Scooterguy Mount With Tanaka 47R Engine

[5-7HEAVEN]

I surely hope so, Ed.

See you Sunday at 0800. I'm riding this bike downhill to McD's, even if I have to push it home.

 

[5-7HEAVEN]

The Continuing Saga...

I took my bike to the adjoining park for test and tune. It ran decently, and both chains had good distance between each other.

HOWEVER, the bike chain STILL managed to jump of the chainring in 7th and 8th gears. This is occuring at slow speeds and always when upshifting, not downshifting. At least now it's jumping off between the chainrings, not breaking or binding, just riding smoothly on the spacers. The engine drive chain is not giving trouble.

Methinks that I need a chain guide to prevent the bike chain from jumping off.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230293091050&ssPageName=STRK:MEWAX:IT

This sprocket will act as a chain guide. It is taller than both of my chainrings, so should keep EITHER chains from jumping off towards each other.

It is also 8mm and drilled for my freewheel, so can be used as an alternate engine drive chainring.

 

[TREEWK]

5-7

I`m Thinking When You Get Into The Higher Gears You Are Getting Out Of Line With The Bb Crank Sprocket.

The Rear Derailer Feeds The Chain Onto The Wheel Sprockets. Maybe A Front Derailer Locked In Place To Feed Chain Onto Front Sprocket When It Gets So Far Out Of Line.

If Your Ratio Was Correct For The Starting Cassette Cogs, The Chain Would Not Get So Far Out Of Alignment.

If You Install The 72 Tooth 8mm Sprocket, It`s Teeth May Grab (snatch) The Bike Chain.

I Go Into Detail A Bit Too Much = For New Members.

I May Have A 24 Tooth On Bottom Bracket To Get My Gears Rite.

I Finally Found A Pic Of The Alum Tubes For Welding In The Frame. Am Sure A Lot Of Builder`s May Not Want To Go That Route. It Is A Bit Involved To Set Up, But Could Be A Neat Looking Mount.

The Tube Has A Split Collar Clamped On It. In Front Of Some Diy Jackshaft Parts. The 12 Tooth Bmx Sprocket In Lower Left Of Pic Is The One Nuttsy Uses`s.

Hope You Get That Chain Prob Corrected So You Can Cruise!! Ron

 

[TREEWK]

5-7

Have You Considered Replacing The 63 Tooth 8mm Sprocket On The Bottom Bracket With A 54 Or 44 Tooth. Then Using Your Larger Rear Cogs?? That Would Solve Most Or All Of The Chain Derailments.

When You Added The Space Between The Front Chain Ring`s It May Have Gotten Worse.

Are You Using The Same 5:1 Gear Box As Me? Your Mount Looks A Lot Different. More Pic`s?? Ron

 

[5-7HEAVEN]

My bike chainring has 22 teeth and is less than 4" in diameter. My engine chainring has 63 teeth and is 6.375" in diameter.

This 72-tooth sprocket is 7.375" in diameter. If it snags the bike chain, I will machine off its teeth.

Ron, I believe that you are correct. The missing front derailleur is allowing the bike chain to jump off the sprocket.

I already ordered the 72t sprocket, since it was so cheap and had the correct bolt pattern. In the meantime, I'll go scrounge around for the front derailleur.

I have time on my hands, so I removeD one bike chain link. My chain is a little too long.

Front derailleur, front derailleur...I got a MEAN feeling that's all I need to stop the chain jump!

I'm gonna go look for my old one, to see if it'll fit with the tiny 22t bike chainring.

It can't hurt.

 

[TREEWK]

5-7

Maybe A 30 Tooth In Place Of The 22 Would Let You Use All Your Rear Cogs.

I`m Wondering As You Implied, If The 22 Tooth Sprocket Will Be A Bit Small For For The Front Derailer. I Don`t Know, Just A Thought. The Derailer Could Be Modified If Need Be. Ron

 

[5-7HEAVEN]

Ron, thanks for the tip on the front derailleur.

