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Discussion Starter · #1 ·
Gideon gave me his Tornado over a year ago to put back in running order. It's been a long drawn out affair but it is progressing.
The latest upgrade is the alternator drive shaft / Z25 gear.
Its the first one I've come across that still had the original M8 screw securing the alternator coupling. I always understood that it was secured with a Belleville washer, but no. It was a weird lock washer.
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Automotive tire Font Rim Circle Auto part

I've opened up the lock washer in the left pic. Its similar to the one they used with the M10 screw, before the Belleville washer.
So then it was time to remove the clutch.
First problem - Gideon had dropped the bike on the RHS, damaging a clutch cover screw.
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Not much to work with there, so it was time for some drastic measures. Arc welder to the rescue ...
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.... and out it comes.
Now for the clutch removal. Normally at this stage the 36 mm nut will come off by selecting 6th gear, locking the rear brake, or the front sprocket with an old chain if the chain has been removed, and hitting it with the rattle gun. No dice this time. So I tried the breaker bar. I could feel movement, but it wasn't the nut, so I was beat. What I needed was a holding tool to lock it rigid, and I found one on gumtree. Turns out Paul, an inmate here, was the supplier. After a brief dialogue I ordered one, and waited.
2 weeks later it arrived in the Antipodes, and 15 minutes later
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In the past I have employed my missus to hold a steady on the Z25 side and I'd drift the shaft loose, but she was in her pj's watching the news, so I thought I'd try Redbaron's method - a long M5 rod through the shaft and screwing it apart.
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It worked a treat.

Senior Member
6,093 Posts
Discussion Starter · #4 ·
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Basket's back in, torqued to 80 Nm with Loctite 648, which seems a bit excessive, but that's what's specified.
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Alternator drive shaft bolt is torqued to 50 Nm with Loctite 243. The book says 648 but I've never used it. You'd need heat to get the M10x1.25 bolt undone, or risk destroying the head. Well, that's my opinion. I've done 5 so far, not counting this one, and none have come loose with 243.
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The clutch stack height is spot on 50.0 mm. It could go as low as 48, which could make neutral selection easier as the lift would be greater, but I'd have to change some plain plates, and I don't have them. So it stays as is.
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Last but not least, for this post, the pusher plate is pristine. No ridge and not worn in the least. This clutch hasn't seen much work,
So it's ready to replace the clutch cover and refit the alternator, after checking it's drive shaft nut (I have found them loose in the past)

Senior Member
6,093 Posts
Discussion Starter · #5 ·
While I'm working on that side, I checked the cam chain adjuster depth - 49.4 mm. Max depth is 57.5 so there's plenty left for the chain.
The free spring length is only 55 mm though. The length to overcome the ratchet is 1.3 mm & bolt bore depth is 3.3, so this spring can only reach 55 - 4.6 = 50.4 mm. So it's only got 1 ratchet notch left.
WOW! Serious!
Time for a 70 mm spring, like the 1130s use.
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Senior Member
6,093 Posts
Discussion Starter · #6 · (Edited)
Time to install the alternator.
The M10x1.25 R8.8 bolt I used to secure the alternator coupling has a head that hasn't been reduced, as is the Benelli practice, so the clearance between the bolt head and the alternator shaft needs to be checked. I use Plasticine to gauge the clearance, by assembling the alternator, sans o-ring, then slicing the result in half.
Wheel Water Motor vehicle Automotive tire Rim
Automotive tire Gas Cylinder Composite material Metal
.... 5mm clearance. Plenty.
Next, the o-ring. Over time it swells and if any attempt is made to re-use it, a small chunk can be taken out of it. If that damaged section happens to be near the bottom, eventually it will leak oil.
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As you can see, this one has been reused as is. There is a ~ 3 mm chunk out of it.
In the past I've removed 20 mm and super-glued them back together. After that, they can be reused multiple times, as the swelling will not continue, for some reason. It just doesn't, so they are better than a new one. I normally place the join at the top, just in case it doesn't seal perfectly. I've never had a problem.
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I use a new scalpel so that the cut is very clean, and fairly square.

BTW. New drive rubbers were also installed as the originals had come apart.

Senior Member
6,093 Posts
Discussion Starter · #7 ·
Should have seen this coming.
I wanted to move the water pump out a bit to route the side stand switch behind it and out of the way. To do that, the pump inlet manifold has to be rotated to get to the top mounting bolt. Firstly, the manifold bolt head was damaged so that required some TLC, then for the hell of it I removed the manifold to find this ....
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Just what possessed Benelli to specify a mild steel dome nut I can't imagine.

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It was replaced with a stainless steel nut. I bought a few of these when I first discovered this issue way back in the mists of time.

The stand switch cable is now neatly tucked out of the way behind the pump and clutch command lever. A begger to remove if needs be, but mine is still fine after almost 20 years and 144,000 kms, so it's a small impost to bear.

