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Old 12-12-2011, 06:44 PM   #12601
showkey
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[QUOTE=BLZBRKR65;17496629]
Quote:
Originally Posted by showkey View Post
Since you must ground the neutral switch it sounds like an interlock wiring /diode issue. Page 17.0 in the Honda TA shop manual explains the system.

Page 18.0 shows the interlock and how it relates to engine cranking and the clutch switch plus neutral switch.

The interlock system has two diodes. The interlock controls both spark and cranking as they relate to neutral, clutch handle and shifter position. Most times interlock does not relate to reving and engine run quality but it is possible if CDI grounding is marginal. Unmodified bikes can have this problem when the side switch is faulty with a marginal corrode connection.

The side stand switch grounds the light green/yellow wire allowing spark.
Grounding the light green/yellow should allow spark at all times.

Does the side stand light work and neutral light work as expected?[/QUOTE

Thanks for pointing out the electrical schematics on the manual. So, are you saying that the diodes may be faulty? Sounds like your spot on regarding the side stand safety switch. I have noticed that the side stand light seems to come on/off at times intermittently. I have checked and cleaned the connections to no avail. I had replaced it too with a good known working unit with the same results. How do you ground the light green/yellow side stand switch? Just put them together or insert a wire between both terminals and secure them together? The neutral switch light works fine. Looking forward to your reply. Thanks!
Normal CDI box is grounded through the neutral switch or the side stand switch. Spark is alllowed only if the stand is up or the bike is neutral.
Engine cranking is allowed only if the clutch lever is pulled in or the bike is in neutral.
Both safety systems share switches and wiring to get the above to happen.
My NT is in storage but I do recall that the NT used the kick stand rubber to move the stand up in a drive away instead of the kick stand switch to kill spark as the safety system.

The diodes are in the system are there to stop the neutral switch from operating the side stand light and the clutch switch from operating the side stand light.
I do not think the diodes are the problem. But wiring and coonections could be?

The LG/Y can be grounded a the frame on a stock TA wiring and CDI box to allow spark at all times.

Normally CDI grounding is not related to running poorly. BUT is it possible when the ground path is marginal and a few others have reported poor or marginal spark because of this poor grounding. The poor grounding could be the side stand switch quality, the ground to frame itself or the the wiring connections being faulty or marginal.
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Old 12-12-2011, 07:06 PM   #12602
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Ok , so without reading every single page in this thread,

what do I need to buy and do to convert an 89 TA to a rear disc brake set-up ,

looking for the nicest , cleanest way to do this mod.
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Old 12-12-2011, 08:51 PM   #12603
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Usually involves buying a rear wheel from a euro model 1992, I think, along with the rear disc holder (I believe this will slide onto the drum brake tabs on your 89 swingarm but could be mistaken), caliper, hoses and master cylinder.

New master cylinder tabs have to be welded on the right frame. Be certain to remove your CDIs, battery and all electrical ground points from the frame before you weld. You want to electrically isolate the wiring harness from the frame before you hit it with many more amps than it was ever designed to handle

There is also a different attachment part that gets attached to the inside of the brake arm. This one runs the master cylinder rather than the brake rod.

That's the Cliff Notes - now may I ask WHY?

The rear drum brake I've always found adequate since most braking happens in the front. The only advantage I've seen with the disc is if you are building a long travel rear suspension....then the flexible hydraulic lines solve many problems.

If you're just looking to improve braking in general...go for improvements at the front.
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Old 12-12-2011, 10:39 PM   #12604
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That's the Cliff Notes - now may I ask WHY?

The rear drum brake I've always found adequate since most braking happens in the front. The only advantage I've seen with the disc is if you are building a long travel rear suspension....then the flexible hydraulic lines solve many problems.

