A forum for owners of Yamaha TTR250 trail and enduro bikes!

TTRfan · Super Guru

Apparently cross-head Japanese fasteners don’t actually use a Phillips style head!

Cubber · Super Guru

Not a lot in it, Brian, but the right tool for the job is required for a proper job.

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JIS headed screw

Martyn

pug · Guru

Lot's of strange things happen out in that neck of the wood's spent some years working in China/ Hong Kong/ Taiwan/Japan an so on in the early 80's there was no standard foot is 12 inch's. In Engineering they all had there own foot measurement and worked to Metric from that I use to spin your head out with parts coming in from all over the place who ever made them cheaper an trying to convert it all over. Then by the later 80's the Japanese kicked ass and pulled it all in to line the jap's where still half using the us foot 12 inch's for half there stuff up till then as well a left over from the US rebuild after WW2

Pug

petenz · Super Guru

pug wrote:
Lot's of strange things happen out in that neck of the wood's spent some years working in China/ Hong Kong/ Taiwan/Japan an so on in the early 80's there was no standard foot is 12 inch's. In Engineering they all had there own foot measurement and worked to Metric from that I use to spin your head out with parts coming in from all over the place who ever made them cheaper an trying to convert it all over. Then by the later 80's the Japanese kicked ass and pulled it all in to line the jap's where still half using the us foot 12 inch's for half there stuff up till then as well a left over from the US rebuild after WW2

Pug

i had a tape years back "70s" that had the foot broken into 10 segments "inches"

& each segment "inch" divided into 10 segments...

no wonder it was in the bargin bin at the hardware store...

it wasn't that meany years ago I tossed in in the bin still

looking like new.... never did use it..

..

pug · Guru

Yep it use to do my head in working it out think it all came down to orientals have smaller feet and there was no full standard system with the old boy's working in what they had used all there working life's

Martyn

peteBLUEttr · Super Guru

The orientals have smaller feet haha.

Cross heads are crap ain't they best off swapping em out for hex heads or whatever. Slotted heads even worse.

hanzo · Senior Member

Brake fluid resevoir screws gotta be JIS !!! Your best philips in your toolkit never fits them .There was a feature in classicbike about fasteners and it was first time I had heard of them too and screwdrivers to take them out are different to philips head drivers .

TTRfan · Super Guru

I read a bit more about this and apparently you can modify a Phillips bit to fit nicely into a JIS style head by carefully grinding the tip away until the edges of the bit fit tightly into the tapered slot of the JIS head biggrin

Brian

petenz · Super Guru

TTRfan wrote:
I read a bit more about this and apparently you can modify a Phillips bit to fit nicely into a JIS style head by carefully grinding the tip away until the edges of the bit fit tightly into the tapered slot of the JIS head
Brian

that would be correct....

have noticed the phillips drivers are more pointy...

I have a few less pointy phillips drivers... must be JIS ones..

..

locky · Guru

I have a screwdriver thats made by Facom, i think it's JIS. Iv'e used it for years for stuff like the brake reservoir screws etc. It's a perfect tight fit and never damaged a screw head.
I have seen JIS screwdivers for sale somewhere.

peteBLUEttr · Super Guru

Jis have a very squared shape to the cross, and on certain jis fasteners you look at, the squareness is VERY prevalent.

In the gaps of the cross on Philips screwdrivers there is an adjoining ridge which only enables them to be inserted part way into the jis fastener, thus rounding them off if you try to use.

Jis was Japans way of improving what the Americans did with the phillips, Phillips fasteners round off even with their own correct size screwdrivers half the time, especially when you have to torque em relatively high.

You can pick up jis drivers for a few quid each.

locky · Guru

Just looked to see if you can buy JIS screwdriver bits, can't find any anywhere. The screwdrivers are easy to get.

peteBLUEttr · Super Guru

There are some in this set CLICK

Or they are branded as Vessel(JIS standard) from these 2 companys
HERE
OR HERE

hanzo · Senior Member

Great thread this and some excellent input from members .I am wondering is the brass drain screw on the carb a philips or JIS as this seems a common problem on the forum obviously been made of brass a good fitting bit is essential your veiws gentlemen and im sure Brian will investigate one in stock

peteBLUEttr · Super Guru

I thought it was a combo one slotted and cross, without going over my garage and looking exactly I'm not sure

-- Edited by peteBLUEttr on Sunday 1st of November 2015 06:31:56 PM

TTRfan · Super Guru

Drain screw head.jpg

I can't get my phone to focus well enough to get a good photo but I think you are right Pete - one of the slots is wider than the other as if to make provision to use a plain screwdriver - although I wouldn't recommend it.

Trouble is I am pretty sure I haven't got a JIS screwdriver to test fit - I only found out such a thing existed a couple of days ago!

I will have a look tomorrow as I have drawer full of screwdrivers and bits so just maybe.....

Brian

Andy B · Member

I worked for a Japenese company and the equipment we worked with used these cross head screws throughout .

The best solution was to take a couple of screws to the shop and just find the best fit from the selection of drivers and bits they had on the shelf. Often the Pozi bits work better than the Philips ones, and what does seem to work well are the bits from an impact driver - being so hard they tend not to wear and cam out so easily.

TTRfan · Super Guru

hanzo wrote:
Great thread this and some excellent input from members .I am wondering is the brass drain screw on the carb a philips or JIS as this seems a common problem on the forum obviously been made of brass a good fitting bit is essential your veiws gentlemen and im sure Brian will investigate one in stock

Hi hanzo. I don't think the drain screws are brass. A magnet works on the new one I have here.

The best fitting driver I can find is a Phillips S2 PH2.

hanzo · Senior Member

My mistake Brian dont know why I thought that I do remember chewing one up before .Saw some JIS drivers on ebay by a company called vessel quite pricey the description says they are for use on honda motorcycles.