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Discussion Starter #1
I'm taking my 400 overseas in the near future so brought a new belt as a spare. Given that I had a little time to spare i thought I'd check the existing belt dimensions just to be safe. The existing belt was fine but while I was at it I thought I'd "crack" the variator and clutch nuts in case I ever needed to do this on the side of the road. It wouldn't budge so I eventually tried my pneumatic rattle gun but even that wouldn't loosen it. At this stage I decided that "if it ain't broke then don't fix it" but a question still remains of what to do at some stage in the future? I imagine if I take it to a shop an industrial strength rattle gun will get it off. BTW I've never had this nut off but know from the service history that a shop has replaced the belt - probably over-torquing it.
So thinking about the nut I started to think about the various holding tools that folks have made usually inserting pins between the variator fins to stop the thing turning - all a bit wobbly. I note that the aluminium cover has two 6mm holes that hold the air intake cover on. I'm wondering whether such holes could be used to insert 6mm high tensile bolds all the way through to mate with the fins without taking the cover off (photo1)? The holes already go all the way through. Can one "crack" the variator nut first with the cover on then, remove the cover to get to the clutch. Has anybody tried this? For your information the bolts engage the fins about 10mm from the outer edge so probably quite strong.

Also has anyone just tried using a disc lock to stop the clutch turning whilst getting the nut off (photo2)?

IMG_4162.jpg IMG_4165.jpg
 

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Interesting idea, but I would be seriously concerned about the strength of the cover at those holes, and if you break it, could be pretty expensive to replace. An impact wrench should zip it right off, so it very well could be over-torqued. Best thing would be to get a proper variator holder tool. The Suzuki one is quite expensive, but if you have some rudimentary tools you can make one fairly easily that can be used for the variator or clutch. Later I can take a pic of the one I made.
 

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if it ain't broke then don't fix it
Fix - no, but prevent from getting broke - more often yes. That nut got seized and increasing the power of impact wrench is usually not the best option here. One can carefully try an induction heater or a torch if in a hurry, but if time brooks i would remove the rust and apply some penetrant, e.g. acetone + ATF mix and try again later. An aftermarket holder should be available for tenth of the OEM price. Most of the folks make one themselves thou.
 

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Discussion Starter #4
Fix - no, but prevent from getting broke - more often yes. That nut got seized and increasing the power of impact wrench is usually not the best option here. One can carefully try an induction heater or a torch if in a hurry, but if time brooks i would remove the rust and apply some penetrant, e.g. acetone + ATF mix and try again later. An aftermarket holder should be available for tenth of the OEM price. Most of the folks make one themselves thou.
Yes agree about penetrating oil and making a tool. Indeed, I've got a fairly rough one with a long handle but was just thinking that a couple of bolts don't take up much room when travelling.
 

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Discussion Starter #5
Interesting idea, but I would be seriously concerned about the strength of the cover at those holes, and if you break it, could be pretty expensive to replace. An impact wrench should zip it right off, so it very well could be over-torqued. Best thing would be to get a proper variator holder tool. The Suzuki one is quite expensive, but if you have some rudimentary tools you can make one fairly easily that can be used for the variator or clutch. Later I can take a pic of the one I made.
Yes the strength of the cover is something I've thought about. In actual fact the holes are fairly well braced for a sideways thrust. My feeling is that this would be fine if the nut weren't over-torqued. Any of you folks that have already destroyed an inner case previously like to give this a go?
 

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Suppose there was no need for that -- that cover is made of sorta Silumin or Alusil alloy, not very strong to serve as a nut breaker. Some use similar approach to crack open stuck cover from the clutch side, but hardly for anything stronger than that.
 

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Your best bet would be to make a holding tool if you have the means.
I made a non-adjustable tool that fits both, the variator and clutch; it takes up no more space than a large wrench.
I wouldn't try the bolt technique; even if the cover withstood, the small bolts on the fins would be a lot of pressure in a small area ... near the inside edge ... of aluminum.!
 

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I guess everyone's different, but I never had any luck with strap wrenches (tried several, never really found one large and heavy-duty enough for the task). Getting the strap centered and keeping it centered artound the pulleys sounds easier than it really is. The handles weren't long enough to brace against the floor so I had to try and hold it in place while also holding the socket on the nut and leaning on the wrench. Even IF you get a good grip there is a little "cushion" due to the fabric strap and not a solid hold like you really need to torque it back down. Just my experience, YMMV.
 

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Discussion Starter #10
Thanks for all of the replies guys all are sensible.
Im still interested in the concept that "Yes this is the way we normally do this but is there an easier way".

