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Author Topic: Africa Twin Fork issue - Honda SA ... Now what ...  (Read 9593 times)

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Offline Sycamore

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #100 on: May 15, 2018, 11:34:02 am »
Some thoughts:

-Honda gives Showa the spec and price point for the fork, which Showa then delivers.  Similar in nature to BMW and WP for the F800GS
-The tube is very unlikely to permanently deform.  I'd think that backing off to a more acceptable torque for a lower triple: 15NM will still allow the fork to work as intended.  10NM is very little, especially for a heavy bike
-If I had an AT, I'd measure the gap between the bush and the outer leg (feeler gauge) and then put shim stock (strip cut from coke tin, etc) behind the bush to get the gap to 0.15mm.  I believe that most ATs run in the 0.2 - 0.25mm range stock, which is rather loose

Not knocking this post, I think putting a shim in there is a good idea for the torque issue.

But somehow I have to smile at the idea of the owner of a new Africa Twin cutting up strips of coke tin to patch his bike  :lol8:
 

Offline Cracker

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #101 on: May 15, 2018, 11:43:44 am »
Surely if the anodising is coming off where the bottom triple is clamped, the it's clamped too tight. Or not round when clamped.

18nm

Actually Honda specs 35Nm for the lower clamps :o

Two additional issues is that the slider bush on the lower legs is under sized and that a significant length of fork leg protrudes above this bush.  This combination allows the stanchion to contact the inside of the slider, wearing the anodizing (specifically in the area of the bottom triple clamp).  However, this also causes leading edge damage of the bush, which allows the stanchion to deflect inside the slider under load, potentially causing seal failure.

Forks worked fine on 1980"s light weight dirt bikes............. problem is additional weight and stress it now has to deal with.

If this underlined bit is happening then you have a design issue, not a torque/crimping issue.

Coke can/shim might help but I'd be wondering WHY they put the bush lower down on the stanchion. There must be a reason for that, it's not normal practise.
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Offline armpump

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #102 on: May 15, 2018, 12:36:49 pm »
Surely if the anodising is coming off where the bottom triple is clamped, the it's clamped too tight. Or not round when clamped.

18nm

Actually Honda specs 35Nm for the lower clamps :o

Two additional issues is that the slider bush on the lower legs is under sized and that a significant length of fork leg protrudes above this bush.  This combination allows the stanchion to contact the inside of the slider, wearing the anodizing (specifically in the area of the bottom triple clamp).  However, this also causes leading edge damage of the bush, which allows the stanchion to deflect inside the slider under load, potentially causing seal failure.

Forks worked fine on 1980"s light weight dirt bikes............. problem is additional weight and stress it now has to deal with.
Quite a few riders (local as well) have opted to change the forks out to KYB/WP 48's rather than try and fix the original Showas. It seems the size of the fork as well as the design/overlap contributes to the issues. Personally I don't think that 43mm forks on a 200 plus kg bike are enough, even if you are only hitting potholes on the pavement. I read with interest that there is (speculation of) the T7 having 43mm's. I don't think its enough, even though that bike (speculation again) seems it will be lighter than the AT. It would be an interesting experiment to work out the sliding surface area of a 43 vs 48 mm fork bush. I expect it would be quite a difference.
Again, I don't think this is a lower triple clamp torque issue. The damage seems to happen only on one face of the internals, rather than the entire circumference if the fork lower was being crimped too tight. You might even find that Honda specced the torque to be that high to try and work around the wear issue, by reducing flex induced wear.

Remember these on VMX bikes

 

Offline Ian in Great Brak River

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #103 on: May 15, 2018, 12:38:19 pm »
Some thoughts:

-Honda gives Showa the spec and price point for the fork, which Showa then delivers.  Similar in nature to BMW and WP for the F800GS
-The tube is very unlikely to permanently deform.  I'd think that backing off to a more acceptable torque for a lower triple: 15NM will still allow the fork to work as intended.  10NM is very little, especially for a heavy bike
-If I had an AT, I'd measure the gap between the bush and the outer leg (feeler gauge) and then put shim stock (strip cut from coke tin, etc) behind the bush to get the gap to 0.15mm.  I believe that most ATs run in the 0.2 - 0.25mm range stock, which is rather loose

Not knocking this post, I think putting a shim in there is a good idea for the torque issue.

