Author Topic: '71 triple tree help  (Read 2396 times)

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Offline gecko672

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'71 triple tree help
« on: November 11, 2008, 09:45:35 AM »
First time to post after months of soaking up info on this forum.

I have a '71 cb750 that has a broken upper triple tree around the bolts that hold the forks. Its the one that has the gauge bracket built into the top tree.
There are replacements on ebay but they really go for a high price. While Im waiting and watching for stuff on ebay, I wanted to ask are there any later year triple trees that will bolt on without modification. I dont know the fork sizes for later years. Did they stay the same? is the trail different? I dont want to do a crazy conversion, just use a more available substitute.
There are plenty of spares for the later models and i like the idea of a separate gauge bracket.
I've looked around this forum for quite a bit and cant find anything that relates to swapping out  k0,k1,k2 triple trees.
If I've missed a post somewhere a lead to the link would be great.

Cheers

Thanks for the help.
CB750 1971 K1

Offline Alan F.

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Re: '71 triple tree help
« Reply #1 on: November 11, 2008, 09:51:43 AM »
I've got a K8 and a K3 upper triple, I'll trade either one for your broken one if you have all the pieces.... Got any pictures of it?

Offline gecko672

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Re: '71 triple tree help
« Reply #2 on: November 11, 2008, 09:54:48 AM »
I do have it all. Just curiouse why do you want it?
Do the k8 and k3 substitute right in?
CB750 1971 K1

Offline Tower

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Re: '71 triple tree help
« Reply #3 on: November 11, 2008, 09:55:48 AM »
From the perspective of mounting forks to frame, all K0-K6 (and probably out to K8) triple tree configurations will mount up.  From perspective of mounting gauges, switches, or lights, they are grouped according to configuration (K0-K1,K2, K3-K5, K6, K7-K8).

Offline Alan F.

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Re: '71 triple tree help
« Reply #4 on: November 11, 2008, 10:05:48 AM »
If it seems repairable I'd repair it, paint it, and hide it away for future use.   It is a fairly rare part isn't it?   And it's cast alloy right?

Offline gecko672

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Re: '71 triple tree help
« Reply #5 on: November 11, 2008, 10:13:38 AM »
AlanF,
Im sure its repairable but the break is right at the point where the piece flexes to tighten onto the fork tube. if I could describe it in words..if your looking stright down on the right side opening that holds the fork its broken at 12 o'clock. Maybe repair is an option. Does anyone have an opinion on repairing it? yes its cast im sure.

Tower,
O.K. Thats good to know. The only part I didnt quite understand was the grouping of gauges comment. so each year grouping had a configuration change? If I get a later model say a k6 as long as I have the brackets and straps for that year, I should be able to mount my k1 gauges. Is that right?
Thanks again.
CB750 1971 K1

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Re: '71 triple tree help
« Reply #6 on: November 11, 2008, 10:21:16 AM »
I have seen them weld repaired and they held up fine.  CycleRecycleII in Indy has a good one sitting on their counter for sale.  Even a Goldwing front end will bolt right up so your options are wide open.  Check my website under links for CRCII site. KingCustomCycles.com

Offline Alan F.

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Re: '71 triple tree help
« Reply #7 on: November 11, 2008, 10:25:03 AM »
www.aluminumrepair.com  I've used quite a bit of this stuff, once you get used to it's flow charachteristics....it's like soldering with a 35 watt iron and 60/40 rosin core.  Very confidence inspiring.  You can get small quantities on ebay for relatively cheap, practice on some scraps first and save the part yourself.  

Offline gecko672

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Re: '71 triple tree help
« Reply #8 on: November 11, 2008, 10:44:16 AM »
Wow that stuff looks amazing. is it really that good. I just watched a youtube clip and it looks almost to good to be true.

You say it works that well?
maybe I will do a repair. Thanks for the heads up.
CB750 1971 K1

Offline Alan F.

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Re: '71 triple tree help
« Reply #9 on: November 11, 2008, 11:35:32 AM »
Looks impressive, but remember that guy probably has dozens of hours working with the stuff.  Practice is key, your second try will be better than your first.  Use propane not mapp, and work at a comfortable height (not on the floor) and work on a surface that can take some heat.  If the bond looks nice and shiny, and you didn't use too much of the rod, things should be fine.  If you use too much rod, just file off the excess.  Just like soldering, less solder makes the strongest bond, more isn't better or stronger.

The real test will be when I fab an alloy fuel tank with this stuff.....

Offline Tower

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Re: '71 triple tree help
« Reply #10 on: November 13, 2008, 11:01:31 AM »
Right @gecko672. The gauge clusters along with the corresponding indicator lights were mounted differently according to the groups I've mentioned.  Although not strictly, as there are work arounds for everything, substantively though, replacing one of those would necessitate replacing all of them.

Offline gecko672

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Re: '71 triple tree help
« Reply #11 on: November 13, 2008, 11:38:37 AM »
Thanks,
Im going to give the hts-2000 a go . Might as well nothing to loose as the part is broken anyway. I'll post a picture wheather it works or not. Just waiting for the rods.
cheers.
CB750 1971 K1

Offline Alan F.

