Were Your Engine Mods Worth The Bother.

My XS Has A....

  • Big bore kit, totally worth it.

    Votes: 4 25.0%
  • Rephase. totally worth it.

    Votes: 0 0.0%
  • Big Bore and Rephase, OMG.., or at least totally worth it.

    Votes: 1 6.3%
  • Big Bore....meh...

    Votes: 0 0.0%
  • Rephase...meh...

    Votes: 0 0.0%
  • Big bore and Rephase....meh.

    Votes: 0 0.0%
  • Big Bore, not worth it.

    Votes: 0 0.0%
  • Rephase, not worth it.

    Votes: 1 6.3%
  • Big Bore and Rephase, not worth it.

    Votes: 0 0.0%
  • Bone Stock motor like God intended.

    Votes: 10 62.5%

  • Total voters
    16

MacMcMacmac

Failed Hedonist.
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Let me know if its worth spending money on the motor. Just lining things up for a winter (HUSH YOUR MOUTH) project.

Or maybe just drop the whole idea and get a Gen 1 Virago and stuff an 1100 motor in it.

(why not both...)
 
In my humble opinion, projects like big bore kits and rephasing your motor are projects that are done because you enjoy the process, I’m sure that making it a 750 and maybe adding pipes and bumping up the jetting will increase the performance. But after you spend thousands of dollars and hundreds of hours you will still have a 40 year old motorcycle that any 16 year old kid on a beater SV650 can blow into the weeds. :laugh2:
But if it’s a job that would bring you pleasure, by all means do it. I’m sure it would be fun to do and you will have a slightly hotter XS650, that you would enjoy riding. :thumbsup:
 
My xs surprises a lot of people with how quick it is, not rephased could never see the net gain from the cost, you can get a very quick xs with just a few mods
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I've read a lot about most of the enginemods you can do.
I have a 750 kit in my 75. If and when I rebuild another XS it will get a 750 kit. The 10-12% power increase is nice.The great reduction in above 4500 rpms vibration is well worth the cost.
I'm noty sure just why this happens. Perhaps it's the weight of the forged pistons, maybe the heavy duty rods perhaps a bit of both chagned the eengine balance.
Perhas froged pistons can be found for stock or oversized that can still be used in stock jugs will have a similar effect.
I have not tried a different cam. Still using the stock 75 cam.
I did modify the rocker arms to use the volkswagen type elephant foot adjusters. I like these very much.
A bit of port work was good. Mostly just cleaned up casting ridges.
Almost forgot. All my bikes run Pamco E-advance igniotions.
Engine work often requires intake and exhaust work. I built my own headpipes with 1 5/8 " pipe. Tried several different cheap mufflers and most ran good. Some louder than others, some not so loud. I Have a set of the Kawasaki Ninja EX 500 carbs tat after a bit of tning run very well.
I also have an 83 that is pretty much bone stock and enjoy riding that too. One mod was to replace the burnt out TCI with a Pamco E-advance, the other was on the stock air filters. The fuzzy fiber stuff on them was crumbling off. I peeled this off and reglued the cage to the end caps. I bought some 3/8' thick heets of foan from Uni-Filters and cut them wide enough to be a snug fit bettween the end caps and long enough to wrap around with plenty of overlap. Easy remove, clean, oil and replace.
If your bike is stock and doesn't need a rebuild then you can enjoy it as it is. If it needs engine work then going with a few of these mods won't cost a ton of cash and are nice improvments. What I might do before I go to engine work I would go through a few other mods first. Like tapered steering head bearings, Bronze swing arm bushing, new rear shocks, rebuild the forks and doing some of the Minton mods with new straight rate springs, experement with different fork oil weioghts and ammonts to find a combo that works well for you. Possibly even cartridge emulators.
Brake improvements. A 12 mm front master cylinder greatly improves braking action and feel. The stock pads if not worn can be removed and clean any crud or glaze off. Wire brush in a drill works. The rotor a sanding block with a medium grit paper to clean off any glazng or rust. Pulling out the slider from rubber and the rubber that the mount bolt goes through and cleaning out any crud in the calipers holes, A bit off lube on the slider when reassembled lets the slider not bind up the caliper.
While your on the brakes swapping that rotten old rubber hose for brauded stainless steel lines is a great idea.
These are most of the best mods you can doo without spending a lot of money and get a grewat improvement in your bike.
Leo
Rear brakes if disc you can't really change the M/C size but clean up on the
 
In my humble opinion, projects like big bore kits and rephasing your motor are projects that are done because you enjoy the process, I’m sure that making it a 750 and maybe adding pipes and bumping up the jetting will increase the performance. But after you spend thousands of dollars and hundreds of hours you will still have a 40 year old motorcycle that any 16 year old kid on a beater SV650 can blow into the weeds. :laugh2:
But if it’s a job that would bring you pleasure, by all means do it. I’m sure it would be fun to do and you will have a slightly hotter XS650, that you would enjoy riding. :thumbsup:
Well said. If you want better all ‘round performance get a new bike. I think most XS owners have them to putter away on in their spare time. Messing with mine over the winter maintained my sanity. Better start planning for this coming winter.
 
