DT 175 steering bearing issues ......aarghhh

[Migthy Mule]

Hi all back again thanks for all your previous help, ended up getting the barrel bored out to 1mm (previous post) and got it back after about 10 weeks at the shop.

before fitting the engine back in the frame I needed to replace the steering bearings, simple job I thought - can of worms it turned out to be firstly the top of the stem is horribly worn so im wondering if I need a year specific part or were they the same for all models, mine is 1979. Will an early twin shock version fit ?

Secondly after fitting the bearings there is still loads of movement at the bottom fitting, I had to tap the top race in gently with a plastic mallet but the bottom pushed in by hand is it possible for the receiving piece in the headstock to ware? the original bearing set up needed tapping out (nice snug fit) and there didnt seem to be any play in the fitting. I have tightened it up to the point that it no longer drops from side to side under its own weight but there is still play there..... should I keep tightening im not sure if it may need over tightening to get the bearings properly seated but I dont want to damage them.

Thanks

[Migthy Mule]

Not sure its supposed to look like this, I suppose its possible this could cause the movement, though you would think it would be at the top ?????

been perusing ebay seems the current bottom yoke assembly is the same as a 1981 model( it has the casting to take the horn and fitting on it for the mud guard) could it be that its the wrong one and this is causing the movement.

To answer my earlier question it seems the twin shock versions had a different fitment for the mudguard so are the later ones all the same I have seen 2 types one has the casting for the horn and one type has bolt holes, thanks

[nayruf]

Hi

Your stem looks stuffed, hard luck.

PM sent

Aj

[Airhead]

I have a spare bottom yokeset which some bright spark has sawn off the horn mounts! If you send me your yoke I will fit the stem from mine into yours FOC (I have a hydraulic press at work)

[Migthy Mule]

I have a spare bottom yokeset which some bright spark has sawn off the horn mounts! If you send me your yoke I will fit the stem from mine into yours FOC (I have a hydraulic press at work)

That would be great sounds like its the same, pics below. To save you the hassle If you would be willing to send me the bottom yoke as it is ill fabricate a bracket and put the horn somewhere else, I could pay pal some money to you, this project has been going on far to long and I cant wait to get out on it

[Airhead]

OK PM me your name/address

[Migthy Mule]

Got home today from work to find the yoke set had arrived, rushed down my tea and put the kids to bed in record time and set about fitting it but.....

after putting it all together there dosent seem to be enough thread visable above the top bearing

This is obviously without the top seal in place,

there is just enough thread to get the nut on and tighten it but it don't seem right to me

when I placed the top yoke on there seemed a huge gap between the to of the yoke and the stem top

I took it all apart again, wipped most of the grese off and checked the cups were seated properly

Tried driving the race further down the stem

But with no luck

Im sure this is not right, before I contact the bearing company can anyone shed any light?

difficult to judge from the photo but there is about 3-4 mm thread visible

[Airhead]

no thats not right Sam, that top bearing is sitting way too high it doesnt look to be seated to me

make sure there are no burrs stopping the fixed race from seating.

Place the bearing in the deep freezer for an hour before fitting

Warm the top of the headstock up before fitting the chilled bearing

work quickly and try to re-fit

Dont use your new yoke to try to pull it down, use a long bolt 16mm diameter or some screwed rod if possible, keep the strain away from that fine thread on the yoke stem

[Migthy Mule]

Thanks yeah I figured its not right, I cleaned out the headstock, carefully before fitting but ill stick the fixed race in the freezer overnight and have a go tomorrow but it looks to me as tho its right up, If gain anything itll be a mm at most, the top bearing looks to stick up quite high but I think I need to gain at least 5mm more, Im wondering if the bearing is wrong

do you think its worth putting the stem in the freezer, and warming the bottom bearing, I tried knocking if further with a drift but it didnt budge, there does seem room at the bottom. but im not sure how far down its supposed to go

Ive changed the steering bearings on my Blade and Z550 in the past and never had any such issues, I will not be beaten by this bike !!!

[Airhead]

yes I didnt realise it could also be an issue with the bottom bearing! that one should sit flush down on the bottom yoke, sure freeze the stem and warm the bearing for that one

[Migthy Mule]

its no way near flush, that may well be the problem then, ill stick it in next to the frozen peas overnight, allways used to do this for wheel bearings but never needed to do it for steering bearing in the past, ill bring some threaded bar back from work too, thanks for the tip

[Migthy Mule]

No joy stem in freezer for 48 hrs and bearing warmed in oven, large piece of pipe and a lump hammer, all in vain still as before, I have contacted the seller on Ebay I think the bearings are wrong.

[Migthy Mule]

Brief away stint for work over and now back to the bike,

Bearing company are claiming its the right one for my bike model etc, they suggested I left out the grease seals to gain some thread.

but this got me thinking - should the bearings really bear on the seal? (see photo above) surely the bearing should bear on the cast shoulder of the yoke and the seal should fit around it, or is this how Yamaha intended it to be ?

[Airhead]

I'm baffled by this Sam and think that you have hit on it with that question. Its years since I fitted mine and i'm not about to strip the bugger down to find out

I would say the fixed bearing should fit directly on the bottom yoke yes

werent there any instructions?

what size hole is in that seal...too small to go around the fixed race?

could it be that the seal goes over the top of the fixed race?

post some piccies of all the bits

[Migthy Mule]

Hi Paul, no there were no instructions, the hole in the seal seemed odd - it wasnt a tight fit round the spindle but was way too small to fit around the cast shoulder/fixed race,

you would think that the metal of the seal would be a little soft to take the forces inflicted on it and in time could cause the bearings to be out of line.....

I have email d Yamaha in the hope they can shed some light.

[Airhead]

Cant see it right that the bearing sits on the seal! thats why your yoke stem isnt going high enough into the top yoke, theres something wrong with the way you are assembling it and Yamaha never fitted these in the first place so dont hold your breath there!, seiously if you cant resolve this you may have to consider leaving out the seal...at least for now?

[Airhead]

Looking again at the photo I cant make ou whether you have fitted TWO seals below the roller cage?, surely there should be only one at the bottom and one at the top bearing, bottom bearing seal flat side down and top seat flat side up...does that make any sense?

I can definitely see a seal flat side up in the photo...wrong!...and it looks to be on top of another?

[Airhead]

see this Sam

http://www.triumphra...rk-springs.htm

and taken from the above link, you can definitely see the seal hollow side uppermost...and the bearing being driven down onto it

[Migthy Mule]

http://yambits.co.uk/dt175mx-steering-bearing-seal-p-22412.html

this looks better

[Airhead]

hmm you havent read what I posted?...two seals?...one upside down?