That is the stem not the frame of the bike. That happens, forks break. We can play the what of game forever. I personally have never seen a engine rip off the bike, a frame crack completely I half ect. You still have 4 mounting points on the bike to the engine that will keep the bike in tact. What if a astroid hits the earth, what if Rosie O'donnel turns strait, what if a car blows a red light and gets yah. Just because it is there doesn't me it is a must. 1000's and 1000's of people do it with zero issues. Carry on with this lovely conversation.
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top engine bracket
- Thread starter cobrasneverdie
- Start date
Look this all would be fine if we were just arguing amongst ourselves and in the end the man that draws the short straw buys the next round .
However we have an audience that never gets any smaller .
So I will take a stand
This is complete and unconscionable , irresponsible behavior . Writing such unfounded and unsupported crap is nearly as bad as someone reading it and believing it to be true.
We have a responsibility to our own judgment and it's consequences to be sure but what is missing here is personal accountability for how our opinions affect others . Have a care . What we write here becomes the recorded history of who we are and what we do .
~kop
However we have an audience that never gets any smaller .
So I will take a stand
This is complete and unconscionable , irresponsible behavior . Writing such unfounded and unsupported crap is nearly as bad as someone reading it and believing it to be true.
We have a responsibility to our own judgment and it's consequences to be sure but what is missing here is personal accountability for how our opinions affect others . Have a care . What we write here becomes the recorded history of who we are and what we do .
~kop
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I could give a damn less what the OP does, what anyone does, but what I posted is 1000000% legit and is a fact. Tell me it isn't and that people don't? It has been done and it will continue to be done regardless of what anyone says. Again there is a thing called common sense. If you feel that you need to have it then by all means keep it in, if you feel like taking it out go for it. I get get sick of hearing people say it's there so it ends to be. That's just bullshit.
neanderthal
neanderthal
keep it....solid bike
hack it off.....bike may or may not have some issues
seems simple enough. im a neanderthal and i run mine. these stocker xs' do sure shake and shuffle a lot. its not a v twin.
hack it off.....bike may or may not have some issues
seems simple enough. im a neanderthal and i run mine. these stocker xs' do sure shake and shuffle a lot. its not a v twin.
Fine , now facts .
The two tabs that form rear mounting of the XS engine are notoriously weak and prone to cracking . I have yet to inspect a 30k + mile XS that has not had cracking in the rear engine mounting box . Under severe use as in club racing or simply aggressive riding on marginal pavement it will eventually result in breakdown of the rear mounting structure.
Add to this that one) I may have seen more high mileage XS's than any 5 members here or on any 5 forums save for possibly a handful of individuals . Two) my experience spans pre delivery and inspection of the 1972 models to this day . Three) I have yet to see rear engine mounting damage that was not accompanied by a loose or incorrectly installed top engine mount . four ) you think it shakes now ? Do a back to back comparison and tell me you can't tell the difference . Five) Oddly enough the only front engine mount damage I've seen was an obvious inferior factory weld coupled with a hard life and corrosion .
~kop
The two tabs that form rear mounting of the XS engine are notoriously weak and prone to cracking . I have yet to inspect a 30k + mile XS that has not had cracking in the rear engine mounting box . Under severe use as in club racing or simply aggressive riding on marginal pavement it will eventually result in breakdown of the rear mounting structure.
Add to this that one) I may have seen more high mileage XS's than any 5 members here or on any 5 forums save for possibly a handful of individuals . Two) my experience spans pre delivery and inspection of the 1972 models to this day . Three) I have yet to see rear engine mounting damage that was not accompanied by a loose or incorrectly installed top engine mount . four ) you think it shakes now ? Do a back to back comparison and tell me you can't tell the difference . Five) Oddly enough the only front engine mount damage I've seen was an obvious inferior factory weld coupled with a hard life and corrosion .
~kop
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Jeeter - Roger in 1975 was a good one, but not the only one I've seen. Lotta amateur stick-weld stuff in the local minor circuits entertained the crowds. Seen one snap off at the starting gate, embarasing...
Cobra - A prudent move would probably be: "If you are concerned and have to ask, don't do it."
Some folks are lucky and/or non-demanding and maintenance-minded and get away with it. Some know what they're doing, anticipate and accomodate. Some don't care, abuse the bike for awhile, then dump it on somebody else. Good example of risk management.
