View Full Version : TZR 250 1kt changes to electrical..flywheel......... ?

OSPREY - n/a
17-Jul-08, 04:12 PM
I bought one engine yamaha TZR 250 1kt for my Osprey Hovercraft and I need some help.

I will cut the gearbox and I will use the K & M (Pulley 16 tooth H section steel, fits straight onto TZR crankshaft , and the pull start cup - manual wind )

I want to ask : to fit this parts on engine it’s need it to remove these (look the picture)


and then how the engine work without these parts ?

1.without generator

2.without flywheel

What are the changes to the electrical system ? (to start the engine generator without)

I will use electric water pump !

Lockey - n/a
17-Jul-08, 04:17 PM
you shouldn't have to remove those parts, i'm running exactly the same set up as u describe but i still have all thats in the picture.

OSPREY - n/a
17-Jul-08, 04:21 PM
yes but i need to install these pulley and manual start (I had bought it !)



can you upload some pictures from yours ?


Lockey - n/a
17-Jul-08, 04:27 PM
I can't at the moment as its in pieces, but the pulley bolts straight onto the fan end of the crankshaft, then with the starter cup you drill 3 holes in the cup then 3 holes on the fly wheel and tap a thread into the holes on the fly wheel and the starter cup should bolt onto the fly wheel.

I know its a bit long winded but that is the jist of it

Lockey - n/a
17-Jul-08, 04:40 PM
If you're still confused heres a photo of the fly wheel.

If i'm wrong, can someone correct me please?

jon_curtis - n/a
17-Jul-08, 05:18 PM
im no expert on tzr's but you cant run the engine without the gen and flywheel, where do you think the spark will come from?

lockey sounds exactly right, from what i have seen of these engines, you bolt the cup on the fly wheel, and the pulley on the other side of the crank! where pressumably, the clutch and gearbox once was!

OSPREY - n/a
17-Jul-08, 09:46 PM
thanks for your help !

now I understand.

if someone have pictures from a complete engine with these parts (pulley ,munual wind start) it will be helpful for everyone .


Lockey - n/a
18-Jul-08, 09:51 AM
I've managed to get my engine back together, heres a few photos.

Here's the pulley


Here's the starter cup


and here's how it's bolted in


tonybroad - n/a
18-Jul-08, 09:25 PM
If you are putting the pulley directly onto the crank make sure the engine can't move

do not put rubber mounts onto the engine put them on the frame and mount the engine solidly or the pulley will become misaligned

i have an electrical wiring diagram for the TZR electrics for a hovercraft if you need it - let me know