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Discussion in 'Some Assembly Required' started by sailah, Nov 9, 2012.
Sounds like you need another project
I have one Street tracker
<table border="0" cellpadding="4" cellspacing="0" width="100%"><tbody><tr><td class="alt2" style="border:1px inset"> Originally Posted by mousitsas
My guess is that you miss the fact that a 650cc twin places the same impact forces as a 300cc single, the 650 just has two of them (but not simultaneously).
"I didn't miss it, I just don't think it reflects the reality of how I ride. I can ride a big bike smooth, as easy as a smaller bike. Maybe if I were riding normally but I tend to launch hard on pavement and without some cushion in the driveline, that power gets transmitted to the wheels abruptly. whether it's 300cc or 1000cc, that torque gets delivered to a wheel without any cushioning to speak of other than slack in the chain and the knobs distorting.
Maybe I don't know what I am talking about, but it appears obvious that whacking the throttle hard on a bike that weighs close to 400# with a rider that weighs 230# and with more hp and torque, that driveline forces would be elevated. Pulses from the less lumpy motor I can see being smoothed out in just normal riding. I don't think the normal riding is what is destroying the hub. I think it's the wheelies and hard acceleration on a hub that was never designed for that kind of power, not to mention the longer sprocket bolts that are cantilevered out further due to the 1/4" spacer for chain alignment.
I'm not saying you are wrong, it's just hard to wrap my little brain around your argument, that's all."
I'm about halfway between you on the thump vs twin. I would say the twin has about 65-75 % of the load of the same size single. The twin usually has little torque in the low RPM range where the single effect is worse.
I think the drive train snatch has a BIG load factor in drive train failures.
As to the 1/4 offset sprocket, the tighter the bolts, the less bending. locktite between the surfaces would help if the load doesn't break them apart.
yeah I cranked the bolts down, used loctite and new flanged nylocks. I will be keeping a very close eye on them.
I've got 1700 miles on my 3/4" spacer & bolts, no worries, no issues
You think in terms of torque, rater than in terms of a hammering action the drive train sees every time there is explosion in the cylinder. It is this hammering destroying rear hubs, not torque. So, despite of how you ride your bike, the hammering is that of each one of your pistons.
Sorry, not buying that argument. My hub is on its way out and has been on the bike 1200 miles. Hardly enough time for the metal to have fatigued. I understand the argument you are making, I just don't agree.
If your argument were true, we wouldn't be having this discussion. My sprocket bolts wallowing out the hubs were caused by me riding like a jagoff and doing wheelies. Which is a function of torque applied very quickly. There is enough give in the chain to smooth out the pulses of the motor. There is not enough give to smooth out a hard whack of the throttle, which is why the front end comes up.
One key to making spacers and bolts live nicely together on sprockets is to have the hole in the spacer a butt-hole tight fit on the bolt.
If the holes are oversize, that allows room for the bolts to tip/lever against the hub, causing the wallered-out threaded holes.
You should basically need to drive the bolts through the spacer with a mallet.
You could salvage the hub by using Time-Sert threaded inserts. Basically like a helicoil, but it's a solid insert that is a bit bigger & stronger. Use the mill and open the holes up with the bolt circle function on the DRO... don't just drill them out by hand or they will come out crooked.
This could be true if it was a motor using NITRO METHANOL fuel.
nah, in your case, too much ouzo = hammered...
Ok I will be even more brief, since too many words confuse.
Impact forces cause metal fatigue and aluminum being very brittle, is particularly susceptible to this.
What breaks after you hammer that throttle has been first severely fatigued by lack of a cushion medium. Otherwise why cush drives exist? For the torque alone? No. An electric motor with 10 times the power and torque wouldn't ever need one.
Lattice structure and all that.
Got the bike back on my sweet new lift table. Let me just pause here for a minute. Up until now I did all my work clambering around on some cold ass floor and contorting in all sorts of directions. No more. This is the mack daddy of all lift tables. It's 36x72, full hydraulic, weighs 700# and can lift 2500 lbs. Made by Southworth, they come up for sale often at industrial auctions. I scored mine for $300 and put another $100 into it with a nice old skool crane up/down pendant and various rewiring etc to my 3 phase.
Anywho, trying to tackle some lingering projects from last year and refine the idea of the ninja a bit more.
Got started on the chain tensioner assembly. My bike has a wicked chain droop at full extension and I need to at least keep it to a minimum.
I designed out the arm and cut it on the waterjet today. Put it in the lathe in the 4 jaw and bored it to fit the 6200 bearing.
Bearing is a very snug slip fit. I should have left a little in there. I'll use bearing retainer and it should be good.
Here's the shot looking up under the bike. The pivot will have a shoulder bolt which I'm waiting on. The roller I made from a piece of Teflon I had laying around. I bored it out for 2 bearings and it rolls nicely.
The idea is to attach a spring to the other side of the arm and it will pull tension on the chain. I spent a lot of time with the bike up and down, figuring out where it was at rider sag, where the chain was at full droop. I think I have a good enough compromise to keep things cool. I'll weld the boss to the frame and figure out where to attach the spring and also how to stop the slider from going up past a certain spot. I got a 20lb/in spring as my best lever arm calculation could give me. We'll see how it works.
I also checked my sag I had been running last year I was WAY too light. Static sag was in the 80mm range with race sag at 170mm as I had the shock. I took measurements of the preload and started cranking it in. I ended up with quite a bit of preload measured from the shock body to the collar with calipers. But with that I got 40mm static, and 125 race. Now I can get the suspension worked on and hopefully dial it back to where I had it.
