Newbie here...looking for right engine/parts for towing on hills

GoldenMotor.com
J

jmden

New Member
Jun 14, 2017
27
4
3
53
Hi,

Absolute newbie here. Have purchased on older steel frame mountain bike to try this on.

Looking forward to being part of this forum and learning. So here's my scenario: Looking at towing up to a 200 lb trailer on old 4WD trails in the mountains with some hills. Don't know if it would be best to do some 2-stroke engine upgrades like bikeberry.com boost bottle, an expansion chamber, 'race' muffler, etc. for extra power. Found a 60 tooth sprocket at custommotorizedbicycles.com that maybe the most important part for more torque to rear whee for towing power. Am I on the right track or not? Not interested in speed, but towing on hills kind of power.

Also, this engine needs to reliably work when it's raining as we are up in remote mountains and I understand they (engines, ignition) are not weatherized. What mods do you guys do to get them to work in wetter conditions?

Thanks,

Jon
 
Dave31

Dave31

Active Member
Mar 1, 2008
11,199
47
38
Aztlán, Arizona
Hello Jon welcome to the forum glad you joined us.

My experience with the boost bottle was very disappointing. I used the boost bottle on so many builds and only one time I can say I noticed a difference. It smoothed out the motor and gained 2mph more then without it. But that was with only one motor the others I tried it on did not make a difference what so ever. I gave my boost bottle away and never tried using one after that.

A 60T sprocket is the way to go for that low end torque and a performance pipe with a longer header length will also help. It has been my experience the longer the header the more low end torque I can get out of the motors.

For riding in the rain I just use some RTV silicone to help seal up the mag cover and around the rubber seal for the wires. Never had a problem in the wet.
 
J

jmden

New Member
Jun 14, 2017
27
4
3
53
Thank you, Dave 31. So no problems, given those steps with the RTV in the rain. OK. Good. I'm hearing that the 50cc four stroke engines (thatsdax has a good one apparently) are the way to go for torque too, but then I've got crank mods I'd really rather not do. Thoughts on 4 stroke vs. 2 stroke for hills and towing?
 
Dave31

Dave31

Active Member
Mar 1, 2008
11,199
47
38
Aztlán, Arizona
The right set up I believe a 4 or two stroke would be just fine. I've built a few 4 strokes over the years but never for myself only for customers. So it;s hard for me to say which would be better, all my riding has been on a 2-stroke.

I like the 2-stroke but it suits me better I do most of my riding now on trails and off-road. Maybe those who have ridden the 4 stroke more then me can give you better input.
 
5

5-7HEAVEN

Well-Known Member
Aug 2, 2008
2,661
240
63
Welcome to the club, new members!
If I were me, I'd install a Dax XC50R Magnum engine 4-stroke engine. Instead of the Dax transmission, I'd use the simple and cheap 5:1 pocket bike transmission and a shift kit. For the rear, use an inexpensive 8-speed cassette.

It would be a monster trailer-puller uphill off road.

Using the correct sprockets, you'll be able to gear it down so you'll have the capability of a 120-tooth sprocket in first gear. Moreover, in 8th gear, you'll be able to cruise easily at a comfortable speed of 35mph.

The only high-performance item would be a simple, inexpensive generic "poo poo pipe.

Good luck!
 
J

jmden

New Member
Jun 14, 2017
27
4
3
53
5-7HEAVEN,
I'm intrigued by your comments, but being a newbie you are talking right by me. Could you provide a link or two to the products you mention and perhaps some info on how to put it all together? I did talk to Dax the other day and that was the engine he recommended and he also recommended a shift kit, but I'm not sure where to look for this and how to install it. Thanks.
 
5

5-7HEAVEN

Well-Known Member
Aug 2, 2008
2,661
240
63
I'm sorry, I forgot myself. Dax and I basically recommended the same setup.if someone competent nearby can assist you in the installation, it'll be the best setup for your needs.
Most vendors try to sell you their belted drive setups, even Dax. That forces you into a single-speed with a large sprocket on the left side. Basically, the 4-stroke bolts onto a horizontal mounting plate, along with their tranny. Then the chain hooks up to the rear sprocket.
However, you can rotate this 4-stroke engine to face the right side. Bolt on a pocket bike transmission, which then reverses the engine rotation. There are parts available to chain the transmission to a sprocket near the pedals. Then a smaller inner sprocket chains up to the gears on the rear.
 
Last edited:
5

5-7HEAVEN

Well-Known Member
Aug 2, 2008
2,661
240
63
Although there are no step by step instructions, it's pretty basic stuff. Everything can be made to line up. If the bottom sprocket doesn't line up, inexpensive parts are available to align everything. We can advise you of the necessary sprockets and gear ratios needed to make your bike work well.
Basically, if you can get 8th speed geared to15:1, then first gear will have a super low gear to climb sttep hills easily.
Here's the Titan engine kit for left-side single sprocket drive:
http://thatsdax.com/
When you feel more skillful, to switch to right-side drive thru the rear cassette, you'd need this kit:
http://sickbikeparts.com/4-stroke-engine-products/
and this inexpensive transmission:
http://www.ebay.com/itm/GEAR-REDUCT...535842?hash=item27d08b9fa2:g:Q30AAOxydgZR7cy6

Once you go to the shift kit, you'll never revert to left-side single sprocket.
Just my opinion, of course.
 
