Crazy Custom Frame Hobbit

Hey All,

I'm going to be trying to build a crazy custom frame Honda Hobbit. Inspired a ton by Joe S's Honda Hobbit, as well as Craig Dueck's Motobecane, I wanted to build a chain drive hobbit that sits within a double cradle frame. I've always loved the small 70s Honda motorcycles, but also really want the ease of a CVT for puttering around the city. As such I designed something along the lines of the old VanTech race frames.

Here's the general design

HobbitScreenshot.jpg

The engine will be bracketed to sit right next to the final drive. I'll need to extend the output shaft a little, but will be going to a Puch rear wheel. I know that I can attach the sprocket to the Hobbit rear wheel, but the whole engine would have to be off center to make it line up with the rear sprocket.

I forgot to snap a picture of the mockup for the brackets, but here's the lineup I'm thinking for the engine:

IMG_20200202_1351371.jpg

Essentially my goal is for the frame to function as a kit frame, and I can toss most small engines in there. I'll be treating the Hobbit engine + final drive as a single unit: Cyliner+crank+transmission that just gets bolted in

Front end will be from a KX80.

Frame will be 7/8" chromoly tubing. Was considering 3/4" but the machinist I'm working with strongly suggested 7/8" if I want it to be a daily rider.

I'd love any advice you guys have!!

Re: Crazy Custom Frame Hobbit

You could spring mount the hobbit engine and go single variated like a Moby...otherwise some pillow blocks and a jackshaft could line up it rear sprocket...

Definitely cool, but if I were going build a custom frame id just go with a chain drive engine. Derbi would be cool. Vert morini Franco or maybe an Aprilia. Senda..Hell even mb5 or ar80.

Good luck tho.

Re: Crazy Custom Frame Hobbit

I feel you. I was very tempted by the gpr50 crate engines they had at '77 for a while. I ended up deciding to go with the dual CVT Hobbit for 3 reasons:

1) I'm building rear sets for a motorcycle right now, and building out linkages and a foot brake setup is just so fucking annoying

2) My wife rides a stupid fast moped, and I'd like to have something in the same range as that. It's just plain fun racing moped, and if I ended up going with a 6-speed it would take away a lot of that fun

3) Dual-variated vs single-variated or non-variated is just so much better. Seattle has giant hills everywhere and I love being able to climb them on my Hobbit with no trouble.

HOWEVER, one thing I love about this build is that at any point if I decide I'm annoyed with the process of making the Hobbit engine work I can always grab something else. As long as it's less than 1'2" long it'll fit in the frame.

Re: Crazy Custom Frame Hobbit

Straight up and down 90deg shocks suck shit. Throw angles on them to make them work better. Worst riding bikes I've had have 90deg shocks

Re: Crazy Custom Frame Hobbit

Yea this wasn’t my idea

Re: Crazy Custom Frame Hobbit

It wasn't??

Re: Crazy Custom Frame Hobbit

Ahhh good to know! Let me play with the design. Probably just steeper uprights at the back to give more room to angle

Re: Crazy Custom Frame Hobbit

> Colin Ratcliff Wrote:

> -------------------------------------------------------

> It wasn't??

Naw it wasn’t lol

https://www.mopedarmy.com/forums/read.php?1,4343221,4343804#msg-4343804

This will be actually pretty cool because I just get to sit back and watch.

Re: Crazy Custom Frame Hobbit

Are you using a jig? Tig?

Re: Crazy Custom Frame Hobbit

Yes to both!!

Re: Crazy Custom Frame Hobbit

Oh shit I totally read through that whole thread a while ago and it's where I got a ton of the inspiration!!

Scooter engine might work but honestly using the reduction gear in the final drive and basically faking a torque converter with the reduction gear included should be perfect AND the cheapest way to do it. I have a spare Hobbit wheel and plan to cut out the center hub and make it into a flange. That way I can attach a shaft with a sprocket to it. Pillow block on the other side and easy peasy.

Re: Crazy Custom Frame Hobbit

Updated design! Thoughts?

hobbitscreenshotv2.jpg

Re: Crazy Custom Frame Hobbit

What's the dimensions?

The biggest thing is going to be rideability. What's the length between the bars and the seat front.

I run a hobbit with a very long tank and without bars pulled way back like I have it would suck to ride.

Re: Crazy Custom Frame Hobbit

Haven't figured out the tank dimensions exactly yet. I figure once the frame is set, I'll get the engine set 100%, and then after that it's tank and seat

Re: Crazy Custom Frame Hobbit

Dirty30 Dillon /

90* shocks utilize the valving spring in the most 1:1 ratio, so a cheap hard shock will ride like shit at 90*, and fine at 60*.

If you have a properly valves shock with springs tuned for the rider and bike weight, 90* will work excellently. Sadly, said shocks don't really exist. So cantilevering the shocks helps offset this issue.