Other plans are to remake the side stand from steel this time. My aluminum was a failure because I welded it and lost the strength. I trust steel more and with some decent DOM shouldn't weigh much more
I also want to start working on the rally fairing, projector headlights etc. I'll see how the winter goes.
I also got a new set of cush drive wheels, they are coming tomorrow can't wait.
nice to see you going on. I was a bit afraid that you had given up the build. Although that doesn't seem to fit into your vocabulary ...
Kind regards, Bambi
Awesome, this has always been my favorite dirt ninja build, I'm glad to see you're going to continue on with it
Sent from my XT320 using Tapatalk 2
Thanks guys. I rode it all last year so I surely did not give up. This winter is refining the things that didn't work so well and a couple additions.
I'm mostly concerned with getting the suspension all done and fixing one hose with the fuel system that prevented the upper tank from draining.
I would like to get the fairing done but since the bike can't compete in the alcan, I'll table that until I have time.
I might replace the stock gauges with the trailtech vapor I have, we'll see if I can make that work.
Got some good work done on the Ninja. I've been working on getting the chain slack issue resolved for this year. I had a EE chain guard from an old bike but since teh sprocket is spaced over on the bike it wouldn't work as built. I machined up some UHMW plastic to space out the guard. Then I tapped the rear bolt hole for M10. I had to cut a bolt down on the lathe to fit that hole and it needed to be exact as about 1mm from that hole is the spinning sprocket.
Then I finished up the chain tensioner I have been working on. At least this version of it, I suspect I will need to get a lighter spring but it seems to work great. The roller is Teflon on double bearings. I tapped and welded a boss to the frame for it to pivot on. I welded a little tang for the spring to grab. And the final part that is a work in progress is an upper limit stop. I don't want the tensioner working on the chain when the bike is just cruising with normal load, just when it is drooping. I have a aluminum machined part that I can remake if needed that limits the travel of the tensioner. If I decide it needs to be different I'll just turn it smaller or make another.
I'm finalizing the suspension sag numbers and plan to send everything out to Alex at Konflict for his special work. We talked about lowering the bike an inch or so and a full revalve. Should be pretty turbo when done.
I also scored some new wheels. I now have a Cush drive rear 18 and a really nice 21" talon for my dirt wheels.
I also bought new excels in 17&19" and will lace them to a Cush drive hub as well and the same talon front hub. I will seal this set for my road wheels and run some street oriented rubber.
Lots of good work going on. Next project are some pannier racks for my wolfman expo bags. Not sure if I will get to the front fairing before the season starts, we'll see.
Then I designed, built, welded and powdercoated (black chrome) a wheel truing and balancing stand. I plan to drill holes in my table to bolt to but I still can't bring myself to do it. The stand works awesome.
I like the indicator pad on your balancing/truing stand. Nice touch.
I made my balancing stand out of an old swingarm and some left-over aluminum tube from a railing job.
Regarding your tensioner, it looks as if the pivot bolt head is perilously close to having contact with the chain. Perhaps moving the pivot location downward would help.
Also, a really nice mechanism for an adjustable stop is a simple disk with an off-center hole in it. Locate your top-most position and rotate the eccentric into contact and lock down the mounting bolt. Dun.
Regarding mounting the balancing stand... you could make some low-profile channels which the balancer feet slip into - basically "z-bent" sheet - which would provide some adjustable width as well.
Been racking my widdle brain to come up with a good pannier attachment system that doesn't look completely ghetto, is light, hugs the frame of the bike, easily removable in the field using regular bike tools, and strong enough to take a hit.
I decided to make some frame mounts that would just poke through the side panels. They would also act like sliders in the case I wanted to screw in some Delrin blocks. I started off with 1" 0.065" DOM tubing. Coped them using my coping attachment I made for my lathe, which works so well I should patent it. No chatter, easily adjusted, no drama, uses power feed from the lathe, awesome. Then I machined some threaded inserts for an M10 bolt and welded them in the tubes. I attached the tube to the bike in a strategic location where the side plastic bulges out and welded them in after measuring, squaring etc.
Here's the notcher for the lathe. These pics were when I first made it. The notches I did for the Ninja were easy 90 degrees. But you get awesome fit up with no gaps anywhere.
Here is the front one with the plastic on
I made these hoops a few years ago. They are 1.05" 5083 aluminum tubing. Pretty darn light. I haven't worked out exactly how they are going to attach but something like this.
I need to work on the back "studs". I suspect I will also make them just protrude from the plastic and then attach arms to the hoop.
The back studs are so short I decided to just machine it out of a 1" rod. I drilled and tapped it just like the front and then bored out a bunch so the wall thickness was close to the front. Here's what a notched tube looks like off my super notcher. I welded the rear bosses to the frame. I made them from leaded steel as it machines so nicely. Doesn't like to weld very well though.
I drilled out the hoop to fit the bung I made. I will weld this bung in and it should be plenty strong.
The back will require a longer tube. It was either that or weld on some arm to meet it. I think doing it just like the front is the best way. I'll have to see if I have aluminum rod that long or I'll make up some caps for the tubing.
Here's how it's hanging.
Once I get it all welded up I will see how strong it is. I will plan a brace across the back above the license plate. That should be plenty. The aluminum is fairly soft and it can get bent back should it crunch.
I'm also planning a rear plate rack to bolt a rotopax. Not sure how that will get attached.