Senior Member
6,093 Posts
Discussion Starter · #9 ·
You'll get her back Gideon. I'm only sorry it's taken so long, but that seems to be the way of it. I take on too many jobs and have too many on the go at any one time. Then I go for a ride and put the schedule back even further ;)

The latest job was to add a support brace to the support hanger mount. That mount will flex and the bolt has been known to loosen and cause an annoying knock when braking. JohnnyO tracked down the cause many years ago, and I braced mine at about the same time. The TreK doesn't even have that brace, but of course, it's not a race bike.
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This is what it looks like under the headstock. The steel 'U' will flex, and should have been braced. It's difficult to get something in there that fits well. Mine and a couple others worked out well. Yours has a slight taper that's narrower at the bottom. It's difficult to deal with.
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This is what I made to brace the mount. It's not perfect, as the next pic shows.
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The radii at each end are about 7mm, but it could have been sharper, as you can see a gap. It does the job though. Just.
If I get inspired I'll have another go at it later.

Senior Member
6,093 Posts
Discussion Starter · #10 ·
A few months ago Nell got a new set of 4 AWG battery cables which left the old paired 8 AWG cables available for another Tornado - Gideon's.
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The battery shown is dead. Shorted to be sure (to be sure).
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Negative to the breather box bolt.
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Positive in parallel with the existing connection to the solenoid.

You've all seen this before I expect. Many of you have done it and confirmed that it makes a big difference to the cranking speed. I've also halved the length of the cable to the starter which will improve things just a little more, but perhaps imperceptibly.

While I was rooting around, the coolant air bleed hose was re-routed to remove the airlock that Benelli created while attempting to defeat the airlock in the return hose. No idea what they were thinking when they did this. Maybe it had good intentions that got lost along the way.
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This route works. When on the track stand, there is now a continuous rise from downstream of the thermostat housing to the filler cap, That, combined with the 2 mm hole at the top of the OEM thermostat allows trapped air on both sides of the thermostat to rise to the filler. No more weird and wonderful bleeding methods, such as suspending the bike from its tail, rocking it from extreme side to extreme side, or vacuum pumps, are needed. The only drawback is the slow movement of air through the 2 mm bleed hole. (I fixed that on Nell with a manifold on the upstream side, which allows coolant to recirculate while the thermostat is closed. It was convenient to add a bleed pipe on that side. I'll tell you about it some day - If I haven't already.)

Senior Member
6,093 Posts
Discussion Starter · #11 ·
Always wondered how on earth the fuel line could get kinked, as some have reported. It's quite stiff, but look what I found when I installed a Goodridge MCD04V Quick Release?
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I think I've sorted that by installing the connector there
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Ear clamps are ideal since they take very little space. You'll notice one on the tank adapter as well. The hose had a small split that if left much longer would open up, with the possibility of a fuel leak.

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6,093 Posts
Discussion Starter · #12 ·
Next the valve gaps need to be checked. The clutch cover isn't installed yet so the engine can be rotated by the clutch using a tool I made up years ago. It's easier to turn if the plugs are out ...
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No prizes for guessing which plug was serving #2!
This Tornado hasn't had the airbox drain modification and the coil seals were dry. The #2 plug is still fine, but rust grit has dropped off into the plug well. One way to get that out is with an oily paint brush, but it's a pain because you can't get a good look at the bottom of the well and that grit is best not allowed to enter the combustion chamber.
3 things you can do to stop this happening:-
  1. redirect the airbox drain to the front of the engine, away from the #2 plug well
  2. close the gap at the top of the coils with epoxy to make it harder for water and grit to pass the top seal
  3. use silicone grease on the top and bottom seals (NOT RTV silicone)
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Gideon's airbox with the modified drain.
You might notice the tip over switch (TOS) mount has been changed. JohnnyO suggested this before I bought Nell, when I told him about the test Tornado shutting down at high revs. He explained that the TOS is mounted too firmly, allowing vibrations to trigger it. A piece of sponge rubber and a loose cable tie solves the problem.

Finally, the intake air temperature sensor has been removed and the mounting hole filled with RTV Silicone. In that position the sensor will be warmed by the heat rising from the engine when idling at a standstill. That fools the ECU into thinking the intake air is hotter than it actually is, and it leans out the mixture to compensate. As the measured temperature rises, the engine idles rougher and rougher.
To measure the true intake air temperature, I'll place the sensor in the left air intake adjacent the headlight. That's worked well for Nell

