Honda Rebel Kubota

[sideshow]

Do you have a picture of the front end? I'd love to see how that truck light looks as the headlight! Looking good!

-Alex

[UAofE]

So exciting, its almost ready to roll out!

Mounted the battery, finished the electrics. Mounted the battery to the right side of the swing arm. Its the only place I could find that wasn't either difficult to access or hanging too low to the ground. The EarthX ETX12A has plenty of power to crank the engine even without the decompression valve set.
The starter key switch is mounted to the engine shroud.




Still need to fabricate the exhaust, throttle cable and belt guard for it to be roadworthy. I was planning to do it tonight but the flying insects got so bad I decided to call it off and finish Saturday.




The oil cooler is also mounted to the engine shroud so the bike's movement can cool it. With that hole blocked off, the air normally going out the cooler will instead go over the block and head for additional cooling.
The Kubota OC95 doesn't have an oil filter proper, instead it has a series of meshes and magnets in the pickup tube. I added a external filter (NAPA 1085 or Kubota HH1C0-32430) inline after the oil cooler.




For sideshow. The horns are HELLA 003399801 Supertones, yes, they are loud.

[sideshow]

thanks! Looking great!!!!

[UAofE]

It lives!

Followed the forum's advice and ditched the stock dampened load screw for a solid socket head bolt.
Need to make a belt guard. Road tested taping my pants leg and shoelaces, my foot is right up against the clutch in riding position.
My tinytach is missing its transducer, probably still on the V-Twin yanclone.
EarthX battery crapped out on the first try cranking to bleed air out the the injection line.
I need to run a cable from the choke lever to the rack lever to shutdown the engine. Currently using a hooked rod.

Still some bugs to iron out before its roadworthy;
Voltage regulator doesn't work. Alternator puts out 25VAC at 2500rpm but zero current from the regulator.
The throttle bracket is too high. At full throttle its trying to pull upwards on the cable.
Handlebar blocks hit the fuel tank seam on full lock turns.

Its got decent enough power even without touching the full load screw from where I randomly installed it. Slight smoke on takeoff but none at full load and the oil temp didn't go above 150*F.
Easily maintains 45mph and current top speed of 55mph, but I have it geared for 70mph@3600rpm. Should have no trouble getting there with load screw adjustment.

https://www.youtube.com/watch?v=erjGB9YheUg

Straight pipe exhaust. Noise is fine in riding position but its VERY loud behind I am told.





Had to get a Royal Enfield part on the bike somewhere....

[alexanderfoti]

Looks great!!

I would be surprised if you can hit 70mph with 10hp, but let us know if you do.

[coachgeo]

I'm with Alexander. From reading in here pretty much everyone over the years with a 10HP has had same goal as you and no matter what they did, never got above a cruise ability of 45-55mph and not much of anything beyond that either. Go for it though maybe you'll find the magic combination?

[UAofE]

70mph may come with the turbo in a few weeks.

[alexanderfoti]

Aha, I have read many many failed attempts of the turbo on singles. They build boost but don't flow I belive. Will be interested to see your results.

My d850 will cruise at 70 top speed 75.

[UAofE]

First fuel fill: 6.1 hours, 105miles, 1.343gallons, 77.96mpg (all US measurements)
About 15mpg better than the stock Rebel gas engine. There is still room for improvement as the engine breaks in, I learn how to control it and the CVT more efficiently, and the turbo is installed.

Installed the windshield. Vibration broke a horn bracket and I lost it under the back tire.
3 of the 4 jackshaft setscrews also vibrated out. I used blue loctite the first time but I will use red this round.




Got the replacement EarthX battery. Still need to find/make a proper hold-down. The battery only weighs 1.3lbs so it doesn't add significant mass to the swing arm assembly. (The stock lead-acid battery was mounted to the swing arm a little further forward in the center)

[alexanderfoti]

Excellent numbers. I have no doubt you can get that up to 85-90 US MPG, my yanclone averaged 113 with mostly town riding, a nice slowish open road would give 150+ (uk figures)

[UAofE]

Another point I just remembered is we filled it with the bike vertical on a swing arm stand while its normal fueling position is leaning on the side stand.

