Top yoke pinch bolts
 

Eyup

Noticed that the bolts that are in the top yokes are very short and engage in only half of the threaded part of the pinch clamps. This is poor engineering practise of that there is no doubt but is it normal for Yamaha? I now know these bikes are built in Italy which is never a good thing. I have owned itallian bikes in the past.

The bolts in the lower yokes are full length thread engagement. anyone care to have a look at theirs for me to confirm please?

Regards

Al

Have you looked in the workshop manual ?

You will find that the clamps should fist be tightened at the front, the the rear - it's how it is supposed to be. So you will always have a gap at the rear of the clamp.

If you were to ask, I would say take it to a dealer if you are not sure.

Upper yoke bolts (east-west) 1 crest short of full thread.
Lower yoke bolts (north-south) 2 crests short of full thread.

I think you may be misunderstanding.
Its not the bar clamps, its the yoke clamps. "the big casting at the top of the fork tubes", The bolts are way too short.

Length of the bolts has no bearing on the gap at the yoke, but they should have full thread engagement and they don't.

Won't let me post a pic
Al.

Here you go, picture of the yoke showing very clearly that they have the wrong bolts in them, This is a brand new bike! are they all this bad?

Al.

Ah , sorry, misread.

Thanks for the effort, confirms my thoughts. Both yokes should be full thread engagement. anything less is very poor engineering.

I have emailed the pic to the dealer and will see what he has to say. I dare not look at it too long as I may find another problem.

Al.

Just my 2 cents worth.

A bolt is as strong as it's weakest point, if a bolt has a diameter of 8mm it is of no use having it threaded in a hole that is 30mm deep when the weakest point is the 8mm diameter. There is also the strength of the thread to take into consideration, if you have a weak thread you need a longer threaded portion to hold the bolt.

A basic rule I have always used, is a thread in alloy should be double the diameter of the bolt to be secure. A thread in steal should roughly be 1.5 times the diameter of the bolt.:smilies0119:

What Kev said.

Steel in steel, by the time you have got about three full turns in the thread is stronger than the shank of the bolt. Steel in ally you need another couple of turns.

Add a bit of safety factor to that and you've got the 'rules of thumb' above.

The only reason there is more (unused) thread in the yoke is that it's easier and cheaper to drill and tap a through hole than a blind hole. Not because it's needed for strength.

Just to add a few more thoughts...

- Just been out and looked at mine, and they're about the same as in your photo. I think there's plenty of engagement.

- Motonacio has an XTR, not a Tenere. They have different yokes AFAIK. Therefore they might have exactly the same thread engagement, but less 'spare depth' caused by drilling a through hole.

- I doubt your dealer put those bolts in there. Most bikes I have seen being uncrated in dealers have had the front wheel and the bars off, but the forks already in.

- Over-engineering is also bad engineering ;)

I don't want to bore anyone so look away now if threads are dull for you. If you want to learn a lot about them in 30 seconds then read on.........

I know a bit about fasteners, I have worked as applications engineer for the Germans most of my professional life and spec fasteners every day to automotive,aero engine and defence. Ever heard of Helicoil? the genuine article? that is one of the products that the company I worked for produced. They are often mistaken as a thread repair solution, In fact 99.9% of them go into Aero engines and other high tech applications from new to allow for greater tightening torque and so clamping forces to be applied, but back to the point.

Addressing one point raised, 3 turns of an ISO metric coarse 80 H6 (Standard M8 to most) @ 1.25mm pitch would be 3.75mm deep and would fail. Often in motorcycles particularly in Aly engine casings you will find ISO Metric fine. Reason for this is that you can acheive a higher clamping load from a lower tightening torque because it has more threads over a given length having a pitch of 1mm for m8 for example.

Its therefore not the case that 3 turns is max strength for a bolt in steel or otherwise. It depends on the substrate, class of thread fit. H6 for example, grade of bolt 8.8 10.9 12.9 and so on ....these are tensile ratings not bolt sizes and most fastenings on a bike/car are 8.8..in ordinary stress areas.......a 12.9 grade 8mm will strip a 6% SC aly casting at 3xD after peak proof load is passed whereas a 8.8 grade 8mm will break itself at 3xD at a lower torque and leave the Aly in tact at 6% silicon content.

