277° rephase cost VS vibration reduction (2024)

Opinions are like assholes.... everyone has one... and they all stink.

I'll throw my opinion in here, smelly as it may be.... and a disclaimer: I've never ridden a 270 XS, so...
I'd go for it if it were me. All it cost's is money... and your money at that, not mine.
It's not as if you're planning something irreversible, you can always switch it back to the 360°. And if you decide it's not for you, I suspect you could come pretty close to getting your money back by selling the 270° bits on.... an investment if you will.

Building a 270° (or 277°) is on my bucket list. I figure that if I love it, it's money well spent. If I don't like it, I'll sell the parts on to someone else and call it a wash.

Thanks for all the replies, I understand this whole topic and question is strongly related to what someone is looking for. And therefore very subjectieve.

@articxs:
By scrolling this forum I found and old but interesting topic about the physics of cranks and vibrations. Pretty technical but interesting.

https://www.xs650.com/threads/what-is-the-difference-between-a-277-and-270-degree-re-phase.19680/

My other bike is a modern 270° MT-07, I know you can't really compare our old XS to that, because it as additional counterbalancing shafts but the vibes are perfect. There are some but I can ride it all day.

Some interesting info I got talking to Jerry from Heiden tuning (who's been building and tuning XS for 30 years and had quite some interesting documentation from the original XS development and racing) He also mentioned the balance factor. And I'm no expert at this subject at all! But from how I understand it's always a compromise. And by testing different cranks with different balance factors they eventually settled on the XS as we know it. He said the engineers did a pretty good job back in the day. We talked about the 277 crank and vibes. He estimated a reduction in 25%. But I was and still am interested in what people here have to say!

But talking about vibes with him I learned that my pursuit in removing as much weight from the bike as possible, is definitely not helping with the vibrations I feel. So I realise that.

And even in his career the whole subject of vibes is not and exact science. He ones came across and stock Xs that was really and he said "really smooth", so he dismantled everything and tried to reverse engineer it to only find:.... Nothing! He couldn't figure out why this bike was so smooth.

Just adding to the mystique of vibrations

And Jim you are right it's not an irreversible mod. I just want to learn as much as I can before spending that extra 1300€

For thinking out loud here
Someone and Mr Heiden
Having the pipes at the same side makes the Pipe Length and Resistance different
I have heard of problems with straight pipes. Tuning the length and resistance.
pressure waves bouncing back hurting the gasflow
Is there not a risk that the Symmetry Left and Right cylinder is Gone / is Bad
And with higher gas velocities this Non symmetry is making unbalance left cylinder and Right .Perhaps causing vibrations

Perhaps I am wrong here but it can save some work later also should rephasing happen.

Since we are on the subject of vibrations, what about the influence of a 750 cilinder/piston set? Does it increase vibes?

I got the first gen Big Bore look cilinders but they are 650cc. The paint is coming off and want to have it blasted back to bare aluminium. I've got an option to swap in my cilinder for a 750 that's already bare alu.

Bigger pistons, bigger vibes? Or not that simple?

Bjorn said:

Since we are on the subject of vibrations, what about the influence of a 750 cilinder/piston set? Does it increase vibes?

I got the first gen Big Bore look cilinders but they are 650cc. The paint is coming off and want to have it blasted back to bare aluminium. I've got an option to swap in my cilinder for a 750 that's already bare alu.

Bigger pistons, bigger vibes? Or not that simple?

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That would mostly be depending on piston and piston pin weight. Larger bore would not necessarily mean heavier pistons. Also, when piston/ pin weight changes, the balance factor also changed, unless the crankshaft is modified. (Balance factor determines the proportions of vertical "shaking" vs horizontal "shaking"

Bjorn said:

Since we are on the subject of vibrations, what about the influence of a 750 cilinder/piston set? Does it increase vibes?

I got the first gen Big Bore look cilinders but they are 650cc. The paint is coming off and want to have it blasted back to bare aluminium. I've got an option to swap in my cilinder for a 750 that's already bare alu.

Bigger pistons, bigger vibes? Or not that simple?

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Clever piston design can achieve similar weight for 750 as 650cc pistons. I have never put pistons in a XS650, so a bit of research is required on the options and things such as piston weight.

A lot fewer/more expensive ignitions on the market for a rephase. The vape system is 2 pickups and 2 CDI boxes. Pamco used to be around $100, but the current offerings seem to be $300+.

I have only ridden a standard XS a little, but the rephase doesn't seem that different. Like others have said the vibes are still there, just different spots.

Piston weight doesn't seem to make a huge difference on some bikes. I have a big bore in my DRZ, so +4mm piston size. Wiseco, JE and others the piston weighs 50+ grams more than oem, but wossner is only 10g. I didn't notice a difference going from stock to big bore wiseco, to wossner.

