faulty batch of Tokico 4-piston-radial calipers in ´08 I suppose

[Berlin Germany]

hi guys

coincidentally, a few days ago I came across two radial calipers from a K8 (which had an accident a few years ago).

the previous owner always complained that the (k8-)braking performance was very poor and I tried to improve this braking performance using steel braideds and very aggressive brake pads, but without much success.

unfortunately, this K8 was in an accident about 5 years ago, ready for scrap, so I only have parts of it in the workshop.

after I drove a Gen1 that was also equipped with these gray Tokico Gen2 calipers about 2 years ago, I was quite surprised by its great braking performance and decided to use the old '08/'09 calipers mentioned above when I had the opportunity disassemble and inspect them carefully.

this happened now (last week) and what I discovered was sheer horror.

because these two calipers also had the massive error that the second hole was only made but not completely drilled.

what a huge piece of bullshit - no wonder the braking performance was so terrible.
(like at gen1 ´s as i already mentioned here)

below are two photos of the two brake calipers (with only one hole and only one small rubber seal each)

how idiotic does a manufacturer have to be to let such crap go through its in-house quality assurance and massively endanger the life and limb of countless motorcyclists.

OK OK - the accident mentioned above was purely due to a driving error on the part of the owner - the poor braking effect at the front was NOT the reason.If the driver/owner had said something about poor braking performance shortly before the accident, I would definitely have examined the brake calipers in detail back then.This is also why there was a long delay in my test of the Gen2 brake calipers. sorry 4 that.

right caliper
(find the fault)

left caliper (both parts)
(find the faults)

 

[IG.]

Interesting... These are rear brakes, and who uses them anyway? I have gen 1, and never use rear brakes except to check that they are functional, and on those very rare occasions when riding on the grass for a few seconds (track day excursions).

As to the pictures, showing presumably incompletely drilled holes, I am not sure this is a defect. The only way to verify is to compare with similar calipers from other bikes, preferably different make year.

Here is why I think this may not be a defect... First, one hole may be enough to transfer pressure from one half of caliper to another half. Remember that brake fluid barely moves when brakes are applied, and therefore this may be completely adequate. Second, this could be CNC programming issue, i.e. let's start holes on both sides, but later drill only one of those, which is decided in a completely different manufacturing step.

In the end, you could be right, and this is a defect as having two holes seems to make sense.

Please let us know if you get to the bottom of this.

 

[Berlin Germany]

Please let us know if you get to the bottom of this.

these 2 calipers are front calipers from the k8 and 100% sure no rear calipers .

and the 2nd drilling is definitely not done but 100% needed to get the DOT - pressure to the 2nd piston directely too

as like as at the gen1 calipers

dear ig - how far goes ur knowledge about calipers and their kind of working ?

to me seemingly very low - sorry - so pls stop ur comentars

my bottom of the theme is to leave these calipers in the round box / shelf - at us another word for scrap box
what I may use for other cals (and what I will save) are the poistons , the 2 springs and all the screws - thats my 2nd bottom

and
perhaps you read my two pages (by the links above - could help to understand)