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holeshot

426 clutch fixed - too long

8 posts in this topic

I finally had a chance to ride my 426 after installing the Hinson basket. Previous to this, the clutch was lurchy, grabby and noisy, so I decided to install the Hinson basket, which has slots cut into the tangs to scoop oil into the plates. I was more than a little skeptical about this, because it seems that Yamaha could have come up with something this simple. The next thing we'll hear is that Honda has the Japanese patent on making a decent clutch.

I changed only the basket (nothing else) and after hammering it Saturday morning, the clutch still performed perfectly. This is not an endorsement for Hinson, because any other aftermarket basket may work as well or better.

There is an article in the most recent issue of MXA (the magazine we love to hate), that outlines installing a Hinson basket on a YZ250. There are some differences for the 426 basket, and some issues are not covered in the documentation, so I'll explain below:

1. The MXA article shows drilling the rivets from the backing plate side of the clutch. This is a "no no" - the backing plate must be re-used, so the rivets should be drilled from the basket side. The proper drill size looks to be 5/16", but I only had ¼", so I drilled into the rivet about ¼" down, and then drilled at an angle for 360 degrees around to undercut the rivet flange. Eventually the rivet flange will pop off, and the rivet will push out easily (there are three rivets)

2. Whereas the YZ250 will have eight countersunk allen screws, the 426 will only have three, roundhead Allen screws holding the backing plate to the basket. Others have posted that the screw heads will hit the oil pump gear if not ground down (Hinson gives no warning of this). I ground a little off the screw heads, installed the basket and hub, kicked it over few times and then removed everything. When I looked at the oil pump gear, I could see that the screw heads had been scraping against the gear. I colored the face of the gear with a felt marker, went through the procedure again to verify the interference. I could have done myself a favor and ground down the screw heads so they didn't protrude more than anything else on the backing plate, right from the start. Don't even think about not using Red Loctite , because these three screws are all that separate you from nirvana and oblivion.

3. When installing the basket and gear back on the shaft, you may have to push it in and out about 15 or 20 times before the gears mesh so it slips on all the way. Patience is required here (of which I have little).

Hinson deserves some credit for building a basket that works, but also deserves to be slapped for not informing the customer about the interference problem. Maybe another brand would be a better choice.

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Originally posted by holeshot :

The next thing we'll hear is that Honda has the Japanese patent on making a decent clutch.

No **** Holeshot!!

I too went with the Hinson. My stock basket was clearing pump drive but hitting case. Hinson basket doesn't have same clearance problem as my stocker :)

I used a too-large bit on the basket side. This resulted in material from the head of rivet being removed to the base of basket. This worked well 'cause you can really feel when the bit begins to rub the much harder basket material. When this happens you are through and the rivet will fall out. Just another way to skin this cat...

My clutch behaves much better with the Hinson, and I didn't even replace the boss or pressure plate.

The only other company I've seen making baskets is Talon, I think White Bro.s carries them but I've never heard a thing about them.

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OK, I recieved my Hinson basket today, the three allen head screws are already ground down on the top, will I have to grind more or did Hinson realize and fix the problem, I will be installing the basket tomorrow night so any advice about the bolts would be appreciated.

Norman Kissam

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Norman,

I wouldn't grind anything until I was sure I had a clearance problem. The allen screws on my Hinson basket clear everything fine, despite the fact that the stock basket's rivets were rubbing the case just above and to left of counterbalancer shaft.

You might want to use a marker on screws and mock it up to check for clearance prob.s

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The screws on mine were countersunk slightly, but not nearly enough to clear the oil pump gear. I was at a parts counter recently, and heard the story of a 426 owner desperately looking for a new oil pump gear, because screw heads for the Hinson basket destroyed it.

I doubt I my bike would have kicked over if I installed the basket without grinding. The basket and gear assembly are the first thing that go back on (per the exploded view shown in the manual) and this is the way mine came assembled, so there's no way it could be installed wrong.

When you've loctited the screws in place, you'll notice the backing plate has springs and louvers in it (I'm not referring to the six springs at the pressure plate). If had to do it again, I would grind the screws down with a Dremel tool, so they do not protrude further than anything else on the backing plate (right from the start). I verify this by putting a straight edge across the springs and screws.

But if you have an attitude like mine, you won't believe it until you see it. If you don't want to grind the bolts down right away, put it in neutral, re-install the basket and hub, and tighten the main nut lightly. Make sure everything has slipped on all the way and GENTLY kick it over, listening for any binding or scraping noise. Pull everything off, and examine the oil pump gear for any scrapes or damage.

The main nut can be tightened/loosened by putting the bike in fifth gear and sticking a tire iron through the wheel so it rests against the rim lock nut. This will keep the basket from turning without purchasing a special tool.

I find it surprising that the tolerances are so loose that some are finding a major interference and others aren't.

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Originally posted by holeshot :

The screws on mine were countersunk slightly, but not nearly enough to clear the oil pump gear. I was at a parts counter recently, and heard the story of a 426 owner desperately looking for a new oil pump gear, because screw heads for the Hinson basket destroyed it.

I find it surprising that the tolerances are so loose that some are finding a major interference and others aren't.

That is bothersome to me as well. I've now completely removed and checked the clearance between the Hinson allen heads and case/pump gear/counterbalancer gear THREE times because I can't believe I am not having this problem. It is even weirder when you consider that my stock basket's rivets rubbed the case (pump gear is completely unblemished, though) but Hinson doesn't, despite looking like screws protrude farther from backing plate than rivets on stocker did.

Has stock basket's rivets been contacting pump gear on anyone's Yamaha?

BTW Holeshot, that is a good tip on locking rear wheel to remove nut, I never thought of that and used my impact wrench. This kind of bothered me, does anyone see any reason why an impact/air wrench shouldn't be used on bikes (I did use good torque wrench to reinstall)?

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If I had an air wrench, I'd use one. :)

Don't know why your stock rivets would hit the pump gear :D

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Well just finished the install, everything cleared without grinding, I race harescrambles and plan to practice Saturday so I guess that will be the test, I hope this cures my problems. Thanks for all the info.

Norman Kissam

Beaumont, TX

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