Senior Member
6,093 Posts
Discussion Starter · #14 ·
Now the fun really starts.
When I first checked the valve gaps I found all but 2 needed adjustment, and those were on the high side. Always good to check your work though .. on the second time around it became all but 1.
So the cams are off and the buckets and shims removed.
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Now is not a good time to get them mixed up. So easy to do.
Adjusting the gaps on a Tornado is a bit more involved than usual. The valve springs are so strong (1000 N) that in a short time from new, the shims have an indent hammered into them by the valve stem. So far I haven't found a shim type that can withstand it, although Chris at Precision Shims in Melbourne is working on it. What I have discovered over time, is that the hammering work hardens the shim, so if a new shim is setup on the tight side, the gap will settle out at the high side and progress no further - mostly.
If there's one thing you don't want to do, its go changing shims more often than necessary. The manual specs the cam cap torque as 13 Nm, which for an M6x1 thread is extreme in aluminium, and worse in the alloy Benelli used for this head, which is too soft. If you use 13 Nm, the threads will strip after several valve gap adjustments. I've had to replace all of Nell's cam cap bolts with M6 studs after installing helicoils. You don't want to do this if you can help it. Some you can't get to with the engine in the frame.
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Nell's cam cap studs.
When Gideon's caps get re-installed, the torque will be no higher than 10 Nm - which is still high for a lubricated M6 bolt in aluminium.

But I digress...
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The indent in this shim is clearly seen here, by the flash reflection at the edge of the indent.
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I determine the actual shim size by measuring over a ball bearing. In this case, the original shim thickness is 2.275 mm. Over a 4.760 mm ball in the indent, it is 7.025 mm, resulting in an actual shim thickness of 2.265 mm. So the indent is 10 um. I've seen this as high as 50 um.
In this case, the valve gap was measured at 405 um. The specified range is 300 - 350 um, so clearly, if it was set up correctly, there's been 45 - 95 um of wear happening else where. Maybe the valve stem has mushroomed slightly or the seat has a layer of carbon built up. Who knows, but it's worth keeping an eye on it over time.

Now that we know the actual shim height, the new shim height is calculated :-
ht = old shim + actual gap - specified gap
min ht = 2.265 + 0.405 - 0.350 = 2.320
max ht = 2.265 + 0.405 - 0.300 = 2.370 (which is the preferred value to compensate for indentation)

Now repeat for the rest ...

Senior Member
6,093 Posts
Discussion Starter · #16 ·
Hey Errol, I know you have a supply for shims, but just letting you know, I have a full set of Benelli shims if required. I got them, with more parts form a guy that was going to become a dealer but didn't last for some reason. Nigel.
Thanks Nigel. I'll keep that in mind.
The OEM shims do get indented in the Tornado though, as do Chris' standard shims, but his D2 shims have so far been the best in this respect.
The TNTs are probably not as nasty to their shims since the valve springs are weaker. Not sure about the R160 or 1130 Tornado.

Senior Member
6,093 Posts
Discussion Starter · #17 ·
Not much apparent progress yesterday. I'm like a duck. Not much happening above the waterline, but furious below.
The new shim sizes have been determined, a couple have been moved, those in stock are fitted, and an order for the rest is in train.
Plenty to carry on with before they turn up though.

Senior Member
6,093 Posts
Discussion Starter · #19 ·
I need to check Nell's valve gaps to see if she needs any shims I don't have. Chris will do a batch of his Benelli specials so I should include these in the order.
So the order is held up for a bit.

In the mean time I'll digress and discuss Gideon's bent bars.
When I first looked at the bike, the bars looked a bit off, so after some time I removed them both
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(a bit small - sorry)
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So first I checked the price of new ones. They include the clamp and cost ~125 € each plus shipping, so I thought I'd have a go at straightening them. Worst case - they crack. They are stuffed anyway as they are, so in for a penny ...
I had a couple of other bent bars lying about and they all bent at the taper, just like these, so I needed something to grip that taper ..
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This is what I came up with. A tapered collar that screws to the end and a straight collar split in halves to support the bar.
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like so.
Then to the press
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The bar shown has already been straightened. It took just over six tonnes. It's not quite straight, but good enough, and no cracks.

The proof of the pudding ... The Test

The ground away chunk at the end was fixed by welding a slice of a pushbike seat stem to it, and spinning it to size inside and out. Not perfect, but good enough since you don't see it anyway

Senior Member
6,093 Posts
Discussion Starter · #20 ·
Then there's the new chain and sprockets
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Which means the wheel needs to be aligned.
I use a length of fishing line wrapped from the front wheel to the back and returned on the other side.
Initially the front wheel is turned so that the line has an equal gap to the edge of the tyre on both sides.
Then a dowel is inserted between the two lines just behind the front wheel. It is the same length as the rear wheel is wide.
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You can see the dowel installed
I've put a support at the rear to hold the line at the correct height, but you can simply wrap it around the wheel - as long as you lock the wheel from turning.
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Then it's just a matter of adjusting the alignment screws until the left and right gaps from the line to the tyre's edge is equal.
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If the dowel length were perfect, the line would touch both sides. It's better to be slightly over than under.

After that's done, every time the chain is adjusted, count the number of flats that pass (1/6 th of a turn) and do the same on the other side. Just don't forget how many have passed, or you'll have to get the string line out again.
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