Kubota Z482, BMW R series conversion.

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Mouse
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Kubota Z482, BMW R series conversion.

Post by Mouse »

Just Realised I didn't cross post this from the Rat Zone.

This is the latest in the continuing saga of the next diesel project. The engine is a Kubota Z482 twin cylinder 13.5hp engine from a lorry refrigeration unit. the last instalment saw the crank getting rebuilt as the big ends had gone.

This weeks task was to get the gearbox mounted onto the engine and then the whole power unit mounted into the frame. I want this to be a 'no cuts to the frame' project so it can be a legitimate engine change when it comes to paperwork etc.

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After faffing about for hours I cant work out if the engine will just fit or just not fit into the unmodified frame so theres nothing for it other than carry on regardless. Firstly the height of the clutch assembly is taken and 1.0 mm added for clearance.

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then support spacers cut to length.

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And placed in position ready to weld.

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But first I take my dial gauge and check the flywheel. the flywheel is OK but the gap in the main bearings is measurable on the dial gauge. After a brief check of the manual it is within tolerance but will have to be taken into a count a bit later on.

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The BMW airhead gearbox has an 8mm push-rod through its middle but the Germans being the nice efficient people we love them for made the hole an accurate 9mm. the upshot is a 9mm piece of ground bar is purchased for cheap and a point is cut on it. The upshot is this will locate in the hole in the gearbox and the accuracy of the ground-bar / hole is so tight it can be ignored.

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Pressure is kept on the bar end at all times to ensure it is correctly located on the engine shaft.

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Perfection. One end of the spacer bars has already been welded to the gearbox adaptor plate. This will allow me to slide the thing about until its aligned.

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The dial gauge is clamped onto the engine and pointed on the gearbox. Pushing from side to side there is a constant 0.15mm free moment when the gearbox is jiggled from side to side.

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After much jiggling and tapping I'm convinced it is located in the middle of the free play and the whole thing is welded solid.

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However after welding its not centralised. When I push the rod up to the engine shaft it is consistently pushed to one side, there is nothing for it but alter the centres of something.

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The direction for correction is marked.

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Then one side is filed away and the other bashed with a hammer (Oh for a proper blacksmiths anvil) so the metal is expanded and the hole is closed and so on....

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Eventually I'm convinced I cant get it any better as I reach the limit of my measuring devices.

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Then the whole assembly is put in the frame and jiggled about and chocked up on bits of wood and scrap until it goes in the frame.

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It rather looks like it should be there 8)
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Free space on the out put of the gearbox.

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The rocker cover can be removed so the valve clearance can be adjusted and the 710 cap accessed. :D

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This side of the engine clears the frame.

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So does this side.

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Perfection!!!

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The next problem is how to hold it all steady whilst I make the engine mounting brackets.

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After a really hot cup of tea I decide to simply weld it in place and then cut the welds away after the brackets have been made.

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Thus
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And thus, three points should do it. :)

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Left template.

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Right template.

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A conveniently sized bit of steel from the scrap skip last time I visited the steel supplier.

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Because a double bend is needed and I cant find my larger hammer and don't have a blacksmiths anvil I decide to cut the bracket in half so I only have to do one bend then simply weld the two bits together.

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Weldy, weldy, stick weld.

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Knock the flux away :D

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Same goes for the other side.

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Weldy, weldy, my house is on fire!!!! :shock:

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Another perfect weld :D :D

So that's it, the engine is mounted in the frame and no frame cutting or adaptation of the engine was required.

The list of things to do is almost infinite, so I'll have another beer and forget about it for the night. :D



.
Kubota Z482 which is plodding on with unnerving reliability. Three years so far.
1900 Diesel Bike being rebuilt with better clutch control.
Mouse
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Re: Kubota Z482, BMW R series conversion.

Post by Mouse »

Todays latest update

The engine is a Kubota Z482 from a lorry refrigeration unit but also fitted to the aixam micro cars and also still in production and used in many other industrial applications so all parts are available of the shelf 8) The engine was obtained for very cheap as it had damaged big end bearings that were repaired at a local engineering shop.

Since the uber fail the other day where the 1900cc diesel bike spat its con rod out at 70mph I have been rather busy and have basically got the thing finished in 7 or 8 days, thasts everything in this post. That's MOTd taxed and insured in a week which will explain the lack of attention to cosmetics, which is not unusual for me but I wanted this to look 'standard' The reason for the big rush is that I have NO transport until this is finished and being self employed that means no more money and winter has left me more than skint etc.

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This is how the bike was 8 working days ago, not including two days taking it to the MOT and a day lost to a much needed hangover.

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Basically the bare engine and gearbox in the frame with NO ancillaries at all!

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But it does look very nice.

