TRX 1995 One dry big end bearing

[flyinghigh001]

Hi Everyone,

Both of My big end bearings failed and shes only done 28K. I then I fitted two new ones (colour black) checked the oil delivery at the test port and
and the oil test port started to weep as soon as she started up so I assumed the pressure was a lot better after having two sets of new shells fitted.
Went for a short slow ride but the engine sounded different, sure enough it started to rattle after five or so miles so I crawled home and found no 1 con rod set burnt out
but no 2 set was in tact but with fatigue marks.

Any ideas, I have blown all the ports out with a compressor, in the engine and the sump ports, Oil filter is new the mrv is free and the return valve ball works fine, correct
viscosity oil fitted.


Regards

Tony

[cobbadiggabuddyblooo]

Did you plastiguage the rods to check the right clearances and check the run out on the crank??
It may be the bottom cap has stretched on the rods.
It's worth your while to replace the check valve seal too. The one with the little steel ball.

[SDN]

That's a bit of bastard luck - doing all that work to have it detonate on you after only five miles - have you checked the oil pump?

[flyinghigh001]

Hi Cobba, SDN

I checked the caps to three decimal places and got 45.000 mm at 45 deg intervals and the oil gap was exactly .005 mm or 5 micrometers.

Just to pick your brains a bit, if the oil came up to the head test port can we assume its got pressure enough to get to number 1 piston crank shells?
the ports in the crank should give it loads of oil. When I stick the pumps in oil they seem to pump quite well and the gears don't look scored or worn.
there are three galleries two to crank and one with what looks like a flow restrict-or, similar to the jets in a carb, will any of the seals cause lack of or no
oil to my crank shells. When I fired her up after the last re-build there was loads of oil getting to the cams.

Can anyone confirm the colour codes to numbers on the rod and web and how you get to the colours I am getting to doubt my experience and lack of expertise
as I have never had this problem before thanks.

Scratching my noggin a little, thanks guys for the response Tony

[Rod.s]

Did you used run in grease on the bearings, were the rods in the right way around with the hole on the top side? The oiling circuit is a two part circuit splitting and going to the head and crank. Check, check and then check again

[cobbadiggabuddyblooo]

Have a look on my rebuild thread as it explains the coding to make sure you get the right colour and clearance bearing to suit. Numbers are printed on the rods and crank to determine what colour you need. I had this engraved in on the back of the engine case too on my bike.
All this info is in the workshop manual too.

[flyinghigh001]

Big ends.

Hi everyone, I think I have solved the problem and it gave the opportunity to clean places I couldn't reach too!

When I yanked the engine out to get the microscope out and check every chuffing part ,I had to loosen the big oil feed pipe from the oil tank at the rear
of the engine, low and behold there is a massive oil strainer inserted and is impossible to remove without taking oil the tank off or swinging arm assembly
or lowering the engine forward or completely out which did, When i pulled the pipe out it was 90% blocked with white metal, black engine seal and loads of
lint cloth. I have the photos to prove it as it was going to be a what to look for forum. I'm one happy biker although I have ordered all the seals and gaskets
for the engine Doh!. Anyway thanks for giving me a few things to look at whilst scratching my noggin.

Tony

PS this one is nearly as embarrassing as my white smoke forum.

[cobbadiggabuddyblooo]

There are 2 strainers in place
1 is in the oil feed pipe from the top sump and there is another strainer which picks up the oil (return) that you access through the bottom pan on the engine.
I found grunge around both of mine.

[SDN]

well glad you found the source of the problem, just a shame you had to go through the pain twice. I did check and clean both strainers when I re-built my engine, they were all clean. Also thankfully all my bearings, mains and big ends were in good nick after 50,000 miles - so Japanese engines are fairly robust

[flyinghigh001]

TRX has been re-assembled. Wow what a difference oil makes, been on a fairly long running in ride and she has got some propper grunt. Clearing the crappo and
TLC of the oil delivery system did the trick, engine running really well and I am chuffed to death with the performance.


Thanks for your input Guys

[SDN]

Glad you are back on the road