Denso 40 Amp Alternator

#1

Some Background. My Dressed 1000 and I spend a lot of time at the tunnels and bridges in the area parked in traffic. A lot of time idling in mid summer with the fan cycling on and off. I sit there and watch the voltage slowly going down. It is very nerve-racking so I have decided to up-grade the charging system. I have a 75 on the table that I am building so I am using that as my "Jig" to get this setup for my dresser.

This will be a several part document to show how to install a 40 Amp Alternator on a GL 1000. This particular model has an internal regulator which simplifies installation greatly. It does require a feedback circuit to tell it how much power to put out. I have contacted the Manufacturer to attempt to find out some rpm vers output info and such. My goal is to have at least 30% of max output available at idle. I thought while waiting for that info I would start the installation process.

Denso Part # 100211-4531 I saw one for 129 of Flea Bay but most go for 159 at tractor supply stores like this http://www.mascostartersandalternators. ... _list&c=12 I aquired mine through a friend and the price was right.

#1 Rule No criticizing my poor welds!!

Fore and aft alignment is not finalized yet so I have set it up to shift it minor amounts using washer stackups to adjust it.

The Upper Bracket required trimming to go around the frame tube. Also you will notice that it has not been slotted for belt tensioning. I am hoping to find a belt that will require minimal adjustment and once the drive pully size is determined I will resolve this issue.

Both brackets

Plain flat stock did not provide enough lateral support so I cut more peices and welded them to the back to stiffen them.

When bolted up it is plenty strong.

#2

Tch, tch, tch, just look at those welds

.

Seriously, great job so far. Do you think wet weather will bother that alternator in its exposed position? Very interesting project will be watching your results also interested in the wiring mods you will have to make.

tirejoe · #3

Way to go WF ! You will love the improvement in performance, water will not affect the charging of external alternator.

#4

I am not going to criticize the welds but that frame could use some touch-up paint.

Nice job, I look forward to the rest of the thread.

#5

Sagebrush wrote:Tch, tch, tch, just look at those welds .

Seriously, great job so far. Do you think wet weather will bother that alternator in its exposed position? Very interesting project will be watching your results also interested in the wiring mods you will have to make.

It is an heavy duty alt from a John Deere Tractor. Meant to be out in the weather. You should have seen the crap that came out of it when I hit it with 120 psi

I did a bench run and it works fine.

#6

straight forward wiring. output post-heavy wire directly to battery. yellow wire- to switched 12V positive. brown wire is for dash light that indicates charging.m [idiot light] one to one pulley size, charge comes on about 1500RPM

#7

Thanks Doug. Pretty sure you told me all that before but what I am wondering is if I over drive it a bit to get charging at idle on the bike can it handle the higher rpm for the long term?

I know most tractors are traditionally low rpm and high torque machines. And I would think that something designed for that application would also be rpm limited? If I set this up with a 1.5 to 1 drive ratio to achieve 1500 on the ALT at engine idle will it hold up to a constant of 6k while running the bike at 70 mph and often much higher bursts? Over gearing it 50% when I hit redline on the bike would result in the ALT turning at 12k. that is my area of concern?

#8

should not be a problem. the tractor engines turn at about 3000 but the alt. is over drivin to about 6000. one to one on mine i ran at 5500-6000 at highway speed with the G.E.M. rearend for years with no problem. worst case the bearings are easily replaced. if it don't hold up let me know, i'll get you another one

lsgyger · #9

Glad you're doing this on a '75. Might be an interesting mod to make for mine. Keep up the good work, WF, and I'll be following this closely.

BTW, since I don't weld, I think your welds a fantastic!

detdrbuzzard · #10

making your own "poorboy kit" ? dan is working on one too for his 1100

#11

Alright Doug you convinced me, I will work on the pully based on a 1.5 ratio. If she grenades, she grenades

#12

don't think it will WF. but if it does, let me know. i have spares on the shelf. same price as the last one

peteybug · #13

Great idea Wf. thought I was the only one that put non bike parts on a bike!

I,v thought about putting an alternator where the tool tray is and running a shaft out the front with carrier bearings.

#14

peteybug wrote:Great idea Wf. thought I was the only one that put non bike parts on a bike! I,v thought about putting an alternator where the tool tray is and running a shaft out the front with carrier bearings.

I love my tool tray but that is a very interesting idea. 8)

#15

straight forward wiring. output post-heavy wire directly to battery. yellow wire- to switched 12V positive. brown wire is for dash light that indicates charging.m [idiot light] one to one pulley size, charge comes on about 1500RPM

Interesting where tractor engines have gone in the last 50 years. My dad's old '56 Super 88 Oliver Diesel topped out at 1700rpm.

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Denso 40 Amp Alternator

Denso 40 Amp Alternator