Early Showa twin chamber oil lock collar OD?

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8/27/2018 10:09 PM

Would anyone know the OD of the oil lock collars on the early (Pre 2011) Showa twin cartridge forks?

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Melbourne, Australia. Current rides: '11 RMZ450, '84 CR500, '06 DRZ400, '79 KX250 with 400 engine, '06 GSXR1000 full Yosh racebike.

8/29/2018 9:13 PM

Johnny89superbike wrote:

Would anyone know the OD of the oil lock collars on the early (Pre 2011) Showa twin cartridge forks?

I believe they are 28mm, same as the 48mm showa twins and kyb. (Don't %100 quote me on that)

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8/29/2018 11:38 PM

Hi, thanks for your reply. Yeh the oil lock collars have an OD of 28.1mm in the 47's on my 2011 RMZ450, l just ordered set of aftermarket items to see what OD they are. There are many Honda's & Suzuki's that use these forks, l wondered if earlier models ran a smaller OD, for aftermarket companies to offer larger OD items. Maybe some models use a bottoming cone with a larger lD?

Even with 100cc of oil out of my forks and the compression adjuster set on the softest setting, l could not get the forks to use the last 38mm of travel (and l weigh over 200lb). So l wonder how many other bikes are having the same issue?

I am progressively grinding-down the OD of my oil lock collars to finally use all my travel. The correct way to keep the forks off the bottom is with oil quantity (rise in air pressure). No good having 305mm of travel if you can't use it all.

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Melbourne, Australia. Current rides: '11 RMZ450, '84 CR500, '06 DRZ400, '79 KX250 with 400 engine, '06 GSXR1000 full Yosh racebike.

8/30/2018 12:08 AM
Edited Date/Time: 8/30/2018 3:12 AM

This is going to relate to all these models.......

CR250 97-07
CRF250 04-09
CRF450 02-08
CRF450X 09
KXF250 06-09
RM125 01-02
RM250 07
RMZ250 07-13
RMZ450 07-12

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Melbourne, Australia. Current rides: '11 RMZ450, '84 CR500, '06 DRZ400, '79 KX250 with 400 engine, '06 GSXR1000 full Yosh racebike.

8/30/2018 1:37 PM

Johnny89superbike wrote:

Hi, thanks for your reply. Yeh the oil lock collars have an OD of 28.1mm in the 47's on my 2011 RMZ450, l just ordered set of ...more

I see, I ran into the same issue on my 2011 crf450, you could actually feel it bottom metal to metal, but when you checked the oring it still had 2 inches of travel left, it turns out someone had put larger oil lock collars on and they were smacking into the top of the bottoming cone. I wound up using a set out of some 47 showa twins and all has been fine ever since, that's the only reason I knew that number off the top of my head ?

I'm not aware of any other sizes though, aside from kit forks which are usually 29mm. I would think if your lock collars and cones are oem you shouldn't have any issues, at that point I would look into a valving or spring issue.

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8/30/2018 8:18 PM
Edited Date/Time: 8/30/2018 8:21 PM

Cool, thank, l really appreciate your info :-)

All the springs & valving are stock, it is the bottoming cone/collar that is preventing the use of the last 38mm of travel, the forks do not stop short with a clang but like a hydraulic-lock type thud.

After checking part numbers, l see that 2011-2013 RMZ250 and 2011 & 2012 RMZ450 use the same bottoming cone/collar combination, so l wonder if Suzuki spec'd smaller lD cones for these models?

Due to the lack of performance, bottoming cones need never be more than 10mm long, they are only to cushion fully bottoming, oil, spring & valving should control the rest of the stroke.

I will keep testing as l grind down the OD of my fitted collars, plus l have some Factory Connection collars coming to measure. I'm actually thinking of removing the 'oil lock collars' alltogether, then tune my anti-bottoming qualities with oil level. That way l will always have maximum travel to use.

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Melbourne, Australia. Current rides: '11 RMZ450, '84 CR500, '06 DRZ400, '79 KX250 with 400 engine, '06 GSXR1000 full Yosh racebike.