Selective Engineering

[andyaber]

You won't find an engineering drawing where no tolerances are allowed.

So blue printing can be seen as trying to make your engine a cherry not a lemon by building to as close to the specified tolerance or fit as possible.

[buzzboi]

Yes... he is the owner of the bike shop!!! lol... But at the same time, he's a good guy, and he's not actually saying it to try and rip me off... not too sure when he raced, but it may have been information that he got back then, or it may be something that was done by the team and his memory of it is a bit fuzzy... who knows!?!?!

Has anyone in Australia had any luck with getting the crank repaired? My guy reckons it's easier and safer to replace the entire engine, but all I've found so far has more then double the mileage mine does. I'm guessing that repairing the crank depends very heavily on the skill of the welder and machinist... so if I choose that path I need to find someone as local as possible who is bloody good at it, I can't afford for this to become a regular repair. (Still hoping this isn't actually the problem though, goes in for diagnosis next week)

How about the TDM engine... I have neither the skill to do it myself, nor the money to pay someone else to attempt the 900 conversion... but the 850 TDM, is it the same? With all the same mounts, etc? I think I read that the gearing is different, but is that it? I know I need to be looking post 96 to get the 270 degree crank, but honestly a lot of the stuff I'm reading here is going WAAAAYY over my head... lol... but I'm trying to give myself as many options for repair as possible, and then working out which is the best from that.

Thanks for your input guys... It does help a lot!

[fung]

ok.
check the engine/head mounts as trx is slung under and tdm is cradled.
cheers
fung

[phuk72]

..however i am very stressed to hear of the problems people are haveing due only to neglect..

Are you serioulsy suggesting that oil usage is down to neglect?

If you are, you are completely wrong my friend.

All yamaha 5 valve head engines have a perspensity to drink oil. Some don't but most do. Yamaha even issued a press statement / Yamaha workshop guidance in the early 90s (and has reiterated the same message since) that using up to 1 litre of oil per 1000 miles was perfectly normal and within expeceted tolerances.

[BigAl-TC]

I think the neglect refer's to people not checking the oil level often enough.

[alextrx850]

I think the neglect refer's to people not checking the oil level often enough.

Thanks bigAl

[phuk72]

OK - and good point.

It not like its fecking hard to check the oil level

[Stankflapper]

All yamaha 5 valve head engines have a perspensity to drink oil. Some don't but most do. Yamaha even issued a press statement / Yamaha workshop guidance in the early 90s (and has reiterated the same message since) that using up to 1 litre of oil per 1000 miles was perfectly normal and within expeceted tolerances.

Thinking out aloud here............Then why the fuk didnt YAMAHA fit any "low oil" indication system to this engine??????????????

[phuk72]

Thinking out aloud here............Then why the fuk didnt YAMAHA fit any "low oil" indication system to this engine??????????????

They did


















It's a glass circle on the side of the engine

[Stankflapper]

I always look at that while riding along & running out of oil,, till I realised you have to stick your head up your own arse to see it..... Then it occurred to me what you are trying to tell me Phuk!!!!

[alextrx850]

As far as i have heard, with the TDM boys in Germany,they have also messed with this oil problem and tried to fit idiot lights or pressure switches, however the oil pressure is apparently not consistant or quite low volume at idle..hence confuseing to a rider...we once owned a Humber Vogue..it would do the same..[the oil light would come on]

While Yamahas engine build would have been of a high standard overall, it seems they couldnt find a way to give a switch with a certainty...[oil pressure wise]..?

So if the lubrication pressure is fluctuating ,..regarding the RPM..it might be a direction to not have a too tight motor..??
interesting chat

[Stankflapper]

we once owned a Humber Vogue

You LEGEND Alex!

[andyaber]

I read once that the 5th valve was for letting the bullsh!t in, or was it out?

[SDN]

My understanding of blueprinting would be careful selection of standard components to get the optimum running conditon

So for example if you select a piston that was machined to its upper limit (less metal taken off) and head and barrel machined to the lower limit ( more metal taken off ) you could end up with higher compression.

The engine is the carefully put together making sure that minor manufacturing faults are corrected then you avoid the Monday / Friday engine and all it's attendent woes, or unfortunate stack up of tolerances, which in mass produced items means there are some "bad uns"

[Stankflapper]

I read once that the 5th valve was for letting the bullsh!t in, or was it out?