Clutch lightness mod?

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Clutch lightness mod?

Postby beta250rrowner » Fri May 31, 2019 8:46 am

Just browsing YouTube, found this lil gem

https://www.youtube.com/watch?v=t0J3TNj9lFQ

I thought great, nice cheap mod

But then I noticed this comment rubbishing the idea

. those springs are now compressed 1.2mm tighter than they were before provided the bolts reach the end of their travel making the clutch stiffer 'most likely you tightened to the same torque as before so the clutch is exactly the same just the bolts are not griping all the thread . . by your logic if you stack 10 washers on it would be even lighter . but in truth the springs would be so squashed there wouldn't be any travel left in them when you pull the clutch making it stiff as hell . seems to me to lessen the pre load you have to use bolts that are 1.2mm longer so the springs are more relaxed


Edit:

Just found this reply to the comment

The washer fits inside the spring. The bolt head to spring mating surface, is recessed on the outside, where the spring makes contact, to center the spring. The bolt inner face to clutch basket surface, is designed to bottom out on the basket. When you add the washer, it sits inside the spring, essentially extending the bolt face guide for the spring. By doing so, it raises the recessed portion of the bolt, off the basket, by 1.2mm or however many washers you add. It's hard to see because the camera angle and lighting. As far as worry about threads, most nuts only contain 3-5 threads, there is plenty, and if it worries you, apply some blue locktite.


I'm struggling to visualise so can anyone shed some light on whether this could be effective or not? I struggle to visualise what either poster is saying but I get the impression the mod works well from the reply.

Also inner diameter of washers, would these be okay

https://www.ebay.co.uk/itm/FORM-A-FLAT- ... ZAWUgnX8gQ

I figure I'll need a new gasket as well, but it is a simple, nice n cheap mod because at the moment I can't operate the clutch with 1 finger so it means I can't cover the clutch and grip the left hand grip well.
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Re: Clutch lightness mod?

Postby babelfish » Fri May 31, 2019 10:09 am

The mod work just as designed. The added washers make the bolt "longer"

It's a washer suitable for a 6 mm bolt = M6.
The inner diametre is about 7mm.
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Re: Clutch lightness mod?

Postby Deck1 » Fri May 31, 2019 10:54 am

babelfish wrote:The mod work just as designed. The added washers make the bolt "longer"

It's a washer suitable for a 6 mm bolt = M6.
The inner diametre is about 7mm.


Maybe this will help
Attachments
Clutch spring shimming.jpg
Clutch spring shimming.jpg (116.25 KiB) Viewed 9035 times
Dale in Colfax
2016 500RS
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Re: Clutch lightness mod?

Postby beta250rrowner » Fri May 31, 2019 2:27 pm

That pic is really helpful deck1, thanks.

babelfish, I assumed the bolts are m6. If they are m6 those washers should be okay right? Not sure what you mean about the inner diameter being 7mm though.

This sounds like a quick and cheap mod assuming I don't drop any bolts or washers into the engine whilst doing it! I speak from experience of previous disasters...
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Re: Clutch lightness mod?

Postby DBSI » Fri May 31, 2019 3:46 pm

If you are trying to lighten the clutch pull by changing the spring force the clutch will slip!! A) You need to change the lever pull ratio. Several people make this lever. Its the same as some of the KTM's. B) You need to change the plunger diameter in the master cylinder. This is an old KTM RFS motor option. You put the smaller diameter 125-200 master cylinder on (1mm smaller). The lever throw increases. This is not an easy option as those are mineral oil systems. Yours is brake fluid, They DO NOT MIX! you would need need to thoroughly flush one of them.
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Re: Clutch lightness mod?

Postby NW_250RR » Fri May 31, 2019 4:35 pm

https://www.tworide.net/product-page/be ... ch-springs

Road my buddies 300RR this past weekend who has these installed. It indeed lightened the pull pretty good. I noticed no slip.
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Re: Clutch lightness mod?

Postby moto367 » Sat Jun 01, 2019 4:41 am

I changed out the slave cylinder. Can't recall the part number off hand but do a search and you will find it. It really makes a difference and will have no chance of slippage.
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Re: Clutch lightness mod?

Postby hooter » Tue Jun 04, 2019 10:47 pm

I installed a Midwest Mountain Engineering clutch lever on my 300RR and it has significantly reduced the clutch pull.

http://midwestme.com/
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Re: Clutch lightness mod?

Postby babelfish » Wed Jun 05, 2019 6:37 am

beta250rrowner wrote:That pic is really helpful deck1, thanks.

babelfish, I assumed the bolts are m6. If they are m6 those washers should be okay right? Not sure what you mean about the inner diameter being 7mm though.

The id of the washer is around 7mm. Your link sent me to a page with no spesific washer selected so I had no way to know.
This sounds like a quick and cheap mod assuming I don't drop any bolts or washers into the engine whilst doing it! I speak from experience of previous disasters...

It is, but there is always the danger of clutch slipping. Mine don't with current oil. Also I drive mostly technical stuff. Slippage are more prone on high grears at the rpm where the powerband arrive.
Now I am also waiting for my midwest lever. :)
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Re: Clutch lightness mod?

Postby hawaiidirtrider » Wed Jun 05, 2019 6:35 pm

Got these mods too. I put the Midwest lever before and it helps. Still I just run stock levers / stock clutch etc on my current bikes. My hands don’t cramp. If they start to cramp that means the rest of my body is just out of shape and probably cramping too.

https://youtu.be/ydZyFR-iDWc
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