Number of threads engaged drastically effects the load on EVERY one of the pitches.

Put a 10KN tensile load (nothing to do with torque)on a 12.9 10mm with 3 threads engaged and although the bolt can take it at 3 or 4 full threads, a 0.04% carbon steel (mild steel to most folk) nut or tapped hole in a similar steel component cannot. Increase the depth of engagement by a factor of 3 and reduce load on each pitch by a much higher figure. (determined by many factors) which cannot be covered here.


There are hundreds of factors in play. including the Cr3 coating on the bolts in this case which produce a 410 hour salt spray resistance to red rust but also reduce the friction C/E and therefore influence the torque required to obtain a given clamping load. Cr3 Trivalent Chrome FYI is the shiny stuff your bolts are coated with. You will recall a few years back when nuts and bolts were yellow? that was Cr6 with yellow passivation AKA hexavalent Chromium and was outlawed a few years back as it is a cancer causing agent.

I need to establish what the torque value is supposed to be before I can determine if they are long enough. I understand the economics of drilling and tapping thru holes. Particularly on this application as the threads have probably been cold formed as is ofted the case on Aly castings of this nature, typically this requires a longer lead on the tool than you would find on a "tap" which is a rare thing in mass production.

In summary
The bolts in my yokes are OK if they are capable of imparting the designed clamping force without compromising the material they are screwed into.

Anyone got a workshop manual with the figure in?

Al.

Thanks
There is no way the dealer did it, I know that for sure as they all have the factory Torque marks on them. Under engineering is worse than over engineering, As i have said, they may be capable, but they look terrible.

Thanks for checking yours.

Al.

hey Al.. a think you an Kev are gonna be like sandpaper pals....:067: but hey Kevs got it the gither on here,, an nodoubt another gurus a good thing.. but when the arguing starts...man its time tae get out o the kitchen...:confused2: ma bolts in that picture go right thru.. a think ye know by now the Yam centre ye got yer bike fae is not a yam centre,,its a bike shop wi a yam name on it wi the back shop full a wee boys wi dirty overalls on,, smoking fags an texting...what they called again....asbo`s aye teir workin off their hours that the judge thru at them an guess whit...on your bike....seriously,, atink ad take the bike back tae REputal dealer an cause havoc....man yer payin fur the real thing an a safe bike.. so why not get wit ye paid fur... take it back. an ye`l feel :brave::099:

Lucky you.

I posted 'rules of thumb', emphasising that that is what they were, to point out that threads are generally stronger than most people think they are. The reason I did this, rather than launch into some detailed thesis on the merits of VDI2230 is twofold:

a) because your OP gave the impression you didn't know anything about threaded fasteners. "Terribly bad engineering practice", "Clear that they have the wrong bolts in them" and all that jazz.

b) it is extremely boring.

Now it turns out you do know all about bolts, or at least enough to attempt to baffle everyone with bull****, and you've revised your opinion to "they may be capable, but they look horrible".

I'm not really sure what your point is? Are you going to spend your free time analysing every single threaded fastener on the bike because it was 'built by Italians'?

Personally I'll be out riding mine and not worrying about the pinch bolts. It's more fun. I'd recommend you do the same :D

Jeasus, I'm a sad individual. I even dragged out an old revision guide from my days studying Engineering & Geometric Drawing, just to make sure I understood it right. Of course the Chemsitry was staight forward.

Nowthen. You are not going to enjoy this bike at all if you carry on pulling things to bits. There are more than enough people around who will spend a lot of time pulling the bikes to bits, saying how much they hate them, they rust, they rattle, wind blast, I get wet when it rians etc etc.
Then there are the people who accept that there are finaincial reasons why bikes are builts and spec'd in the way they are, these people (I would like to think as myself as one of them), are happy to get out there and enjoy the ride. It's a bike, not a 747, technical tollerences are one thing, but it has to relate to the application.