When I mounted the Scooterguy kit, I tossed the derailleur, figuring I'd use the Jump-Stop, just like guys using SBP kit. A new derailleur fits in there along with a new Shimano chain.

My testride took me 5 miles to my workplace. On the way, the bike threw the chain twice to the right and once towards the left. The sharp chain angle in 8th gear and over-revving first gear caused the chain throws. If I ease up in first and not use 7th and 8th gears, that should eliminate chain throw.

My plan is to replace my 11-tooth drive gear with a 14-tooth sprocket. That way, first gear becomes more usable and 6th gear is the same 14.32:1 as I presently have in 8th gear!

This should do it. If not, that ebay sprocket I just purchased will be put to good use.

 

[Bonefish]

5-7,

Not sure if this helps at all, but this is how mine is setup.

9T sprocket on the tranny.

SBP 30T inner chainring,

Have 4 or 5 S.S. washers on each bolt I got from Home Depot between inner and outer chainrings

SBP 44T outer chainring

Bottom Bracket Axle Length = 127mm

Back cassette = Gary Fisher 8 speed, that ranges from a 30T thru an 11T, I do not use the Lowest 30T cog, nor do I use the 2 Higher Cogs(7th and 8th gear)

I run Walmart chains. I run a 1/2 x 1/8 BMX Bell Chain on the engine drive chainring, and I run a 1/2 x 3/32nd's Bell Speedy chain on the back cogs. I do not run the 9 speed 5/64ths chain they sell.

I do not have any problems with chainsuck.

I fashioned a fixed tensioner wheel that runs on the load side of the engine drive chain that needs to be tightened up according to chain stretch every once and a while. That will subside when I can find a spring to fit my needs.


I understand with your gearbox, more reduction is needed than mine. Yours is 5:1 where as mine is 6.9:1.

A 30T inner chainring would probably do the same for you as taking out a couple of links, adding additional tension which might be a plus.

You might have success with running that 72T on the outer, and then running a 30T on the inner to get the reduction you need.

I'm at Mc Donalds right now, It was a wet ride because it rained this morning, but mine is still rolling.

Yesterday I took a Sunday stroll on it. It was a long one....................................................

75 miles

I use mine everyday as a daily commuter.

Once you get the bugs/adjustments worked out, you will probably be saying.............

Why in the **** was I ever running a friction drive?

 

[TREEWK]

5-7

I have the jump stop installed and no front derailer. Have not had any problems.
If i was using all 7 speeds I may need front derailer.

My rear chain master link clip came off once from chains rubbing each other in 6th gear. Fixed it before the chain came apart. I had the clip facing correctly.

Because of weighing over 300 lbs, my 5th gear is about 18:1 ratio. Had it up to 32mph with gps (very very accurate). Thats too fast at my weight with bicycle components!! I just cruise at a comfortable speed for me. But remember , I drove my 600 hp stock car for 20 + yrs.

Yes changing the motor sprocket is the easiest way of doing it. Imo you made the chain/sprocket angle worse when you increased the spacing between the two chain rings on the bottom bracket. You might keep that in mind. My crank removal tool sure works nice!! . ron

 

[5-7HEAVEN]

Thanks for sharing your info, Bonefish. That came in handy. The 72t MIGHT be the key.

Ron, the gearbox is 5:1 and seems to be a good combination. The front derailleur seems to be working, just needs slight adjustment. I reralize that by widening the gap between chainrings, I aggravated the chain angle. However, now when the chain falls off, it doesn't jam and break, just rolls on the spacers.

I WAS gonna ride to work yesterday, but got a flat in the rear.It was VERY easy yanking the wheel, unlike when using my friction drive and Staton chain drive.

Took a ride last night on my bike. Without the second muffler, it was slightly louder, but much smoother with more power. I only threw the chain once, in 8th gear.

Ron, I saw pics of your race car. Ford, yes? Hawaii Ed is helping me getting my 1957 Chevy BelAir sport coupe back on the road. 400+hp 383, 4-speed close-ratio, maybe trips or dual quads this time. I had a '57 coupe in 1967, this is my "bucket list" vehicle.

Riding my bike to work today!