The odometer is accurate according to my iPhone's GPS, but the speedo needle lags considerable behind actual speed. Cruising it catches up to actual speed but, for example, stopping from 45mph it will still be slowly coming down from 25mph by the time I am at rest.

[UAofE]

Did a 145 mile run today, 1.51 gallons, 96.24mpgUS.

Need to figure out how to adjust the driven clutch to hold RPM longer. It accelerates great at 3600rpm up to exactly 45mph then the clutch upshifts the belt 1/2", the engine lugs down below 3000rpm and I can't make it downshift to keep RPMs up and accelerate.
I will make a post in the CVT section.

[bf109v7]

Does the enginge have much more power at 3600 than at 3000? The main use of this engines is a 50Hz Generator, and threfore the best power is normaly at 3000.
But your Thead here is very interesting for me. I want to put a M.C. KAWASKI Diesel (Yanmar clone) in a 250 Kawaski EL. And use the same belt converter. I testeted the engine in al boot, and tried also to torbocharge it. die not deliver more power with the charger, so I took it of. I am waiting now for the converter to come from the Staates to me to the Philippines. It is on the way now 9 Weeks.
Alex

[UAofE]

Yes, that 1hp is noticeable. The engine's best efficiency to power ratio is at 3000rpm.

You can see the clutch shifting up early is a big problem as the engine is only making 7.75hp at 2500rpm instead of 9hp 3000-3600rpm.

[UAofE]

The rain gnomes must have been out last night, my speedo started responding to road speed correctly.

[UAofE]

246miles, 2.425gallons, 101.44mpg(US)!


I intended to fit the turbo last night but I ended up doing a bunch of repairs instead.
I discovered the headlight housing had failed. Another mile and it would have fallen off. No time to wait for a replacement so I just welded this one back together.



Disassembled the drive clutch. It had a fair bit of dirt in the outer cover but the weights, springs and belt surfaces look very good. I applied some of Comet's dry lube to the weights working surfaces.
Couldn't figure out how to disassemble the driven clutch.
Reshimmed the chain drive sprocket 3mm right to correct some tooth wear.
Relocated the horn to the chassis frame. 3rd horn died in less than a week mounted to the front fender.

Installed a shutdown cable utilizing the old handlebar mounted choke lever.

[UAofE]

I have decided to push off the turbo indefinitely.

The intercooler I have is just too awkward to plumb in the time available. My friend that is letting me use his garage and machinist equipment is leaving for Iceland next week, and I have have major plans most of September.
So instead I will make a new exhaust today and incorporate the MagnaFlow 53103D diesel catalyst as a muffler.

http://www.summitracing.com/parts/mpe-53103d/overview/

[UAofE]

That sprocket made a huge difference! It now accelerates properly 30-45mph, I can maintain 45mph in areas I would have dropped below 35mph before and I can reach 55mph on flat ground.

Oddly though, it still locks into high range at 45mph as before but now have better torque to continue accelerating.


The exhaust is also finished. The catalyst make a very big difference in noise, at idle the engine itself is actually louder than the exhaust!



I also modified the front forks with a 1/2" spacer on the springs and an extra 1/2 oz 15wt oil each. The ride is a bit more bouncy but it also doesn't nose dive as bad stopping.

[bf109v7]

That sprocket made a huge difference! It now accelerates properly 30-45mph, I can maintain 45mph in areas I would have dropped below 35mph before and I can reach 55mph on flat ground.

Oddly though, it still locks into high range at 45mph as before but now have better torque to continue accelerating.


The exhaust is also finished. The catalyst make a very big difference in noise, at idle the engine itself is actually louder than the exhaust!



I also modified the front forks with a 1/2" spacer on the springs and an extra 1/2 oz 15wt oil each. The ride is a bit more bouncy but it also doesn't nose dive as bad stopping.

Is your diesel engine much havier than the original gas engine?
And it in the description of the catalyst it says it it free flowing. so I would not expect any silencing efect. I ran my diesel in a boat to test it and to break it in. And I ran it with an open pipe as exaust. And not only in idle, the loudest noise comes from the engine itself.
Alex

[UAofE]

Is your diesel engine much havier than the original gas engine?