Some people have even been off the road for long periods, yet they come back and get a second one - To these people, I raise my hat (if I had one), and no - I don't want to see his ass again.

If you want detailed technical discussions on the merits of bolts, I can think of two or three people who might be able to engage with you. But most of us just like to ride bikes.

I just have a rummage in the big jar of 'bolts that have come from somewhere' and find one that fits. Then use that.
Apart from that time when I used cable ties to hold on a rear caliper on my TR1, but don't worry, notice the plural, I used two for safety.

Al, as GULGO says, you can spend ages going through the bike with a toothcomb and finding the faults it has. They're there, but it's more fun just to find them out as you go along. By all mean do pre-emptive maintenance before winter and apply grease and ACF50 to everything you can get at, make sure the loom isn't snagging under the seat on the frame, and that your reg/rect connector is packed in grease and securely fitted, then ride the arse off the thing, that's what it's there for. By 10,000 miles you'll find the rear shock is shot, and if you're over 5' 10" you'll probably get windblast buffeting going on, but **** it, I haven't found a single exciting bike that doesn't have some issues that need sorting. Some call it character, make of it what you will.

LOL

None taken:icon_mrgreen:

I suppose I have over analysed the bike a bit, I suppose this is because it was delivered with issues like the missing tool kit and paint defects in the tank. AND I had time to do this as riding it much has been difficult whilst my ribs continue to mend. So I don't feel too bad about it!

As has been said, its a motorbike not a Jet turbine engine.

Tell you what, I will take a chill pill and ride the thing and worry about it if it falls to bits.




Al.

Correct me if I am wrong but aren't
 

The engine and box of gears Italian, and MBK build the rest of the XT660 in Picardy - France. So wouldn't this be a French assembly issue rather than an Italian one. Oui monsieur, surely you agree that it just doesn't look as finished as it could.

Nothing wrong with checking your bike over I do it every time I get a new one, as most bikes are put together by the human hand.

It does appear you knew the answer to you own question & were only checking to see if other XTZ riders have the same bolt length.
:pjrflash_Q2CCBE:

built in Italy an france using Jap chinese an austrian parts... they are called a jap bike but ridden by many cultures, and they are a cheap mode o transport compared to a honda transalp or a KTM.. fur th esame year o bike,, yed be payin well over the odds.. were o were could ye get a 3 yearold bike fur under half price o the new price.... a lot tae take into consideration..... a suppose a old emz wid have still got ye fae A tae B.. or wose still a Zundapp.. or a hate tae say it a CZ with the kickstart that folds down to make a gear lever....

anyway.. we`re only haein a wee bit o banter here... i know yer first post was about,, the build quality o the bike comming out of a dealer.. i still stand by an say take it to a reputable dealere an make noises,, as yer put together out o the crate is shocking,, an a think we`ve all digressed fae there,, an now as see were arguing about what kinda steel the bolts are made fae... its probably chinese junk... but hey ,, its cheap. it goes, its good on gas... it has a few problems.. but they can be ironed out.. they look good.. the get ye fae A tae B in reasonable comfort, :typing[1]: what more can i say,, everyone an their granny has one,, they are like Vauxhall caviliers, after all if yer looking fur a nice motorcycle.. go buy one.. if yer jist looking fur a half decent aul motorbike.. buy a yammy xt.........:Christo_pull_hair:thats wit kin happen when ye start wi the problems.. but ave found out no matter wit bike or car ye have.. the beuty o the internet is theres a forum fur everything.. an they ALL have problems... so i ask masel...why bother... when yer sittin on it riding it, behind they bars wi yer full face crash helmet on,, an ye have Horse vision... whit does it matter wit colour it is,,, whit kind o bike it is... how it looks... as they all go the same..but what a will say.. when ye get off it an throw yer helmet down.. git yer fags out an look at it,, ye`l say.. aye that bikes not bad after all......:blob8:

Afk40

If I may........

Your posts are very entertaining and worth the effort of reading in detail despite the difficulties associated with the phonetic. However, having digested your wordage on each occasion that it has been my pleasure to exchange, I somewhat surprisingly find myself asking out loud for a sconn whilst attempting an accent appropriate to proceedings. (and failing)!!!

