Bad Vibrations? READ THIS

[sparklow]

Thanks for this discussion Hugh, the explanation makes sense. Yamaha put those rubber fittings here and there for a reason!

 

[hard_y_rd]

Well if I ever get my 256 motor going, looks like for now the filings will be rattled from my head. Cause like the scrawny gal, I'm built for speed. Plus my wallet is empty. Likely want to do a rephase once the bike is road worthy.

 

[Halloweenie]

Like any other mod to these old bikes, the more you are willing to do yourself, the more money you can save..

We build a TON of 277 crank and cams - and lots of beginning wrenchers have found the XS rebuild to be a simple enough task using the manuals, and this forum for help when they get stumped..

Hugh

Hey Hugh! Have you thought about marketing a DVD or digital video? A UK mechanic, Steve 'Sausage' Porter, made a DVD of a complete engine rebuild for antique Vespas, done in real time. I bought one years ago for about $50 when I bought my first scooter, and I had no way of paying for a mechanic to do things. The DVD is great, he shows you how to get around not having the factory tools and nifty tricks like putting grease on new gaskets. I know that an XS is more complicated than a two-stroke, port-timed, antique scooter, and I also I know there are a lot of helpful videos on Youtube; but I'd think a DVD or the like, of good production, showing how to do many of the "common" modifications, would a welcomed product. $50 for a video and having confidence you aren't screwing things up is a lot cheaper than a mechanic or having to buy more parts once you've screwed up using just the manuals. If you want to take a look at the disc I have (just in case you are curious) just drop me a line. Hell, it might even help to stem the tide of emails asking for help.

 

[sonicarb13]

Love hearing other guys are out riding these things hard! My first 650 chop is my daily driver. Put a few long trips on her in the last couple years, 600 miles in one day on that palm sander of a hard tail! I have a couple engines laying around and would like to do a re-phase. I'm sure they are worth every penny. I work in a custom machining, fabricating shop by day with a group of guys that are just as crazy about choppers as I am. I've been all over the country to custom bike shows and looked on this site a bit but have not seen anyone that has done a rubber mounted engine. I am in the beginning stages of another build and plan on building a single down tube frame with rubber isolators for engine mounts. Anyone else seen this? Might have missed it on here somewhere.

 

[jetmechmarty]

What iggy options are there for 277 that do not involve using points or the advance mechanism.

 

[Punkskalar]

What iggy options are there for 277 that do not involve using points or the advance mechanism.

Pamcopete is working on a unit that doesn't use the mechanical advance unit. Probe engineering supposedly has an ignition that will work as well, but I've not been able to get ahold of one to test it. I like the Pamco because it's all self contained, no extra magic black boxes to hide or worry about shorting out...

 

[CDNTX650]

I dont find my close to stock 74 to bad in the vibes either. The better state of tune they are kept in the smoother they run too,.. But in reality...,The KZ650 is usually on the highway before the XS. Or the Versys if i need creature comforts like luggage and heated gear...

 

[RpNSht]

ive had various bugs to deal with since getting my rephased motor back together. despite these issues i was able to kick over my bike and ride it around. my bike was super vibey and i always thought that a stock xs650 must be incredible vibey if the rephasing was supposed to dampen things. frankly i was confused as to what alfredo and hugh spoke about because my bike was so out of control.

well turns out i executed some bug solving last night, including cutting a rung off my advance springs, adjust carbs, throttle, and valve adjustment (two jam nuts came loose changing my settings way out of spec). after buttoning the bike up. i kicked it over in one kick without much pressure at all. the bike fired up and purred like nothing i had ever experienced.

finally i now know what alfredo and hugh have been talking about this entire time.
i still need to dial in my carbs but if theres any doubt about rephasing an xs650- ignore it. you will be happy beyond belief. and the hard work, effort and cost will be more valuable than imaginable.

alfredo speaks the truth in this post and hugh is the man to go to.

im a true believer in rephasing and will do it on ALL my future builds no matter what- its a must!

thanks alfredo for a good posting about this and thanks hugh for figuring this out.

Some of you might know that I have spent some time rebuilding my motor, running my motor, rebuilding my motor, running my motor and rebuilding my motor over again. It's been a few years since I jumped on here knowing absolutely nothing (haven't come far from that btw) and really made an effort to dive in. I won't say much about the community that Travis built (xs650.com) because I know everyone here gets tremendous benefit from it. Wheter you just browse and never post, are an active asshat to everyone or an active contributor. You all get value here. No question.

What I do want to take a second and talk about is vibration. There are a lot of things that you can do to your xs that make it more reliable, sleek, sexy and fast. Most of these things are very well covered in other posts, but the one thing that I personally feel is understated is the RePhase. I have had the fortunate, and unfortunate, pleasure of experiencing the very same xs motor in various states and configurations. Now, if you are a professional racer or motor builder then I am sure this luxury is afforded to you all the time. I just don't think thats what makes up 80-90% of this community. I think there a lot of guys and gals like myself who are budget and time conscious and really want to get it right out of the gate. No time to test and test and just want to cruise.

