Machining Triple clamps - Is it safe?

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12/7/2018 4:19 AM

I am about to change the forks on my bike, 05 RM 250.
The question: is machining (boring out) of the triple clamps to fit bigger diameter forks safe?
How much material can be removed without risking damage to the parts?
Triple clamps in question are aftermarket Scar units, I would not risk it with cast, stock triple clamps.

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12/7/2018 4:56 AM

Depends. How thick is the wall on the clamps youre looking to modify and what bore are you starting with and what are you wanting to go to?

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12/7/2018 6:33 AM

I've heard of riders removing 1 mm of material to be able to fit bigger size tubes on non-oem clamps. I'd also suggest consulting with the aftermarket clamp manufacturer Scar on asking them this question. In the US that is not a well known triple clamp manufacturer so it would be crucial to know what the substrate of the clamps are made of.
Depending on the durability of the clamps substrate it will put your mind at ease if you go forward with the mod..

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Speak softly and carry a big stick.

12/7/2018 7:18 AM

Turbojez wrote:

I am about to change the forks on my bike, 05 RM 250.
The question: is machining (boring out) of the triple clamps to fit bigger diameter forks safe?
How much material can be removed without risking damage to the parts?
Triple clamps in question are aftermarket Scar units, I would not risk it with cast, stock triple clamps.

I'm not sure about the scar clamps but I have done a few sets of stock cast clamps over the years and have never had an issue. I always have them machined to a snug fit. I will also say that they pass the durability test. PhotoPhoto


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12/7/2018 7:23 AM
Edited Date/Time: 12/7/2018 11:44 PM

Just put in a search for Scar clamps & found out they're made of CNC machined aluminium 7075-T6.
https://www.scar-racing.com/triple-clamps-125-250-450cc-3325?___store=default



I'd still suggest contacting their tech dept..
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Speak softly and carry a big stick.

12/7/2018 8:06 AM

Turbojez wrote:

I am about to change the forks on my bike, 05 RM 250.
The question: is machining (boring out) of the triple clamps to fit bigger diameter forks safe?
How much material can be removed without risking damage to the parts?
Triple clamps in question are aftermarket Scar units, I would not risk it with cast, stock triple clamps.

JWACK wrote:

I'm not sure about the scar clamps but I have done a few sets of stock cast clamps over the years and have never had an issue. I always have them machined to a snug fit. I will also say that they pass the durability test. PhotoPhoto


holy crap, now there's a jump!

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12/7/2018 8:53 AM
Edited Date/Time: 12/7/2018 8:53 AM

Done it on a few oem clamps over the years. No issues but were are talking minimal 1-2mm bore increases

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12/7/2018 2:55 PM

Turbojez wrote:

I am about to change the forks on my bike, 05 RM 250.
The question: is machining (boring out) of the triple clamps to fit bigger diameter forks safe?
How much material can be removed without risking damage to the parts?
Triple clamps in question are aftermarket Scar units, I would not risk it with cast, stock triple clamps.

JWACK wrote:

I'm not sure about the scar clamps but I have done a few sets of stock cast clamps over the years and have never had an issue. I always have them machined to a snug fit. I will also say that they pass the durability test. PhotoPhoto


You're crazy man, I love it!!!

Thanks for all the input, I will take all measurements tomorrow and will report back!

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12/7/2018 2:57 PM

H4L wrote:

Just put in a search for Scar clamps & found out they're made of CNC machined aluminium 7075-T6.
https://www.scar-racing.com/triple-clamps-125-250-450cc-3325?___store=default



I'd still suggest contacting their tech dept..

I will contact them, that is great suggestion, thank you sir!

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12/7/2018 8:24 PM

Been doing it for years on several different brands, never an issue.

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12/8/2018 1:42 PM

Turbojez wrote:

I am about to change the forks on my bike, 05 RM 250.
The question: is machining (boring out) of the triple clamps to fit bigger diameter forks safe?
How much material can be removed without risking damage to the parts?
Triple clamps in question are aftermarket Scar units, I would not risk it with cast, stock triple clamps.

we did all the oem clamps last year at jgr. remember If you are going from like a 54 to a 55 or whatever it may be. you are only removing .50mm on each side so its very minimal

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IG @jaredkeller96

12/12/2018 2:13 PM

Just got the forks today. From what I measured it seems like I will need to open up 1mm (in diameter, so 0,5mm of material) on both upper and lower clamps to make the new forks fit.

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12/13/2018 1:33 PM
Edited Date/Time: 12/14/2018 1:53 AM

After comparing, I think I will have the stockers opened up. Scars are really thin

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12/14/2018 1:55 AM

Pretty crazy, scars are VERY thin in comparison
Photo
Photo
Photo
Photo

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12/14/2018 6:46 AM

Turbojez wrote:

Pretty crazy, scars are VERY thin in comparison
Photo
Photo
Photo
Photo

That's thin!

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12/15/2018 7:28 AM

You're also talking about billet aluminum vs cast aluminum too though. Billet is much stronger allowing you to have those thinner walls. Can't hurt to ask the company themselves but I wouldn't trust the stock cast ones more just cause they're thicker. Surely the billet material makes up strength difference from the thickness I'd think.

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12/15/2018 11:48 AM

If your in doubt get emig racing to make you some new clamps to match your bike and new forks

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12/17/2018 9:03 AM

I've machined multiple sets for myself and others. Never had a problem.

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9/2/2020 4:35 PM

Bit of a long shot, but would anyone have for sale, a KTM/Huksy top clamp that's been opened up 1.5 - 2 mm?

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KTM250SX YZ125 YZ85 PW80 ZX6 FZX700

9/2/2020 6:56 PM

I personally think it's safe.

However, I highly recommend you DO NOT use Emig Racing (Gary) for triple clamp boring. He scrapped 2 sets of hard-to-locate 2008 Honda CRF450R clamps (they were a 1 year assembly). He didn't offer to refund me on the $250 I paid for his machining work and of course there was something wrong with my clamps ... and like an idiot I humored him and sent him more clamps to try to get things right. My bad and $500+ vaporized.

I would only deal with a reputable company like Ride Engineering on something like this ... and they won't bore your clamps due to liability (I explored have them do it first).

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9/2/2020 8:07 PM
Edited Date/Time: 9/2/2020 8:18 PM

Rider 5280 wrote:

I personally think it's safe.

However, I highly recommend you DO NOT use Emig Racing (Gary) for triple clamp boring. He scrapped 2 sets of hard-to-locate 2008 Honda CRF450R clamps (they were a 1 year assembly). He didn't offer to refund me on the $250 I paid for his machining work and of course there was something wrong with my clamps ... and like an idiot I humored him and sent him more clamps to try to get things right. My bad and $500+ vaporized.

I would only deal with a reputable company like Ride Engineering on something like this ... and they won't bore your clamps due to liability (I explored have them do it first).

“Fool me once - Shame on you!”
“Fool me twice - Shame on me!”

:-)

Sounds like terrible service from a number of standpoints (Quality of work/Customer service!)

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