But somehow I have to smile at the idea of the owner of a new Africa Twin cutting up strips of coke tin to patch his bike  :lol8:

Uncle Allen would rather be buried alive that have Coke can shims .... Windhoek lager shims, thatís a whole new option though ...   >:D
1978. It's 6am, mid winter...two up on a XL 185S ... off to my first casino ever with all of R40 and we've got a full tank of fuel, so enough to get there we reckon.... that's determination...

Old bike: '82 Eddie Lawson Replica Replica.
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Offline Malmoer

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #104 on: May 15, 2018, 12:57:58 pm »
Never liked honda :pot:

But always said that they made good bike :patch:

Now it seems some of their bikes is still good :pot:

Anycase a freind of mine had some issues regarding his ignition. We had to trailer the bike back from Zone 7. Honda sorted it quickish
Same friend also had issues with the left fork seal popping after i was asked to show him if the bike can wheelie. Also sorted quickish

But to take a day of trailer or ride the bike to the dealer wait the whole day is not fun, even if the repair was for "free"

My bmw F800gs hundreds and hundreds of wheelies nada nothing no issues with forks seals. It just makes you feel a bit uneasy as to when the warrenty runs out whats next.
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Offline Roxtar

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #105 on: May 15, 2018, 01:16:49 pm »
My bmw F800gs hundreds and hundreds of wheelies.....

Just cannot get that pic into my brain for some reason.... please post a video Malmoyr.... :biggrin:
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Offline peteb

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #106 on: May 15, 2018, 01:50:09 pm »
Surely if the anodising is coming off where the bottom triple is clamped, the it's clamped too tight. Or not round when clamped.

18nm

Actually Honda specs 35Nm for the lower clamps :o

Two additional issues is that the slider bush on the lower legs is under sized and that a significant length of fork leg protrudes above this bush.  This combination allows the stanchion to contact the inside of the slider, wearing the anodizing (specifically in the area of the bottom triple clamp).  However, this also causes leading edge damage of the bush, which allows the stanchion to deflect inside the slider under load, potentially causing seal failure.

Forks worked fine on 1980"s light weight dirt bikes............. problem is additional weight and stress it now has to deal with.
Quite a few riders (local as well) have opted to change the forks out to KYB/WP 48's rather than try and fix the original Showas. It seems the size of the fork as well as the design/overlap contributes to the issues. Personally I don't think that 43mm forks on a 200 plus kg bike are enough, even if you are only hitting potholes on the pavement. I read with interest that there is (speculation of) the T7 having 43mm's. I don't think its enough, even though that bike (speculation again) seems it will be lighter than the AT. It would be an interesting experiment to work out the sliding surface area of a 43 vs 48 mm fork bush. I expect it would be quite a difference.
Again, I don't think this is a lower triple clamp torque issue. The damage seems to happen only on one face of the internals, rather than the entire circumference if the fork lower was being crimped too tight. You might even find that Honda specced the torque to be that high to try and work around the wear issue, by reducing flex induced wear.

Remember these on VMX bikes


So here's my take on fork evolution. Maico were the first to have 'leading axle' forks, they did it for handling/steering. All the other manufacturers at the time did 'in line' axles. Then they also started leading axle designs (for handling/steering/rake/trail). They soon realised that you could have more overlap (ie greater distance between the bushes for less flex) by extending the fork tube below the axle, and have the stanchion extend into this area. They still had flex issues, even with beefier and beefier stanchions. So the design went to 'gull wing' lower triple clamps to try and get more overlap with bigger suspension travel, but conventional fork design didn't allow enough overlap for MX purposes. The original Upside Down Forks (like we have today) was to address this overlap issue, because it gave the triple clamp distance to further increase overlap, (It had a knock on effect in that we no longer had forks extending below the axle and klapping every rock in sight, which used to lead to all kinds of tricks with irrigation pipe to protect them). Cartridge forks evolved at the same time, but the primary reason for USD forks was to address overlap.
Why Honda would choose to reduce this overlap with a plus 200kg bike and skinny forks evades me. Doesn't make any design sense.
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Offline armpump

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #107 on: May 15, 2018, 01:57:46 pm »
Bean counters having their say................. these units cost big $$$


 

Offline Cracker

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #108 on: May 15, 2018, 06:09:05 pm »
Coulda fitted std 48mm KYBs with stronger springs - job done!
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Offline volroom

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #109 on: May 15, 2018, 06:45:19 pm »
in my mind its unacceptable for an established quality motorcycle mfg to make a mistake like this. There attitude is wrong... it sucks. They should not act as if they are 'untouchable'. They should appease their clients..

