Progress Report from the California Coast...

[jeremy]

Finally, an update on my progress with the HATZqavarna Clubman build:
I got out to my shop last weekend and began again. Frame was on the newly re-assembled wheels (dropped from 21" to 19" front, stock 18" rear), forks, brakes and bearings all gone through. Brand new 1B30 engine in a box, new CVT also on hand. These things have been so for months, but always some bloody thing more important to do, until finally just I allowed my passion to prevail on Sat and Sun, now I can't concentrate on my work.

Anyway, cut out forward frame section to make way for engine placement and new frame members ( going back in 1" steel tubing, welded, in the manner of a featherbed--two down-tubes, joined at the steerer gussets). Got the old, ditchpump engine up on wood blocks and located the CVT roughly with its jackshaft and pillow-block bearings. Now trying to visualize the engine and CVT support member, which thanks to you all, will be a modular, shock-mounted unit slung in between the new frame loops with two tack points forward and two at the upper back, where the old engine bolted into the enlarged central frame section. I'm looking online at some stiff 70-durometer, neoprene steel-sleeved bushings (www.vibrationmounts.com) Any movement will have to be taken up in the final drive chain, not in the CVT belt. Here's how it looks:









Now there are so many factors to marry together, it's humbling and makes your head swim if you try to figure them all out before forging blindly ahead and remediating as you stumble over them, which I am loath to do. I have salvaged some frame parts from a friend's rusty old Yamaha lump, which are just what the doctor ordered--buddy peg rear triangles, which came with rubber muffler shock-mount and a niftier brake pedal assembly, as well as a pair of shock-mounted foot pegs. So I'll have double vibe protection in some places, though haven't addressed the handlebars yet...

The old Husky dirtbike is light, simple and elegant with its flanged alloy rims, conical brake hubs and relaxed frame geometry. Should allow the smaller engine to approach adequacy in my case, though I am still worried about stopping power with these small drums and not much benefit from compression slowing (would be nice to have a "jake-brake"!). Good news is that there won't be that much bike-mass to stop, I'm still guessing under 250# all-up.

I'll offer more images as it happens.

[taildraggin]

Great combination; looks like a good match.

*Really* big rear sprocket; was it set up for speedway?

[jeremy]

I meant to mention that...conversations with Don of HOFCO/COMET, the maker of the torque-converter, indicated this ratio in the final drive: 13- or 14:70. He explained that they are geared for snowmobiles, go-karts and the like so need to be geared-down for big wheels like ours. In a nutshell, starting from the engine top-out of 3600, I go to slight overdrive in my particular CVT which boosts to over 4000, then 13:70, then the circumference of the rear tire. When you work it out, you get your theoretical top speed (for those who haven't had to do this yet).

I ordered it from a company called Sprocket Specialists in Oroville, CA. (www.sprocketspecialists.com) They have most bikes in their computer database and can CNC anything you want in aluminum, or I think order in steel also. I just told them the make and year-model and what size bolts, and paid extra for the lightening holes, an option. Also could have had any of a number of colors anodized, which costs but may increase durability as well.

I've set it up so I can still increase the jackshaft gear a tooth or three to raise top-end, but likely won't need to around here. They (SS) say that below ten teeth the chain has to bend too tight and that's not good (they sell the output shaft gears as well, steel).

When I was a kid I had a crude little minibike and you had to be careful not to lean too far to the right, or you'd run on the sprocket...

[Sphere]

That rear sprocket is massive!

What is the projected speed? 40mph?

[LocomotiveBreath]

I'm out in the Southern California Desert, I also venture to Northern CA to see my kids from time to time, if you need any help, just give a shout.

Dave

[jeremy]

Thanks, Dave--I've enjoyed reading your posts since signing on. Tell you what you could do: bring gobs of cash up so I can stay home from work for a couple of weeks and make some progress on this thing!! Seriously, though, thanks for the offer and I expect I'll be asking for some guidance along the way. The scariest thing I have ahead of me is to tear open my new Hatz 1B30 and switch some governor parts to change it from a constant-rpm generator motor to a variable-speeder. They use sheet-steel spring-plates stacked in varying numbers and thicknesses on a little shaft, and I guess I don't have faith that when I put it all back, it'll perform as I want. Plus, it seems the fasteners are locked down so tight I'm gonna strip them trying to get them off-allen head bolts are shallow and seem sloppy too. Think I'm going to get some metric allen key tips and put them on my Makita rattle-driver--maybe that'll help. I hate taking new things apart, it seems almost impossible to get them back as nice as the factory had them. But maybe it'll go alright once I'm in there.