If you're just looking to improve braking in general...go for improvements at the front.[/QUOTE]

I'm with you Ladder. For trail riding I prefer the greater feel and therefore control you have with a drum rear, especially on rocky downhills where you really don't want to lock up the rear.
The gentle pull from the rear to steady you going into a corner (I beleive) is more easily achieved with a drum.
Historically (as I remember it) discs were intorduced because they cooled down more quickly between applications; not because they had inherently greater braking power.
I don't ride my TA hard enough to cook the rear brake (I leave that to my DRZ400). I don't beleive fanging TAs flat out is what they were designed for, nor is it the best way to get the most out of them.
I've found a good rhythm, balance, throttle control and steady mid corner speed is what they respond to best.
FWIW

Cheers
Tim
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Old 12-13-2011, 01:56 AM   #12605
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Quote:
Originally Posted by therealbigman View Post
Ok , so without reading every single page in this thread,

what do I need to buy and do to convert an 89 TA to a rear disc brake set-up ,

looking for the nicest , cleanest way to do this mod.

Having owned a 1991 TA with factory disc rear brakes, here is what I remember about the set up. You will need:

Swing arm, which is narrower than the 89-90 swingarm
Rear Axle ( shorter than US models)
Rear Wheel with disc
Rear brake Caliper
Rear brake caliper holder mount
Master cylinder, fluid reservoir and hoses
Modified rear brake light switch location, the US switch mount conflicts with the Master cylinder location.
Modified rear brake pedal to mastercylinder linkage ( I think?)

I'm a little rusty on the details but I think that was everything.

I agree with Tim on how to get the most out of these bikes, I saw no great advantage with this rear disc brake other than the cool factor and that it did not squeak.

I found the pedal pressure a bit hard to activate the brake and I had no "feel" as to what the rear of the bike was doing. I prefer the mushy rear pedal feel from the drum brake.

Front disc is a different story, you can feel everything through your finger tips but the rear disc brake action just felt too isolated from me.
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Old 12-13-2011, 05:13 AM   #12606
thebigman
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Quote:
Originally Posted by Ladder106 View Post
Usually involves buying a rear wheel from a euro model 1992, I think, along with the rear disc holder (I believe this will slide onto the drum brake tabs on your 89 swingarm but could be mistaken), caliper, hoses and master cylinder.

New master cylinder tabs have to be welded on the right frame. Be certain to remove your CDIs, battery and all electrical ground points from the frame before you weld. You want to electrically isolate the wiring harness from the frame before you hit it with many more amps than it was ever designed to handle

There is also a different attachment part that gets attached to the inside of the brake arm. This one runs the master cylinder rather than the brake rod.

That's the Cliff Notes - now may I ask WHY?

The rear drum brake I've always found adequate since most braking happens in the front. The only advantage I've seen with the disc is if you are building a long travel rear suspension....then the flexible hydraulic lines solve many problems.

If you're just looking to improve braking in general...go for improvements at the front.
Quote:
Originally Posted by Backonthebike View Post
That's the Cliff Notes - now may I ask WHY?

The rear drum brake I've always found adequate since most braking happens in the front. The only advantage I've seen with the disc is if you are building a long travel rear suspension....then the flexible hydraulic lines solve many problems.

If you're just looking to improve braking in general...go for improvements at the front.
I'm with you Ladder. For trail riding I prefer the greater feel and therefore control you have with a drum rear, especially on rocky downhills where you really don't want to lock up the rear.
The gentle pull from the rear to steady you going into a corner (I beleive) is more easily achieved with a drum.
Historically (as I remember it) discs were intorduced because they cooled down more quickly between applications; not because they had inherently greater braking power.
I don't ride my TA hard enough to cook the rear brake (I leave that to my DRZ400). I don't beleive fanging TAs flat out is what they were designed for, nor is it the best way to get the most out of them.
I've found a good rhythm, balance, throttle control and steady mid corner speed is what they respond to best.
FWIW

Cheers
Tim[/QUOTE]

Quote:
Originally Posted by mas335 View Post
Having owned a 1991 TA with factory disc rear brakes, here is what I remember about the set up. You will need:

Swing arm, which is narrower than the 89-90 swingarm
Rear Axle ( shorter than US models)
Rear Wheel with disc
Rear brake Caliper
Rear brake caliper holder mount
Master cylinder, fluid reservoir and hoses
Modified rear brake light switch location, the US switch mount conflicts with the Master cylinder location.
Modified rear brake pedal to mastercylinder linkage ( I think?)

