A forum for owners of Yamaha TTR250 trail and enduro bikes!

Padowan · Senior Member

Simons 350 build

TTRfan · Super Guru

RE: Blueing of crank

Padowan · Senior Member

Great stuff. No up and down, there's a small amount of side to side, but I assume that's normal clearance.

The only thing that's really slowing me down at this point is a lack of boxes to arrange all the removed parts into, did too good a job clearing rubbish out of the garage!

TTRfan · Super Guru

Sideways play (unless excessive) is not a problem as it is needed to keep the piston and crankshaft alligned through its stroke.

The big strong veggie boxes from your nearest supermarket (with a layer of newspaper in the bottom) are ideal wink

Padowan · Senior Member

I found some crates my wife had in the shed for storing vegetables from the allotment! Lined with card and now full of bits. Knocked up a clutch holder, but now I've hit a stumbling block on the other side as I don't have a puller for the flywheel. I've tried the rear axle, but can't seem to get enough leverage to tighten the axle and pop the taper. I also tried fitting an blind bearing puller and slide hammer, but was concerned I'd only be pulling it out by a single thread and might damage it. Will have to order one in.

TTRfan · Super Guru

Simons 350 build

ttr steve · Super Guru

Good work so far, loving the clutch holder biggrin biggrin

Padowan · Senior Member

While I try to sort out getting hold of a flywheel puller I thought I'd tackle a couple of other jobs on the list.

One nicely helicoiled exhaust stud hole.

Padowan · Senior Member

Well that was harder than expected to get the flywheel off. Couldn't get adequate aligned leverage from using the rear axle, so ordered in a puller. I prefer 2 part pullers as the smaller inner pusher has a finer pitch thread, so ultimately a stronger push for a given rotation. After finally taking delivery of the puller this morning I set to work. Screwed in the puller and started winding in the inner. Nothing, a bit of rotation, but flywheel stuck fast. On removing the puller it was clear I was simply driving the inner into the crankshaft - the downside of a 2 part puller when the shaft has a tapered hole!

To rectify the situation I found a suitable sized countersunk bolt to fit into the shaft, to give the puller something to push against.

Another go with the puller and off it popped with a bang. Needed more effort than I would have thought, but then again its cold today, so things will likely be on the tight side!

Not a lot left to remove before I can split the cases now.

-- Edited by Padowan on Tuesday 1st of December 2020 11:14:02 AM

TTRfan · Super Guru

Well done Simon! Good thinking on using the countersunk bolt smile

I also had the same issue as you with a two-part puller which I destroyed and went in the bin. I now use a solid one and am lucky enough to have a windy gun and the flywheels always pop right off.

The standard Yamaha ones Steve sells are pretty good - see here.

Good to get your updates biggrin

Padowan · Senior Member

I've also got a windy gun, which did a great job of driving the tool into the shaft!

Padowan · Senior Member

And we're in!

Padowan · Senior Member

All the gubbins out and organised. Now to send the cases off to have the opening enlarged.

Bearings are all Koyo, would that be original, or Brian, can you remember if you've been in this engine before?

mossproof · Super Guru

Bearings are Koyo from the factory I believe. Are you going to replace them? If not, they need sealing off or removing - you will never clear the machining swarf from behind them otherwise.
Well done with that flywheel - harder than it should be! (Gorillagrip Sussex?

)

Padowan · Senior Member

I think that while I'm in this far, it makes sense to not scrimp and replace the bearings (and seals). The current ones all feel lovely, so it seems a shame, but like you say, swarf will get everywhere. Although there is small part of me that is thinking that it'll only be soft aluminium swarf...

ttr steve · Super Guru

Just remove them before machining, I replaced all mine, but didn't really need it

mossproof · Super Guru

Padowan wrote:
I think that while I'm in this far, it makes sense to not scrimp and replace the bearings (and seals). The current ones all feel lovely, so it seems a shame, but like you say, swarf will get everywhere. Although there is small part of me that is thinking that it'll only be soft aluminium swarf...

Soft aluminium swarf will still bu@@er up your starter sprag and oil pump! Cleanliness is next to godliness

I covered mine in thick polythene sheet stuck down with silicone sealant, but if you've got a hot air gun (or an understanding partner who doesn't mind the smell of 10W40 with the sunday roast) they're not too hard to remove.

