Horizons Unlimited - The HUBB

Horizons Unlimited - The HUBB (http://www.horizonsunlimited.com/hubb/)
-   Yamaha Tech (http://www.horizonsunlimited.com/hubb/yamaha-tech/)
-   -   Engine Trouble (http://www.horizonsunlimited.com/hubb/yamaha-tech/engine-trouble-6042)

jrm 9 Jul 2003 19:51

Engine Trouble
 
Hi,

For the last 2 months my XT600E has been making a knocking sound. It was first noticeable at low rev's and has since got progressively louder, initially I thought it was the cam chain. I checked the tensioner which seemed to be fine, and put it two notches forward, but the noise is still there.

Could this noise noise be the main bearing? If it is the main bearing what other parts should you replace at the same time? (the bike has done about 24000 miles)

Any advice appreciated.

KlausXT600 9 Jul 2003 20:07

the chain tensioner is automatic type.
do not adjust!
sources of the sound might be main bearings or rod bearing. check also woodruf key on right end cam shaft end and nut, also on balancer shaft.
if bearings have to be changed you have to dismount the whole engine. so you will see what has to be replaced / repaired.

24000 miles is not very much, i wouldn't expect an engine overhaul at this age.
did you treat her bad? ;-)

regards
klaus

AFrear 9 Jul 2003 20:37

It may not be the main bearings but the conrods top 'eye' (hole) where the pistons cross pin goes.

I had my camshaft assembly renovated by a company who drilled out the top eye of the conrod and placed a brush in rather than replacing it. 3000 km's later now and the same knocking sound is back at around 1300 rpm. After the engine heats up the sound isn't so bad but can still be heard.

If you are going to renovate or replace the conrod then you should consider doing a complete top and bottom rebuild you'll need to open the engine anyway.

The parts I changed were the piston (+rebore), timing chain, oil pump, fifth gear set and main bearings. I also had the valves reseated. In retrospect I wish I had just changed the engine as if I now have to pay for the conrod to be fixed again it will cost more than if I had bought a low mileage ’98 motor from a junkyard...


[This message has been edited by AFrear (edited 09 July 2003).]

jrm 11 Jul 2003 00:31

Thanks for the prompt reply’s guys.

Klaus is there any way to check these items without having to opening the whole engine? And do you know what XT engines would fit into the frame (My bike was registered in 1997 but I think it is a 94 model, the frame number is 3TB-063415, engine 3AJ00)

Afrear, do you know of any good breakers who might have a spare engine for sale. I am based in London.

Thanks
JRM

KlausXT600 11 Jul 2003 01:30

to check the conrod you have to dismount cylinder and piston.
to check nuts and woodruff keys: right side cover.
to check main bearings: split crankcase

any e-start engine starting from 1986 will fit, or any engine starting from 1990.
but there are two different ignition systems.
you can use ignition/alternator from old engine.

regards
klaus

AFrear 11 Jul 2003 15:18

Hi JRM,

Sorry don't know anywhere you could buy an engine in London. The shop where I could have bought one is here in Denmark and they were imported from Germany.

Let me know what you find out.

jrm 10 Feb 2004 19:07

Hi Guys,

I have opened up right hand side of the engine as metioned above and most of the items metioned appear to be ok. The only thing that seems faulty is the plastic oil pump drive gear. How loose should this be? at the moment there is quite a lot of free play, is this normal or should it seat firmly in position? Could thid be the cause of the noise?

Any advise welcome.

JRM

FredXTZ 10 Feb 2004 19:42

JRM, sounds like the nut on the crankshaft pinion has loosened!

------------------
Fred, XTZ660, Holland.


All times are GMT +1. The time now is 22:29.


vB.Sponsors