Kickin BSR ideas around.....

[AirJunky]

Hey guys,
Been browsing thru the site for a few days now & have some ideas about building a BSR for myself. I have seen some things I like & others I don't think will work for me. I thought I'd write a few ideas down & see what the more experienced builders thought. Please feel free to comment as you see fit. :thumb:

First of all some things that I don't think will work in my situation.... the lowered BSRs with racing slicks are probably not going to do terribly well around here. We live in a shared waterfront community & keep a wake boat a few blocks from the house. The neighborhood owns a 300' beachfront property & a 14 acre greenbelt. So while there is plenty of pavement, theres also some off-roadin to do too. And it seems like a shorter barstool would be better with the lower CG.

We have a Harbor Freight nearby, and I happen to have one of their flux welders & a stick welder. I don't know how to use either very well yet so this project is going to be fun. I found this frame on Ebay (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250562503053) & like how the cut down seat allows me to set it up a bit lower, and still use a "real" barstool. The guy's price is pretty good, but I kinda like the idea of building it myself. So I'm thinking about applying the seat uprights to the Classic Cruiser plans Mike sells here.

http://i144.photobucket.com/albums/r169/AirJunky/Barstool%20racers/frame.jpg

Last night I ran across Outlawracing.net..... and specifically their "Sandstool (http://www.outlawracing.net/gallery-sand.php)" with the ATV rims & tires.... WOW, that thing is cool! Maybe a bit extreme, but would get around off-road really good!

http://i144.photobucket.com/albums/r169/AirJunky/Barstool%20racers/sand20.jpg

Recently I lifted a golf cart & installed new rims & tires on it. I'm about finished with it now and still have the golf cart rims & tires. I thought they would look cool on a BSR..... just a notch down from the SandStool. But I wondered about things like the final drive ratio & the strength of the rear axle & front spindles. If I plan on running a 6.5 hp HF clone engine on a modified Classic Cruiser chassis, should I upgrade the chassis, spindles & rear axle a bit too? And what sprockets should I run so I don't lose a lot of torque running 18" diameter tires?

EDIT: Also, I'm pretty sold on the idea of using mt bike handle bars. Any thoughts about using a twist throttle vs a thumb throttle like on a sled or ATV? Specifically I'm wondering which has better control while doing wheelies? I've riden bikes & quads quite a bit & am thinkin I'd rather use the thumb throttle.
Love to hear your thoughts on the whole thing. And have a great weekend! :cheers:

[AirJunky]

Come on guys. Don't everyone all at once.

So what clutch options are out there now days? With Comet & the TAV2 out, is there another way of getting the power from the engine to the axle?

[KiwiMike]

I would build one from scratch as there is a better sense of achievement when you get it finished.
As far as welding is concerned, just get a couple of scrap steel plates out and teach yourself, as practice makes perfect.
You could enroll in a local polytechnic welding class too and refine the craft. It isn't that hard, if you can draw a straight line on a piece of paper then you can weld.
There are some great posts on this site about welding and some good reference links.
The other alternative is tack weld it all together and take it to someone who knows how to weld making sure all the areas to be welded are cleaned up, as Mig (Metal Inert Gas) welders do not like rust. I really suggest this option as you don't want it falling apart at 35mph.
Now the design part. It sounds like you want to take this thing offroad. I would not suggest too much off roading on a barstool. I'm an old fella and my arse and spine isn't what it used to be.
Suspension and all the headaches that come with the design and set up of such a toy would take too long to build.
Stick with the occasional dirt road and asphalt.
There is a guy on this site who is making one out of an old four wheeler if you want to go that route.
As for the toy, with big wheels, looks good but it would be a slug with a 6.5 hp engine try to drive those big wheels.

[AirJunky]

Thanks Mike. I wondered about the loss of torque due to the big tires. But some of them seem to have more than enough to spare. I've been reading some more about that Comet TAV2 & it sounds like they are gearing it down a bit to get more torque.

Thanks for the tips too. I ran across the frame on Ebay & like the seat riser design (allowing me to run a shorter stool). I have a buddy from work who says he can help with the welding. So I'm thinking of using Mike Bean's design with the seat riders. I've emailed him a couple times & have not gotten any response yet. In fact, it doesn't look like he's been on the site in like 3 weeks.

[tech9]

Have you ever seen that monster with the big wheels run? It's got a Briggs formula engine which puts out about 15 HP.That thing accelerates like an off road motor bike.Just can't seem to find the video anymore .even the video on their site is not playing .

[AirJunky]

The video works fine for me. Click the Download link or here the WMV file (http://www.outlawracing.net/video/sand.wmv).

