Correct crankshaft end play/axial clearence?

Ultimately .004" - .008"
Of equal if not more importance is axial bore alighnment and race fit.



Best Regards,
Dale

that's 0.1-0.2mm is the metric equivelant powerfeind. so i guess KTM may be the boys to follow here.

should i put this in the owners doc?

Taffy

Dale,
If in fact the axial bore alignment is out .What is the procedure to correct this,machining the cases and making a off-set bushing or is it possible to machine or order a off-set bearing.I see from your photo that you check this spec with a mandrel, is this something you made yourself or a purchase item.On a side note, a Yamaha Br250(snowmobile)has a plastic(or nylon) bushing between the crankcase and the crank bearing,is this to allow a certian amount of tolerance for a out of alignment set of cases?On the berg engine how much out of alignment can a ball bearing tolerate before it causes excess wear?Sorry for so many questions,just got carried away!.....nsman

Hi Nsman,
My personal procedure for correcting axial misalignment is that of boring the offending case via a pilot indexed from the opposite case then fitting an OS outer race.

The arbor is homemade.

The ball is far more tolerant of axial misalignment then that of the roller bearing. (Hence the sudden onset of failure regarding early model 650 main bearings)

The mandrel is ground .0006" -.0008" undersize to that of the specified inner race ID.

Hope this has answered your questions.

Kind Regards,
Dale

Yes, thank you again......nsman

Dale

you talk of "an oversize outer race". how does that go?
you get the cases measured first, you decide whether there is need of the work?
you order oversize bearings whilst the work is under way.

so can i ask what the code of the o/s bearings is? or is it a 'doddle' and in the bearings (stock) list?

regards

Taffy

Taffy said:

Dale

you talk of "an oversize outer race". how does that go?
you get the cases measured first, you decide whether there is need of the work?
you order oversize bearings whilst the work is under way.

so can i ask what the code of the o/s bearings is? or is it a 'doddle' and in the bearings (stock) list?

regards

Taffy

Click to expand...

Hi Taffy,
Most often the right crankcase bore is undersize to begin with and as a result I can often axial align said bore and still provide proper interference fit of the outer race.

In the rare occurrence that I must use an OS outer race:
I phone my bearing supplier, whom in return phones his bearing supplier, whom contacts the manufacturer, whom alters the outer race OD specifications prior to final grinding. Some of the major bearing distributors have unfinished bearings on the shelf awaiting final sizing. I bore the case to fit once I have received said bearing. Such is indeed a big pain, fortunately most of the time I can get away with a tighter bearing running clearance (C2 as opposed to that of C3, etc.) with a slightly enlarged outer race case bore that has been properly aligned.

pheeeeeew! You are wearing me out Taffy 8O

Now please, tell all just how pretty that new LRX2 camshaft is and that if it performs just half that of its appearance it will be a true gem

Best Regards,
Dale

aaah dale, indeed-a work of art sir! you look at it and it's all one shade of creamy grey. a lot of work went into it for sure!

but like all racers i have to be patient sir! only change one thing at a time.

i went through the teeny process of a rekluse clutch and straight to a LHRB system last sunday. got used to it after half a lap. because it was a time card event i knew that i had time to faff the firsat two laps and by the end of those two i was dialed in!

i'm adjusting the ignition this week and the clutch engagement. as the nights are drawing out i will try to get that done as a bit of mid week green laning!

if satisfied i then have the camshaft to fit. 35/29 later after that.

must ask you though dale. with the cam and FCR39 and the 29mm exhaust valves; which headers will it be ready for/ the 501/550s at 28mm i/d or the 650s at 32mm i/d?

the results with the cam will be mentioned here for sure.

regards

Taffy