Honda 750 with Kubota Z482

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Re: Honda 750 with Kubota Z482

Post by alexanderfoti » Tue Jun 24, 2014 11:32 am

I have piped my fuel return into the pipe from the tank, before the lift pump + Filtres. . Seems to work ok.

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Re: Honda 750 with Kubota Z482

Post by coachgeo » Tue Jun 24, 2014 11:37 am

Pretty sure hot diesel fuel does not negatively affect performance in a diesel engine. Actually it may improve it cause it will become less viscous and fumigate into the cyclinder more finely allowing for more complete combustion. The question is though did the engine designers intend to have fuel help lubricate the injection pump. diesel is an oil remember. also did they intend the incomming fuel to help COOL the injection pump a little bit. Less viscious oil does not lubricate as well and obviously hot diesel won't cool it as well. On the Kubota.. I dont know??

I forget... does the kubota have both a injector overflow/ return line AND a injection pump overflow/return line?

I will say many many who have done Veg. Oil conversions have plumbed returns back into the feed line. Does your fuel filter have a return line directly or indirectly? Some OEM filter housings are also the systems fuel air bleed and this you must consider when replumbing the fuel system.

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Re: Honda 750 with Kubota Z482

Post by albertaphil » Tue Jun 24, 2014 2:18 pm

Hot fuel is less dense than cold fuel and injection pumps work by volume, not mass. I learned this when I noticed my tractors would lose power as the day progressed. On a hunch I installed a fuel cooler and it solved the problem. New tractors are made with fuel coolers.

Having said that, it seems that keeping fuel hot IS the game with WVO, so it would depend on what kind of fuel you plan to run.

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Re: Honda 750 with Kubota Z482

Post by coachgeo » Wed Jun 25, 2014 2:30 am

albertaphil wrote:Hot fuel is less dense than cold fuel and injection pumps work by volume, not mass. I learned this when I noticed my tractors would lose power as the day progressed. On a hunch I installed a fuel cooler and it solved the problem. New tractors are made with fuel coolers.

Having said that, it seems that keeping fuel hot IS the game with WVO, so it would depend on what kind of fuel you plan to run.
Interesting... thanks for that tid bit. Wonder if that has more to do with how the accelerator portion of the injection pump for tractors is set up compared to thosed used for automotive. hmmm.

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Re: Honda 750 with Kubota Z482

Post by pietenpol2002 » Wed Jun 25, 2014 3:40 am

Thanks to all for the feedback and the accompanying discussion. After furher research it appears elevated temperatures are quite undesirable. Coach's points related to IP cooling and lubrication being 2 key factors. Below is a link to a very interesting paper addressing the matter on a TDI forum. And then we seem to be nearing the point that this discussion should be moved to the "Fueling and Injector Issues" section.

http://forums.tdiclub.com/showthread.php?t=20401

For the record, below is this evening's results. Exactly 5 hours to produce 2 simple brackets for the brake cable. And life is good.
6-24-14 Honda Kubota 009 Resized.jpg
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Re: Honda 750 with Kubota Z482

Post by Nanko » Wed Jun 25, 2014 9:17 am

In my opinion cooling or heating has very little effect on performance.
By the time the fuel reaches the combustion chamber it has the same temperature as the injector which is thermally connected to the cilinderhead
The volume of liquid inside the injector is large compared to the injected volume,time enough to heat up.
Last edited by Nanko on Wed Jun 25, 2014 2:04 pm, edited 1 time in total.
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Re: Honda 750 with Kubota Z482

Post by alexanderfoti » Wed Jun 25, 2014 12:47 pm

Mercedes W210 E320 CDI has a quite sizeable fuel radiator at the back of the car on the underside, about the size of an oil cooler from an XJ600. I wonder if its for fuel return as its a CDI system so the fuel has to be pretty toasty on its way back to the tank.

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Re: Honda 750 with Kubota Z482

Post by pietenpol2002 » Mon Aug 04, 2014 11:22 pm

Today's result. And Freud would be pleased with the placement of those power controls.

Left to right as follows.
1. Starter pull handle from Pratt & Whitney aircraft engine
2. Glow plugs fired by 60 amp starter button from 1937 Cadillac
3. Stop cable from Ford diesel tractor
030 Resized.jpg
029 Resized.jpg
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Re: Honda 750 with Kubota Z482

Post by coachgeo » Tue Aug 05, 2014 3:51 am

Love your selection of practical Gizmo's with an almost steampunk attitude.

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Re: Honda 750 with Kubota Z482

Post by alexanderfoti » Tue Aug 05, 2014 7:12 am

Looks great! Make sure you tie the stop lever to the "Throttle" and not the decompression lever.