When I first started riding the first rebuild (360°) it vibrated like a wild angry animal at speeds of 60+. If I tried to go up to 70+ the vibration was REALLY bad, sometimes I could barely keep my hands on the bars. I actually felt like it might shake loose, despite others saying it was normal. I was able, through the help of loads of forum members, to tune out some of this. The problem was it was still there. Lots of suggestions that would certainly do the trick to tone it down; squishier grips, bar snake, etc., but nothing that made a huge difference without a good amount of kit/add-ons. The vibration always felt wrong to me. I mean, I get the mechanics and why it does it, but it never really felt like something I could look forward to experiencing when riding the bike. And to me, I wanted to look forward to riding the bike. Enter the rephase. I read a ton about it and it seemed like the holy grail. So, I did the hard thing to do after spending all that time and cash on rebuilding the motor and tore it down again for the winter to do the rephase.

Saving the money and the time took awhile. I went all out this time. PMA, 5th overdrive, rephase crank/cam, but kept my bore from the original rebuild. No 750 kit in the budget and from all of what I could read the 750 just gets you to the max speed quicker. Doesn't really do too much for you unless you are racing or are really interested in getting to your cruising speed a little quicker. Neither of which are my interest or worth the $$$ to me personally.

To start to shorten this story up, I put the motor together twice with all the newly worked parts. First time I had the cam off one tooth and the base gasket was seeping. Once it was all together I ran it for about 50 miles, but even then I could tell the dramatic reduction in vibration. I never got it above 65, because of my past experience with the bike starting to vibrate like crazy before. Because the bike still vibrates a little more around that range, so naturally when it started to vibrate a little more I got scared and thought it was going to be as bad as the first rebuild.

Enter this past sunday. I was meeting up with some friends to take a ride to Nags Head (about 110 miles one way) to give the bike a proper shake down. This meant getting on the interstate which in my area means a posted speed limit of 70mph. Needless to say I clinched my butthole and went. The bike ran incredible the entire way. There is a spot where the vibration gets a hair more around 60mph (I am assuming its about 4.5k, but have no tach hooked up) but its an incredibly smooth vibration compared to the 360° phase. All went well barring some slight clutch cable adjustment needed. Even at speeds of 85-100 it barely vibrates more than a subtle hum. I have solid grips, solid mounted bars and also have all motor mounts hooked up and tightened down. I never maxed it out, but it certainly felt like it wanted to keep pulling even at 100mph. I was scared and impressed at the same time. My little xs was pulling away from a 70s ironhead and a 2000s harley 883. There were a few times when I just rolled on the throttle for a few minutes and got up to around 100+ and would look back and those guys were gone. They were right beside/behind me pulling and then they just vanished. None of us could really fathom that they couldn't keep up. Both of those bikes will get to 60+ faster than mine, but neither can keep up. I never maxed it out, but it always felt like it would go more and more and more.

So, long story short; While there is a lot that you can do to remove the vibration from the stock configuration, there is nothing you can bolt on that gives you as much of a dramatic improvement as doing a rephase does. Also, the 5th gear overdrive is an absolute MUST if you are doing a rephase. The benefit of the rephase, I feel, is dramatically understated on this forum. From my personal experience. I don't want to start an argument, just state what my experience has been.

Lots of thanks to Hugh and Pete for teaming up to offer such a great/painless upgrade available for this motor. If it's within your means to do this now or in the future. Do it. And give Hugh and Pete your money. Others may be able to do it, but these guys are certainly the top shelf.

 

[650Skull]

I have been reading this and a lot of other threads where the chopped bike is vibrating to much to be comfortable, problem when a frame is striped of its excess weight and made lighter, according to Hugh. Seems to be a recurring theme and seems the solution, (according to this thread), is a rephrase.

My take on this is.

The XS650 frame, though not perfect, (what frame is), was designed with rubber mounts, (Rubber mounted risers, foot pegs, seat and tank), to insulate the rider from the vibration from the 360 engine. Engine mounts were designed to hold the engine ridged and distribute the vibration through the frame. The rearguard, taillight, indicators, Instrument bracket mount and instruments, rubber flange between carbs and air-boxes, frame side-covers, battery box, (insulated all the electrical components,safety relay, reg-rectifies, solinoid), relay rubber mounts were all designed to protect these components from getting destroyed from the vibration. Some of the vibration would have been absorbed by these.The 78/79 Special taillight was top heavy and with the rubber-mounting on the guard and light it still would crack the guard around the bolt holes.

A motorbike frame is designed to flex and dissipate the stress's to designated areas so they can be absorbed to stop metal fatigue. A swing arm is one of the biggest anti stress components on a bike.

