Author Topic: Grinding down the Top Tree?? (Read 4177 times)

LoopsAndLogic · « **on:** April 21, 2008, 02:19:56 PM »

While I was about to grind down my handle bar posts on my 400F's top tree, I noticed that there would be some
"speed holes" left on the bracket, because Honda didn't fill in the bottom of the brace.

I see that there's ribs that support and brace the top tree bracket, but could those speed holes fatigue the brackets
strength??

This is the last part that I need to finish before I can ride already. It's killing me that I can't ride yet.
Fork seals are no fun either with that bottom bolt.....

Thanks for the help

LL

kghost · « **Reply #1 on:** April 21, 2008, 10:52:01 PM »

Don't hate me.....

On the frankenbike I chopped the mounts off and welded in a plug....http://gallery.sohc4.net/main.php?g2_itemId=10427

Terry in Australia · « **Reply #2 on:** April 22, 2008, 12:01:02 AM »

Yeah, that's a good job Tim, well don. While I doubt that the the top triple would break unless you dropped the bike pretty hard, weld-filling will make it much stronger. Don't just fill it with bondo or JB weld though, sure it'll look nicer than what you've got now, but won't add anything else, except weight. Cheers, Terry.

jason teamshralp · « **Reply #3 on:** April 22, 2008, 12:31:42 AM »

found this after reading your post. since there won't be bars there will be a little less stress on the tree.

just don't let it get too hot while your grinding them off.

before...

after...

they were from this site...http://springvinmoto.com/gallery/Richards-Cafe-project

Tower · « **Reply #4 on:** April 22, 2008, 07:12:34 AM »

Man, that grind looks "severe". I know its easy to get carried away with a grinder and take more than is really necessary. We might be looking at one of those situations, no?

tsflstb · « **Reply #5 on:** April 22, 2008, 08:12:08 AM »

I worked mine over with a hacksaw and hand file. I filed out the holes to follow the webbing underneath. One day I'll have that milling machine I lust for and really clean it up. Anyway, it's been like this for over a year and haven't had any issues. There are no steering, acceleration or braking forces passing through the top tree with clip-ons. It really just serves as a washer to clamp the steering head and locate the forks now.

Bodi · « **Reply #6 on:** April 22, 2008, 12:03:48 PM »

"There are no steering, acceleration or braking forces passing through the top tree with clip-ons"

The top triple tree works with the bottom tree to carry all front wheel forces to the steering stem. A lot of force goes through there.
Under braking for example the bottom of the tree is pushed back while the top clamp is pushed forward by the fork tubes with roughly equal force, transferring these forces to the steering head bearings. Basically, the front brake doesn't push the frame straight back... the front brake force is primarily transmitted to the frame as a moment acting on the steering tube, trying to lift the rear wheel off the ground. With enough force, you get a stoppie.
The steering input is removed with clip-ons but that is a tiny fraction of the force acting on the top triple clamp. Steering forces, in total, don't amount to much at the triple tree: since the bike leans into turns there isn't much side force ever exerted on the steering tube.
The remaining metal should be more than strong enough for the job. Those slots look nice, too.

tsflstb · « **Reply #7 on:** April 22, 2008, 12:34:51 PM »

Yeah, I probably could have worded that better. I agree the forks are still trying to twist and move under acceleration and deceleration while the top clamp holds them. With clip-ons you've just moved the place where the forces are applied, maybe reducing that rocking moment slightly since your body weight (under braking) is transferred somewhere between the upper and lower clamp to the forks.

lordmoonpie · « **Reply #8 on:** April 22, 2008, 01:49:19 PM »

I can't weld aluminium so tapped and plugged my holes with a bolt, ground them off and polished flat and then powder coated for a clean finish....looks nice even though I say so meself!

LoopsAndLogic · « **Reply #9 on:** April 22, 2008, 03:12:29 PM »

My clamp will be coming out just like tsflstb's.

Right before I was going to proceed with my cutting, my father dropped a few questions about the clamp.
Then I started to be concerned about the stress that this clamp takes on.

Well, if that's it, then away I go!!!

Nice clamp tsflstb. I don't think you need a mill......your magnificent hands seem to be doing the job

Thanks!

LL

tom8Toe · « **Reply #10 on:** April 22, 2008, 03:23:19 PM »

Twinline Cycles here in Seattle just rounded off the top tree and therefore still maintained the structural integrity. I think it looks pretty decent.

eurban · « **Reply #11 on:** April 22, 2008, 06:55:11 PM »

If you have some spare $ this place http://www.mginproducts.com/mg%20parts.htm can supply you with a top bridge w/o handlebar mounts. I believe the ttr400 site (fellow is a member here) may fab them as well.

tom8Toe · « **Reply #12 on:** April 22, 2008, 07:51:14 PM »

Quote from: eurban on April 22, 2008, 06:55:11 PM

If you have some spare $ this place http://www.mginproducts.com/mg%20parts.htm can supply you with a top bridge w/o handlebar mounts. I believe the ttr400 site (fellow is a member here) may fab them as well.

I think 400fourstore.com has some pretty sick looking options as well.

eurban · « **Reply #13 on:** April 23, 2008, 04:40:35 AM »

I think they get them from Mr TTR . . .

LoopsAndLogic · « **Reply #14 on:** April 23, 2008, 01:25:52 PM »

That looks nice tom8Toe, but I don't have aluminum welding supplies to fill in the holes...... $:-\$

I just don't have the right torch tips for my gas welder. Been welding steel since I was 14.

I do have some of that Aluminoid....but I haven't tried it.

After looking at tsflstb's setup, would anybody think that there could be damage from any sudden obstacle or bumps in the
road??
Like rail road tracks, and stuff like that.

