I should think that they would be easy enough to have turned from Oilite bronze stock by any high school machine shop student for the price of a pizza. I have wondered about using needle roller bearing myself. IIRC Suzuki's GS (ca. 1978) was the first mass produced street bike to have needle rollers in the swinging arm. Oh what a superb machine.
IMHO Mcmaster Carr is a top notch company to deal with.
Can anybody confirm if the bronze bush will need grease for lubrication and if yes, how can that be done? Is it by putting a nipple grease feed on the shaft bolt?
Of COURSE the bush will need lubrication! gun-drilling the shaft bolt - and knurling it for grease distribution would be a good thing - but you COULD add a couple of grease fittings to the pivot lugs on the swing arm as well and keep the bolt solid.
Scooterbob has it wright, I'm planing on doing the latter, If I can get some internally groved bushings.
I'm guessing that you'd want to braze weld a couple of lugs on the swingarm to have something to screw your grease fittings into ..... you COULD even get uber clever and plumb them together and make one easy-to-reach fitting ...... Hmmmmmm .......
That's what I was thinking, groove the bushing, drill and tap it for the greas fitting, drill a hole to fit it, and have the bushing and grease fitting screw together and 'sandwich' the steel of the swingarm.On a less intensive path, couldn't you just make urethane bushing instead of bronze? Gotta be easier to shape and less play but not none, doesn't transmit all the stress to the swingarm. Of course, they need to be lubed too or they stick and squeak. Rubber is more forgiving.Scott
My estimation would be that if they are plastic, they are already something like polyurethane, and I doubt that any real improvement would be found with bronze.It might just be best to leave them as they are.
Molybdenum disulphide filled Nylon 6/6 http://www.mcmaster.com/#nylon/=7sqjejor 6/12 http://www.mcmaster.com/#nylon/=7sqlfu
Any other way of reducing side ways or X movement of swing arm?
Tom , I recently sorted a 55 frame out for another british bullatier (dan ford), the frame was old and the paint was tired after having it chemicly cleaned , you can see all the braizing on it?I then got it proffesdsionally painted for himthe earlier UK bikes used a bronze bush settup at the back with pleanty of grease nipples , I replaced the shaft as it was a bit "dull" , what a nice setup!enfield thought proper in those days , the outer large nuts were made in such a way that a screw was placed in the frame and locked the nuts , the quality of the frame inc the headstock , made the indian frame look like a "photocopy" read from a distance ,,,
OK, the swing arm is out, pretty simple affair as you could imagine. The flex in the swing arm becomes apparent as soon as you remove the axle nut.It's a simple Japanese arch type design,without any reinforcement. The swing arm springs open about 3-4 mm.The bushings are made of a white plastic material. The exposed ends of which,on either side appear to have been reamed with hamster teeth, where the spacer slides through. The spacer has no movement, the swing arm pivots on the pivot bolt inside the spacer, metal to metal, bone dry. There is a .5-1.0 mm 's worth of slop inside the spacer/pivot bolt. Yikes!!! No wonder my high speed highway jaunts are a scary affair. It's like a Ducks ass after he gets out of the pond. . Time for a redesign Boys?
look back in history , (as posted above) when enfield (great britain) made proper frames , rather than "photocopied" frames?look at the old phosper bronze settup , seemed to work for over 50 yrs?
glad to see your making progress.Like I said in the PM its not the front end.In 1971 Yamaha Introduced the Poly Urathane Bushes on the RD in 1972 people had shifted to Bronze bushings. We have been making and exporting these for over a decade.Fixing the bronze swing arm bushings or the rollers I mentioned is a band aid fix at best.Its not going to cure your stability issues. Instead of becoming unsafe at 100 kmph it now do it at 105 kmph.For that your going to need a new swing arm.Since you have it off.Can you post the measurements i.e. how wide is the head stock.I can then see what other more modern bikes we have here which have better swing arms can be bolted on.Most of the other bikes here are mopeds i.e. 100-150 cc but they have better build swing arms. Which hold up even on 50 HP RDs.
Well, the swing arm on the UCE bikes is longer than the older Bullets.Perhaps that's an issue.If there's room for some gusseting or bracing, that might help.I know that on the older Bullets, they are stable at over 100mph, even with rubber bushes in there. And they can carve a turn quite well, too.Maybe the longer arm is showing some flex?
I haven't worn the original tires out yet, when I replace the front I'll try a 3.00 or 3.25 they should be nearly as tall as a 19, I'll keep the low profile rear because I'm short. But to be honest my bike handles fine I just don't care for low profile front tires. I'm looking at the pirelli MT66 3.00x18 for the front.
Stability on a bike should increase with straight line speed, unless the geometry is way off, or there is another factor upsetting the straightness if you will. I don't think the geometry is that far off.