Based on KopCycle's report, sounds like engine mount soundness is another area of inspection during purchase and rebuild. Haven't seen any lower rear mount issues yet in this forum. Would love to see any pics and hints/telltale-signs...
Cobra - A prudent move would probably be: "If you are concerned and have to ask, don't do it."
Some folks are lucky and/or non-demanding and maintenance-minded and get away with it. Some know what they're doing, anticipate and accomodate. Some don't care, abuse the bike for awhile, then dump it on somebody else. Good example of risk management.
Based on KopCycle's report, sounds like engine mount soundness is another area of inspection during purchase and rebuild. Haven't seen any lower rear mount issues yet in this forum. Would love to see any pics and hints/telltale-signs...
Nope, it's motorcycling, just opinions and you will have to make your own choice.
My opinion? a top brace should be there, the factory brace is ugly and heavy.
Kop; broken rear engine mounts on an XS650? never seen one, haven't heard this before.. Haven't been specifically looking, but I'm probably in the top 5 or 10% when it comes to the number of XS650's that have passed through my shop. I've pulled at least 15 engines.
Can you describe the the breakage. and or show a picture? I'd like to start looking.
I will say the early bikes could get squirrely.
Liftedzuki
XS650 Addict
Removing it, probably a bad idea,.
Building a better looking top mount, nothing wrong with that!..
I'll be redoing mine next winter /teardown
Building a better looking top mount, nothing wrong with that!..
I'll be redoing mine next winter /teardown
Couple of shots of rear mounts early (71) and late (81ish)
No question, Yamaha was adding structure.............
No question, Yamaha was adding structure.............
Jeeter
XS650 Addict
and is also global, and full of brand new motorcyclists, let alone those that are just experienced enough to be a danger to themselves and others (such as the comments that TwoManyXS1Bs made about "stick welded front ends falling off on the starting line".). Yea, so I'm gonna go "mom" on ya here and say that "if everyone were jumping from a cliff would you as well?"
The problem is that so many people take what they read in forums as some sort of sacred wisdom. And when the logic of "everybody is doing it, so should I" is thrown around, then it becomes dangerously benign. See, as soon as someone that is reading this stuff decides that member so-n-so has integrity and practical wisdom (or is just someone that is saying exactly what the reader wants to hear, whether it be good or bad dope) they begin taking anything that particular member has to say very seriously. Even if that particular member that the reader has placed on a pedestal is wrong. Which brings me to ......
I could not agree more. We have a responsibility, and we must remember that we are NOT only speaking amongst ourselves, but that we have a global audience that has 24 hour per day access to every word we publish ..... for as long as this forum exists (and perhaps longer).
~Ahem~ ... well then. Ok, I'll play. Um, yea. There IS "such a thing as common sense" .. yup, I could not agree more. And we should show some of that common sense when we post. (touché! wink wink!)
The problem with "common sense" is that .. well .. it's neither. It's neither common, nor sensible. Another problem is that there are MANY MANY motorcycle enthusiasts/riders/owners/forum readers that do not possess that thing called "common sense". Am I right? You bet I am (that lack of sense in many riders, y'know there's one of those "facts" that seem to be so important in a thread that is based on opinions).
So anyhow, I feel the same as some members here, that we have a responsibility to those that are less experienced and yet take what us "experts" have to say very seriously. We need to respect that reverence that others pay upon us, and make sure we make it perfectly clear that what we're saying is our opinions. And that what we suggest as "good stuff" may not be good stuff for novice and or naïve riders.
If we're gonna throw around statements like "ten bazillion people do it every day, and will continue to do it for a long time to come" (wow, reminds me of the excuses my dad used to use regarding his choice to smoke cigarettes, right up until about a year before he died of smoking related diseases) we need to qualify what we're defending.
My unwillingness to go along with the non-use of the mount on the stock frame comes from my experience on both the racetrack and the street. The bike won't have any greater tendency to slide sideways on unexpected surfaces (sand or fluids on the road, let's say it's on a blind corner, your speed is roughly 60mph+) .. no no .. the slide is the easy part. It's when the rear tire re-hooks once you clear the sand/water/gasoline (hey, dumasses forget to put their gascaps on all the time, when they go around a corner gas sloshes out of the fill-hole onto the road .. very slick stuff when wet) the un-braced frame may have a greater tendency to load and unload, causing an increasingly violent "tank slapper" (more like bucking bronco) until it pitches the rider off, hopefully NOT into oncoming traffic.