Comparison to modern liquid cooled bikes with EFI and combustion chamber and piston designs that allow use of 87 octane pump gas with 11:1 static CR is sort of beside the point. My 700 with ported head, Shell #1 cam, 8.8:1 static CR, 33 mm. Mikuni 4-stroke pumpers, and suspension mods to match, hits 118 mph at 7500 rpm and turns in mid-50's per gallon in mixed riding. I'll take what I've done with the old D model over the years over what the RE and Kawasaki air cooled twins deliver any day.
 
as long as you have enjoyed the process and results that is all that matters.

Very true, however, a thread like this does offer guidance to the uninitiated. There is a lot of info out there that would have you believe a 277 rephase will bring a great increase in power, when in fact, it does not. It does change the character of the engine. As for me, I don't like it. I don't fault anyone for doing it, if that's what they like. Rambling.... sorry
 
Very true, however, a thread like this does offer guidance to the uninitiated. There is a lot of info out there that would have you believe a 277 rephase will bring a great increase in power, when in fact, it does not. It does change the character of the engine. As for me, I don't like it. I don't fault anyone for doing it, if that's what they like. Rambling.... sorry

I agree the need to offer guidance but this should be based on facts e.g. a 277 rephase does not bring a great increase in power not whereas comments such as 'x, y or z isn't worth it' is an opinion and may not be universally accepted.
 
Just to clarify, I never said the rephase was for performance gains, although someone said his hi perf race engines suffered no crankcase issues once the crank inertia of a 360 degree firing order was lessened with a rephase. Seems like sort of the same issue steam engines had with hammer blow damaging tracks.

I was just wondering if the change in vibes and the overall engine character changes were worth the effort. These two mods are simple enough to contemplate as home jobs, well, at least once the crank has been dealt with. Loosening up the valve clearances is also an easy task. I never realized the opening event of this cam was so long and drawn out. I'd have a hand at porting if I had a spare head to work with but my confidence level for getting it right is low.

I'm not trying to make a fire breather, just add some useful torque in the low and midrange. Mechanical sympathy encourages me to lessen the high rev vibration, even though I know the motor can probably handle it just fine. There is no way buying a faster, newer bike is going to scratch the same itch as owning an XS. it is a unique bike. I doubt even the "new" retros would.
 
Just to clarify, I never said the rephase was for performance gains, although someone said his hi perf race engines suffered no crankcase issues once the crank inertia of a 360 degree firing order was lessened with a rephase. Seems like sort of the same issue steam engines had with hammer blow damaging tracks.

I was just wondering if the change in vibes and the overall engine character changes were worth the effort. These two mods are simple enough to contemplate as home jobs, well, at least once the crank has been dealt with. Loosening up the valve clearances is also an easy task. I never realized the opening event of this cam was so long and drawn out. I'd have a hand at porting if I had a spare head to work with but my confidence level for getting it right is low.

I'm not trying to make a fire breather, just add some useful torque in the low and midrange. Mechanical sympathy encourages me to lessen the high rev vibration, even though I know the motor can probably handle it just fine. There is no way buying a faster, newer bike is going to scratch the same itch as owning an XS. it is a unique bike. I doubt even the "new" retros would.
Yes, the 277 is smoother at higher RPM. It's definitely better if that's how you drive it. The faster it turns, the smoother it gets. I'd say quite the opposite of the 360 engine.
 
Right, Max, the value is in the satisfaction derived from doing the work and achieving the result you want. As to smoothness, rephasing is going to move the vibes, not eliminate them. The Devil is in the details. Balancing rods and pistons and blueprinting the crank to reduce runout are the only methods I know of to actually reduce vibration rather than just moving it around--not cheap and not flashy, but effective. Mama Yama says runout up to .002" as measured at the journals is acceptable. That's a whole lot of thrashing around!
 
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IMO worth and value for money are subjective.
Also temporal. You don't want to look back saying what was I thinking...

Wondering what mods Jay has done if he would reveal them. Got to be fast, going by the clothing...
 
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