Big picture thinking...Engine question...

mseriously

mseriously

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How far is too far? How far is enough?

I've had a few xs650's and each have their own quirks. I've yet to do a full motor rebuild from the ground up but I'm getting closer to pulling the trigger. I just wonder how far I can go in the performance department while not sacrificing reliability.

So. Here's the "broad picture" plan. It'll be a daily driver. Striving for drive-ability. Not looking to blow the doors off of things, but, enough to get out of the way. Keeping it "stock" like. Lower profile seat. Chopped rear fender a bit.

Probably big bore 750. 5th gear upgrade. Want to stiffen up the clutch...maybe get another plate in there. I'd like to do hydraulic clutch mod...probably one piece clutch rod. Having a stiff clutch pull kinda sucks after a few hours riding around. Upgrade the electrical system. PMA, Pamco Pete, possibly Hugh's new igntion? Dual exhaust with some good mufflers for back pressure. EX500 carbs as I've had great experiences with them. UNI filters. I want to do an oil cooler and filter...might look into doing XSJohn oiler mod as well...want to do some head work but don't know how and have no experience...cam upgrade and rephase a possibility...

SO. Is all of this worth it? Where should I draw the line....am I missing anything? Sure I could buy a modern Triumph or a liter bike and just ride it...but there's a great deal of SOUL SUCKING BULLSHIT that's riding around out in the world. Some things can't be bought and there's nothing like riding a bike that you know inside and out.

What say you guys? What's your opinions and experiences? Let er rip.
 
You must have a large budget........................have you added up all the items to get a total cost?

For a daily driver, the 650 cc size engine will work just fine. If you drive a lot of expressway, the 5th gear change is a good thing...............if mostly city/town riding, then the regular stock gears work well.

The stock alternator does a very good job. For 70 to 79 years, replace the original rectifier and original regulator with more modern design parts such as an E-bay 3 phase rectifier, and a nos automotive regulator. That will give you 14+ volts all day long. The PMA is not an upgrade, its just an alternative alternator design, that produces about the same output. The only advantage the PMA has is that it allows for no battery to be used. You would get to enjoy kicking the engine to start.

The Pamco ignition is an excellent ignition, and is even better by buying the e-advance option. Gives great spark and is very reliable.................nice linear advance curve. So much better than points and fly-weight advance unit.

Sounds to me that you have already made up your mind, that you want to re-build an engine. You've convinced yourself that just buying a new bike and driving it will leave you craving for that hands on wrenching experience. Seems like you know you're going to do an engine re-build.
 
Generally 70-75 run hard horses is the max before crankcases start breaking. Getting those ponies 4-5K and up is fairly easy, straight forward and well documented, the trick is getting torque down low where it's useful and fun on the street. IF you can, did build a "stump puller" motor, I'm not sure how well the rods would take it.
 
Even if you keep the battery a PMA has one big advantage, the bike can be started when the battery is flat. Of course when everything is working normally your battery should never BE flat, but life happens.
 
+1 :thumbsup:I agree with everything RG has said.
The stock engine has plenty of grunt if its set up properly.

First thing I would do is fit an electronic ignition with electronic advance and give the bike a damn good service .
The difference in performance between spot-on timing & advance and 'somewhere near' is enormous.



retiredgentleman said:
You must have a large budget........................have you added up all the items to get a total cost?

For a daily driver, the 650 cc size engine will work just fine. If you drive a lot of expressway, the 5th gear change is a good thing...............if mostly city/town riding, then the regular stock gears work well.

The stock alternator does a very good job. For 70 to 79 years, replace the original rectifier and original regulator with more modern design parts such as an E-bay 3 phase rectifier, and a nos automotive regulator. That will give you 14+ volts all day long. The PMA is not an upgrade, its just an alternative alternator design, that produces about the same output. The only advantage the PMA has is that it allows for no battery to be used. You would get to enjoy kicking the engine to start.

The Pamco ignition is an excellent ignition, and is even better by buying the e-advance option. Gives great spark and is very reliable.................nice linear advance curve. So much better than points and fly-weight advance unit.

Sounds to me that you have already made up your mind, that you want to re-build an engine. You've convinced yourself that just buying a new bike and driving it will leave you craving for that hands on wrenching experience. Seems like you know you're going to do an engine re-build.
Click to expand...
 
Like you, I've owned heaps of great bikes over the years and enjoyed them all for different reasons. Now at 62 I decided I wanted to attempt an engine rebuild myself for the first time. I've just finished reassembling except for the electrics and carbs. I said to my boys the other day - eventually starting this thing up and hearing it run will give me a bigger blast than all the other bikes I've had - because I did it myself and now have a rough idea as to what the hell is happening inside that engine. Whilst I only went for a stock rebuild, if things work out, I won't be frightened to pull her apart and maybe go for a re-phase down the track. Highly recommend having a crack at doing your first rebuild. My XS engine is going into a custom frame so I've got enough on my plate figuring that out at the present time. Good luck!
 
I have owned and built many and the best one I had as a daily driver still pounds the streets under a different owner and all I did was freshen up the motor with pistons and rings and a PAMCO. Left the trans alone because it was just a around town bike and rode great even that it was a hard tail and I just had fun with it. If the stock charging system works leave it alone. I have had more bikes come into my shop that were upgraded and had problems because of poor design over the years. But bottom line is ITS YOUR BIKE YOUR MONEY go for what you want.
 
Having gone the whole way with a Road Glide, 113 c.i., etc., etc., sure it was great and satisfying, but it made as much sense as putting a crate motor in a 60 passenger bus.

For your XS, a 750 kit makes sense if you need pistons and a rebore anyway, otherwise stock ish and reliable wins the day. Lots of $2000.00 used modern bikes would have the XS for lunch no matter how much money you put in the motor.

Make it look nice and run reliably and all your peers will envy you.
 
It does feel good to say "Yeah, I built it." Real good.
 
I was fairly impressed with the 750 kit I put in my 75. It not only increased the HP but also reduced the vibes.
At idle the vibes are about the same, where the stock bike get a bit viby at around 4000-4500 rpms my 750 kit doesn't, it justs goes faster.
Leo
 

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