Land Speed Racing Mk2

[Tetronator]

Cool beans. Felt like I should post something here. This entire tread is just your posts...
But I enjoy reading it, so I guess you're just being very descriptive. Keep it up!

[HondaJohn]

Thanks Tetronator! I'll do my best to keep overwhelming you guys with description and data!


To estimate sprocket sizes, I created a spreadsheet to calculate the approximate gear ratio for the final drive, and used trial-and-error to zero in. Ultimately, I decided to go with a 54 tooth rear and a 14 tooth front as the conservative testing ratio.

Theoretically, this combination should be good for a top speed of 74 mph at 3600 engine rpm. However, I cannot account for friction and wind resistance, so I will confirm that speed by real-world testing before I trust the math.

[HondaJohn]

The latest progress. Details to come.

[bf109v7]

Install.gif (2.03 KiB) Viewed 33073 times

I am afraid you driven is installed wrong way. As you have it, the belt will go out of line when it shifts up. in the driver it will move to the right, on the driven to the left.
Alex

[HondaJohn]

Normally that's absolutely correct! However, Comet sells a yellow reverse-wound spring P/N 204524A (scroll to the bottom of the page: https://www.gokartsupply.com/4044seri.htm) that allows the driven clutch to be mounted with the movable sheave and spring outboard instead of inboard. This solves my alignment problem, but since the clutches now expand/contract on opposite sides from each other, the belt will inevitably wear out at an accelerated rate from misalignment and side-loading. For racing, I can live with that though.

[HondaJohn]

Annoyingly, Comet doesn't publish any alignment information for the reversed installation, so I am going trial-and-error...

[bf109v7]

Normally that's absolutely correct! However, Comet sells a yellow reverse-wound spring P/N 204524A (scroll to the bottom of the page: https://www.gokartsupply.com/4044seri.htm) that allows the driven clutch to be mounted with the movable sheave and spring outboard instead of inboard. This solves my alignment problem, but since the clutches now expand/contract on opposite sides from each other, the belt will inevitably wear out at an accelerated rate from misalignment and side-loading. For racing, I can live with that though.

I read somthing from COMET, that this spring is meant when also the driver is mountet the othher way round. Iven if the Belt will last till the end of the race, you will loose the race because of the big power loss in the CWT with the belt of aliment. My jackshaft came loose an moved 5 mm. I noticed it direct because I lost speed.
Alex

[HondaJohn]

Hmm. I haven't seen that in the literature they sent..... Do you have a link or scaned copy of where you saw that? I'm not too worried though. This is being set up for straight-line top speed, not road use or frequent acceleration/deceleration. As long as the alignment is correct in top gear position, it will work fine. I cannot mount the pulleys too far away from the bearings to reverse them though. I would rather burn out some belts than bend a transmission shaft by applying torque it too far away from a supporting bearing.

[bf109v7]

I saw this somewere in the internet, but I am not sure were. Sorry. And I am in the Philippines with very slow Intrenet. But, as I see, you are in the USA, why dont you call COMET? I lost about 10 M/h oft the top speed. when my jackshaft moved 5 mm. Cant you turn the driver on the cank?
Alex

[pietenpol2002]

Hey John,

If in fact you choose to act on Alex's suggestion to contact Comet, below is a post from back in July that might be of help.

The Comet guru you want to talk to is Don Jackson at Certified Part Corporation. CPC acquired the assets of Comet and Don came along as a part of the deal. He was still with them fairly recently and undoubtedly possesses more knowledge of tuning the Comet CVTs than anyone else in the states. Contact info below. However, their website isn't the best.

Certified Parts Corporation
1029 S. Jackson Street
Janesville, WI 53546
Phone: 608-774-0481
Fax: 608-743-4109

Web site:
http://www.certifiedpartscorp.com

[bf109v7]

Did you get info from them? About distance to the bearing. Mine is quite far, and no problem. Drove 1200 Km with it up to now.