Padowan · Senior Member

Shhh. Don't tell the missus...

Getting the cases nice and clean, then I'll pop them in the oven to try to drop the bearings out.

What are people doing with the starter idler and clutch shaft roller bearings are people replacing those too?

TTRfan · Super Guru

Padowan wrote:
What are people doing with the starter idler and clutch shaft roller bearings are people replacing those too?

I didn't replace mine and don't think Steve did either.

I was really tempted to re-use all my internal bearings coz they all seemed good but I had bought new ones and, as I am not intending to rebuild any more TTR engines, I thought I had better use them!

That said, the AllBalls main bearings are cheap enough and I think they should probably be replaced as a matter of course.

I am racking my brains to think of anyone ever posting on here having suffered a bearing failure. I did once replace a worn transmission output shaft bearing (the one the sprocket fits on) as the seal had failed and had let some grit or dirt in. I would think that is the bearing that does most work in the whole gearbox.

Who are you getting to bore your cases?

Brian

PS Great progress wink

Padowan · Senior Member

Not decided yet on who to bore them out. I had some head/cylinder work done on the BMW GS a couple of years back by the guys up at Exeter Engineering who were very professional. Knowing that Dave Massam has done it before and will know how best to jig them up, I'm tempted to give him a call.

TTRfan · Super Guru

Padowan wrote:
Bearings are all Koyo, would that be original, or Brian, can you remember if you've been in this engine before?

I honestly can't remember Simon disbelief

Other than when fitting a big-bore kit, the only reason I would have split the cases would have been to replace the gearchange shaft as often owners leave the gearchange lever loose and it kills the splines.

Padowan · Senior Member

In the oven, let's see how many drop out...

TTRfan · Super Guru

Make sure you have really good gloves on Simon! Most of mine fell out just by banging the cases on a block of wood wink

Padowan · Senior Member

6 of them are out, after 30 mins in the oven and a gentle tug with the slide hammer. Mains are holding fast, will leave them in longer and have another go. Got some very good gloves, don't worry!

TTRfan · Super Guru

The nice thing about the mains is there are some convenient gaps in the casting to tap them out with a punch from the outside biggrin

Padowan · Senior Member

7 out, one main stuck fast, even after ~60mins at 190C. Was reluctant to tap them out from the back as you'd not have a central aligned pull and might damage the seat as you 'wobble' the bearing out...

-- Edited by Padowan on Wednesday 2nd of December 2020 08:03:13 PM

Padowan · Senior Member

Last one out after another stint in the oven and some persuasion with a punch and percussive implement. Having put the bearings through the washer and ****ting one out, they'll all be getting replaced. At least the cases are now ready to go off somewhere.

Hopefully I can clear the smell from the kitchen before the wife comes home!

ttr steve · Super Guru

Blame Brian, I did biggrin

TTRfan · Super Guru

Padowan wrote:
Hopefully I can clear the smell from the kitchen before the wife comes home!

Our pizzas that night were disgusting - they tasted of burnt WD40 disbelief

JOHNYBOY · Super Guru

i like your style brian plenty of banter all good my pal

Padowan · Senior Member

So after a long delay and all sorts of lockdown restrictions, distractions and procrastinations on my side, I finally found some time to take the cases to an engineering shop for then to open them out to take the larger cylinder. Barum Engines, turned them around super quickly considering they said they were chockablock when I dropped them off. Collected them this morning, all seems in order and I'm ready to start reassembly (after a thorough clean)

Padowan · Senior Member

Having now given everything a decent wash and blow dry, the first task will be to get all of these in, probably tomorrow, after a day in the freezer.

mossproof · Super Guru

Well done Simon. Progress at last!
Don't forget to check there is clear space between the starter motor and back of the barrel before the final build - the fins there are too long out of the mold so they need filing back. Hopefully I did it before I dispatched it! (Can't tell from your pic)
Good luck!

ttr steve · Super Guru

Good work matey

How much did barums charge you? they did mine (think I paid forty odd quid) and a customer with the 350 kit was asking if they could do his.

Padowan · Senior Member

They charged £60, and despite being very busy and me telling them I was in no rush, they turned them around within the week.

TTRfan · Super Guru

Good to see that you can make progress now Simon smile

ttr steve · Super Guru

Padowan wrote:
They charged £60, and despite being very busy and me telling them I was in no rush, they turned them around within the week.