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Re: Honda 750 with Kubota Z482

Post by pietenpol2002 » Tue Aug 05, 2014 1:00 pm

Make sure you tie the stop lever to the "Throttle" and not the decompression lever.
Fortunately, the Kubota has a dedicated shut-down lever on the pump to couple the pull cable to. But no decompression lever. We'll see how kick starting goes.
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Re: Honda 750 with Kubota Z482

Post by alexanderfoti » Tue Aug 05, 2014 1:18 pm

pietenpol2002 wrote:
Make sure you tie the stop lever to the "Throttle" and not the decompression lever.
Fortunately, the Kubota has a dedicated shut-down lever on the pump to couple the pull cable to. But no decompression lever. We'll see how kick starting goes.
Ah completely forgot its a 482, even though its in the title! :oops:

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Re: Honda 750 with Kubota Z482

Post by pietenpol2002 » Thu Aug 07, 2014 2:18 am

For mock-up purposes I hung the girder today. The shot below in silhouette is intentional as I suppose I don't possess the confidence to reveal all the unsorted bits. The math seems to be working out quite well with roughly 4" of trail. I have a rebuilt set of later model 750 forks to bolt on. But, I've always wanted to do a girder. Whereas telescopics under full compression (i.e. hard braking) can reduce the trail and wheelbase by as much as 4'', I was able to set this up such that the front axle travels almost vertically when the suspension is compressed. Should make for better handling when braking in turns. Time will tell. All needle bearing pivots and aluminum construction makes for light and smooth action. But, plenty to do yet until it's fuly functional. Suggestions and critique are most welcome as I'm swimming here in uncharted waters.
Honda Kubota 8-6-14 008 Resized.jpg
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Re: Honda 750 with Kubota Z482

Post by pietenpol2002 » Fri Aug 08, 2014 1:03 pm

And then the week's work was interrupted by an intruder in the shop in the form of an AVL Enfield needing the dreaded starter sprag cllutch replaced. The sprag clutch wasn't the hard part. The hardest part was looking at the Enfield, and then looking at the Yanclones, and thinking.........................................
Perhaps when I get back there this morning they will have snuggled up and mated sometime during the night.
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Re: Honda 750 with Kubota Z482

Post by pietenpol2002 » Mon Nov 17, 2014 12:56 am

Here's another question for the board. You'll note from some of the pics in this build that the oil pan is at an angle that may question the abilitly of the oil pickup to do it's job. From Mouse's rebuild you can see what that pickup looks like.

http://www.aarrgghh.co.uk/ratbikes/Z482/Z482_21.jpg

My question is this. What if I cut off the circular pickup and attached to the pickup tube a cylindrical screen (like the one below) that would be positioned near the bottom of "V" in the angled oil pan? It would require welding or brazing a fitting to the tube with the screen then threaded to the fitting. The oil dip stick will of course require modification no matter what I do. Other suggestions????

http://www.surpluscenter.com/Hydraulics ... 9-7884.axd
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Re: Honda 750 with Kubota Z482

Post by coachgeo » Mon Nov 17, 2014 2:18 am

can you put a box inside the oil pan that causes the oil to sit level with the engine tilted? A baffle sort of thing like they do in a fuel tank. Holes in the low middle or bottom of the box sides. Thus when bike leans the baffle helps keep oil at the pickup instead of off to one side partially starving the engine of lube?

Other wise if you got a steel pan just cut it offan inch or so from the rim and splice in a wedge of sheet steel to the sides of pan tilting the pan bottom back to level with the engine tilted?

For either you might have to splice in a bit of tube to the oil pickup before the screen, to move it down further into the oil?

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Re: Honda 750 with Kubota Z482

Post by Mouse » Mon Nov 17, 2014 10:20 am

When I tilted the VW engine over I had the same concern. What I did was fill the removed sump pan with the normal amount of oil quantity but actually used water so not to make a mess. Then I tilted it to the working angle keeping mental note of where the pickup sits and how far the dip stick protruded into the sump pan area . For that engine it made no difference at all because the pickup was always well below the minimum dip stick depth.

As this is an industrial engine there will be several sump options and therefore several pickup tubes will be in production so it is worth noting which would be the shallowest and compare your setup with that.
Kubota Z482 which is plodding on with unnerving reliability. Three years so far.
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Re: Honda 750 with Kubota Z482

Post by pietenpol2002 » Mon Nov 17, 2014 12:13 pm

Thanks for the suggestions guys. And the reminder to stick with the rule of parsimony "simplest of two competing theories is to be preferred". My tendency is toward greater complexity. So, I'll step away from the angle grinder and test whether the existing design is sufficient.
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Re: Honda 750 with Kubota Z482

Post by pietenpol2002 » Mon Mar 23, 2015 2:01 am

Just an update that I've been packing things up as I'm in the process of moving the entire shop and thus no progress on the build. No small undertaking. Stay tuned.
Ron
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Re: Honda 750 with Kubota Z482

Post by BoxerOtto » Mon Mar 23, 2015 3:29 am

i think you will have great joy while riding your bike, it looks excellent. i'll be keeping an eye out for your progress into boosted territory.

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