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How Much Hp Can Most Db's Take?


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#1 robbor OFFLINE  

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Posted February 04, 2013 - 11:50 PM

Ive got 2 david bradleys that havent run and been in storage for 30+ years. Im thinking about just swapping the engine rather than tinker with these old motors.  Anyone have any idea how much HP The DB gear boxes and axles can take?  I have a few brand new in the box honda motors 11hp, wondering if i will ruin anything if i dont horse it.  id like to run a plow in sandy soil thats full of smal cement chunks that need to be removed and normal soil with berry root clumps that need to be removed.

Also do thes tractors have neutral? in moving the tractor to its first daylight in years i couldnt get it to roll backwards, seems like it has one way hubs?  Im amazed these tractors are such low hp, expected 5 or so. I need to check the models i have.


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#2 DougT ONLINE  

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Posted February 05, 2013 - 12:00 AM

Welcome to the forum, Robbor. I think the biggest engine they used on the Bradleys was a 5 HP. On the other hand, if your not forcing it hard enough to break you should be alright. You might want to look at a potato plow to get the concrete chunks and the roots out. It will help seperate them from the dirt just like it does potatoes.

 

The tractor doesn't have a nuetral and is natural to pull hard backwards. The belt pulley needs to turn free to make it easier.



#3 Lauber1 OFFLINE  

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Posted February 05, 2013 - 01:37 AM

ive had a 10hp on one before, but i wouldnt worry you'll run out of traction before you tear up to many things.

 

ALSO WELCOME, to the site................. :thumbs:



#4 Alc ONLINE  

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Posted February 05, 2013 - 06:44 AM

Welcome to GTTalk robbor !   I'm new to the DB walkbehinds too , getting 3 last year and by all means get at least one going , I keep finding jobs that they can do so handy in the garden and around the house ( snow plow blade)  Oh yea,  please post some pictures



#5 Amigatec OFFLINE  

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Posted February 05, 2013 - 07:31 AM

Can we get some pictures please?? Also some model numbers will nice as well. If the motors will turnover, I may be interested in them.

#6 Moosetales OFFLINE  

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Posted February 05, 2013 - 07:44 AM

Welcome to GTTalk. Wow, you found a great "barn find" in your own backyard. As Amigatec asked, pictures please...you'll get use to us and know we LOVE to see pics and video of your machines.



#7 Virginia Mike OFFLINE  

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Posted February 05, 2013 - 08:05 AM

This tread brings a thought to mind.

An over powered DB will dig holes or, jump up and down, but has anyone ever seen a gearbox stripped or, with a broken chain?



#8 boyscout862 ONLINE  

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Posted February 05, 2013 - 10:39 AM

Welcome to GTT. If you change out the engines besure to save the originals in a safe place. Good Luck, Rick



#9 Steven N OFFLINE  

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Posted February 05, 2013 - 06:41 PM

Welcome and great hearing about your tractors. I have ran, I think an 8 or 10hp, in the past on one of my walk behinds with no problems. But I was always aware that it was over powered and concious to avoid any potentially harmful situations; but did not encounter any that concerned me in the projects that I was doing at the time. Good luck with your project.



#10 Amigatec OFFLINE  

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Posted February 05, 2013 - 07:01 PM

The problems I can see are the clutch, and the frame. On the first tractors they used spring clutches. For the most part these were used on tractors below 2 HP. When the 2 HP + motors were phased in, the clutch was upgraded to the Ball Lock type, these tend to slip less. On the 5 HP + tractors, most of these have a stronger 2 piece frame, the early frame were made from pipe and clamped to the side of the tranny, the 2 piece frame is made from steel rod and is bolted to the tranny. I have heard stories of the older frame bending when to much HP is applied. If you use weights and fill the tires you may get more traction then the clutch and frame can handle. The biggest motor used on these was 6 HP.
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#11 VSTROM803 OFFLINE  

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Posted February 07, 2013 - 04:30 AM

This tread brings a thought to mind.

An over powered DB will dig holes or, jump up and down, but has anyone ever seen a gearbox stripped or, with a broken chain?

Yes, I've seen two with stripped gears on the clutch shaft. I think that it was most likely do to neglect though. When the axle seals began leak I think some owners just neglected to keep a check on the oil level. These little tractors look to be built tougher than a lot of equipment I see with larger motors.


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#12 robbor OFFLINE  

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Posted February 07, 2013 - 04:59 AM

thanks all. Ill have to look up the model numbers to see exactly what they are. They look like the smaller models not 3hp but have to check. Motors wont be for sale.

Both are my dads that have been in storage for to many years. One is complete with the sickle bar mower, other is cowl off and stored no attachments on it. But i think we have a plow, cultivator. Was thinking about tire chains if i needed traction. ill check them next week. I also have a old riding tractor.mower to look at that would be more usable for my needs, same vintage as the DB, but with a gear box and a auto rear end.



#13 olcowhand OFFLINE  

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Posted February 07, 2013 - 10:08 AM

The original engines on the Suburban 4 wheelers was 5.75hp, but if compared to today's engines, they would hang right in with modern 10+HP engines.    I think they would handle 12hp easily.



#14 robbor OFFLINE  

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Posted February 16, 2013 - 10:30 PM

I got to look at on of the david bradleys the other day.  model 917.5751.

Pulled the plug and gave it a squirt of oil.  Checked the oil fill and was empty from  sitting tipped but clean n slightly oily so we filled it. Spin it over a few times with the plug out the we gave it a good squirt of starting fluid and she popped once on the 2nd pull and ran for a few seconds on the 3rd pull.  I dont really see anything to replace on the carb. fuel tank looks ok. will clean the tank just in case, grease the hub and try her out in a few days. I gotta check the oil in the gear case.

I took a quick look at tractor #2 looks atlot worse than this one, alot of rust.  Ill get it out this week and take a look.


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#15 Amigatec OFFLINE  

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Posted February 17, 2013 - 05:10 AM

The tranny use 30W motor oil.
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