Any old-school mechs in CHCH?

[mdnzz]

Got an XS1100rh 81 model, had it in at the bike shop and got a compression test done as I thought something was up.
Came back with the readings 200,20,25,250 :eek5::gob:
Ok so lets be thinking massive rebuild?
Got work mech to test and readings came back 140,120,135,140. Ok so 2 and 3 something is up.
Have rung several other places but they all seem to be scared of working on these old machines, so does anyone out there know of a good guy able to have a little look at it for me?

cheers all

[Voltaire]

Got an XS1100rh 81 model, had it in at the bike shop and got a compression test done as I thought something was up.
Came back with the readings 200,20,25,250 :eek5::gob:
Ok so lets be thinking massive rebuild?
Got work mech to test and readings came back 140,120,135,140. Ok so 2 and 3 something is up.
Have rung several other places but they all seem to be scared of working on these old machines, so does anyone out there know of a good guy able to have a little look at it for me?

cheers all

big difference between the two sets of readings...
What brought you to take it in for a compression test?
Was it missing? smoking? running rough?
Could be valve clearances?
give us internet wannabe mechanics some more info?
in fact put up a post on the classic forum here!!!
They are not that old school....some shops just don't want to work on old machines.
I pulled down a Z1000 years ago..quite easy...just 4 125 motors on a common crank really.

[mdnzz]

ok for the wannabes then lol, took her in because she was ticking up the top end very noticibly. yep big difference in readings. have had her out for a run get to about 140 then it feels like it dont wanna go higher. yea yea I know I ride therefore I should know mechanical stuff, err no sorry came from working with people give me a body I'll fix that but a motor, err whats that little dohicky next to the thingymajig????

[Voltaire]

repost on the classic forum as there is a guy called toycollector in ChCh and he has a couple of 4 cylinder older jap bikes, he might be able to point you in the direction of a frendly mechanic.
I think there is even a guy who has had lots of xs 1100's.

top end noises...hmmm
with you getting two different sets of compression readings...maybe one with cold motor and other with hot...I'm thinking tight valves..
but rattley top end sugests small ends of piston/rod or cam chain.
If the bike can do 140kmph and the oil light is not coming on, I think its more likely top end and not tear down.
cheers

[ManDownUnder]

Head gasket leak between cylinders 2 and 3...?

[racerhead]

Head gasket leak between cylinders 2 and 3...?

Yep this would be my guess aswell.
Not a major problem if it is, only a top end strip.

[T.W.R]

The 1st reading is :crazy: and theoretically the bike would struggle to run if at all. The second reading is about average for a bike that age that hasn't had any major surgery to date and the variation isn't that extreme remembering #2 & #3 cylinders run hotter anyhow.
Sounds like you need a good tune-up and if you want to go further a valve lap etc

get a leak down test done to get a more precise finger on where #2 & #3 are loosing pressure

[AllanB]

Give Duane a call at Duanes Bikes & Skis 344 6069 unit 6/91 Waterloo Rd.

He was at Norjos for years (worked there when I had new Kawas in the early 80's) so did his training on the old air cooled engines. Does work on Ducks as well.

As far as parts go you'll find the aftermarket is your friend as factory bits will be hellishly expensive.

[mdnzz]

Give Duane a call at Duanes Bikes & Skis 344 6069 unit 6/91 Waterloo Rd.

He was at Norjos for years (worked there when I had new Kawas in the early 80's) so did his training on the old air cooled engines. Does work on Ducks as well.

As far as parts go you'll find the aftermarket is your friend as factory bits will be hellishly expensive.


Duane has worked on this bike for the previous owner and no 'hasn't the time' to work on it again, she's gettin old and bits have been broken here an there and modified over the top, but testimony to the ol girl she still wants to run

[BBzz]

The 1st reading is :crazy: and theoretically the bike would struggle to run if at all. The second reading is about average for a bike that age that hasn't had any major surgery to date and the variation isn't that extreme remembering #2 & #3 cylinders run hotter anyhow.
Sounds like you need a good tune-up and if you want to go further a valve lap etc

get a leak down test done to get a more precise finger on where #2 & #3 are loosing pressure


I would say that the first reading the compression tester wasnt sealed in # 2 & 3 pot

Easy test to see if its Rings or valves gaskets:
Run the motor to normal operating temp
Remove plugs do compression test (throttle wide open)
Put a little bit of oil in each cylinder (couple of squirts with oil can)
Spin the motor over a few times
Redo compression test (throttle wide open)
If the compression is a higher reading Rings if the same valves head gasket

The second reading is not that bad

[mdnzz]

I would say that the first reading the compression tester wasnt sealed in # 2 & 3 pot

Easy test to see if its Rings or valves gaskets:
Run the motor to normal operating temp
Remove plugs do compression test (throttle wide open)
Put a little bit of oil in each cylinder (couple of squirts with oil can)
Spin the motor over a few times
Redo compression test (throttle wide open)
If the compression is a higher reading Rings if the same valves head gasket

The second reading is not that bad


Doing this is how we got the second readings.

[T.W.R]

I would say that the first reading the compression tester wasnt sealed in # 2 & 3 pot


Actually closer to the point would be to say the Compression tester was F@*KED giving a reading like that :yes:

A healthy XS11 should read around the 170-190psi area

[mdnzz]

Actually closer to the point would be to say the Compression tester was F@*KED giving a reading like that :yes:

A healthy XS11 should read around the 170-190psi area


Yes but this also has been kitted out to a 1197 so would expect compression slightly above that perhaps?
Also, the bottom gasket is twice the size of normal, was told this was because originally the compression was so much that the startor had trouble turning it over, also note no kick start fo same reason

[T.W.R]

Yes but this also has been kitted out to a 1197 so would expect compression slightly above that perhaps?
Also, the bottom gasket is twice the size of normal, was told this was because originally the compression was so much that the startor had trouble turning it over, also note no kick start fo same reason

1.1 sports didn't have a kick start fitted as stock.

unless the big-bore kit included high dome pistons, that and the base gasket would equalise each other out so there wouldn't be a substantial change

[Katman]

Excessive inlet valve clearance (ticking top end?) can also give a slightly lower compression reading. The valve opens later and closes earlier thereby letting less air/fuel into the cylinder which won't compress to the same pressure as a normal lungful.

[pete376403]

1.1 sports didn't have a kick start fitted as stock.

unless the big-bore kit included high dome pistons, that and the base gasket would equalise each other out so there wouldn't be a substantial change

Big bore kit will give higher compression, all other things being equal. Remeber compression ration is swept volume (sv) + compression (space above the piston) volume (cv) / compresion volume (cv).
The big bore kit gives a greater swept volume, but the compression vol remains the same so the Cr is now higher. The Cr might only change a little but some engines are pretty close to the ragged edge already when running pump gas.

[R1madness]

Gidday mate, We can look at it in the New Year if you can wait. Give me a ring at the shop on MONDAY between 10am-4pm (its xmas hours) 3829503. Cheers
Ian