Can you weld the cog on the output shaft?

[Mattd]

Hi

Trying to fit a honda 250 engine into my vintage Zundapp Bella scooter, need to reduce the length of the output shaft so the rear cog on the back wheel lines up with the front cog. Does anyone know or has anyone welded the front cog onto the output shaft ? and is it a permanent soloution ?

Cheers

Matt

 

[the snooper]

probably could do it but would the heat damage the oil seal ?
could you not just move the rear sprocket out a little

 

[brightspark]

Hi

Trying to fit a honda 250 engine into my vintage Zundapp Bella scooter, need to reduce the length of the output shaft so the rear cog on the back wheel lines up with the front cog. Does anyone know or has anyone welded the front cog onto the output shaft ? and is it a permanent soloution ?

Cheers

Matt

the shaft out of gearbox will be hardened and probably be splined if u cut it back and weld a cog on to it u will probably ruin the oilseal if it ever needs replacing or gearbox taking apart your stuffed

 

[RedOrZed]

could you not just move the rear sprocket out a little

- much more better

welding can and has been done, however it's a horrid evil disgusting bodge it's a pain in the 'arris when you come to change it, can you be sure you've got it dead square, and you can never be really sure the weld has taken properly. It's ok for penniless couriers taking the risk and poor students, but if you're doing up an old bike it's worth putting a bit more effort, IMO

moving the engine over a bit and spacing the rear sprocket out are the preferred options.

What's happened to the original engine?

Can you put up some pics? I can put you in touch with people with more engineering experience

 

[brightspark]

- much more better

welding can and has been done, however it's a horrid evil disgusting bodge it's a pain in the 'arris when you come to change it, can you be sure you've got it dead square, and you can never be really sure the weld has taken properly. It's ok for penniless couriers taking the risk and poor students, but if you're doing up an old bike it's worth putting a bit more effort, IMO

moving the engine over a bit and spacing the rear sprocket out are the preferred options.

What's happened to the original engine?

Can you put up some pics? I can put you in touch with people with more engineering experience

moving the engine over is an option but it will offset the balance of the machine ok if your not fussed on speed and handling i supose

 

[chunkolini]

Unable to picture this at all.
A Honda 250 motor in a scooter? Surely on a scooter the motor and drive thingies are all built into the swingarm.

However I can remember reading about the maniac who in the late 80's was grafting yamaha LC350 motors into scooters. A mad bastard* if ever there was one. But what a laugh that must have been at the traffic lights...............

Chunko'.
*apologies for lapsing into profanity, but what else could you call him?

 

[breezer]

RD350 & RD350LC engines in Lambrettas is a common-ish thing to do.

Back in the late 80s quite a few were made by Frank Sanderson & Alan Rosser from Lancashire under the name of Rossa's. Apparently Alan raced a Sierra Cosworth up on the A64 into scarborough & beat it.

Rosser was allegedly something of a bad lad / chancer character and was found shot dead in his garage after previously being kidnapped, beaten with iron bars & dumped at the side of a motorway somewhere. Frank is still doing bike engine conversions into Lammies as well as automatic scooter engine implants.

 

[breezer]

http://www.youtube.com/watch?v=1r10vlLUbig

and here is Rosser himself attracting a little attention... both good & bad

http://www.youtube.com/watch?v=B2AUBRfOrSk

 

[awemawson]

Sounds more like a Scrapheap Challenge bodge rather than an engineering solution

 

[brightspark]

Sounds more like a Scrapheap Challenge bodge rather than an engineering solution

half of them are skinheads on wheels

 

[RedOrZed]

moving the engine over is an option but it will offset the balance of the machine ok if your not fussed on speed and handling i supose

depends on how far. 6" over yes, a couple - not really. It's not a precision race bike here

 

[Mattd]

Not that easy

Thanks for the comments and to answer some of the points raised.

The engine fits within the frame and under the body, therefore apart from the points raised about centre of gravity if the engine was moved to one side it would not fit under the body.

The cog needs to move up the output shaft (closer to the oil seal), not further along it.

