Bandit project trike

[joeld0803]

I forgot to answer the weld question. I used a 220 MIG wire feed welder and all welds seem to be holding well so far.

It's made from mild DOM tube, a combination of .120 round and square tube , .080 round and square tube, and the main structural frame down the lower center (what I call the backbone) is .188 square tube.

I would have rather made it from Chrome molly but cost would have been alot more and then I would not have been able to weld it myself without buying a TIG. Since this is a first time prototype for me...........if it works out well I may sell this one and start over with better materials on the next one if there is a next one.

I started the project in April so not even one year in on it and I have a running design. If I had been building this at home it may have been done sooner. I have been soing this at work after hours and on weekends in my own time as time allowed.

The very low center of gravity doesn't allow much sway in the turns nor the wide front wheel base. Not sure if a front roll bar will be needed to be honest and twisting is minimal due to the fact that I am using pretty wide back tires on it and the back wheels are pretty close together. What I have noticed is that the chain tends to try to slip on take off as well as in the really sharp turns due to the positive trac rear axle. I built and put in a chain tensioner to help and it has but it still isn't perfect. I have plans to load it on trailer and bring it home in about a month and test drive it more in my neighborhood to really get a good idea of the handling. I live somewhat out in the country and there are some back roads here where I can take it and not worry about the PO PO so much until I get it licensed. I still worry about the licensing part due to the fact that I am using a 4 wheeler rear swing arm and axle on it.

I need to install a larger sprocket on the rear to lower my drive ratio a little more. I can get it rolling and moving and once moving shifting is no problem but the 1st gear ratio is a little too high for the weight difference still. I am running a 48 tooth currently and think I will need around a 52 tooth. I am thinking the top speed should get up to arount 115 mph if I wanted to go that fast which I do not. Right now if I had to guess it weighs around 1000 lbs give or take a 100 lbs.

[joeld0803]

I am currently only running off one of the fuel tanks. I am going to join them with a crossover line for maintaining balance on the level and they will each have fuel valves with lines and a T to deliver fuel to the carbs. I had the lock on the other tank modified to fit the bandit key so one key starts it and opens both locking fuel caps.

[Liteway]

Thanks for the reply. It sounds like you are only experiencing the normal amount of problems to be faced in the debugging process of making a "ground up" design work. Considering the short time you have been working on it, its commendable it already moves under its own power.

Keep up the good work.


Loyd.

[tryota]

Looks pretty heavy , but hey if it is rock solid thats what counts. My 3 wheeler is wayover built but hey It was my first one so I know what I can do to lighten it more and still be safe. TRYOTA.

[mtntech]

You have come a long way in a year. I wouldn't trust that rear axle however. Remember it was designed to be used with lightweight, very low (3-5 PSI) pressure tires. They cushion the axle from impacts, something your heavier, higher pressure wheels and tires won't. You are also asking it to bear more weight as well.

[fredvv44]

what if the rear axles were cut short so the wheels were right up against the diff.?
Fred V

[Liteway]

Just happen to think, if your chain is coming off in tight turns (high lateral loads), might not this be caused by the sprockets becoming misaligned as the swing arm twists?

Take off the tires and jack up the back from under one of the rear hubs and then check sprocket alignment. Put something/someone in the drivers seat to weight the chassis while checking.

[joeld0803]

To answer the statements.

The chain isn't coming off. It slips a tooth under harder acceleration is all. The sprocket alignment is dead on right now but originally I had play in the swingarm bushing that was causing it to go out of alignment. I resolved that with shimming to reduce side play movement in the bushing area.

The axle is from a Can am Ds 450 which is a motorcross design built to withstand jumping and landing hard from time to time while racing it. The shaft is Chrome molly and I ordered a billet aluminum double row bearing carrier for the axle as well which is a stronger upgraded bearing carrier and the dual rear bearings in the the housing are double row which makes them wider. It's an upgrade available for the DS 450 axles. I dont planning on jumping railroad tracks and I don't think there will be any issues as far as the strength goes but the whole project is a work in progress so I am not totally sure what will happen until I start getting some drive time on it.

I was considering shortening the axles down and tucking the wheels in as close as possible but the axle is both threaded on the ends as well as splined and haven't located any machine shops capable of rethreading and resplining and the shaft starts out thick but gets thinner to the outside so not sure if machining would even be possible. It could eventually make the metal weaker if messed with. The shaft is Hollow for weight removal and it seems to be very strong as I have been testing the suspension on it but under driving conditions will be the real test.