Cutting and changing the shape of the frame in any way is going to affect the way it works. Installing a hard-tail, removing the frame gussets, leaving out the top engine mount and installing solid handlebar risers and hard mounting foot-pegs changes the whole dynamics of where and how much the vibration is distributed to and the comfort of the rider, (common complaints of excessive vibration at reasonable speeds).

Without that normal flex in the frame and the removal of the engine mounts and frame gussets the normal stress points are not there any more and that could, (and as in some cases posted on here), will cause the frame to brake.

Rephrasing, (277) seems to solve the problem and make the bike comfortable by reducing the vibration.

The thing i am thinking is, the vibration is reduced with a rephrase but it is not removed completely and the vibration that is still there is more intense and at a higher frequency. An unmolested 277 rephrased XS650 will still cause enough vibration through the insulated handle-bars to create discomfort to the riders hands on a decent ride. With the change in the vibration pitch, what will the effects on these ridged and modified frames without gussets and engine mounts be. Will metal fatigue be a problem or especially these home welds, that will have poor penetration or edge undercutting problems, hold up.

I don't think it excessive vibration is caused by just making the frame lighter, usually the frame has been altered, Rear section cut off and altered or front gussets removed or racked or altered, top engine mount removed, i think this is the biggest percentage of the cause of excessive vibration to the striped down frame.

You cannot blame the design of the engine for problems when you re-engineer a frame or motor mounts.

Not criticizing Hugh or alfrado just looking at cause and affect and where the blame for excessive vibration is. Rephrasing could be masking a problem that is caused by something else

 

[Punkskalar]

Skull - I can agree to a point... But without a doubt, the Rephase is nice, even in a stock chassis. We just put one in several "Stock" bikes, and man they are a pleasure to ride...

 

[Scrambled]

I like Sonic's rubber mount idea . Rubber mounted Harleys have been around for a while ( since '82 I think ) best thing they ever came up with .

 

[650Skull]

Love hearing other guys are out riding these things hard! My first 650 chop is my daily driver. Put a few long trips on her in the last couple years, 600 miles in one day on that palm sander of a hard tail! I have a couple engines laying around and would like to do a re-phase. I'm sure they are worth every penny. I work in a custom machining, fabricating shop by day with a group of guys that are just as crazy about choppers as I am. I've been all over the country to custom bike shows and looked on this site a bit but have not seen anyone that has done a rubber mounted engine. I am in the beginning stages of another build and plan on building a single down tube frame with rubber isolators for engine mounts. Anyone else seen this? Might have missed it on here somewhere.

This was originally done by some british engineers and later Tony hall was building aftermarket Ascots till his demise. Read somewhere someone else had bought the franchise off tony's estate and was looking to see if a market was still out there.

link to my album with the info on the

 

[ProSimex]

I dont have a problem with my stripped the f down minimalist bike at speed. She just rips right along, although getting her much over 100mph has been an exercise in tuning (she does). I really really like the vibes at idle and the fear that she wouldn't hop around the lane at a light has kept me from a re-phase.

A bike without vibes feels unnatural, like its electric. My buddies old cm400 and my brothers ninja 600 were bad for that, like i was just floating along, not riding a bike.

 

[650Skull]

ProSimex, The sound of the rephrase offsets the lack of vibes, no way does it not feel like a real bike.

Agree it is not an XS650 feeling bike

 

[Scrambled]

I dont have a problem with my stripped the f down minimalist bike at speed. She just rips right along, although getting her much over 100mph has been an exercise in tuning (she does). I really really like the vibes at idle and the fear that she wouldn't hop around the lane at a light has kept me from a re-phase.

A bike without vibes feels unnatural, like its electric. My buddies old cm400 and my brothers ninja 600 were bad for that, like i was just floating along, not riding a bike.

I have ridden an old (1963) XLCH Sportster and a stock '78 Honda cb750 back to back , literally hoped off one and got on the other , it felt like the Honda wasn't even running .

 

[ProSimex]

the work of the devil I say! Seriously though I would need to ride a re-phase before i could drop the money.

Gooood Vibrations!

 

[retiredgentleman]

I think the minor vibrations my 360 degree engine has, is one of the main reasons I really like this bike. When my son starts up his CB600RR, I have to ask him if the engine is running. If I wanted a silky,smooth life, I would sit at home and watch TV.

 

[jetmechmarty]

As I said before, the 277 I rode vibrated plenty. The difference being the 277 vibrations decrease with increased RPM and the 360 vibrations increase with increased RPM.

Please note Hugh's comments that followed mine. He's the one with all the experience. My comment is based upon a 20 mi test ride.

 

[Phail]

I was told that I should fill my frame with bb's and silicon to help with the vibes. I think I'm going to do that soon as I get my frame back from surgery. Going to do my bars too.

I'm also planning on doing a 750 rephased 5th gear too. Just need money and time. LOL

 

[ProSimex]

jesus, do you want a 700lb bike?