Alex

[HondaJohn]

Nope, I haven't been able to call them yet. The information and reference pictures you have all been posting have been extremely helpful though!

[bf109v7]

My jachshaft is made from an old pripshaft of my boat, 3/4" stainless steel. The spocket is weldet to the shaft.
Alex

[HondaJohn]

Here are all the various pieces that had to be fabricated. It's always those last details that drive you crazy and eat up your time!

K&N Round Filter Adapter

[HondaJohn]

CVT Cover

Rear Struts

[HondaJohn]

Frame-Stiffening Bracket

Secondary Shaft Keyways

[HondaJohn]

FIRST TEST RIDE!!!!

https://www.youtube.com/watch?v=Vc6YWrCHibY

[pietenpol2002]

BEAUTIFUL!!!!!!!!!

And will you make the May LTA event in Maine?

[HondaJohn]

Actually going to the Ohio Mile this year, but not sure whether I will make the Spring or Summer event.

[coachgeo]

Actually going to the Ohio Mile this year, but not sure whether I will make the Spring or Summer event.

Hey that is real close to me. Got an idea of a date? Maybe we can plan a diesel bike meet up around that date?

[gilburton]

Pity these engines are not available in the UK.
Some time back there were reports of the cranks breaking on the V twins and my own theory was that the constant variable demand on the revs by a manual gearbox was causing a strain on a V twin.
It will be interesting to see if the more constant revs demanded by a CVT will be easier on the engine as they are basically designed for constant revs.

Nice build though

[HondaJohn]

That was my thinking as well. Plus, I wouldn't expect the belt to hook up hard enough to apply serious shock to the crankshaft (not as bad as a chain or a toothed belt). I think the belt would burn up long before the crankshaft snaps.

We are shooting for the Spring Event. This is taking place from April 29th to May 1st.

[HondaJohn]

Change of plans! The Spring Event fell through, so we are now taking it to the Summer event on June 18th and 19th. No complaints from me... that gives me 2 extra months for fine-tuning

[HondaJohn]

Finally got some nice sunny springtime weather, so I rolled the (mostly) complete Sportster outside for proper photographs.

[HondaJohn]

The final countdown to Ohio has begun, so I wanted to post the rest of the build pictures beforehand. This nose cone has spent nearly a decade hanging from a hook in my garage, and it is finally being used for its intended purpose.

This fiberglass nose cone was homemade by myself and my friend Ben for my first land speed attempt. This early bike was not well-made, and I ultimately saved a few of the better pieces and scrapped the rest.

This post is also a memorial of sorts. Through a cosmic twist, I am posting these pictures precisely five years to the day that Ben was fatally injured in a motorcycle accident. He was one of my closest friends, and I still think of him often. I am grateful that I have one of his expertly-fabricated pieces of bodywork, and that I can honor his memory by using it on this bike.

The donor was a heavily thrashed Suzuki dirtbike, and it was hilariously badly assembled by a high-school-age your truly, with zero build quality or safety features. Ultimately, the gas tank, foot pegs, nose cone, and some wiring were put into storage, and eventually recycled into the Biodiesel Sportster.

I made a large and heavy mold out of plywood, screen, and several gallons of Bondo that was then hand-sanded into the final shape. Ben was employed at a marine store at the time, and had become an expert at creating fiberglass parts, so he laid down the glass and made a strong and flexible cone. It was then cut and sanded into shape, given a thin coat of Bondo to smooth out the outer surface, and installed.

[HondaJohn]

The cone hung on my wall through college and various jobs and projects, before we decided to give it a second life on the Sportster. I sanded off the old peeling red paint, trimmed it down, repainted it Satin Black, and built a new mounting bracket to bolt it to the Sportster.

[HondaJohn]

[coachgeo]

When you coming to OH and where again?

[HondaJohn]

We will be at Airborne Park in Wilmington, Ohio this Saturday and Sunday (6/18 - 6/19)

http://ecta-lsr.net/events/

[pietenpol2002]

Best of luck John. And of course we're going to need the video.