I'm a little rusty on the details but I think that was everything.

I agree with Tim on how to get the most out of these bikes, I saw no great advantage with this rear disc brake other than the cool factor and that it did not squeak.

I found the pedal pressure a bit hard to activate the brake and I had no "feel" as to what the rear of the bike was doing. I prefer the mushy rear pedal feel from the drum brake.

Front disc is a different story, you can feel everything through your finger tips but the rear disc brake action just felt too isolated from me.

Well 3 for 3 , looks like its gonna stay just the way it is,

I figured it was maybe an easy bolt on mod that would look good,
guess I was wrong.

Thanks for all the info and opinions.
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Old 12-13-2011, 08:41 AM   #12607
Ladder106
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Quote:
I figured it was maybe an easy bolt on mod that would look good,
guess I was wrong.
Actually, you were right. It does make the bike look more "modern".

If I were you and still considering this. I'd go for adding a aluminum swingarm and rear wheel from the RD03/04 Africa twin.

You need the same parts as Mas335 suggests (he's better at this than I am) and it will be expensive but it adds a nicely made arm to the rear.

As I said, if you're considering the long-travel suspension mods, the AT arm and disc makes thing much easier since the geometry changes with the solid brake arm get a bit difficult (not impossible) when the rear wheel moves down another 2 inches or so. The hydraulic lines eliminate all these problems and are then, IMHO, worth the expense.

I have not seen any improvement in rear braking with even this setup. I have the AT arm set-up on my bike and the standard TA arm on my sons bike. The drum has better feel and can be feathered to juuuusst about lockup on the dirt during a muddy or rocky decent. With the disc you get a kind of "lock...release....lock....release" action so it's not as precise.

The only time I've run out of brake on the TA was riding with some BMW guys on a steep decent from a ridge down to the ocean with a touring load and standard front disc. After about 3 miles the front began to fade gradually. Gave me enough warning to know it was time to stop being silly.
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Old 12-14-2011, 03:00 PM   #12608
Backonthebike
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Just to shoot my own argument down (to a degree) I notice on the DRZ400 thread (where I also live coz I've got one of those) a number of people are talking about a left side bar mounted reservoir and brake lever, which can either replace the footbrake or complement it; it's apparently good for technichal stuff where you want both feet firmly planted on the pegs, but still want some rear end retardation.
BUT, that sort of stuff is not where you get the best out of the TA; Rolling along a desterted back road, looking at ruined farmhoused and sheds, ghost towns, scenic vistas, with Canned Heat or Dire Straights burbling in the earbuds is as close to Heaven as I'm gonna get.
Cheers
Tim in Orstralia
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Old 12-14-2011, 05:07 PM   #12609
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Ok , since you all shot my plans down to do a rear disc set-up


let's move on to the next ,

I want to build another wheelset, do any other hubs work for this bike other than for this model , if so , which ones ,

front's................
rear's.................

what spokes and rims do yall recommend ,

Sure would like to go with a set of Takasago's w stainless spokes.
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Old 12-15-2011, 02:02 AM   #12610
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Marko, you might check in with Woody's Wheel Works in the vendor section, they seem to have the answers on custom wheels and that might help with you the spoke/rim options.

As for hubs, I don't know of any substitutes but if there are any I'll bet Ray knows.

Attached: Winter tune up from the frame up.
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Old 12-15-2011, 08:24 AM   #12611
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Hubs are a tough one.

Off the top 'o' my head, I know of no straight "bolt-in" replacement for the standard Honda parts.

But with some spacers and machining, almost anything is possible.

Things to get right with different hubs

(A) First the new hub has to support the RIM in the same center-line used by Honda. The only accurate way I know to measure this is to remove the tire and tube from the standard rim, bolt it back into the frame. Then level the frame left to right and drop a plumb bob down through the valve stem hole. Then measure where the rim center sits (somehow) between the inside edges of the swingarm. You do not want to see two seperate tire tracks (like a crab) when riding the bike in the mud.

