Hassling the Husky - Vitpilen 401 stuff

[Easy-X]

Today I did sweat my cock off doing barely anything with the new bike

General check over, tweak and fiddle. Here's what it looks like with the iconic side panels off:

https://i.imgur.com/3b8hp1g.jpg

Just getting a bit more familiar with the construction. There's loads of helpful little stickers like this:

https://i.imgur.com/4Yu6Dvq.jpg

Presumably the expected resistance readings for the fuel level sender. There's loads more, for example the torque settings for the airbox lid are embossed in the plastic.

The previous owner swapped the battery for some reason:

https://i.imgur.com/poELFw1.jpg

Definitely aftermarket but why bother? Packed in front of the battery was the original tool bag still sealed in plastic, untouched. Quite a variety of tools in there.

The build quality generally seems pretty good. Better than the Duke 390 I saw at a dealers and yet I'd have thought both bikes would have come from the same factory in India

Brake lines are all steel braided!

https://i.imgur.com/97DfISC.jpg

Along with Bybre brake calipers, the spoked wheels, adjustable suspension... TBH I'm pretty impressed

Here's the fresh air where the "damper box" was removed and bypassed

https://i.imgur.com/x4QDa49.jpg

I have it in my shed and as far as I can tell it does nothing by quieten and adjust the tone of the exhaust. Fuck me the engine must be near silent with the box in place I will tinker with alternatives to the factory slip-on later on!

The bit marked with the arrow is where someone cut the cable for the number plate tyre hugger. A bit slack leaving it like that, a rubber end cap would have been nice. I don't think it's part of the main wiring harness so I'm hoping at some point I can trace it back, unplug and strip this remnant.

Anyhoo, I did tinker with the suspension (back to the factory defaults) added back the rear grab rail and repositioned the bar-end mirrors. The latter took me more than half an hour to get a reasonable view and I still don't like them. Almost tempted to refit the original mirrors... almost

I was intending to ride the Husky a fair bit today but I had some urgent work in the City so I took the XSR instead. Even so, jumping on the Yamaha (with the aftermarket low profile seat) almost felt like riding a cruiser

It's a very odd bike, the Vitpilen, almost like someone dumped a bigger engine into a 125. It feels like you're pushing a Grom round the workshop and yet the seat height is about the same as the OEM XSR seat. I still don't care for the faux-clip-ons but I shall persevere till the conversion kit turns up.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[A100man]

[Easy-X]

It's not all that right now but in the spring all the wild flowers come up it looks lovely.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[struan80]

Very nice bike mate. Can you post a photo of the whole bike if you don't mind?

[A100man]

[Easy-X]

A weed is just a plant growing in the wrong place
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Ribenapigeon]

Ive been tempted to get one as sometimes my xj6 seems a bit much for the tootling around town I do. There a very good deal money wise as well i just wonder if I would notice the lower power much. I wish there was stil the 701 though, I was very interested in that as a move for my xj6.

[Easy-X]

Same, apart from the stretch of A3 from near my house up to Wandsworth I just wasn't using any of the XSR. I'll have to do one of my tiresome and over the top reviews at some point but for the moment I'll just make some observations of the Duke 390 / Husqvarna 401 engine...

Out-of-the-box there's not much there below 4000~5000 revs. It can still eat 125s for breakfast from the lights but it's not the teleportation device you get with the Yamaha CP2 engine. The single-cylinder does become a bit of an animal over 6000 and heading to 5 figures. Is it fast? Dunno. Certainly feels dramatic However, I still have a range of engine mods lined up and all the anecdotal evidence suggests the low-end can be cheered up a bit.

The USP though is the weight (or lack thereof.) At 150kg dry it's smack-bang between dirt-bikes and most run-of-the-mill medium sized bikes. The XSR feels like a whale in comparison - an asset chewing up big fast roads but annoying round town. The 390/401 is almost a 125 package without the downside of no power.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Easy-X]

Exhaust swap... or not

The old front section is quite chunky:

https://i.imgur.com/At3e30u.jpg

Hang on! The new one looks like it'd actually be restrictive On closer examination though the interior diameter is about the same and half the factory one is catalytic converter anyway.

Unfortunately "rain stopped play" as this is the mid-section:

https://i.imgur.com/UvOW6Az.jpg

This bit replaces a factory sound dampening box so something the previous owner put on. The bracket pinged off with almost no force part way though loosening up the front section (BTW the exhaust stud nuts were barely more than finger tight.) Now waiting for a replacement to turn up.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Ribenapigeon]

How many miles are on it? What did you pay?

The local ktm dealer was flogging them off for £4k brand new a year back when they dropped dealing Huskys. I wish I'd bit the bullet and traded in for one.

[Easy-X]

[Easy-X]

Part way through the exhaust system...