[Liteway]

Thanks for reply, sounds like you have given the design more thought than I would have imagined.

Also, thanks for the postings, this is an interesting and unusual build to follow.

[joeld0803]

Oh and by the way,
Happy New Year to all who visit this website.

There has been a vast amount of knowledge shared here and I appreciate it.

This project has been a ground up project without any plans or blue prints so alot of it has been trial and error and it has been a challenge but an interesting one. Considering my background mainly haveing been in gas and diesel engine repair all my life......to do something like this has been rewarding and teach me that anything is possible if we set our minds into doing it.

As someone commented on here before I ever started it.........."just start the project".
Alot of people want to do one but never get up the backbone to jump in and start it due to fear of never completing it or doing it wrond or whatever. At least I am trying and thanks for the encouragement.

I have actually also found out from the suspension issues that I have faced that the majority of the weight of this thing is up front on the front wheels. Not too much weight of it is riding on the axle to be honest.
Again time will tell if I have to go back to drawing board on the rear set up or not but I am hoping for decent results.

If something should happen while driving and the rear axle does get bent later down the line..........it is replaceable.. and repairable......LOL. No matter what..........something has got to give in the event of a misshap and that goes for everything built out there.

[mtntech]

Hats off to you for getting this far in your build. You are right that most ideas never see the light of day. As far as the chain issue, is the tension constant throughout the swingarm travel arc?

[joeld0803]

The tension appears to remain constant but I may need heavier springs on it. It may just be that the chain is binding occassionally and not neccessarily jumping. It's the original Bandit Chain and I had to cut it to install a master link in it. It has 30,000 miles on it too so it has some wear. The main issue is on take off from stop and only if I try to take off hard. If I accelerate reasonably and get it rolling smoothly it doesn't happen.

[joeld0803]

On take off the tires bite and cause the rear swing arm to travel downward reducing shock load and slacking the chain which is why I put the tensioner on it but I may need to reduce the amount of drop travel allowed on take off to minimize it by installing some sort of torsion limiter

[Liteway]

Been there on the jacking thing. Lowering the swing arm pivot point will reduce this affect, but of course you have to pay attention to how that effects chain tension as the rear sprocket moves through its arc. Not only does the jacking affect chain tension , it can unsettle the chassis when applying throttle coming out of a corner, and is quite annoying going through the gears.

[Liteway]

Just curious. Why is a chain tensioner necessary? These are usually seen on off-road stuff with 8" or more travel where the chain gets loose at extremes of swing arm travel because its difficult to engineer a way to make the counter sprocket and swing arm pivot concentric with one another. If you could , tension would stay constant throughout the range of motion. Ironically, the only place I have seen this accomplished successfully, was on my son's otherwise poorly made Chinese dune buggy. Must be other examples though.

Anyway my point is, if you have the swing-arm pivot located as close to the counter sprocket as it was with the motorcycle, with no large increase in suspension travel, you should not need a tensioner.

[DaveJ98092]

Joel, I for one would refresh that chain and drive gears when possible. 30K miles and lots of setting you could very well have a sticky link.

On your tensioner, I would mount it closer to the rear sprocket so as to make the chain climb up the bottom of the sprocket some, more teeth in contact.

The test would be to put some dots of "White Out" on a link and the front sprocket and then spin the link to the rear sprocket and dot it. Then make a hard run and see which sprocket it skipped on. You may need to spin the sprockets a few times to line the dots up but if it does not skip they will realign in a few rotations.

[Liteway]

Hello Dave.
In all likelyhood the slippage will be at the front because only about 1/3 as many teeth are engaged with the chain at any point in time. However , as you say, 30,000 miles on chain and sprocket and its time to replace them anyway and it might be enough to stop the slipping.

Its not going to help the jacking problem though.

Also he has a 2" square tube between the sprocket and the swing arm pivot, putting them too far apart. He may be able to work around this with a tensioner, but it doesn't go to the root of the problem.

[DaveJ98092]

My first thought would be that the front would slip first too.

Chains and sprockets are not cheap.

[mtntech]

Put a GoPro back there and take it for a spin. Then you'll know exactly what's going on.

[DaveJ98092]

+1 ^