From the discussion there are essential two issues: The first is the the ability of the inner case to withstand the lateral forces being applied by a wrench on the nut which ultimately gets applied to the pins and the case. That force should be N Newtons which is calculated by using the force, the length of the lever, and the radius of the nut (I think). That force is then held by the fins BUT the radius is now much, much longer - approximately 72mm compared to 12mm (the nut). So according to my flawed understanding of physics the force on the fins should be approximately one sixth of the force at the nut ie N/6. Is this enough to bend/shear the high tensile 6mm bolts or shear the case where the forces being applied through the bolts is N/6 but at a radius of the length of the bolt which is about 15mm at center. At a guess I'd put that at more-or-less back to N Newtons but as there are two bolts the force should be N/2.

The second issue in all of this is the standard tool. Most of what I've seen is a bar that inserts a couple of fingers against two fins. The force applied by such tools is applied over the surface of the fingers let's say 20mm (again at an increased radius so much less than at the nut). My theoretical method applies that force across 6mm bolts so the force would be about three times more in one spot but still distributed evenly across the total length of the two fins. Can it cope? I suspect that it would easily cope but I'd still like to try it on an old cover... Another thing about DIY tools is that I bet that they don't apply the forces exactly and evenly on the two fins - in fact, probably one does most of the work...

Any engineers out there that can do the real math or even comment on the metallurgy realizing that the bolt holes have a little bit of bracing?
 

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Yes, the standard tool only holds against two fins, which was a bit of a concern for me, but that's what the Suzuki tool has. If there are only two points that hold the variator, the force must be the same on both points.

Since apparently no one on here has done this before, I think you're going to have to be the guinea pig if you really want to know. You can do calculations all day but will never really know until you try. I wouldn't try that method until the nut was loosened by other means. Maybe try heating it or soaking overnight in something like PB Blaster.

I'll post some pics of my tools below with comments (easier to do from my phone).
 

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Here's the tool I made. It's a little under .25" thick by 1.25" wide - not critical as long as it's sturdy. The stock I had was too thin so I glued two pieces together with JB Weld, hence the bolts in it that appear to do nothing. Needs to be long enough to brace to the floor, 16" - 18" is good. I made one bolt slightly longer by about the thickness of the metal stock so they protrude the same. Also slipped a piece of neoprene tubing over the bolts to help spread the force a little. May not do anything but made me feel better.

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This is the Honda tool for the Helix, which I was hoping to use on the Burgman. The spacing is correct but the fingers are too thick to fit between the fins. There are more fins on the Burgy and so are closer together. Too bad because having six fingers really spreads out the force.
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Here is a tool I bought, but the drilled holes didn't match up if using more than two, so I drilled new holes in order to use six bolts. On the 'B' side I put two bolts. The radius is smaller than it could be, but is outweighed by having six fingers. Once again I used tubing to cushion the bolts, which also helps compensate for minor errors in the spacing.

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BTW, not sure why the pics posted differently (eg, first two aren't "clickable", different sizes)...I posted them all exactly the same way.
 

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Discussion Starter #16
Here's the tool I made. It's a little under .25" thick by 1.25" wide - not critical as long as it's sturdy. The stock I had was too thin so I glued two pieces together with JB Weld, hence the bolts in it that appear to do nothing. Needs to be long enough to brace to the floor, 16" - 18" is good. I made one bolt slightly longer by about the thickness of the metal stock so they protrude the same. Also slipped a piece of neoprene tubing over the bolts to help spread the force a little. May not do anything but made me feel better.
You've a champion Gary - thanks for taking my proposal seriously.

Yes loosening the bolt initially is probably a requisite. You're right I'll never know until I try it... I wonder how many people over the years will ask what the outcome was...

Another option is, of course, to take the cover off and spread the load with small spreader bars then put the cover on and buttoned up slightly before attempting to loosen the nut. This is effectively what you are doing with the neoprene. I guess your bolts are about 8mm mild steel perhaps high tensile? I wonder why these never bend or shear at the base. Perhaps my first experiment should be to use aluminium bars to make a tool such as yours and see whether the bar bends too much with the rotational force - I don't think so. In fact, my first tool like your's was made with 1.2mmx20mm square tube - it was fine.

Yes I've made a tool the same as yours and the problem is that they are prone to tilting, slipping and possibly damaging the fins as they spring out. This could fixed by a little stabiliser foot at the base but it all end up as a workshop tool - not suitable for on the road.
 

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Discussion Starter #17
Here is a tool I bought, but the drilled holes didn't match up if using more than two, so I drilled new holes in order to use six bolts. On the 'B' side I put two bolts. The radius is smaller than it could be, but is outweighed by having six fingers. Once again I used tubing to cushion the bolts, which also helps compensate for minor errors in the spacing.
Ha... Yes I've already gone to the trouble of marking out the fins on a sheet of paper with the possibility of indexing the fingers. You're right, the radius of those fingers is sub-optimal with the purchased tool but a circle with a stub/extensible handle could possibly be made.

Thanks for your help.
 

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If you're into woodworking, I've seen a couple made from plywood, maybe 5/8" or 3/4", round where it fits on the variator, tapering down to the end. The advantage of the two-piece metal one is you can use it for the variator or clutch.
 
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