As you rightly suggest it is all good banter here (as indeed should it be) and I certainly never take things too seriously of that yeee caaannnna be sure. Laddy!

I will be hoping to quizz you about the Islands in months to come as a touring vet and associate of mine has intimated that Skye and the general area ought to be visited in 2011 as part of our touring season. I find my DK guide somewhat lacking in this respect and have to confess that Hillington and the RR establishment, combined with a brief stay in Inverfarigig total my experience of your fair land and as such, I shall be seeking to solicit an opinion from yourself on the merits of such an undertaking.

We could even use a guide if you know of a reputable source, In all probabillity, 4 lads and 4 bikes will be amongst our number


Cheers

Al.

Al... Nae bother at all.... anytime.. pm me fur ma email address fur Direct stuff an some pics o Ma Island,,, a could give ye...., as tae a touring guide an map... its all in ma head.. a could show ye or take ye,, whitever one ye choose.. if ye wanted a trip an some detail.. Yes a think ad be yer man... an am not boasting o ma knowledge o Scotland.. ye`l find,, that most Scots know their land well.. but we all have favourite places......ave been up an aroon our land many many times.. in a van or a car,, the furthest North ave been on ma bikes.. ullapool, North West, 250 miles fae Glesga...

a could show ye a beach near there,, that if ye were blindfolded,, then took the Tie die wraps off,, ye`d think ye wir in Gran Canarie...have a look on google earth.. its Achmavelvic beach... jist awesome.. yje pics there below wi me standin there an ma kid goin fur a swim.. its on the Gulf stream.. its warm water... a could show ye some palm trees,, an a think yel need tae see this tae believe it,, but they Grow Bananas as well...

ave been known tae take the tourist tae places Tourists dont know about,, its like that aul advert when the used tae advertise beer on the telly.. Heinakin.. reaches the parts that other beers cant reach... ave wanted tae head all over europe an a have tae some places,, aye an on ma bike... but ave never jist messed wi Scotland,, an the funny thing is,, the grass is always greener on the other side..

bikers come fae all oer the world tae see this land o ours,, in the height o summer time its like the Isle o man wi bikes,,, all foreigners... looking tae wild camp.. an chill out.. next year God willin,, id like tae go Tour the states,, ave been twice.. an toured a wee bit on a bike.. a pal o ma pal did Australia.. on a Horse fur a year....

well I know a guy in the Florida keys whod lend me a bike..That wid get me tae Kansas,, then another buddy in Kansas wid lend me his,, as ave had them before,,an that wid take me tae Albq, New Mex,. then another buddy wid lend me his bike tae go up tae Collarado... a could go around in a circle if a wanted tae.. i have friends in Canada,, Rochester upstate NY,, Florida, Chigago, pensalvania, Kansas, alb, L.A, a few of then there, Washington, then do the loop....in 1990 a did fae NY tae Calif, an Back, me an ma wife, it took us 9 weeks......man it wis awesome...anyway am away on a tangent,, an ye dont want me talkin,,,, as a dont stop..

well its now 4.42 am ave jist finished watchin Easy Rider on You Tube.. so am away tae bed,,as am a bit o a nite owl.. fur a couple o hours an then if the e=weathers guid,, al head on out the morra.. Rootin tootin Scootin aboot on ma scoot......... ma email. jist PM me, an al let ye have it.....nae bother Al... cheers. Me. some pics below..

that wis some shot eh !!! in the last pic

well am up an ready tae face the Plot again... see ye later..... its now 9.49am...

I've only just found this thread, and i'm still chuckling from reading it, but seeing as the question never got answered - the torque setting for the top yoke pinch bolts is a mighty 23Nm, or 17ft-lb in old money, so thats probably why the bolts are the length that they are.

personally i like threaded holes deeper than they need to be - if the thread gets stripped you just ream out the top half and pop in a longer bolt, easy! Ikleyal works at the other end of the timeline to me - i see things when they're a few years old and things are starting to seize/snap!

Too much, bolts will start to change their shape. My experience on XTR 2007.