Last edited:
C

curtisfox

Well-Known Member
Dec 29, 2008
6,046
3,949
113
minesota
Don't forget the rear wheel, need one with heavy spokes 11, or 12 gage. With all the low gearing and trailer, would be wise to get one. Also good brakes, ...................Curt
 
J

jmden

New Member
Jun 14, 2017
27
4
3
53
K, guys, this jackshaft kit idea has us really thinking, but I need to better wrap my head around the concept/what's needed in terms of a parts list. I need some links to some kind of tutorial/youtube vid and parts. I still think I'd like to go 2 stroke so I don't have to use the wide cranks, but not married to the concept.
 
5

5-7HEAVEN

Well-Known Member
Aug 2, 2008
2,661
240
63
Here's what I'd recommend: Take measurements of your frame center. Make sure the engine you select will fit. Contact Dax; ask him if his 4-stroke engine will bolt onto the pocket bike 5:1 transmission.He sells that tranny too. If it does, the tranny will reverse the engine's rotation. That means you won't need a jackshaft to install your 4-stroke engine.
The engine/transmission sprocket will face the bike's right side and align with the bike's pedal sprocket.
Then you'll be able to connect your engine to the bike's 8-speed cassette.
You'll need this:
http://sickbikeparts.com/grubee-freewheel-crank-assembly/
I'm unsure if this bottom bracket is too wide. It MIGHT be just right.

The cheap,, simple and easy way to mount your engine is with angle iron. Since it's for heavy duty off-road use, choose 1.5"X1.5"X36" size. Cut to fit, then bolt the iron on. Do NOT drill the frame to bolt it on! Sandwich the frame between the angle iron. If your frame is steel, weld the mounts on later. If your frame's aluminum, the bolts will secure the engine mounts. If you're leery about the mounts slipping, bolt muffler clamps under the angle iron to keep it from sliding down the frame tubes.
Line up the engine and bottom sprocket first with its chain. Then make the permanent engine mounts.
If you're lucky, the engine mounting holes will align with the angle iron mounts. If not, bolt or weld a flat plate under the engine to the angle iron.

To be continued.....
 
Last edited:
5

5-7HEAVEN

Well-Known Member
Aug 2, 2008
2,661
240
63
Unsure if you can find the correct engine/ transmission sprocket to match the supplied SBP big sprocket. You have other options:
Use T8F chain and sprockets to link the engine and drivetrain.
Use these:
http://www.ebay.com/itm/47cc-49cc-T...ash=item5d6b5ac090:g:icwAAOSwB09YOlzx&vxp=mtr
and this:
http://www.ebay.com/itm/Rear-Sprock...ash=item23851ebea6:g:jskAAOSwcaFZIrUK&vxp=mtr
or this:
Maybe DAX can drill the correct 5-hole bolt pattern, if you ask.
http://us-dc1-order.store.yahoo.net...xYFJRy_xzhnWzcQxiRE_5lDscX8RKr8VaVd80cjDnc-~A
If not, you'll have to drill the T8F sprocket to 5 new bolt holes. It's not hard; you can DIY or send to machine shop. Then bolt the big sprocket to the freewheel. Using five M5 studs or bolts about 60MM long, to connect the inner/smaller sprocket to the outer/bigger sprocket and freewheel. The inner sprocket will "float" outside of the bottom bracket axle (If the inner sprocket was bolted onto the bottom bracket/axle, it wouldn't freewheel).
Distance the inner sprocket to 50mm from the center of the seat post tube(for starters).

Use this for you inner sprocket:
http://sickbikeparts.com/chainring-freewheel-24-tooth/

Buy this to help prevent the chain from jumping off the inner sprocket:
http://sickbikeparts.com/jump-stop/
If the chain ever jumps off towards the bike, it might get caught on the protruding nuts and bolts connecting the inner sprocket to the outer freewheel. When the chain jumps, it MIGHT break or twist, then possibly damaging the derailleur and rear cassette.
To help prevent chain damage if/when it jumps, use 5 nylox nuts on the bolts or studs connecting the inner sprocket to the outer freewheel. Be sure the 5 studs don't protrude past the nylox nuts. The protruding studs are what the loose chain grabs onto and self-destructs.

You'll be using 5 nylox nuts and 15 nuts and lock washers to connect the inner sprocket to the outer freewheel and sprocket, if you use studs.

To be continued.....
 
Last edited:
5

5-7HEAVEN

Well-Known Member
Aug 2, 2008
2,661
240
63
If you use my recommended sprockets and an 11t-34t 8-speed rear cassette, you'll have the equivalent of as 113-tooth rear sprocket in 1st gear. Second gear would be like an 86-tooth gear, third like76t, 4th like 67t, 5th like57t, 6th like 50t, 7th like 43t and 8th like a 37-tooth rear sprocket.
In other words, you'll have the best of both worlds. A wall-climbing stump-pulling 1st-2nd-3rd and 4th gear. You'll also have a cruising final drive, when you unhitch your gear and cruise on flat land.

And of course, you'll have the torque of a 4-stroke engine.

Yes, this is a TON of information.
 
Last edited:
V

Vipboykz

New Member
Jul 9, 2017
2
0
1
24
Looking at towing up to a 200 lb trailer on old 4WD trails in the mountains with some hills.
Thank
 
You must log in or register to reply here.
Top Bottom