The Zundapp Bella (1954 250 cc and electric start, clever Germans !, Oasis Be Here Now Album cover) has the engine central under the body and connects to the rear wheel via tradition chain drive, not direct drive connected to the back wheel like most scooters.

The problem there are virtually no spares about, despite being member of owners club etc, and wanted something easier to service, maintain and has more power. The Honda engine I am using is a CD 250 Twin Carb which should do the job nicely, along with Honda wiring loom

Would be extremely interested for the contact, for the engineering company who may be able to help, as I believe the only option is to shorten the output shaft and reconnect the cog in the same manner as it is now.

Thanks

 

[Pete.]

I know someone who has one complete with engine.

 

[murex400]

RD350 & RD350LC engines in Lambrettas is a common-ish thing to do.

what a engine 3rd bike i owned (rd350 ypvs) rember the guy in the shop sayin to take it easy as it was a big step up from my dt 175 mx , went back after 2 weeks got the power valve wound out etc god i loved hiting that power band was a quick bike till a montego pull out in front of me love to have a go on a scooter with on fitted must be madness

 

[Ratcatcher]

Personally i wouldn't even attempt trying to weld it,the reason being the shaft is hardened steel,the cog is/will be softer and you've got the problem of the seals burning away......
As with all things it's dead easy welding two similar metals but much harder welding different,whilst there are rods out there you've got to think about the stress incurred on the joint especially after the heat from a weld..
What i'd be inclined to do is this:Take the shaft out after measuring and visit a good machine shop and ask them to cut a keyway........
No real heat involved,both steel types keep their strength and it's dead easy to remove afterwards if they can cut a lock into it as well.......
In the past i've welded an old bike of mines kick start and it lasted a week before going,the result was a new engine!!!!!!!!.
Hope this helps even though i hate scooters.......

Rat.

 

[Pete.]

You can weld output shafts no problem, I've seen several bodged in such a fashion over the years. Motorcycle sprockets run on splines anyway so you don't have to weld the sprocket to the shaft, just put weld on the shaft to stop it coming off. That said, if the idea is to weld a sprocket to a shaft with a non-matching spline, I'd forget that idea.

The best way to fix this is to have a sprocket made with an offset. You can have any spline/tooth pattern/off-set you can think of for around £50 by John Hemmings Engineering 01547 530759.

 

[paul33]

I agree with Pete Have a dished sprocket made. I have welded nuts on the end of gearbox shafts to hold sprockets on when the threads have been completely knackered. Its the sort of thing to do to give the the kids a few more miles on their field bikes, some of these bodge ups have lasted for years!

 

[Flathead_Dave]

+1 for the offset sprocket.
If you want to mock it up to check position,or even make your own,try this.
Get a second sprocket and drill two holes in it 180 degrees apart.
Put both sprockets on shaft to index them and spot through.
When both are drilled for good fitting bolts,mark them for position.
Heat centre of inside sprocket to soften,then bore out spline,and grind teeth from outside sprocket.
Bolt the two together and fit to shaft.If it needs moving in more,fit spacer between sprockets.
You can then use as sample to get one made or rivet/weld them together.
Six 6mm csk soft iron rivets should do the job,but you'll need around 14 tonne to press them,one at a time.

 

[Robotstar5]

Zundapp Bella related - a chap I went to college with came from family of bike (and car) restorers, him and his 2 brothers were each given Zundapp Bellas in boxes by their father as a "trade" test, when they had restored them to show condition they were allowed to work on other bikes/cars in the family!.
I visited the house a few times to see the bike collection (30+) ranging from 1927 Levis to 1970's CB750

 

[Mattd]

I get it, I think

Pete / Paul33

Thanks for the comments hadn't thought about your proposal.

If I can just make sure i understand what you are saying, I should use a second sprocket sitting higher up the splined output shaft (the cog is the correct one for the splines on the output shaft) however the second cog which will be the drive cog will be fixed to the original cog using the original fixing method.

If I have got it right makes sense, and know a local engineering shop that should be able to help.

Cheers