Service manual says 86lbs. Kubota says 121lbs (30lbs of it is the flywheel).

And it in the description of the catalyst it says it it free flowing. so I would not expect any silencing efect.

The ceramic cells absorb pulse energy and the honeycomb structure breaks up flow.

[UAofE]

8.0hp, 17.6ft-lb (wheel horsepower, uncorrected)
Just about what I expected for being at 5200ft altitude.



It still runs rich, I need to be more aggressive on the fuel bolt adjustment. Economy dropped to 87mpg because I tried to maintain 55mph on some steep hills.
The CVT belt is starting to chirp off the line.

[UAofE]

Altitude testing was a disappointment.
By 9500ft engine power was so down it didn't have enough torque to make the CVT downshift at all. I was crawling at 30mph @ 2600rpm max.
I was attempting to summit Mount Evans (14,160ft) but I was forced to turn around by Squaw Pass (9,807ft).

A turbo wouldn't be much help in these conditions because I would lose boost at every turn and likely wouldn't be able to build up enough RPM to spool it back up.
I might have to look into a supercharger instead. I have an exposed area on the crankshaft that might provide enough room for a pulley.

[UAofE]

I had been having an occasional issue with the battery shutting off while riding. All the fuses and connections check out and everything returns to normal after sitting overnight. I figured it might be the ripple from the permanent magnet alternator so I installed a filter capacitor.

Ripple before was over 400mV at 3000rpm. After is 35mV max at all speeds.
The immediate difference is a 10rpm increase in idle speed when the capacitor fuse is put in and no flickering of the headlight.

http://www.bandc.biz/electrolyticfiltercapacitor.aspx

[UAofE]

The catalyst exhaust was quiet and I liked that the cat was functional. However, the pipe kept breaking just after the first support.
So I put the original drag pipe back on but added a baffle insert to quiet it's extreme noise.





I also decided to remove the starter. The battery and starter work very well together, its the 5amp alternator. It just doesn't have enough power to operate the glowplug, run the lights and recharge the battery from such a significant drain. At best I was getting one crank per week out of it without the battery's low-voltage cutout kicking in.

[UAofE]

Today I drilled out 3 of the 9 CVT driver weights from 56g to 38g. That takes the mass from 504g to 450g. I tried just 6 pucks (336g) but that just resulted in the engine revving its nuts off without actually putting down much power.
The result is 2000rpm engagement with 2600rpm takeoff (vs 1900/2400 stock), accelerates 30-45mph much easier, has a flat ground speed of 55mph instead of 45mph, and can maintain 45mph up hills instead of dropping to 35mph.

[UAofE]

I got tired of the intake drone from the open filter so I went junkyarding for a new filter yesterday. I found a perfect fitting airbox, from a 1998 Honda Civic DX.
I used a 2.5" to 1" reducer pipe, glued aluminum sheet to the back side for a heat shield, and the snorkel I forget what is from (I think from a Chrysler).

https://youtu.be/cEtbkPmR4H4

It eliminated the drone and actually gives it a much deeper rumble instead. I might put some foam in the lid to quiet it down a bit more.

I need to make a support bracket tonight, then I will post pictures.

[UAofE]

Finally got the tank stripped. It had 2 pounds of paint in 8 layers.

[UAofE]

Got the tank painted, mounted and filled with 2.8g of B20.

Pictures of the air filter box

[UAofE]

I will be taking the bike to Diesels On The Mountain June 4th.
You can watch it remotely on DieselTV. http://www.nhrda.com/media_videos.php

[UAofE]

Changed the front sprocket to 13 tooth. I can now maintain 40mph on hills and top out at 50mph on flat road. With any amount of road decline I can hit the 60mph gear limit easily, whereas before with the 14 tooth I couldn't hit the 65mph gear limit even with long declines. I may switch to a 12 tooth after a while.

Diesels on the mountain went well.
27.165 @ 45.69mph with intake silencer and exhaust baffle
26.343 @ 47.31mph with cone filter and open exhaust pipe.



https://youtu.be/m6BIil9hvto