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First was finishing of the flywheel, some spacers are needed

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Which are made and placed in position. The length is critical or the clutch pressure spring will be at the wrong tension ie to loose and slippy.

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Perfection.

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Then the bandit alternator was chosen again because of its size and comparatively high output of 35 amps. but to fit it a lay shaft is needed so another trip to the friend with a lathe and endless supply of tea.

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Bits brazed up and ready to fit.

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Mocked up in position.

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The shaft end support.

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Then on to the tank that I bought some 10 or more years ago for about £20 which was a song considering its was in apparent good condition. But ho hum the 1/4 bsp threads are stripped and damaged so neither pipe fittings or special custom cocks will fit.

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For a speedy mend I tried to braze some brass 1/4 pipe fittings to the tank only to be reminded that brass has a melting point very similar to braze and it all melted away.

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So that was ground off and more pipe fittings found which were soldered into place a return line was also fitted to the mystery third opening on the tank.

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Perfection!!

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The tank was fitted along with other stuff and the bike starts to take shape

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Some random offerings of exhaust down pipe were cut and brazed together to make a very convincing exhaust system.


No other photos were taken of the build because of a shitty camera and the shear pressure of not having any transport at all and several work deadlines that were starting to woosh past at an alarmingly fast pace.

This is the bike today on its first pleasure ride up to the friend with the magic lathe.

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Other technical points not photoed were the Stainless steel sump that a friend made, the battery mounting, wiring in general, the 10 hours it took top sort the rear master cylinder, the fuel filter and so on...

So far it rides really well and is heaps better than the single cylinder Royal Enfields I have used for several thousand miles.

Estimated top speed so far is about 60mph but it has a theoretical top speed of just shy of 75mph when I've tweaked the governor a bit to give its max of 3600rpm. The governor is set low because of the constant RPM application it was built for. The fuel consumption on the two visits to the MOT station have suggested about 110mpg but I was going reasonably slow and one return leg was at 30mph to stop it boiling because of a broken fan belt. I expect a sub 100mpg as a realistic everyday mpg and 120+mpg in eco mode 8)


I've done about 150 miles and hope to get some more on it before heading off Cambridge way on Monday for some expired work deadlines which will be a 500 mile round trip that may or may not include a trip home on recovery wagon.


I think that with the frame and tank painted and some attention to the rear end it should end up being more than acceptable.




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Kubota Z482 which is plodding on with unnerving reliability. Three years so far.
1900 Diesel Bike being rebuilt with better clutch control.
nanno
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Re: Kubota Z482, BMW R series conversion.

Post by nanno »

Lovely!
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zarquon
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Re: Kubota Z482, BMW R series conversion.

Post by zarquon »

In one word: RESPECT!
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Re: Kubota Z482, BMW R series conversion.

Post by Benzine »

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Re: Kubota Z482, BMW R series conversion.

Post by coachgeo »

you've got skills and knowledge I could only dream of.

I'm in awe :!:
Mouse
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Re: Kubota Z482, BMW R series conversion.

Post by Mouse »

coachgeo wrote:you've got skills and knowledge I could only dream of. :
Most of my 'moments of learning' have been sat on the grassy bank of the motorway waiting for a recovery truck :wink:

Knowledge by repeated failure.
Kubota Z482 which is plodding on with unnerving reliability. Three years so far.
1900 Diesel Bike being rebuilt with better clutch control.
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Re: Kubota Z482, BMW R series conversion.

Post by Stuart »

An inspiration to all :!: :wink:
pietenpol2002
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Re: Kubota Z482, BMW R series conversion.

Post by pietenpol2002 »

Just amazing. Your ingenuity and confidence is quite inspiring. However, it remains a puzzle as to whether your accomplishments are more the result of the tea or the beer.

This project could well be a candidate for entry into "YOUR DIESEL MOTORCYCLE BUILD PLANS" section of the board. Your mounting plates are easily copied, then replicate the trans adapter and it's a bolt-in for those so inclined. Obviously, it's far more work than that, but you may need to make time for a bit of business on the side. And thanks for the pics and narrative. Truly a joy to follow.
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Re: Kubota Z482, BMW R series conversion.

Post by henneberg »

Superb description with clear pictures. Very useful to do the same kind of rebuild. :idea:

I presume the lathe comes into action for the intermediate piece between engine and gearbox :?:

rgds, Erik
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Enfield Ruggerini MD151 654cc build - running: http://www.youtube.com/watch?v=b4UsIn5QLxk
Mouse
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Re: Kubota Z482, BMW R series conversion.