The stock frame ridden without the upper bracket may cause a loading/unloading situation in a hypothetical episode as described above. What happens is the frame sortof "winds up" like a coil spring when the rear tire suddenly gains traction when the bike clears the slide. The frame will wind-up (aka "load"), and then it will need to un-wind (aka "unload") which can be a violent experience if the entire motorcycle does not properly disperse that pent-up "wound-up spring" energy slowly and in a manageable manner. The upper mount may be a part of an entire system that the engineers at Yamaha designed into the stock frame to disperse that pent-up energy (that wound up spring that every motorcycle turns into to various degrees) in a slower and more predictable way. Remove that bracket and you may have totally defeated that dispersion system that Yamaha felt was required when using their stock frame.
So, to the OP ..... take what you've read in your thread here, add it to whatever else you may have read. Make your choice. You've asked the membership for it's opinions on a topic that has no facts, so I guess you may have to take what has been said and make a choice on your own.
Yup, thousands of people may indeed have removed the upper mount without any problems they wish to report. But there are far far more thousands of people that have not removed the upper mount as well, all of whom have nothing negative to say about it's use. So, no help there using that logic!
Have fun, be careful. Do whatever you think is best for you. It doesn't seem that anyone here has anything super-conclusive or definitive one way or the other. It sounds like we have a lot of opinions here, but I've not read anything that fer sher fer sher says to go one way or the other. All we seem to have here is a collection of yay/nays based on experience. It sortof ends there.
Jeeter
XS650 Addict
Something for me to ask about here ..... does the stock XS frame use one of the engine mounts doubled as a swingarm pivot? Said another way, do any of the engine's mounts share a bolt with the swingarm pivot? If so, then the engine is most certainly a structural component and the mount should most certainly be left intact. However if the engine shares a bolt with the swingarm pivot, and the owner is converting his bike to a hardtail, does that not negate the need for the upper mount since the engine is no longer a structural piece that ties the headstock to the swingarm pivot (because there is no more swingarm pivot on a rigid frame). See what I am saying here? If all of that is correct, then those that convert their stock Yamaha XS650 frames to hardtails do not have the need to retain that upper engine mount since there's no more swingarm pivot that needs to be tied to the headstock. 
Gary the early frame shows hairline and spiderweb cracking on the frame tube side of the weld . Yamaha took notice of this and provided a back strap to support the original mount . Once the mounting itself had been strengthened then the downtube began separating from the crossmember . I leave the obvious fixes to the imagination of the individual .
~kop
~kop
Jeeter
XS650 Addict
Ugh ....I was making conversation with TwoManyX1Bs, it had nothing to do with this thread. I think I know the difference between a stem failure and something relevant to this thread. Perhaps I don't, fill me in if not, I'm always open to learning something new.
The Roger DeCoster story had nothing to do with this thread, it was simply Jeeter talking too much again and attempting to have a sub-conversation with someone else. My comments about the broken steering stem were a "oh, by the way, what you said about broken steering heads reminds me of the DeCoster get-off in '75". It had nothing to do with the OP's question of how well or poor the idea is of removing the stock Yamaha upper engine mounts from a stock Yamaha frame that's been modified into a hardtail.
I apologize for my indiscretion.
Are we good now? So, no more feelings of needing to give me a public dressing down because I said something OT? No more comparisons between my OT comment and useless celebrity quotes about "what if?" and meteors, the Illuminati, Rosie O'Donnel's sexual orientation, running red lights, or whatever? Great! Yay! That's super!C'mon dude, there's no need to go there man. Really. There's some folks around here that have a lifetime (over 50+ years) of experiences. They've shared their opinions, and if you do not agree I think your side of the story will be far better accepted by other readers if you tone down the shit-slinging. Speaking for myself, I know I would be more willing to listen to someone that is not trying to imply that I am stupid.
"Thousands and thousands of people do it with zero issues". Any kind of proof on that? Seriously curious, myself. Or is that just another matter of "well since I've never heard of it, it must not have ever happened"? Fair enough. I suppose if there are no footprints on a beach then no-one has ever walked on it either then?