The geometry doesn't need to be off, just inadequate for the speed. Long trail, better high speed, short trail, easier flickability into turns. All the REs are short trail bikes. This is also the reason choppers got long forks. The increased trail was much better for straight line stability at high speeds.You would be surprised how little of a difference you need to make to notice. It's common for some sport bikes to move the fork tubes up in the triple clamps a little bit. 1/4" can make a bike amazingly better at turning, sometimes even dangerously so since high speed stability suffers.All that said, changing tires is a much cheaper way to go about things. Again, tire sizes and profiles can make a huge difference. And as mentioned, tires are cheaper than wheel swaps.Again, I don't think you should necessarily stop moving forward with the bushings, just putting these options in too.Scott
The weights? I dunno. The tire itself already weighs much more and is further out on the rim than weights would be providing for higher angular momentum. And you think your problem is at the rear. Will it really matter? I've also never seen anyone make a motorcycle wheel heavier for better performance or handling.All the other stuff sounds really good.Scott
Certainly worth trying, but if I recall correctly, weight contributes to angular momentum and the gyroscopic vector in proportion to the square of it's distance from the center of rotation. So just buying a heavier style of tire would be way more effective than weights since the outer heavy skin of the tire weighs more and is further from the center. Also, making wheels lighter is generally done because while it takes a linear amount of force to accelerate the chassis in a straight line, accelerating the wheels in rotation up to the same speed takes roughly 4 times the amount of energy. I think there's another formula with a squared factor in it but I don't recall if offhand. Also, the gyroscopic force created by a wheel makes the force required to turn the bars grow exponentially with speed. You can use the mildest counter steering inputs to great effect at slow speeds but racers really need to work to turn a bike that's moving at 150-200mph.There have really been vast improvments in the understanding of how and why a motorcycles handle the way they do in the last 20 years. Fork rake, wheel weight, wheel diameter, and so many other things play a part but trail is really one of the strongest factors. In fact a bicycle or motorcyle stays upright on it's own mostly because of trail, not gyroscopics. I believe there was an experimental rig built with counter rotating gyros to cancel the gryo force of the wheels, still totally ridable because of trail. Without cutting and rewelding the frame or making big fork mods it's hard to modify trail. The easiest thing to do is change tires or suspension heights which may have a smaller effect but still has some.All that said, there are things to keep in mind. Physics is often non-intuitve. This is a theoretical discussion of a single element that may or may not be the cause of a real motor bike that is a complex collection of moving systems. Sometimes something that makes no sense in theory fixes a problem. You could probably get to the root of why but it's often not worth figuring out.Wow! And you thought it was deep before!As you said, a few dollars to see what happens. I just have an ingrained need to know why. Ignore me at your leisure Scott
WOW !!!!!! HEAVEY!!!!, I think from now on it's ProfessorScotty. LOL.
I second the motion All in favor say aye All kidding aside, my sincerest thanks for providing more useful education in that one post than four years of high school science class.
Not that we are not interested in what you are doing, and want you to document every detail, leaving no stone unturned in your quest for improvements, ...but...Look at which picture has had the most hits!
If I remember correctly, the swing-arms from the Enfield twins like the Interceptor had braces like that in them.It looks like you did a nice job.Love the Incredible Hulk holding the swing-arm!For what it's worth, I'm getting some spidey sense tingling that is making me think that you are getting drag-induced lift of the front suspension, making the bike light in the front at speed.Try leaning forward a bit, and see if you can reduce the "parachute effect" of your body against the wind, and see if that helps the stability some. Maybe you need lower bars.
I think pilot weight has a lot to do with it. I agree with r80rt, mine seems ok, but I do not exceed 65 to 70 either, prefer a 45 -50 mph back road to the highway. the Enfield handles those roads far better than the Road King. I am 5"11 at 195 dressed in riding gear.I have never been a high speed rider so I really would not be able to recognize the symptoms that gashousegorilla experienced. But I am glad he broke from the pack and sorted it out for the rest of us. That is how innovation works.-Quinn
I still don't understand it, my C5 handles very well. I think the size of the rider has something to do with it, I'm 5'5" and weigh 175lbs with short legs. I sit a bit farther forward than most folks and I'm not tall enough to catch a lot of wind, it's feels a bit light over 70 but I almost never run over 60-65mph, it's very stable on the twisty roads around here and a ton of fun to ride. Or is this just a goofy theory?
I am late to this discussion but i hope this link helps. The author discusses a few options to brace swing arms which look like useful alternatives to others who want to give this a shot.http://victorylibrary.com/brit/chassis-2a.htmThat swing arm looks like a poor cousin of a torsion-beam axle and though i am no engineer, i am surprised (and not pleasantly either) to see such a design. As Chinoy said, there are motorcycles in India running what would to you folks be lawn-mower engines with better designed swing arms. Dan sir, great work with the brace! I am sure a lot of people will follow your path. I would humbly suggest flat sheets on top and bottom to form a box shape to reduce the possible deflection further. You could cut a circular hole in the middle of these sheets to reduce weight while keeping the stiffness. The only fly in the ointment i see is if something attaches to the small blob(??) between the swing arm pivot and your brace.I had one question. When the swing arm goes back on the engine, how would one ensure that the rear wheel is along the same vertical axis as the front wheel? I have seen C5s with rear wheels canted over to the left (as seen from the rear) when in motion.
Going by the manual when putting the swing arm back in, its should be aligned with two ruler like metal strips bolted on the top and bottom shock absorber.The reason you see the bad angle at the rear is mostly due to the chain adjuster splines not the same no on either side.
The blob as you so kindly put it , again was explained earlier in this thread. I don't see it as an issue unless you were to ride on mirrored roads .
Or maybe you were reffering to my fat little friend? Thanks ,Dan.
I did not mean the brace itself. Between the attach point of the brace on one of the arms of the swing arm, and the bar which also forms the pivot, there seems to be an attach point (The blob). I suspect the brake stabilizer rod attaches there? hehehe
Dan, I suspect their jigs and final products all have a little play. I was just wondering how much. I have a friend of a friend who's a welder and a couple of frame shops in town, I'm sure someone can do it.Also, yeah, just butted up and welded? While it's in the welder's hands I'd have him put some gussets on the joints at the pivot tube. Of course then I'd have to get the bushings out first....Scott
Can we change the name of this thread to 'Gorilla Swingarm Mod avec le 19"wheel'?And how does it ride with the 19" tire and 18" wheel? Scott