'80 or so XS650, Hi-PO rods, stock phasing, welded as I'm going to be buying a 700 BBK from you too along with a Shell #1. I kinda' have to do this it bits, but how much for the crank work? I bought a good crank, cylinder and head off of ebay earlier this year, as to keep from having a disassembled engine laying around. My plan is to have everything ready to assemble, and do it all in a weekend.
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Here is a link to my face book page where i show my work. https://www.facebook.com/gary.hoos.5 You have to scroll down a little.
It's easier to do this by email, gary@hoosracing.com I will send you a quote. with options. If your rods and main bearings are good we would just need big end pins and bearings. (Never reuse them.) $450 plus parts. Mains bearings if needed are around $550.00 but will have to check. Rod pin and bearing are around $250.00 or Carrillos for $750.00 email me
Ace Caferacer
XS650 Member
Don't need a cam driven ignition. I made mine with a double cdi ignition. 83° rephased heritage special. Just connect up a second cdi plus a second pickup coil 83° earlier on the housing. Works perfect together with 2 coils of an Aprilia rsv1000. These are very small, and powerfull, and fit snug under the tank.- this is a tic of mine - i love rephased motors...yes this is changing the crank set up so the pistons dont travel together...the advantage is that you dont lose energy when both pistons are at TDC as 1 piston is always mid stroke when the other is TDC..ie rephase-when one piston is not moving (TDC) the other is at max velocity (mid stroke)...removes the search for energy to overcome inertia when both pistons are stopped together (non-rephased TDC)
- so there is a power saving
- this leads also to less vibration as the motor runs smoother
- better responsiveness
- slightly torquier
- if you do this weld the pins to the flywheels...balancing helps too
- there are 2 ways of doing this
- split the crank in the middle-rotate the right hand side 3 splines and press back together...277 rephase
- split the crank, replace the 2nd flywheel from the right with a slightly modified 3rd flywheel (remove 21mm from the pin boss where the cam sprocket seats), use a 270° pin and press together 90° out of phase...270 rephase
- both of these processes require a suitably modified camshaft and a cam-driven ignition system...a good time to consider installing a permanant magnet alternator and dual lobe points cam
- in my opinion yamaha missed a golden opportunity to produce a truly extraordinary motor by turning this idea down...i have done this and highly recommend this to anyone interested in spending the effort...virtually all modern-day parallel twins are built this way
burns
OWG
IMHO if you dont like the characteristics of this engine buy one that you do.
Oldnwiser
XS650 Enthusiast
Nothing at all wrong with points. They are simple as dirt and a spare pair and condenser will never leave you stranded, get a light for your forehead, a feeder gauge and just do it. Practice in the driveway so you can do it in a parking lot.
Oldnwiser
XS650 Enthusiast
My XS2 that used to have was the best bike bar none. I replaced the points, set the lash to .006 int.012 ex , adjusted the chain, and it rode really well.
Oldnwiser
XS650 Enthusiast
Is this engine a 270/90 or a 277/83? It really sounds well balanced, like a V8. Does it make a difference in power or torque?Here's a vid off a rephased xs650 running....sounds Awesome!!
Oldnwiser
XS650 Enthusiast
There is nothing wrong with points, they are only a trigger for the collapse of your coil and subsequent fire. I use points on my race engine to trigger a 4 pin module and a high energy coil. They are easy to adjust and keep under the seat in a sealed bag. I have just refiled and adjusted the dwell for each and they are exact as a fancy setup that can require a ride home in the back of a pickup and a wait for new parts. Points are usually fine, most quits are the condenser anyway. A simple ignition is good.
Oldnwiser
XS650 Enthusiast
Different strokes for different folks. A 277/83 isnt exactly excessive. Split the crank move it three splines and press it back together. Yamaha has specifications for splitting the crank to service bearings and tells you in the manual what the press has to be in order to be within specifications. I think it is 80,000 lbs or more . A machine shop needs to do that and the press should have a gauge. If it is in specs why weld it together and make where you can’t service bearings and such. They rate the engine at 7500 rpm’s and a rephrase might make a little more horsepower and maybe just move the curves to a smoother range? A machine shop can tell you the truth of whether you should just get it to 65 hp and 60 ft lbs by making it more efficient. Welding the crank renders it un rebuildable but also why add weight when you don’t need to? Make it quick, make it fun. Or just tune in well as a 360 degree. My XS2 with that big overlap cam was sweet, it reminds me of the XK V12 Jaguar.
Having ridden only one 277 XS650, I remember it is very happy to spin faster than the redline on the tachometer. I'm happy with my 360. I just thought I'd throw that out there.
I had an in depth conversation with the late Dick Russell on the matter. In his opinion, the rephase does not make it vibrate less, it just moves the vibration to a different RPM range, I'm assuming less vibrations at the higher range. He saw nothing wrong with a 270, he just didn't feel it was worth the cost. Same with the extra cost of building a 750 as opposed to a 700. He felt that the 700 was a better value.
dps650rider
XS650 Addict
I have had 2 different 360 engines and 2 different 277 engines (built from the 360's) and the 277's are smoother under most conditions especially with increasing rpm. Where they are not smoother is at lower rpm under load due to the uneven firing interval.
That's kinda' the impression that Dick Russell (Grizld1) left me with (RIP Dick)
^To me it's many things. For example it didn't achieve its popularity by needing a different motor. Also it feels like the kind of deal where down the road it's a big ugh, like a dune buggy that should have just been left a Beetle. Or somebody drilled a Martin guitar to put in electronics.
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I'm not sure that modifying the engine is going to affect the value much, if at all. A good example of that are Ford Model A's. Hot rods generally bring higher $$ than stockers. Now if it's an early bike..... I'd probably leave it as it was. But at the end of the day, this is America and he can do what he likes.
Would you ever try to talk somebody out of something? Is it un-American?
I don't know if "talking someone out of something" is what any of us here are doing. I'm certainly not. I'm just passing on information. Now if someone says they are going to try running K-Y jelly in the crankcase, well......then, yeah I might try to convince them of their folly.Would you ever try to talk somebody out of something? Is it un-American?