I agree, that thing is badass. I'm not sure I'm going to go with a 15 hp engine, but then again I'm not talking about putting 25" tires on it either. Maybe 18"s.

So any chance of a clutch like the Horstman or MaxTorque delivering the kind of torque needed to spin 18s? Or any chance of it surviving more than a week?

BTW, I got an email back from mfgsupply.com. Sounds like they are working on a TAV2 clone.... possibly due out possibly next month.

[tech9]

The "Engine" delivers the torque,the Clutch allows the engine to idle without spinning the wheels and when engaged, the clutch holds that torque and delivers it to the wheels.A powerful engine will spin any reaosnable size wheel .It all depends on the clutch capability to hold the torque and the gearing to spin the wheels aggressively.Check out this video. Only thing is ,he's using an off road motor bike engine.http://www.youtube.com/watch?v=j0LiTi39NW0

[AirJunky]

I hear ya, Tech9. I understand the engine has the torque. But if the clutch can't transmit it to the wheels without destroying itself, then it's not really worth building, right? And I understand that having larger tires wears on a clutch, especially hot roddin it all the time.

I see a few guys using those Lifan motorcycle engines. Seems like a 90cc or 125cc with an automatic might be pretty good for a barstool racer. Plus it would get around the need, cost & issues of using a clutch of this type.

[tech9]

You're right , and my next build would definitely be carrying a 125cc or 250cc engine.I think my next build will be one of these. http://www.youtube.com/watch?v=3dr8zcDZ3fQ

[AirJunky]

HEhe, those beer box cruisers are a riot. And QUICK!

So do you think that a Lifan 125 (8 hp) would be as quick or sturdy as a similar racer with a Honda/HF clone & whatever clutch setup? Looks like the Lifan could be a bit more expensive, but possibly less if using a TAV2. Plus it has a generator & electric start in it.

[KiwiMike]

Tech9,
You were right, that big wheeled monstrosity does bloody fly!
Why in the world would you go to all the trouble of putting a World Formula engine on it, when you could have 45hp out of a Honda CR125 for about the same money and have a bullet proof wet clutch?
My Son has raced in the World Formula class in karting. We refer to it as School Bus racing, no power, no brakes, but a hell of a lot of fun.

[tech9]

HEhe, those beer box cruisers are a riot. And QUICK!

So do you think that a Lifan 125 (8 hp) would be as quick or sturdy as a similar racer with a Honda/HF clone & whatever clutch setup? Looks like the Lifan could be a bit more expensive, but possibly less if using a TAV2. Plus it has a generator & electric start in it.Those lifan engines are cheap,under 300.00 not sure if it has more power than the world formula which is over 1000.00. and the lifan is 4 speed so it should.but thanks for pointing me in the direction of the lifan ,that's what i'll use for my next project.BTW i'm form Trinidad and Tobago

[KiwiMike]

Only trouble with the Lifan engine is that the parts are a bugger to find. I had some experience trying to fix one for a buddy.

[AirJunky]

Only trouble with the Lifan engine is that the parts are a bugger to find. I had some experience trying to fix one for a buddy.

So their not exact Honda repros..... to the degree that you can use old Honda parts? Are Lifan dealers like Hooper Imports helpful finding parts?

[tech9]

Only trouble with the Lifan engine is that the parts are a bugger to find. I had some experience trying to fix one for a buddy."SHUCKS" I was just starting to like that motor.

[KiwiMike]

Hey AirJunky,
Go to http://www.outlawracing.net and check out the spec sheet on their BSR which includes some steering geometry.
There is a lot of information, these guys give out, with a list of parts they use.
They use Briggs engines running on alcohol just like we use on our karts.
I just got started on my BSR this arvo, cut all the steel out and will start fabing the frame up this weekend.
I will try to take pics as I go.

[AirJunky]

10 hp alcohol burning, probably pretty lightweight engines. Pretty badass. But probably not real reliable if your not going to tinker on it sorta frequently. HF has 6.5, 11 & 13 hp engines with electric start. And those Lifan engines are available in a 7, 13 or 16 hp version.... more than enough power & burns regular gas.
I understand that there are TAV2 repros coming in the next couple months. So either engine should be an option. Question is, for me, which one is tougher?

[KiwiMike]

The best engine you can buy for a BSR as far as reliability is concerned would be a Honda Industrial engine.
http://www.tractorsupply.com/honda-gc160la-qha-engine-2102816
But you are going to pay out the ying yang for it.
However the clone motors from Harbor Freight would be better value for money, as you can buy two of these new compared to the Honda Industrial.
So if the bugger blew up on you, then you could hiff it in the trash, buy a new one and you would still come out ahead.