I just think that we should not be passing off opinions as facts. We have FOX News and MSNBC for all of that we can eat!
There are some people that will decide to do this, and others that will decide not to. Both will present rationale to support their choices. You gotta make your own decision, and (hopefully) live with it. You can be cool and hip, or you can decide to go with a more conservative approach (y'know, like us frightened old men that have lost all of their spirit of adventure and have become afraid of the spice of life). Haahaa!
(that's called self mockery folks, not a jab at anyone here other than myself).
I have came to figure some folks on this site are on another level. As you stated, nobody has given a legit or factual reason to keep that mount or not to keep it. No reason for typing a essay to me about it with your explanation, I will keep my decision untill it is proven wrong other wise lol. Like I said its been done, will forever continue to be done. As for my what if's, exactly that, what if. I can and did go there, because it's always what if. Again no fact has been giving other then '' they put it there and it needs to be there'' I doubt any of us are going to be hitting the twisties at 100 mph on a hard tail. For you guys that have rode for 50 years, I am happy for you that you have and are able to have done so and stayed safe over the years 
. But please don't play me for a fool. People will do what they want and are free to choose. Now if were talking a Big TWin HD that weights 700 lbs then yeh it might be a good idea to keep them for structural reason. Not on these stripped down 280 lb machines.
. But please don't play me for a fool. People will do what they want and are free to choose. Now if were talking a Big TWin HD that weights 700 lbs then yeh it might be a good idea to keep them for structural reason. Not on these stripped down 280 lb machines.Attachments
The swing arm bolts through the two sides of the frame. If you look at pics of the frame you can see this.
The engine mounts all hook from the engine to the frame. No shared bolts.
Removing the top mount lets the neck of the frame flex more under extreme situations.
It stops the top of the engine from moving front to back as the engine vibrates. With out the mount the top of the engine moves more, this puts more strain on the rest of the mounts. This movement tends to loosen the bolts on the remaining mounts. This increases the strain on the rest of the mounts.
As others have mentioned the rear mount bolt and the upper rear mount bolt areas of the case are a bit weak. This extra movement stress this mounts enough so the cases can crack around these mounts.
The very bottom bolt is in a strong spot on the lower case. The front mount is in a strong place in the upper case.
I doubt this info will change anyone's ideas on what is safe.
One thing you can do is to ride the bike very hard on a twisty road, with all the mounts and the front fender installed.
Now remove one item do the same ride again. Put the item back on and remove the other, ride. Now try it with both items removed.
This may let you know if they make a difference.
I found the front fender that has the heavy bracing underneath helps a lot. Never tried removing the top mount.
Do the testing and see how things are effected.
Leo
The engine mounts all hook from the engine to the frame. No shared bolts.
Removing the top mount lets the neck of the frame flex more under extreme situations.
It stops the top of the engine from moving front to back as the engine vibrates. With out the mount the top of the engine moves more, this puts more strain on the rest of the mounts. This movement tends to loosen the bolts on the remaining mounts. This increases the strain on the rest of the mounts.
As others have mentioned the rear mount bolt and the upper rear mount bolt areas of the case are a bit weak. This extra movement stress this mounts enough so the cases can crack around these mounts.
The very bottom bolt is in a strong spot on the lower case. The front mount is in a strong place in the upper case.
I doubt this info will change anyone's ideas on what is safe.
One thing you can do is to ride the bike very hard on a twisty road, with all the mounts and the front fender installed.
Now remove one item do the same ride again. Put the item back on and remove the other, ride. Now try it with both items removed.
This may let you know if they make a difference.
I found the front fender that has the heavy bracing underneath helps a lot. Never tried removing the top mount.
Do the testing and see how things are effected.
Leo
Fndirtygreaser
XS650 Addict
This is what I see.....
SOME. NOT ALL. ... People that run a top mount or have an opinion as to "yes run a top mount", come off as anything else is wrong or unsafe. Seems as though you guys are intimidating or coursing people(possibly noobs) to run a top mount. Won't go into specifics since I don't want to step on any toes but you give off the vibe that the bike will somehow fail and ultimately crash or worse. If the OP stated he was going to race his bike I don't think anyone would advise him not to run a top mount. Since probably 99% who don't run a top mount don't race their bikes either.