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Re: '71 triple tree help
« Reply #12 on: January 25, 2009, 03:08:58 PM »
Hey gecko, any luck yet?

Offline mateo tomas

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Re: '71 triple tree help
« Reply #13 on: January 25, 2009, 03:20:59 PM »
www.aluminumrepair.com  I've used quite a bit of this stuff, once you get used to it's flow charachteristics....it's like soldering with a 35 watt iron and 60/40 rosin core.  Very confidence inspiring.  You can get small quantities on ebay for relatively cheap, practice on some scraps first and save the part yourself.  

would a small butane bottle torch be sufficient for this stuff... looks amazing

Offline Alan F.

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Re: '71 triple tree help
« Reply #14 on: January 25, 2009, 03:30:17 PM »
I'm not sure about butane, I tried MAPP and it was too hot for the parts I was working on, maybe better for larger stuff.  I used propane as they recommended and got better results.  The website has a number to call with questions, maybe it's mentioned in a FAQ section...

Offline mateo tomas

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Re: '71 triple tree help
« Reply #15 on: January 25, 2009, 03:33:42 PM »
cool... I will definitely be trying this stuff and report back

Offline JLeather

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Re: '71 triple tree help
« Reply #16 on: January 25, 2009, 05:22:19 PM »
The reason it broke there is because someone didn't put back the two "D"-shaped washers that go in the gap on each side.  I know quote a few people who've broken the unicorn-style trees that way.  So, if you do fix it, or buy another one, you should make sure you get those washers and put them where they're supposed to be.

Offline Don R

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Re: '71 triple tree help
« Reply #17 on: January 25, 2009, 07:03:41 PM »
My 70 model has a slightly different measurement from the center of the forks to the center of the neck. If you swap you may also need to swap the bottom clamp also. My 70, 73 and 75 all have different guage mounts. I believe these clamps are steel so it would need to be welded properly for a repair. You don't want a loose fork tube.
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Offline gecko672

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Re: '71 triple tree help
« Reply #18 on: January 26, 2009, 10:01:11 AM »
Hey guys,
So I ended up getting the welding rods and went about stripping the top tree to get it nice and clean, and to my surprise I see its been welded before. The weld has held and broken about 1/4 of an inch further on. I decided to try and weld it anyway just for the practice. I tried using  the propane and I just couldn't get enough heat into the part. I did manage to get one globule of weld to stick but the part wouldn't stay hot and I couldn't tin it.
 I can tell from just messing around that any welds would be really strong  but I just couldn't hold heat in such a large piece long enough to get it tinned. It would just conduct the head through the rest of the triple tree.I plan to get some map gas but for now I'm just trolling ebay for a new part. If anyone has a top tree I'll take it off you. I'll let you know if I get it to work.
CB750 1971 K1

Offline gecko672

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Re: '71 triple tree help
« Reply #19 on: January 26, 2009, 10:05:50 AM »
Hey JLeather,
The washers you mention, are they in the parts manuals? I know for sure I dont have them.
Do you have any pictures/info.
Cheers.
.
CB750 1971 K1

Offline Alan F.

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Re: '71 triple tree help
« Reply #20 on: February 03, 2009, 07:44:33 AM »
Here's the diagram from Service Honda, I think we're looking at part #10

Offline pampadori

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Re: '71 triple tree help
« Reply #21 on: February 03, 2009, 12:18:19 PM »
me too, don't feel bad.  that stuff is complete #$%*.  wouldn't trust it at all with anything that needed real strength.   Tig weld it, or have someone with a tig weld it.    But you have got to wonder why it has cracked so many times.  is the tree made for larger forks? 

Hey guys,
So I ended up getting the welding rods and went about stripping the top tree to get it nice and clean, and to my surprise I see its been welded before. The weld has held and broken about 1/4 of an inch further on. I decided to try and weld it anyway just for the practice. I tried using  the propane and I just couldn't get enough heat into the part. I did manage to get one globule of weld to stick but the part wouldn't stay hot and I couldn't tin it.
 I can tell from just messing around that any welds would be really strong  but I just couldn't hold heat in such a large piece long enough to get it tinned. It would just conduct the head through the rest of the triple tree.I plan to get some map gas but for now I'm just trolling ebay for a new part. If anyone has a top tree I'll take it off you. I'll let you know if I get it to work.

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Offline gecko672

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Re: '71 triple tree help
« Reply #22 on: February 03, 2009, 01:06:18 PM »
I think it is a design flaw, there was obviously a reason they changed the design in later years. I think the spacer is also a key, over torquing it would crack it. Thanks for the part info.
 Just have to find the spacer now, or at least see one to see if you could swap it for a washer.
If any one has this spacer and can post a picture and some measurements That would be fantastic, I'll see if I can make one. Was it metal or rubber?

Cheers all.
CB750 1971 K1

Offline pampadori

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Re: '71 triple tree help
« Reply #23 on: February 03, 2009, 01:12:03 PM »
from memory,  it was about 1mm thick and shaped like a "D". 
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