Other than that, it's just getting things located and making the necessary mounts and brackets, rebuilding seat and tank, running wires, battery mount, you know, basically everything--which I should have finished in a whole lot longer than I'd like. By the by, what part of Northern CA your kids in?

And Sphere--I have arranged for a variable ratio of from 3.34:1 @ 2500 rpm giving around 11+ mph (start-off) to 0.81:1 @ 3600 rpm for a top speed of around 62 mph, by choosing a final drive gearing (jackshaft-to-rear sprocket) of 13 teeth to 70 teeth. That is with the Comet 500 CVT, which offers tunability of engagement rpm and downshift rpm, a 1" belt for durability, plus a bit of overdrive (the ".81" part, instead of '1'). Of course, these ratios are totally theoretical since horsepower is a major factor in the equation, and I don't have much (6.7). So for now, I've chosen a light and small carriage, and shot for what I think is a modest top-end speed. Others may say that only 50 mph is realistic--they may be right, and I could have put a few more teeth back there in the rear. Guess we'll see; I can still run a bigger jackshaft gear to lower ratio if needed.

[LocomotiveBreath]

I was stationed at Travis AFB, (Fairfield) and lived in the Napa-Sacramento-Bay Area for 30+ years. My kids are in a little town near Davis (Woodland) I also used to drive for Safeway, so if you have a Safeway in your town, I've been there.

I'm glad you have enjoyed my posts, Thank you for the complement.

Feel free to e-mail me.
Dave in Barstow

[Sphere]

Just for my understanding, is that huge rear wheel sprocket because of the fact that you employ a CVT? I'm contemplating 10 horses in a cb500, and since the petrol motor is attached to the gears I require something to replace that. But I don't particularly like this solution.

[Sphere]

I've been playing around with http://www.cosportbikeclub.org/misc/SpeedCalc.html and I put 1 (no overdrive) for the primary reduction and gear ratio and used standard Enfield data for the rest.

Code: Select all

Rear Wheel Diameter in Inches                  19
Rear Tire Size - First Number (ie: 180/55)    190
 - Second Number (ie: 180/55)                  35
Primary Reduction Ratio*                        1
Final Reduction Ratio**                         2.4
Gear Ratio* (for one of your gears)             1 (4th) 
RPM                                          3600

These figures predict 174kph, which is optimistic for a 10hp engine. If I increase the final reduction ratio to 4 (48/12 back to front) it levels at around 100kph, which in my view is still unpracticle if you anticipate riding in wet conditions. Now to find a calculator that takes into account hp.

[oilburner]

A simple formula that calculates hp/max speed with decent accuracy (prone position, no wind, level road) is:

mph = (cube root of horsepower) * 30

The easiest way to use the formula is:

(mph/30 ) cubed = horsepower required

examples: (60mph/30) = 2 X 2 X 2 = 8hp
80mph/30) = 2.67 X 2.67 X 2.67 = 19hp

Me thinks 174 km/h (108 mph) on 10 horsepower is a wee bit optimistic.

[Sphere]

Wow. I wonder how realistic it is that people claim to do 100km/h on a 10 horse china diesel, then. Seeing how velocity squared is part of the drag formula, they would have to be midgets.

[oilburner]

100Km/h on 10 hp should be possible... the formula I offered says 8.8hp would be required, and I recall occasional posts by owners of 10hp Chinese clone powered bikes mention reaching that velocity.

[jeremy]

Sphere, The big rear sprocket seems normal to me since my first moto-power project about thirty years ago involved bolting a sheet-metal "Whizzer" belt sheave to the spoke-crossings of the rear wheel on a 1930's Schwinn ballooner-bike. I harnessed a 3 1/2 hp horizontal lawnmower engine through a Comet 30/jackshaft arrangement, and got 20-25 mph on the flats, little faster down the hills, lots slower up.

Perhaps I should have specified even three or four more teeth on that giant rear sprocket, and shot for around fifty tops (mph) but I was intending to not allow the engine's governor to be the limiting factor. I also agree that other factors such as weight (both rider and bike) play a big role in the outcome, so I'm working to keep my bike light (hopefully around 240 lbs, and I'm 165 lbs). So it'll be interesting to see what this 6.7 hp engine will do in my case.

Dave--thanks for that, we just drove by Davis on our way from the coast to the Gold Country Thursday. I'll look forward to needing the help and calling you for it. As I said, I'm nervous about cracking this new case to do governor revisions...seems like open-heart neurosurgery.

[Sphere]

Hehe nice story

Well I guess it's not too big an issue if you don't expect to require a new one a lot.