Finally got the XT350 back on the road.

My Yamaha XT350 , had a knocking sound around the top end and clutch area.


I pulled the clutch casing off, and noticed a small amount of free play on the clutch basket. D6 confirmed this also.

So the decision was made to remove and strip the engine down to find out what was causing the knocking?

I removed the valve cover , inspected the cams , chain and tensioner.
These were ok.

Next the head and cylinder was removed , the piston head was very carboned up.



When i removed the piston and gudgeon pin , there was a small amount of play.
There was also burning marks around the top end of the piston skirt.


I decided to order new rings , and gudgeon pin.

As we were removing the drive gears , we noticed the nut holding the balancer shaft was lose.

(the top centre larger gear is the balancer shaft which the nut was lose)

I think this is what was causing the knocking.

The free play on the clutch was a concern , so the gearbox had to come out.

This is the gearbox main shaft that had free play 2mm



The oil pump, drive , gear cogs , and gear selector were removed.


Next job was to split the casings...

cont..


The casings were pretty hard to split, most of the screws holding them together were x head (hate them) and i managed to shift all but two.

D6 had to chisel them off for me.

casing screws chiselled.



A good tap on the gearbox main shaft with a copper hide mallet soon split the casings after all screws were removed.

This is the casing that holds the gearbox main shaft bearing that had to be replaced.



This is the opposite casing , the bearing had come away with the gearbox shaft when we split the casings.




We used heat and a pry bar to remove the bearing. The seal behind which is located next to the clutch arm wasnt damaged in the removal.

New shiny replacement bearings were fitted , and lubed up.



While i was waiting for the piston rings to arrive , i gave the piston head a good clean.



The casings were put back together gearbox, selector , and balancer shaft.

ps dont drop the woodruff key down the balancer shaft when you come to fit the gear.
You have to split the bloody casings apart again

Main drive gear , and cam chain guide fitted etc...

Next job change valve seals and grind the valves

( this took a while , because i had to wait for a valve compressor to arrive to do the job)

rebuild cont...

The valve too finally arrived and i removed the valves , n fit new valve stem oil seals , n ground each vale for a better seat.

As my bike is shim and bucket , its a good idea to number the shims and buckets with a marker .


The valve removed and seat reground



To check if you have done a good job , just poor petrol in the inlet , and out let ports . if the valves leak , the valve needs regrinding , but dont over doo it .
You will need to re shim if gap is too much on the cams.

My piston rings arrived from Fowlers with the gudgeon pin.

I ordered +50s so these had to be gapped. (wot a pain)

before ..





after...


Only 10 tho gap, but its a good tight fit

valves done, and rings on the piston , the head could go back on.


new piston fitted with gapped rings.



The head fitted , Valve cover and cams , chain all timed in (D6 gave me a hand , coz the bloody clymer manual is very confusing)

I fitted the engine in friday.
Today all the running bits were thrown on , carbs exhaust etc...

Oil in the engine and the initial test run of 20 mile was fine..
As everything was disturbed and i have the gudgeon pin , new rings to run in .
I have to do at least 40mp or so for 100 mile before i open it up.

This is my 1st XT350 motor ive split , so im pretty chuffed it went together n run ok.


ugg

dont see many of these around now.

few years back there were a lot on e bay with blown engines.

got the impression this wasnt one of the better engines

they are a good engine,
just small enough to be abused,and they hold bugger all oil with a service schedule thats too far apart,,,
you can burn the oil out on these in a hard days off roading,
uggs will be fitted with an oil cooler when i get hold of one
worst point being the design of the under bucket shims, a right pain in the arse to do,
luckily uggs was on outer tolerances, and when ground in went to just the right side of the smallest gaps allowed,

D6 said:

they are a good engine,
just small enough to be abused,and they hold bugger all oil with a service schedule thats too far apart,,,
you can burn the oil out on these in a hard days off roading,
uggs will be fitted with an oil cooler when i get hold of one
worst point being the design of the under bucket shims, a right pain in the arse to do,
luckily uggs was on outer tolerances, and when ground in went to just the right side of the smallest gaps allowed,

Click to expand...

" shims are over the bucket" , you should know , we had to pull the feckers out coz i twatted one in, n it got stuck.

Good lesson to be learnt , if it dont budge , remove it and check why not

oh yes, I can see in the photos

Look like the old XS750/1100 ones

turnipbmw said:

oh yes, I can see in the photos

Look like the old XS750/1100 ones

Click to expand...

Yup huge, only thing i had to buy a valve compressor tool , with a small head to fit inside the valve head to get to the valve top washer .

They are pretty deep down .

ugg said:

" shims are over the bucket" , you should know , we had to pull the feckers out coz i twatted one in, n it got stuck.

Good lesson to be learnt , if it dont budge , remove it and check why not

Click to expand...

yup,
bit of a mistype there