Those front forks posted, what would they cost in randelas? In SA doing a mod like this probably does not make sense, especially if you bought the AT because it was relatively well priced
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Offline volroom

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #110 on: May 15, 2018, 06:46:56 pm »
Bean counters having their say................. these units cost big $$$




this is just beautiful...
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Offline 2StrokeDan

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #111 on: May 15, 2018, 07:32:20 pm »
Yah well, it's happening folks. The gap between Japanese/European and Chinese/Indian quality is shrinking fast. :3some:

And unfortunately it's not all leveling up, but leveling down too.  :patch:


Very, very unfortunate.
 

Offline Ian in Great Brak River

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #112 on: May 15, 2018, 08:39:13 pm »
Bean counters having their say................. these units cost big $$$




this is just beautiful...

OK, so I will ask the question ... what is the price of these 4 beauties then ...?
1978. It's 6am, mid winter...two up on a XL 185S ... off to my first casino ever with all of R40 and we've got a full tank of fuel, so enough to get there we reckon.... that's determination...

Old bike: '82 Eddie Lawson Replica Replica.
Other bike: '05 Honda Varadero 1000
New bike: '16 Honda Africa Twin.
 

Offline BiG DoM

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #113 on: May 15, 2018, 08:48:34 pm »
In the region of R50K + for WP Cone Valve forks and similar Ohlins, KYB
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Offline Buff

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #114 on: May 15, 2018, 08:59:35 pm »
This is no different to ktm and their crappy air boxes. The entire internet knows how poor they perform and there's an entire aftermarket enterprise established to rectify it yet ktm persist with installing them in their bikes... Go figure ???
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Offline windswept

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #115 on: May 15, 2018, 09:30:44 pm »
I usually keep away from these discussions, but now I think back to all I have read during the BMW fork problems and I don't see the trolls coming out of the woodwork on this topic. Come on trolls, pull-in. Have your say. >:D 
 

Offline BiG DoM

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #116 on: May 15, 2018, 09:42:51 pm »
I usually keep away from these discussions, but now I think back to all I have read during the BMW fork problems and I don't see the trolls coming out of the woodwork on this topic. Come on trolls, pull-in. Have your say. >:D

Difference is they have not actually detonated like the BMW ones ... and Honda have not claimed rider abuse. But yes most manufacturers are cutting corners to save costs with detrimental results. Examples abound.

It will be interesting what remedial suspension action Honda takes on their adventure and rally models. There is no doubt that this is the bikes Achilles heel.
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Offline windswept

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #117 on: May 15, 2018, 10:00:04 pm »
 :thumleft:
 

Offline Ian in Great Brak River

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Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #118 on: May 16, 2018, 02:00:03 am »
In the region of R50K + for WP Cone Valve forks and similar Ohlins, KYB

Per unit ...? ffs!!
« Last Edit: May 16, 2018, 02:19:21 am by Ian in Great Brak River »
1978. It's 6am, mid winter...two up on a XL 185S ... off to my first casino ever with all of R40 and we've got a full tank of fuel, so enough to get there we reckon.... that's determination...

Old bike: '82 Eddie Lawson Replica Replica.
Other bike: '05 Honda Varadero 1000
New bike: '16 Honda Africa Twin.
 

Offline volroom

Re: Africa Twin Fork issue - Honda SA ... Now what ...
« Reply #119 on: May 16, 2018, 05:33:56 am »
so of course you want to do the rear shock too.. man, that will set you back around R65-70K! crazy. who will pay this?

Your rand simply does not go nearly as far as dollar when you are earning dollars. feasible maybe in America for some, but not in SA. Don't forget the touratech option, if money was no option their extreme rear shock will do. They offer better cartridges for the front, but you will still need to re-anodize the stanchions. The cartridges alone is around R30k plus.
« Last Edit: May 16, 2018, 05:40:33 am by volroom »
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