGvdqzS9%2BpQkPpwh6zRovShuCyi2xH1hmhq2D72mlGpMQCpkaG5NVURQD9KrMDWBMjWo66uB%2Bykb1YVwc0qKwFf5j0Jcn0MmSwGfokcMIn2diUSM7ouGnLcMPKQj%2Bp%2FDZQHaD%2B0itBRW1k5SSlXif%2BfWBsdpdMmxfc%3D%7Ctkp%3ABk9SR-rB-qzXYA
« Last Edit: August 20, 2022, 12:19:40 PM by Astute Greaser »

Offline Gr8uncleal

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Re: 10mm bolt on fork tube
« Reply #12 on: August 20, 2022, 12:33:25 PM »
2R7 explains why most were wrong in thinking M8
M10 x 1 extra fine is probably what your originals are. This thread was also used on the master cylinder banjo as well, which seems in conflict with the caliper M10 x 1.25 fine ::) M6 coarse is 1 pitch. So if you push the the thread of an M6 screw on top of your original M10 this will confirm. De facto thread gauge  :D Oh and an M8 coarse is 1.25 pitch  ;)
You can get replacement screws from eBay but do checkout the head o/dia. Stainless will have to come via china but standard high tensile couple days
https://www.ebay.co.uk/itm/113100739946?hash=item1a5554556a:g:fUkAAOSwZb5bMLou&amdata=enc%3AAQAHAAAAoDPhn1vIYv2%2FBWcYWcX1GPIPxzx6ctXH%2Fojj04LFA7iVHO4%2FvaZF4OGvdqzS9%2BpQkPpwh6zRovShuCyi2xH1hmhq2D72mlGpMQCpkaG5NVURQD9KrMDWBMjWo66uB%2Bykb1YVwc0qKwFf5j0Jcn0MmSwGfokcMIn2diUSM7ouGnLcMPKQj%2Bp%2FDZQHaD%2B0itBRW1k5SSlXif%2BfWBsdpdMmxfc%3D%7Ctkp%3ABk9SR-rB-qzXYA

I tried various of my spare M10 bolts (inc 1.25 pitch) in a spare RD350 fork inner that I have, and none of those were correct, so Mike is almost certainly correct.

Check the pitch by putting a metric ruler alongside the bolt and count how many threads there are within 1cm - there should be 10 for a 1mm pitch.
Yam RD200DX
Yam FZX700 Fazer
Yam RD400C
Yam RD350B
Yam RD350
Yam RT2
Yam DT360A
Suzi GT550J
Suzi 1250 Bandit
Yam RD125A
Yam R5
Yam DT3
Yam CT1C
Yam RD200B

Offline Terryb

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Re: 10mm bolt on fork tube
« Reply #13 on: August 20, 2022, 03:34:27 PM »
Ok thanks so looks like I order incorrectly,have ordered a thread gauge for future reference.