Newbie

[reliantman]

Hi All.
I have had several diesel bike forums on my favorites list for a long time, and have now decided to stop lurking.
I am hoping to buy a Dnepr, in bits, in the next couple of weeks and am thinking about converting it to diesel power.
Having seen the various types of engines in use, I am a bit confused, and would like to ask what the experts would suggest I look for.

Thanks.
Regards Doug Smith.

[balboa_71]

Hello Doug,
I've seen side car rigs powered by 10hp clones to multi cylinder water cooled
inline engines. This depends on how much money you are willing to spend and how good an engineer you are. The 10hp clone will and does power a 3 wheeled Cushman utility car very well, see www.utterpower.com, so weight is not so much an issue. The big thing is having good gearing to suit your engines output. Another popular engine is an air cooled parallel twin, but there aren't many to be found on eBay.

good luck,
Cris

[andrewaust]

Hi Doug and welcome to the forum


Looking at some of the larger builds a Dnepr would be a good platform to start with. I've been looking at the Chang Jiang 750's after another diesel bike enthusiast told me about them.

As far as powering the motorcycle, I'd personally start with a twin and maybe look at a 3cyl diesel, but like Chris has said it depends on what your aiming at power wise and budget of the conversion.

My little 10hp clone in the Enfield is a great engine, but I'm really needing more horses to keep up with the lunatics on the road

All the best with your build.



Cheers

Andrew

[reliantman]

Thanks for your replies. As I mentioned, I do have a reasonble idea of what I want, but it's just getting hold of the right engine.

[oilburner]

Hi Doug;

Assuming you will be staying with shaft drive, here are a couple suggestions you might want to consider when choosing an engine.

1. An original Dnepr with sidecar weighs well over 700 lbs. If you have driven one, you'll know that the engine is no ball of fire with 35 hp and 33 ft.lbs of torque. My guesstimation is you will need about 20 hp to achieve minimum acceptable performance.

2. The Dnepr gearbox and final drive appear to be fairly reliable, even when used with 50 hp BMW boxer engines. If you decide to opt for a car engine or other engine with more than 45 ft. lbs of torque, these components will probably be a weak link. I don't know the situation on your side of the pond, but here in North America, the dwindling Dnepr parts supply has resulted in very expensive parts, if you can get them.

If you choose an industrial diesel of sufficient horsepower with a typical 3600 rpm redline, the Dnepr gearbox and normal 4.62 ratio final drive combo should provide a top speed of approximately 48 mph, if my calculations are correct. A 3.89 final drive gearset (if you can find one) should be good for about 57 mph. If you choose to go with a more powerful/higher revving engine and/or desire a higher top speed, you will have to modify the Dnepr gearbox or consider going with a Moto Guzzi or BMW gearbox/final drive setup. Elsewhere in this forum are details and pictures of the Guzzi and BMW gearbox mods.

3. In any case, staying with shaft drive means you will have to build a bellhousing to mate the engine to the gearbox. If I had to do it over again, I would make the gearbox side of the bellhousing with a removable plate that could be changed for different gearbox bolt patterns. This would make it much easier to change to a different gearbox without major modifications to the bellhousing or building a new one.

4. Larger multicylinder engines require more extensive frame surgery - longer, wider, higher... Overhead cam engines are very tall... auto engines have lots of ugly hoses and the like sticking out that can't be easily hidden...

5. On automotive style engines be sure to check the distance from the crankshaft centerline to the bottom of the oil sump. You need to have sufficient ground clearance beneath the engine without causing execessive driveshaft angle.

Hope this helps

Avery

[reliantman]

Thanks Avery.
I am into trikes in a big way, and if it is not blasphemy to mention them on this forum, I might even have a go at building a diesel trike.
There are a good number of diesel car-engined ones over here, but hardly any with a small lump in.

[Cockney Bob]

Why not try the two cylinder engine out of an Aixam car it is I believe a Kuboto and with variable gears it should do a good job.
Bob

[roverthetop]

reliantman,
i created such a dnepr. it was on ebay just ended. link follows- http://cgi.ebay.com/ebaymotors/ws/eBayI ... ISUA:MT:11, not sure if you can still bring it up or not. i can email specs and pics if you'd like. avery has many good points. i used the lombardini 25LD 435-2. 19 hp. had to stretch the frame by 3.8", raise the top bar, and fab a bellhousing, but no worries. i also had the final drive remade to get a bit more speed, as i couldnt find a 3.89 although i know they're around. she does 55 with the sidecar, but takes some getting used to. had to "fix" many of the factory welds as they were crap. if you decide to go with a "kit bike" as i did, be prepared for a hunk o sh*t. now, had it been available and known to me at the time, i would have gone with this engine i am putting into another diesel bike im doing- a chinese made v-twin horizontal shaft pushing 22 hp- http://www.punsun.com.cn/Showproduct_en.asp?pid=179
the dnepr gearbox should work sufficiently for you, depending on what your needs are. i have but one hill, really, so i'm all right. if she would hold together better, i would squeeze more speed from her, but i am honestly afraid she'll rattle to pieces. i should have changed out every ukranian bolt, but didnt. ooooops
hope that helps. email if you wish, always love to offer help.