CX500 Kubota

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Eddy Wane
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Re: CX500 Kubota

Post by Eddy Wane » Wed Jan 21, 2015 11:51 am

Hi Stephen.
Love the build. It is interesting to see how you have shoehorned the motor into the frame. I have one question. What did you use to mate the driveshaft to the engine? Is it the original Honda part from the CX or custom built?
I am still on with my build using the CX and a Kubota twin but work has stagnated on the bike at the moment. I just realised there is only 24 hours in a day.
Eddy.
Building the bike. Top of my list, bottom of the wife's.

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coachgeo
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Re: CX500 Kubota

Post by coachgeo » Wed Jan 21, 2015 4:25 pm

pietenpol2002 wrote:Thanks for those detailed pics. Always helpful to study how someone else puzzles through the design process. Again, an excellent piece of engineering. Which then leads to the question - and what form will your chain drive take? Do you plan to use a CVT? A gearbox? And the engine - transverse? North/south orientation?
A previous post answers your questions as does his initial pictures of his running shaft drive diesel Honda bike w/north south engine. He finished the bike before he posted his build report so the build report is sorta back assward from what is usually posted 8) Finished bike posted first and detail following.
garbs wrote:The drive system is fairly complicated.

An 80 tooth htd pulley mated to flywheel drives up to a 40 tooth htd pulley. On the 40 tooth pulley shaft is a comet 40 series primary which drives down to the secondary. On this secondary's shaft is a 10 tooth sprocket which drives over to a 16 tooth sprocket on a shaft which is mated to the shaft drive through the stock u joint. I didnt drive the cvt right off the crank because I didnt have enough room to fit a cvt large enough to handle the torque of the engine. This is the reasoning behind the 2:1 ratio of the htd pulleys, the torque is reduced by 50% allowing me to use the smallish 40 series comet. The sprockets after the cvt are used to get the correct final ratio as the ratio in the shaft drive rear end is fixed. ....

garbs
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Re: CX500 Kubota

Post by garbs » Wed Jan 21, 2015 4:34 pm

Coachgeo: Pietenpol was not asking about my first bike. He was asking about my second build. He knows my first bike was shaft drive and as I have mentioned I plan to build the second bike using chain drive. I mentioned how I had to removed this engine for use in my second chain drive build so he asked " Which then leads to the question - and what form will your chain drive take?"


Pietenpol: The second bike will have the engine mounted transverse driving a double v belt up to a jackshaft 1:1 ratio high behind the engine. The primary clutch of a cvt will be on this jackshaft driving down to the secondary on another jack shaft which will be connected to the rear wheel via chain. Reason for doing it this way is:
My engine is already long and will stick out each side. I determined that two 3v narrow v belts can take the power and be quite narrow compared to a primary clutch mounted on the engine 2" vs 5"-6".The secondary will be tucked within the frame and away from my foot area. Im not a huge fan of the look of clutches being mounted on the side with a big cover, I know it works well and many bikes have been built using this mountig that are very nice, its just not for me. I will be using a comet 94c duster and an appropriate secondary which are much bigger than the comet 40 series clone I used for the first bike. The second bike is being built using a goldwing frame. That plus having the engine sideways, means the secondary should just fit behind the engine. The picture shows the layout with the mockup I bult for the 40 series. The reefer oil pan will be replaced with a regular pan.
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Last edited by garbs on Wed Jan 21, 2015 4:51 pm, edited 1 time in total.

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Re: CX500 Kubota

Post by garbs » Wed Jan 21, 2015 4:44 pm

Eddy: I am very fortunate to know a very skilled machinist. I took the whole driveshaft unit to him together (long shaft from diff, u joint and short shaft to engine). The u joints are part of the shafts and are not removable. I didnt want to screw around with the joint as it looked to be in very good working order. He was able to cut the shaft off of the engine side joint, then hollow the joint out for a 4" long 1" shaft to be pressed in. A hole was machined through both and a stainless steel press fit pin pushed through and finally the ends of it were crushed out to hold the pin in. This was all done while the joint was still connected to rest of the driveshaft unit.
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The shaft has to slide into the transmission as it is the whole engine tranny unit is pushed into place. This is a HUGE pain in the ass but manageable.

