crank shaft probs

[spanky]

hi there have just joined this forum after browsing through it many times even before i got my trx.
Now i have a problem and im not at all mechanically minded just bought a 99 trx850 over couple of months ago with just under 70000k`s on it, checked the oil over the first couple of weeks and then neglected to check for a few weeks until the gears got a little clunky only to find it was empty. i had noticed some sort of vibration and asked a mechanic to test ride it only to have him tell me the crank was the problem he didnt even have to ride it out of the driveway of his shop and the only info he told me was it would cost heaps and would b easier to find a new motor. has any body got any suggestions should i look for just a crank or a motor?? and how much would i b looking at?

[Killerwhale]

hi there have just joined this forum after browsing through it many times even before i got my trx.
Now i have a problem and im not at all mechanically minded just bought a 99 trx850 over couple of months ago with just under 70000k`s on it, checked the oil over the first couple of weeks and then neglected to check for a few weeks until the gears got a little clunky only to find it was empty. i had noticed some sort of vibration and asked a mechanic to test ride it only to have him tell me the crank was the problem he didnt even have to ride it out of the driveway of his shop and the only info he told me was it would cost heaps and would b easier to find a new motor. has any body got any suggestions should i look for just a crank or a motor?? and how much would i b looking at?

Have yourself a motor, i think the crank cost 1500€ in Sweden. Here you have a low milage motor...
Low milage motor on Ebay

[trixynut]

Mate, hello and welcome.

Availability and price of cranks or motors depends on where in the world you are? Aussie, UK, Kiwi, Europe?

Also, I wouldn't go buying either til I was sure that was the problem i.e. taking the motor apart.

checked the oil over the first couple of weeks and then neglected to check for a few weeks until the gears got a little clunky only to find it was empty

Trx's use oil, but a tankfull in a few weeks ?? Roughly how many K's/miles you do between it being ok and it being empty?

Post up some more info and you'll get the help you need.

Cheers.

[youngy]

As said above you'd be better off buying that motor on Ebay.

A new crank is £800.

If you can get an undamaged second-hand one, it, with gaskets and shells, is going to cost you in the region of £250 if you're lucky. Plus labour, unless you're going to tackle it yourself.

I have done this and, while it's not a mammoth job, it's not a simple task either.

Your other option is to strip the motor and get the crank reground and custon shells made up.

If the big end pins have really got hot due to lack of oil it is quite possible that the rods will need honing as they warp, and the crank may have bent on cooling. You can get all of that fixed by Applebee engineering for around £200 plus vat, but then you've still got the cost of gaskets and labour to strip and rebuild.

As long as the timing gear hasn't stripped off the crank, the crank is reclaimable.

[col]

theres an engine on ebay at the moment Item number: 200207039139
it £155 at the moment

[youngy]

there's an echo in here.............

[Jak]

there's an echo in here.............

No - it's just that no-one listens to you

[youngy]

eh? who said that??

[brockzila]

Your other option is to strip the motor and get the crank reground and custon shells made up.

can u not buy undersize bearings from yam~????

[youngy]

You can buy shells in 4 sizes, matched to the crank and rod.

When you knacker a big end bearing by oil starvation it generally reduces the size of the pin and puts it out of round, so it has to be reground round and is then a lot undersize.

[brockzila]

im not to happy about using a crank that has been taken past 030--.75mm. so i am guessing the 4th size is 040--1.00mm. so if its any bigger than that most reconditioners i know, and i know alot would just junk it. is the price of the gringing and making up of the new shells any cheeper than just finding a good crank or a worn one that can be taken to like 020 and shels off the shelf used???

[youngy]

When a big end bearing wipes it often leaves the pin 0.1 - 0.15 mm undersisized. This cannot be taken up with standard shells.

The answer to your last question is "depends". How much are you going to get an undamaged crank for? The only way to check the oil clearance is to fit shells and plastigauge the gap. So if it's too big, you need more shells. Do you know that the rods are still round? Or the crank pins for that matter? If either are not then oil clearance will vary, and may be too big or too small. This will lead to a much shortened crank life.

[spanky]

hi guys thanks for all replies, although i really love bikes im what u call mechanically dumb lol so i will b paying someone else to do any work.
i am taking the bike to a yamaha store next week, not because i dont believe the mechanic but cause he had no idea on pricing i can only hope the yamaha shop has more info or has better access to parts.
between checking the oil i would have done a couple of hundred k`s or so. not really sure
bye the way i live in Australia near brisbane also ride a zx6r so have a back up bike whilst the trx is gettin looked at.

[youngy]

you do know how to check the oil on this thing don't you? it's no tthe same as your Kwak.

[spanky]

i understand u need to run it for a while to check the oil, but i was thrown off cause it is heaps different to my other bikes, does this setup make it slower to drain oil as it would have to come from up the top??
i did buy this bike thinkin i would learn more about bikes, looks like im learnin the hard way lol so its good to see theres help out there thanks every one, this bikes gonna b a keeper so you will probably get some more questions down the track too