2-stroke or 4-stroke for cross-country travel?

[duivendyk]

You must lead a charmed life,I am dead set against overheating engines, you should have adequate cooling under hard low speed use.Castor oil may save the day but I don't believe in pushing my luck on a long trip,that is foolish IMO.Other weak spots appear to be conrod wrist pin needle bearings, overrevving probably the culprit result: sudden catastrophic engine failure,also CD unit failures which I'm pretty sure are mostly due to moisture infiltration as are those of the generator (better sealing,RTV) The CD unit should be mounted with the access wires&cables to the rear& pointing down.These engines were designed 40 years ago or so in the UK and need 20 to 1 oil mixture.The crummy bolts,sloppy assembly etc can be corrected&cured during shakedown,provided nothing catastrophic occurs.Then you appear to be reasonably safe as long as you run them at moderate speed.More displacement (torque) is nice to have as long as you can rely on having it.

 

[Dean]

bike mount, like the 80cc kit from bikeberry that i'm looking at that mounts in the V of the bike frame.

pusher, like a 6.5hp on a trailer of sorts pushing the bike around.

Ah, I see now.
Thanks for clarifying that.
I'd choose the "bike mount" style. Less to deal with and lighter, overall. Save the trailer to carry goods, or forego the trailer completely and travel light.
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For those who commented on using Castor Oil, are there any problems with using 100% Castor Oil, as opposed to a mix of Castor and motor/2-stroke oil?

As for carrying extra gas, that's probably not a bad idea, but I feel a better approach is planning the trip so that fuel stops are within a reasonable distance from each other....that and useage of a support vehicle (although I'd be prone to be more of a "loner", myself).
I think this is what Uncle Punk13 did during his infamous cross-country ride.


Dean

 

[SirJakesus]

If you're going bike mount check out the rackmounts. Lots of engine/drive combos to choose from.
I'd suggest staton chain drive or NuVinci for cross country. His kits are the closest thing to "motorcycle" reliability of the drive train available. I took my XR75 on extremely steep/rocky/muddy trails and generally everywhere around here that I always wanted to motor through on a bicycle but wasn't able to on lighter MB's. And it's NEVER LEFT ME STRANDED despite the things I've used it for.

 

[TheOtherStyle]

i was looking at the nuvinci site. 599 for a developer kit??? holy c r a p!!!! (sorry, the site censored that word. i cant believe it....)

for 599, i can buy a 6.5hp, and either make a dual power (pedal and motor) trike with alternator, headlights, taillights, signals, a radio, and storage (tell me that wouldnt be cool for cross country ) or a really beefy little pusher trailer with lots of cargo room, and again, the alternator, lights, etc. i have this bad habit of taking tools and the like with me in my car just going across the county, if i'm taking a motored bicycle with me i'm bringing my junkyarding toolkit with me, along with some spare parts, and of course clothing and supplies. i'd definately want some for of cargo carrying method. a trike, a trailer, or both would allow for that. actually for the price of that nuvinci, i could even get a 10hp yanmar diesel from ebay to hide under everything lol.

the point i guess i'm trying to make, is that i think that a person would be better equipped with having power to spare in the event of hauling goods with them cross country.

p.s. yes, i understand the diesel is probably overkill. yes, i understand the majority of people dont bring more than a tent, sleeping bits, and a couple changes of clothes. yes, i understand i'm screwed in teh head.

 

[duivendyk]

With a large engine (100/200 cc) and lots of torque you might get away with a single speed drive if you didn't go overboard on top speed.Probably something of a gashog.
A power trike + storage trailer has considerable of appeal,power& comfort.,important on long trips.Forget pusher-trailers,dangerous ,still limited storage+ liable to attract unwelcome attention.
Question remains:Can large engine + drive train be shoehorned behind seat on trike.

 

[TheOtherStyle]

ebay has some rickshaw trikes that i think might be up to the task.

http://cgi.ebay.com/RICKSHAW-PEDICA...5|66:2|65:12|39:1|240:1318|301:0|293:1|294:50

if i only had the cash, i'd have one on the way right now. modding that a little bit, such as to add those uberwide chopper wheels could add some capacity, or at least raise the overall strength. plenty enough space for a motor, a cargo deck, etc.

 

[duivendyk]

To follow up on the large engine trike+trailer setup I ran a calculation to se how something like that would perform.I made the following assumptions:
Overall weight: 650Lbs, engine output 6HP at 5.5k rpm and 4.5 HP at 4.0 krpm,wheel size 20".with thse assumptions the speed at 4k rpm becomes 23 mph and at 5.5k 32mph
The reduction from engine crank to rear axle works out to 10:1,this is difficult to accomplish with a single reduction,it will take two reductions therefore.
Hill climbing,4.5 HP corresponds to 6ft.lbs of torque at 4k rpm.Assuming a drivetrain efficiency of 80% the power available at the rear wheels is 3.6HP.It turns out that 23 mph corresponds to 10 m/sec and the available tractive force is 60lbs.This means that with the 10:1 reduction it is possible to ascend a 60/650x100= 9% grade,which I think is quite good.Less reduction would have resulted in a higher top speed but less climbing ability.Possible a dual final drive could be implemented and the appropriate hills/flats sprocket selected with dog clutches for ratios of say, 7.5 or 10:1.that would not be all that expensive IMO.

 

[TheOtherStyle]

good sir, i like your thinking

the question though, is what would be the best way to switch gears? first thing that comes to mind for me, is an upright tube holding a derrailur normally found on a bikes front gears. but, would it be strong enough? or would something else be more beneficial?

 

[duivendyk]

I was not really thinking about changing gears while riding.More like on "the flats use high gear,in the hills low gear",Can be made simple&reliable,but you need engine with enough torque 100-200 cc,Some of the LIFAN engines are in this range,not expensive around $200,reliability,who knows??.

 

[TheOtherStyle]

gotcha, i see what you mean. shift gears when you are idling/pedling instead of under load.

for an engine i was thinking of the 6.5hp someone pointed out that HF carries. 120 bucks, not bad.