Gone up a bit, but still good value. A customer in France was quoted £crazy money, think he has sent it to Barums now

Padowan · Senior Member

mossproof wrote:
Well done Simon. Progress at last!
Don't forget to check there is clear space between the starter motor and back of the barrel before the final build - the fins there are too long out of the mold so they need filing back. Hopefully I did it before I dispatched it! (Can't tell from your pic)
Good luck!

Thanks Simon,

The cylinder appears to have had the fins filed, so we should be good, but I'll do a dry fit before starting properly, just to be sure.

Padowan · Senior Member

ttr steve wrote:
Padowan wrote:
They charged £60, and despite being very busy and me telling them I was in no rush, they turned them around within the week.
Gone up a bit, but still good value. A customer in France was quoted £crazy money, think he has sent it to Barums now

I also had a very high quote from another engineering shop, they were talking 4h+ of labour at £50/hr to jig it all up, and get the bore diameter just right, centred, perpendicular etc. When I queried, they were talking about thermal expansion and heat transfer requirements of the dissimilar metals, which are fair comments if this was a highly tuned small clearance race engine, but I think perhaps engineering overkill for a 20yr old air cooled tractor-donkey-bike!

Padowan · Senior Member

That's 6 bearings in. For the remaining 2, the supplied bearings have lip seals on both sides, I've read about removing a seal, but not sure if that should be both seals, in/outboard seal only and whether the same applies to both the remaining bearings...

mossproof · Super Guru

I think one of the bearings which retains a seal is on a shaft which has an oil feed down the centre and out through the case, in which case the seal prevents pressure loss through the ball race. Unfortunately I can't remember which is which. Have you got photos of what came from where?

TTRfan · Super Guru

To the best of my recollection the only bearing that retained an oil seal was the one arrowed in the photo below (93306-00320?). The seal goes on the "blind" side.

There are loads of photos on my 350 build thread here if you need any references.

5th Feb 2020 3a.jpg

ttr steve · Super Guru

That one costs a small fortune from Yamaha

Padowan · Senior Member

I took Mossproofs advice and had a look at what I took out - why didn't I think of that! Both the bearings that came out have a single seal installed, so presumably those sealed sides go into the bind-side of the case, I have installed likewise.

-- Edited by Padowan on Wednesday 9th of June 2021 09:25:16 AM

Padowan · Senior Member

So how hard should I have to whack the crankshaft to get it seated in the main bearing? Both the bearing/case and the crankshaft are at room temperature so I could chill down the crank in the freezer, but I don't recall disassembly requiring really heavy tw@ttage to get the crank out. Am I missing a trick somewhere?

TTRfan · Super Guru

Is it just the clutch side that is tight or both?

My recollection is that the clutch side can be tight enough to require pulling the crank through the bearing by using a big socket as a spacer and tightening up the crank end nut to pull it through. Will try to find photo later.

I wouldn't recommend using a hammer wink

Brian

Padowan · Senior Member

Excellent. Thanks Brian, why didn't I think about pulling it on! With a combination of the old bearing and several sockets, I was able to use the flywheel bolt to pull it home. (plus I put the crank on the freezer for a couple of hours). Onwards!

Edit, actually I had to do it twice as the con rod was in the wrong position first time!

-- Edited by Padowan on Thursday 10th of June 2021 09:31:09 PM

mossproof · Super Guru

A job that's worth doing is worth doing twice

I use a hot air gun to warm the case to make things a bit easier. Glad you got there in the end.
BTW, the barrel fins have been trimmed so you should be ok.

Padowan · Senior Member

OK. That's it for tonight. Innards in, cases sealed and bolted together and new seals fitted.

Gubbins in:

I've used Drei-Bond with great success on the engine cases of my old GS.

Bead of sealant

Cases fitted together and torqued up. Bead of sealant squeezing out nicely

New seals

-- Edited by Padowan on Thursday 10th of June 2021 10:16:31 PM

Padowan · Senior Member

So having got a lot of the stuff in the RH side of the case following the exploded diagrams in the service manual, I have a washer left over. It's not the one that hides under the shift fork. Is there a washer under the first circlip before the kick start idler gear? The kick start mechanism isn't in my manual so I can't be sure, but this would fit as it'd take any lateral play out of the countershaft...

-- Edited by Padowan on Friday 11th of June 2021 06:29:12 PM