Everyone is entitled to their opinion. And as such should state it and share your experience either running with top mount or without. But once you start saying negetive things about the opposite view of your opinion with no facts to back them up or start to throw out backhanded comments.... Well that's when guys need to realize that some people will get offended and start to get upset.
SOME. NOT ALL. ... People that run a top mount or have an opinion as to "yes run a top mount", come off as anything else is wrong or unsafe. Seems as though you guys are intimidating or coursing people(possibly noobs) to run a top mount. Won't go into specifics since I don't want to step on any toes but you give off the vibe that the bike will somehow fail and ultimately crash or worse. If the OP stated he was going to race his bike I don't think anyone would advise him not to run a top mount. Since probably 99% who don't run a top mount don't race their bikes either.
Everyone is entitled to their opinion. And as such should state it and share your experience either running with top mount or without. But once you start saying negetive things about the opposite view of your opinion with no facts to back them up or start to throw out backhanded comments.... Well that's when guys need to realize that some people will get offended and start to get upset.
neanderthal
neanderthal
it tak no dum dum to reelize the motar shake reel hard.KEEP THE FUCKING MOUNT and worry not OR redesign it as suggested a few times OR remove it and if it brakes then shitty for you, all that hard work and now a you cant ride and you have to tear it apart and re-paint it while all your buddies are out having a blast. if you doing something do it right the first time. Listen to the guru's they've been around. this doesnt fire or counter-balance as a v-twin does guys. this is a different beast. this bike on smooth concrete and a center stand can float across the floor. As far as the rear mount, ive never ever heard of that thing going out. I too would love to see some photos if they are floating around.
Okay some backround for the uninitiated . first the 360 degree crank
Then the 277/83 crank (re-phased)
in comparison the 360 Degree crank jumps up and down pretty good doesn't it ?
This is why all the mounting points take a beating and the loads should be shared/distributed across all of them .
Additional note to the previous posts . Sorry I didn't think to photo the cracks and breaks at the time I just fixed them . Then again the digital image art wasn't as cheap or refined then either . I can add that a sure recipe for mount breakage was a loose top and front mount . Then the engine pivots or cycles about the bottom mount and mayhem ensues ...
And a hearty thanks to the xs 650 club of Australia for the info as it was lifted directly from their site
http://www.xs650.org.au/tech.html
a great resource and I highly recommend you all visit and contribute .
~kop
Then the 277/83 crank (re-phased)
in comparison the 360 Degree crank jumps up and down pretty good doesn't it ?
This is why all the mounting points take a beating and the loads should be shared/distributed across all of them .
Additional note to the previous posts . Sorry I didn't think to photo the cracks and breaks at the time I just fixed them . Then again the digital image art wasn't as cheap or refined then either . I can add that a sure recipe for mount breakage was a loose top and front mount . Then the engine pivots or cycles about the bottom mount and mayhem ensues ...
And a hearty thanks to the xs 650 club of Australia for the info as it was lifted directly from their site
http://www.xs650.org.au/tech.html
a great resource and I highly recommend you all visit and contribute .
~kop
Well, here's my other XS1B's lower rear frame mount, the early weaker style. Please excuse the 31 year-old mini-flake lacquer, gets in the way. There IS a horizontal line coming from the front of the right tab. I recall regarding it as a paint blemish, but may scrape that area later for closer examination...
Attachments
Fndirtygreaser
XS650 Addict
Hey Jake. We all know this xs650 likes to dance. Mines likes to do the stanky leg while on kickstand. Lol But I have no top mount at the moment. I ride my bike daily and try to attend as many shows, swaps , or Sunday rides as I can. I have around 4k miles from about last year till today. Plus god knows how many from the previous owner I got the frame/project from. So I'm definitely out riding and enjoying my bike while unfortunately most are not. Now I did purchase a top mount since the vibrations on the fwy were driving me nuts. And to be honest I didn't really feel any difference. The stock mounts are ugly and bulky. It was messing with my throttle cable. So I decided to take them out. A guy I know made a slim clean mount and asked him to make me one. So when he had time. Or I find another one I like I will probably run one. But until then I ride !! This weekend to the Hippy killer hoedown !! Week after that roll to " Ride above Los Angeles" ride.