I might just try it, and if it does bend, I'll be heading out to buy a spare top tree brace.

LL

jevfro · « **Reply #15 on:** April 23, 2008, 01:57:22 PM »

Quote from: LoopsAndLogic on April 23, 2008, 01:25:52 PM

That looks nice tom8Toe, but I don't have aluminum welding supplies to fill in the holes...... $:-\$

I just don't have the right torch tips for my gas welder. Been welding steel since I was 14.

I do have some of that Aluminoid....but I haven't tried it.

After looking at tsflstb's setup, would anybody think that there could be damage from any sudden obstacle or bumps in the
road??
Like rail road tracks, and stuff like that.

I might just try it, and if it does bend, I'll be heading out to buy a spare top tree brace.

LL

If I understand Tom8toe correctly there was no welding on his clamps. They were just cut about halfway off and then rounded. no holes to fill. right?

tom8Toe · « **Reply #16 on:** April 23, 2008, 02:03:15 PM »

Quote from: jevfro on April 23, 2008, 01:57:22 PM

Quote from: LoopsAndLogic on April 23, 2008, 01:25:52 PM
That looks nice tom8Toe, but I don't have aluminum welding supplies to fill in the holes...... $:-\$

I just don't have the right torch tips for my gas welder. Been welding steel since I was 14.

I do have some of that Aluminoid....but I haven't tried it.

After looking at tsflstb's setup, would anybody think that there could be damage from any sudden obstacle or bumps in the
road??
Like rail road tracks, and stuff like that.

I might just try it, and if it does bend, I'll be heading out to buy a spare top tree brace.

LL

If I understand Tom8toe correctly there was no welding on his clamps. They were just cut about halfway off and then rounded. no holes to fill. right?

From the mouth of the great Fonzerelli "Correctamundo" (?)

LoopsAndLogic · « **Reply #17 on:** April 23, 2008, 05:04:39 PM »

That's "Incorrectomundo".

All 400F's have the holes for the handle bars drilled all the way through.

And even the braces that I've seen on Ebay have them done this way.

Must be a PO thing, or Honda did tap the holes like this.....

LL

jevfro · « **Reply #18 on:** April 23, 2008, 06:15:07 PM »

I'm guessing aluminum threaded rods were just inserted and cut off? You could just leave them a little 'proud' of the surface on both ends and then hammer the ends to make it rivet. This could be sanded smooth and it would stop the possibility of it unscrewing. To help keep the aluminum from becoming brittle keep the heat to a minimum use a hacksaw, file, and other hand tools to cut them off or round off the stands.

kghost · « **Reply #19 on:** April 23, 2008, 07:50:56 PM »

I dunno about you guys but I sure don't worry about it after the holes are filled.

Plus I don't have to discuss the pluses and minuses of the webbing or holes.

Just my two cents.

mystic_1 · « **Reply #20 on:** April 23, 2008, 08:55:21 PM »

Structural integrity aside, I think the speed holes look cool, particularly tsflstb's.

mystic_1

Terry in Australia · « **Reply #21 on:** April 24, 2008, 05:23:05 AM »

Quote from: kghost on April 23, 2008, 07:50:56 PM

I dunno about you guys but I sure don't worry about it after the holes are filled.

Plus I don't have to discuss the pluses and minuses of the webbing or holes.

Just my two cents.

I've got to agree Tim, aesthetics aside, I'd feel much more confidant with your top tree.

Having said that, I'd machine my own top tree from 20mm thick 6061-T6 plate, and it'd be stronger than the OEM item ever was. Cheers, Terry.

kghost · « **Reply #22 on:** April 24, 2008, 07:26:47 AM »

Quote from: Terry in Australia on April 24, 2008, 05:23:05 AM

Quote from: kghost on April 23, 2008, 07:50:56 PM
I dunno about you guys but I sure don't worry about it after the holes are filled.

Plus I don't have to discuss the pluses and minuses of the webbing or holes.

Just my two cents.

I've got to agree Tim, aesthetics aside, I'd feel much more confidant with your top tree.

Having said that, I'd machine my own top tree from 20mm thick 6061-T6 plate, and it'd be stronger than the OEM item ever was. Cheers, Terry.

You know thats a thought but then it wouldn't look quasi-factory

If it were a more modern look Cafe hell yes.

Those clamps from the 400 store are waaaaaay cool

Gregorymoto · « **Reply #23 on:** April 24, 2008, 10:54:43 AM »

I would not worry about it unless you hit somthing.
I know a few folks who have ground down their tree and race at SIR allot, never herd of an issue.

LoopsAndLogic · « **Reply #24 on:** April 24, 2008, 12:32:16 PM »

I'm liking the bolt in the threads idea. Sounds really good.

And after getting a quote from the junk yard, I don't think I wanna pay an extra $45 for a top tree brace.

Thats a $45 mistake, that doesn't have to be made.

Thanks for all the idea's fella's.

Cheers

LL

Terry in Australia · « **Reply #25 on:** April 25, 2008, 12:41:22 AM »

[/quote]

I've got to agree Tim, aesthetics aside, I'd feel much more confidant with your top tree.

Having said that, I'd machine my own top tree from 20mm thick 6061-T6 plate, and it'd be stronger than the OEM item ever was. Cheers, Terry.

[/quote]

You know thats a thought but then it wouldn't look quasi-factory

If it were a more modern look Cafe hell yes.

[/quote]

Well that's true Tim, but I saw plenty of real race bikes "back in the day" with slab trees, (particularly those with "adjustable rake/trail" so it's not necessarily a "modern" look, but there's no doubting that your top tree looks really nice. Good job. Cheers, Terry.

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Author Topic: Grinding down the Top Tree?? (Read 4177 times)