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coachgeo
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Re: CX500 Kubota

Post by coachgeo » Wed Jan 21, 2015 5:20 pm

garbs wrote:Coachgeo: Pietenpol was not asking about my first bike. He was asking about my second build. He knows my first bike was shaft drive and as I have mentioned I plan to build the second bike using chain drive. I mentioned how I had to removed this engine for use in my second chain drive build so he asked " Which then leads to the question - and what form will your chain drive take?"
thanks for clarification. Apparently I was comfuzed :oops: .

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Re: CX500 Kubota

Post by garbs » Sun Nov 19, 2017 2:41 am

I figured it was time to update my build thread. Since my last posts here I have done a bunch of work on a chain drive converted honda goldwing project (put on hold for now). I then went back to this build and swapped the 3 cylinder out for a two cylinder z482 engine allowing me to relocate the radiator up front and allow greater access for maintenance, repairs, and adjustments. My new engine has a normal style oil pan which is much lighter and frees up even more room on the sides of the engine. I also went for a stock manifold into a single straight pipe for the exhaust as opposed to the three pipes I had before. The transmission has for the most part remained the same in design but has definitely been refined/simplified from the original. Since these pictures it has been updated again, I will get pictures of that soon. The great thing about kubotas engines is that the super mini series share the same engine block architecture so all of the custom bits I made for the three cylinder, bolted right onto the two cylinder. Feel free to ask any questions about it, I will do my best to get back with answers promptly.

garbs
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Re: CX500 Kubota

Post by garbs » Sun Nov 19, 2017 2:46 am

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garbs
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Re: CX500 Kubota

Post by garbs » Sun Nov 19, 2017 11:30 pm

Pics of the refined transmission
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garbs
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Re: CX500 Kubota

Post by garbs » Sat Apr 14, 2018 10:41 pm

I am currently rebuilding my bike with a 3 cylinder Kubota as was originally used. Basically the same design as the original build (back to rad under the seat) but everything has been refined to be lighter/smaller/easier to service. Here are some pictures of the new parts I will be using and some of the ones I had modified/redone. I will be glad to answer any questions.

garbs
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Re: CX500 Kubota

Post by garbs » Sat Apr 14, 2018 10:42 pm

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The new to me D722 engine. The original got swapped into a John Deere Mower

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Re: CX500 Kubota

Post by garbs » Sat Apr 14, 2018 10:43 pm

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New oil pan to replace the huge heavy reefer style pan

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Re: CX500 Kubota

Post by garbs » Sat Apr 14, 2018 10:46 pm

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Rear exit manifold to replace top exit manifold on engine

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Re: CX500 Kubota

Post by garbs » Sat Apr 14, 2018 10:47 pm

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Black valve cover with low profile crankcase breather to match black oil pan

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Re: CX500 Kubota

Post by garbs » Sat Apr 14, 2018 10:50 pm

New high capacity Fan and Oil cooler which I will attempt to use as a radiator
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garbs
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Re: CX500 Kubota

Post by garbs » Sat Apr 14, 2018 11:02 pm

New sub-frame assembly designed so that the down tubes are easily removable to allow the engine and transmission combo to be slid forward to allow more space for service, repairs, adjustments. The new plates will remain on the frame under the gas tank, the down tube will unbolt at the top and slide off at the bottom. The down tubes are not fully slid on to the aluminum rails in the last picture as there are burs that need to be cleaned up first. Then a hole will be drilled through both and a bolt used to hold them together.
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garbs
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Re: CX500 Kubota

Post by garbs » Thu May 03, 2018 2:42 am

Making steady progress. Sub-frame pieces are fully assembled, the oil an has been swapped to a normal tin style, the stripped engine was mocked up and the extra pieces were all added, the transmission was assembled, and the gas tank got new front mounts that tie into the new sub-frame design. This is all for mock up and is not final assembly.
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garbs
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Re: CX500 Kubota

Post by garbs » Thu May 03, 2018 2:44 am

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Re: CX500 Kubota

Post by garbs » Thu May 03, 2018 2:47 am

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Re: CX500 Kubota

Post by garbs » Thu May 03, 2018 2:51 am

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