Incorrect spoke lengths can also shift (dish) the rim off to one side or another. I know of two guys who hap-hazardly replaced rims and spokes and wondered why their bike handled poorly until we tried to align it.

(B) The hub (after being made to sit correctly in the frame) must hold the brake disc in the center-line of the caliper. Yes, the caliper can be shifted around with spacers but this us usually very limited since most builds put the caliper withing mms of the rotating bits. This is not a worry with drum brakes (see...drums are cool)

(C) For the rear wheel, the hub must also hold the drive sprocket in the correct chain-line. In other words perfectly straight back from the CS sprocket.

(D) Bearing ID as related to the OD of the axle is also a consideration but is usually easily managed...just something to think about. The selection of bearings is vast but not infinite. It may be possible to get a bearing with the correct OD to fit the hub but without finding the correct ID to fit only the TA axles (which are quite narrow in the front).

(E) The TA is an OLD bike....and never well received or popular here. So going to a builder and asking him for TA compatible hubs is very different from, say, asking for hubs for a BMW GS or DRZ400 Suzuki...you get the picture.

Now, if it were me, given all these considerations. I'd just find another set of TA hubs and rebuild those. You might try eBay UK since their winter roads dissolve aluminum rims in 2 years or so, there may be some for sale. Be warned, however, shipping from the UK always seems about doublel from the rest of europe....dunno why.

Ladder106 screwed with this post 12-15-2011 at 08:32 AM
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Old 12-15-2011, 09:11 AM   #12612
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TA to XR Bearing swap

I have a nice set of XR650R forks that I am thinking about adding to my TA, but I want to keep the TA front wheel. My thought is to swap out the bearings, spacer, and speedo drive from the XR into the TA hub. The OD of the bearings and seals apear from the parts books to be the same Dia, can someone tell why this won't work?
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Old 12-15-2011, 10:08 AM   #12613
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Go back to post #774. Start reading Jeff's descriptions of the AfricaAlp hybrid.

Most of your questions will be answered there.

The Cliff Notes versions is:

Yes the TA wheel will work in the XR forks but you have to change the bearings to compensate for the XR axle.

The XR speedo drive has to be used because the TA axle hole is too small.

The TA caliper will allllllmost fit into the XR fork legs the bottom hole in the folk leg must be uhmmmmm....modified a bit for it to work. Not a prefect solution but it's safe and accomplishes your goal.

Front fender mounting will change since the XR legs do not have the mounting tabs cast into them for the TA front fender.

The XR legs will dramtically change the front ride-height and you must compensate for this with at least a spacer in the rear shock. A new longer (more travel) and better damped shock will make a HUGE difference in the way the bike handles.

Your side stand will have to be modified to support the new suspension. Or you can carry a 4X4 everywhere in your tank bag. It does give you something to throw at the texting-while-driving idiots.

---------------------------------

Be VERY VERY careful with this set-up since the XR forks have much more travel than the TA forks. It is possible to have the front tire hit the down-tube, crashbars, fender etc on full compression. This will lock the front wheel sending you over the bars.

Here's the clearance I had after careful modification (this is with AT bodywork)

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Old 12-15-2011, 10:10 AM   #12614
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Oh wait....you said "R" forks.

The mods I showed you were from "L" model forks. You'll have to experiment with the R version. Brake compatability will likely be a problem area.
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Old 12-16-2011, 08:03 AM   #12615
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Quote:
Originally Posted by Ladder106 View Post

Now, if it were me, given all these considerations. I'd just find another set of TA hubs and rebuild those. You might try eBay UK since their winter roads dissolve aluminum rims in 2 years or so, there may be some for sale. Be warned, however, shipping from the UK always seems about doublel from the rest of europe....dunno why.
+2 ^^^^^^^^ on the above not to mention what would be the expected gain or real benefit by switching hubs?
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