Post by Mouse »

pietenpol2002 wrote:This project could well be a candidate for entry into "YOUR DIESEL MOTORCYCLE BUILD PLANS" section of the board. Your mounting plates are easily copied, then replicate the trans adapter and it's a bolt-in for those so inclined. Obviously, it's far more work than that, but you may need to make time for a bit of business on the side. And thanks for the pics and narrative. Truly a joy to follow.
The transmission adaptor is rather critical as there is virtually zero free play in the clutch mechanism. Practically speaking there is only the gap between the clutch and shaft splines so I'd be uncomfortable making one without matching it to the actual engine it was going to be fitted to. In comparison i've done several electric motor / car gearbox conversions for a small local electric converter someone and the centre of a car clutch is almost floating which allows for a tiny bit of misalignment. This has also allowed me to build up some skill and experience.

I've already got one half serious interest in a engine conversion on a standard BMW and being self employed I'm eager to supply. If I do that I'll document it with greater care and maybe consider a 'kit' if I can detect some real interest.
Kubota Z482 which is plodding on with unnerving reliability. Three years so far.
1900 Diesel Bike being rebuilt with better clutch control.
Mouse
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Re: Kubota Z482, BMW R series conversion.

Post by Mouse »

Superb description with clear pictures.
Thankyou, although it was the briefest write up I can afford the time to do just at the moment what with deadlines wooshing past because of the other bike letting me down.
henneberg wrote: I presume the lathe comes into action for the intermediate piece between engine and gearbox :?:
Yea, The bmw gearbox mounting flange is circular and concentric to the input shaft. I'm lucky I have a willing friend with a lathe big enough to spin a sheet of steel big enough for the job. The face plate of the engine is held in place with engineering location pins. To use simple bolt holes would result in instant shaft / clutch / bearing failure because you would have a minimum of 1(ish) mm slop around the bolts and no hope of a repeated alignment after jigging it up. The flywheel is also heavily modified I'd say there was at lest two whole days on the lathe for lathe work for the adaptor alone not including actually jigging, fitting and alignment. Probably a skilled machinist could do it quicker but that is a costly option for me. If you didn't pick up on it I get it so there is no perceptible movement of the dial gauge which is a tedious procedure and not a job for the quick tempered :wink:
Kubota Z482 which is plodding on with unnerving reliability. Three years so far.
1900 Diesel Bike being rebuilt with better clutch control.
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old clunker
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Re: Kubota Z482, BMW R series conversion.

Post by old clunker »

I like your ideas of re-cycling old motorbike bits, and giving them a new lease of life!

I hope you get many, many, trouble free miles of biking out of your latest 'Frankenstein' creation!

Thanks for your efforts in putting up the build details, whilst grappling with the numerous engineering challenges. I'm sure that everyone here appreciates it.
There's nothing like the smell of burnt vegetable oil in the morning!!

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Re: Kubota Z482, BMW R series conversion.

Post by rednorfolk »

:roll: stunning bud, stunning. :D :D :D :D :D :D :D :D :D :D
Royal Enfield 406cc diesel.
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Re: Kubota Z482, BMW R series conversion.

Post by Sibbo »

Hi Mouse ,

I have access to an old R65 ... but the ratios are wrong for a diesel with a top rpm of 3600. Just for your interest these are the speeds on a stock R65 should you be offered one. This is a '79 R65 with a 31/9 stock final drive. It's not going to work as it stands but maybe with an R80 final drive?
3rd gear
30 mph (48.27 kph) = 3000
35 mph (56.30 kph) = 3500
40 mph (64.36 kph) = 4000

4th gear
45 mph (72.40 kph) = 3750
50 mph (80.45 kph) = 4000
55 mph (88.50 kph) = 4750

5th gear
55 mph (88.50 kph) = 4000
60 mph (96.54 kph) = 4500
65 mph (104.59 kph) = 5000
70 mph (112.63 kph) = 5500
75 mph (120.68 kph) = 6000

You say much better than the Enfield conversion....a bit more power but apart from that ? Noise? Vibration?

and mate , a brilliant job! Image
Mouse
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Re: Kubota Z482, BMW R series conversion.

Post by Mouse »

Scrub the R80 final and find a R100 33/11 , 3:1 final drive as its a bit taller than the R80 one. I find it's just about a perfect match for the Z482 engine and power. I get 60mph as a flat road and no wind top speed and about 65 absolute max down hill.
I will admit to not having a taccho to actually check I'm running at 3600rpm

Odometer currently on 5500 (andabit) miles and furthest from home currently stands at Leipzig area of East Germany so cant be that far out with build design and quality 8)
Kubota Z482 which is plodding on with unnerving reliability. Three years so far.
1900 Diesel Bike being rebuilt with better clutch control.
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Re: Kubota Z482, BMW R series conversion.

Post by arnaud »

I have a spare 33/11 final drive, type with cooling fins and drum brake pads..
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