I'll weigh in...
I admittedly have not ridden a lot of standard 360 crank XS's. I bought my bike for real cheap with a bad crank so was kind of in the same boat; it had to come apart either way. So after doing some reading here and other sources, I went for the 277* with a 750 kit as well.
I just did a 200 mile ride this weekend and wanted to try and ruminate on the character of the engine.

The little bit of riding I have done on a standard xs was test rides when I was looking to buy one. I feel like they are smoother at lower rpms and then as the revs climb they begin to shake and vibrate as you cross 4k toward 6k rpm.
The 277, you can feel the vibes as you take off but unlike the 360, the vibrations don't build as the rpm's rise...I can cruise in top gear, 75-80+mph, at 5-5500 rpm with very little vibrations. I mostly feel them as a tingle in my feet. But my hands never go numb or tingly. (I do run pretty thick rubber grips tho)
So I guess to boil it down, with the 277, the vibes are there, they just stay more low level constant rather than building with RPMs the way the 360 seems to.
So if you want to do longer, higher speed trips, I would recommend it. And as others have said, you can get your money back out of the parts if you hate it.

I can't say enough about the vape ignition; Simple, reliable, makes spark without a battery, super high build quality.
Expensive but worth it!
One of my riding buddies always say...
Buy Nice or Buy Twice!

Thanks for sharing! I'll check the piston weight just to be sure.

@Ratranger i know there are other (cheaper) ignitions out there. But I'm really pleased with the quality of the vape system I have for the 360 crank. I don't really like the camshaft driven versions. I don't really like the price increase I see on the Vape system...

Although the opinions are not 100% equal I do see a trend where people report that the higher RPM's have less vibrations with the 277 compared to stock. That's exactly where I would like to reduce them, for highway miles.

@Steve C how was the install of the 277 vape? Red some posts about the instructions being less clear than the normal version?

Honestly it's been a minute. It was pretty easy except I made the mistake of using a wrench on mine and broke broke one the sensors when the compression pushed the crank around.
Gary Hoos covered it for me tho.
I remember I made a gauge out of a piece of zip tie to set the rotor in the right spot. that was a little fiddly but no issues and it started right up.
You are setting the timing to the left cylinder as I recall...

My 2 cents! You already have an XS 650 and know it's performance. Go with a 750 kit and go down 3 or 4 teeth on the wheel sprocket. The performance and sound through the gears will impress you still and you have lower revs at highway speeds. If you want a freeway flyer, any modern bike 500cc or larger would be much cheaper and better. @Jim above has another good point above that is certainly worthy of consideration.
There is a certain joy in choosing meandering routes that suit our 50 year old relics. Cheers.

There was a fellow on here named John (I think he passed) who had great information on making these motors run reliable and smooth; he emphasized low compression and had some amazing fixes and ideas.

Charles13 said:

There was a fellow on here named John (I think he passed) who had great information on making these motors run reliable and smooth; he emphasized low compression and had some amazing fixes and ideas.

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That would be "XSJohn"....Not sure if he is with us anymore? However, I don't think he was much concerned with running at "high-ish" speeds ...

He passed away several years ago. And he was into low revs when cruising along with low compression etc. as I recall.

dps650rider said:

He passed away several years ago. And he was into low revs when cruising along with low compression etc. as I recall.

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That’s what I’m saying! low compression big bore kit, rephase, low revs, high ratio primaries, od 5th gear, small diameter exhaust, small single carbs, cushy suspension and extreme sprockets equals smooth reliable cruising!

I saw a bike for sale locally that had a big bore kit and iirc, a 277 crank. That may be the best way for me to have one - buy one that’s already built. Gotta empty the garage though. It’s kinda crowded in there and the XS isn’t even in there.

bosco659 said:

I saw a bike for sale locally that had a big bore kit and iirc, a 277 crank. That may be the best way for me to have one - buy one that’s already built. Gotta empty the garage though. It’s kinda crowded in there and the XS isn’t even in there.

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I would say that's definitely a good idea as long as it's built nicely.

It’s funny that there’s been no mention of the difference in engine sound once rephased… that would be a factor for me. In my opinion, aural enjoyment is so important in terms of these bikes, and the rephase totally changes the sound of the engine.

Personally, if I had the choice I would do it just for the sound - I think the rephased XS sounds so gnarly and rad.

Maestro said:

It’s funny that there’s been no mention of the difference in engine sound once rephased… that would be a factor for me. In my opinion, aural enjoyment is so important in terms of these bikes, and the rephase totally changes the sound of the engine.

Personally, if I had the choice I would do it just for the sound - I think the rephased XS sounds so gnarly and rad.

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I gotta admit, I grew up listening to British parallel twins. 360 engines. I liked it then and I like it now. I also love the sound of an Italian L twin, so I’m not disagreeing with you.

I like both sounds too. My MT07 has a 270° crank and i really love the tunes from that akrapoviç! But for me its not really a must.

Still in doubt about leaving it 360 or going 277°. Linda lean towards doing it, but the Money. Also want to do some other stuff to the bike. I guess people can relate haha