Re: Crazy Custom Frame Hobbit

That's a bad way to go.

Think about stance now, and adjust the frame accordingly. A poorly designed setup can make a bike a chore to ride.

Today I changed a bike from one that sucked to ride to a fantastic feel, all by lowering the seat and moving it forward about 4 inches.

Don't build a frame that isn't thought out from the get go

> Colin Ratcliff Wrote:

> -------------------------------------------------------

> Haven't figured out the tank dimensions exactly yet. I figure once the

> frame is set, I'll get the engine set 100%, and then after that it's

> tank and seat

Re: Crazy Custom Frame Hobbit

Russell Huddy /

Look at the “hnr chain drive hobbit” thread

Chain drive hobbit has been done a couple of times that I know of

Re: Crazy Custom Frame Hobbit

Shoot okay that's a really good point.

Top of frame is 27". This allows me to go anywhere between a 28" seat height and a 30" seat height. 30" seat height is the seat height of a CB175, which I found to be incredibly comfortable.

Distance from bars to seat is approximately 29". I have no clue if that's super long or not.

Re: Crazy Custom Frame Hobbit

Yeah I read through that whole thread and it was suuuper helpful. Sadly I THINK to do the Puch sprocket directly on the hub approach I would need to shift the entire engine over to get it aligned.

The only issue I have with the HNR chain drive build is I don't see a way to adjust the engine to account for the belt loosening. I've run into that issue enough on my current Hobbit (with the TJT variator and a kit) that I want to make sure I account for it.

Re: Crazy Custom Frame Hobbit

The main benefit of doing the sprocket on the stock hub is it makes the bearing support on the brake plate work. If you put the spinny bits outside of the brake plate/bearing housing you might have more issues than the engine just sitting a bit to the side. I would focus mostly on the final drive chain line then mount the engine in the frame after. As for the belt, on dual variated setups a little bit of loose belt isn’t that big of a deal, but it is a bit of a low end killer if it’s too loose. Starting can also be a pain if the belt won’t grip. I would say an inch of adjustment should be plenty, I don’t think it’s possible to nail the belt length down before you get it together.

Oh and hi Collin!!!(edited)

Re: Crazy Custom Frame Hobbit

That's super far.

I've found that for me the comfort level is optimal at 18inches to bars, with about a 9 inch rise to grips from seat height. At 21 inches to bars with a 6 inch rise I hated the bike.

I'll measure my big touring hobbit with the 3 gallon tank today.

It's comfy but very unconventional, it's designed like the old pacer motorcycles but I could it ride all day and not be tired

Re: Crazy Custom Frame Hobbit

But yeah, it's all a choice.

A bike that looks like what you're planning is meant for very hunched over riding position, which will be cool to see, but not so cool to do.

Unless maybe you have long giraffe arms

And you also have to crane your neck way back to see the road on a bike like this. On pinball run my back and neck muscles were burning from laying on my long tank to get out of the wind, but lifting my head to see the fucking road sucked lol(edited)

Re: Crazy Custom Frame Hobbit

Bahaha, definitely no long giraffe arms. My '86 GSXR is already super stretched out for me, which at low speeds is zero fun. I'll play with some designs for the tank length today!

Re: Crazy Custom Frame Hobbit

Hey! What up Daniel!

I agree about figuring out the last bits of engine mounting once the rest of the frame is together.

For the hub I was thinking of actually skipping using it altogether, but when I come by next week (front end comes in Thursday!) I'll bring the wheels and show you what I'm thinking.

Re: Crazy Custom Frame Hobbit

Hoping to snag some parts before the Treats sale is over, and wanted your thoughts on:

1) Puch rear axle - any idea what a good option would be? I have a stock Maxi rear wheel, and am thinking that the longest I could find would be smart. Also, get Puch chain tensioners or make my own?

2) Kit/Pipe - I was thinking of going with the Malossi water cooled kit, and Treats recommended the MLM Sidebleed pipe, but I feel like I might need to get a custom pipe considering the frame length - otherwise it'll be super short.

ALSO, considering that I'm making this up as I go at this point, AND I don't have a clutch/variator/driven pulley (rear variator), is there a better approach. Possibly a different variator on the front and a GY6 driven pulley on the back?(edited)

Re: Crazy Custom Frame Hobbit

Some perspective.

This is 22in to the center of bars

But only 15in to the center of grips.

It's awesome to ride but on turns I push the knee way out and fall into the turn. Works great just takes time to get used to.

I tried a mostly straight bars on this and wanted to die.

The pullback bars are basically parallel with the tank, it saved this build, liked it so much I did a tube frame moby style build like it. It's super unusual but it works for me

IMG_7467.JPG

Re: Crazy Custom Frame Hobbit

Jbot is just young Snordley on weed.

Change my mind.

Re: Crazy Custom Frame Hobbit

Snordly es mi papi

Re: Crazy Custom Frame Hobbit

air cooled will be a lot less work

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