Went with the replacement mid-section rather that my atrocious welding repair:

https://i.imgur.com/iX4wYGB.jpg

Front section in:

https://i.imgur.com/xtgewFv.jpg

I buttoned up these bits a touch more than hand tight just for testing and then went through the various end-cans from my shed. Pretty much all of them sans baffle turn the bike into a hammer drill

The winner does sound vaguely like my XSR but I need to move the spring hangers over a bit before I can finish the job.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Ribenapigeon]

Looks nice. Apart from that does a replacement exhaust make much difference?

[Easy-X]

[Easy-X]

In our previous episode we fitted the front and mid-sections of the exhaust system Just the link pipe left.

First I ground off the old spring loops:

https://i.imgur.com/bwW03gd.jpg

Then I welded on the replacements in the new positions...

TBH I was so disappointed with the welds I never took a photo. It was only later when I threw the old mid-section in the junk box I realised they weren't that terrible Anti-spatter spray helped a lot

Anyhoo, the old fella suggested zinc paint to stop things corroding. Ye gods! That was a mistake:

https://i.imgur.com/OmWmmeR.jpg

If you think it looks awful from the photo trust me it looks much worse close up I'm not struck with how the end can sticks out either:

https://i.imgur.com/XZh87Ud.jpg

The good news is it was only a cheap link pipe from China so it matters not if I bin it for something better. I am now more aware that the length/angles of the link pipe are what's crucial so this setup at least gives me a reference point.

And whilst I was initially disappointed with my welding I did at least judge the placement dead-on for fitting the springs

Next step, air box mods. The stock air box has an access lid for the filter:

https://i.imgur.com/F4BtVzF.jpg

With the filter out you can see the airflow comes from below, up through the filter and into the intake bell:

https://i.imgur.com/sCE9Y4P.jpg

I've gone for the DNA two-part filters. The stock filter is replaced by your typical fancy looking oiled filter but the trick is to also replace the lid... with another filter!

https://i.imgur.com/Bk1LV12.jpg

Completely covered by the seat with regards to rain.

De-cat exhaust, airbox mod - next up best be a fuelling mod Enter stage left: FuelX. It seems to be some sort of "smart" oxygen sensor bypass also popular with the Royal Enfield crowd. I'm usually pretty doubtful about such things but no one has a bad word to say about it so tally ho!

Basically you run a cable up to the front of the engine and I've seen far too many YouTube videos with atrocious routing I just took of the rear tank brace and ran the cable behind:

https://i.imgur.com/RhebWRQ.jpg

Again, a lot of people seem to choose terrible places to site the box of tricks that the cable plugs in to even going as far as dumping the tool roll to make space. But there's loads of space behind the panels going to waste:

https://i.imgur.com/Z6PAciL.jpg

I did however route the connector to an accessible spot just in case I wanted to bypass the box:

https://i.imgur.com/cRHRK6u.jpg

Just about got the side panel back on as the sun was setting. Quite an epic day!

I started the engine up and so guess it all works okay. Hopefully the weather cheers up a bit next week for a test ride.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Easy-X]

A few more thoughts...

The relatively harder work of front & mid-sections, airbox and fuel mod having being done I can move onto the refinements. Aesthetically something annoys me with the can I have It'd work a lot better if it were "high side" something like this:

https://www.accessoryinternational.com/merchant2/graphics/00000003/gpr-hu-41-pcev-powercone-evo-slip-on-exhaust_640x640.jpg

It nicely hugs the lines on the bike but unfortunately this example is for the older model where the exhaust routing is completely different. To run the exhaust in a similar way on my model would require a completely custom link pipe, possibly a reworked middle section. I don't think my 5 mins of welding experience would be up to the task but hey, that's what angle grinders and paint were invented for

I'll have another swap about with the contents of my shed plus a few minor bits I have on order but another alternative might be to put back the damper box:

https://i.ebayimg.com/images/g/CpwAAOSwbd1jq343/s-l640.webp

And then skip an end-can altogether:

https://www.pro-race.co.uk/wp-content/uploads/2022/10/HUSQVARNA-VITPILEN-401-2018-2019-GP-S1-SHORTY-GP-EXHAUST.jpg

BTW The cat's in the OEM front section, the box is just a series of chambers. I would leave this option as a last resort as the box is pretty heavy, neat look though.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Ribenapigeon]

The last option looks the best imho.

[Easy-X]

[A100man]

Would this kind of thing help..

https://www.carbuilder.com/uk/flexible-exhaust-pipe-45mm

other sizes available.
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[Easy-X]

[Ribenapigeon]

Go on, fabric some twin underseat pipes

[Easy-X]

[Ribenapigeon]

[Easy-X]

Twin exhausts on a 401 is a concept so ludicrous Google is telling me "nope, no one's done this!" However, it has been done to death on the Duke 390 and that's because the subframe readily lends itself to the concept.

Sorry but I'm going to wimp out and instead go with The Murray Doctrine: add lightness
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Ribenapigeon]