Cylinder Compression...

[anutz]

So...


Had the top off the head...


Measured Exhaust 1 - fine, bang in the middle of 0.21-25


Measured Intake 1 - 0.09, fecking tight, and valves 2 and 3 look just as tight, well out of the 0.11 - 0.20 recommended


Hoping that this will cause good readings when resolved....


No time right now to do any more but based on this wacky result who knows how tight things will be on the valves as i go...


Certainly this piston, with the highest readings has an issue already that could explain the low pressure

[anutz]

A quick look at Cylinder 2 and 3 on intake with the 0.10mm gauge i have, won't fit so these are at most 0.09mm if not worse, need to find some thinner and narrower gauges before i can get proper readings but looking like all 3 cylinder so far have significant tightness on the clearances.

[ram]

hope they haven't burnt the valve seats

[unfazed]

Inlets would be less prone to to burning as they are cooled be the intake  of fuel.

[limax2]

still to check the clearances but for info, how much does a re-bore cost, and would you need oversized piston rings once its re-bored, or do the normal rings just push out a fraction more to seal etc

Not too familiar with the 1000's but they are probably a plated bore so not just as simple as a re-bore. If it is a simple re-bore you would also need a set of oversize pistons and rings. I am old school  and don't know much about re-plating of cylinders, but if that brings it back to standard size you might be able to use the existing pistons but you wouldn't go to the trouble and expense of re-plating without fitting a set of new rings.


Probably just the valve clearances anyway. Good luck.

[anutz]

Update...


Clearances are sorted, but still getting low compression, and double checked a squirt of oil in the bores does nothing...


could this mean valve seats are the culprit...


I am going to re-check my work but i was hoping that it was clearances, as they were well out of spec in all cylinders for at least one valve per cylinder.

[The Male Whale]

Try a leak down test next.

Whale

[anutz]

Hi All,


Not had chance to do a leak down test but i did re-check my work and re-checked the clearances, modified 1 or 2, and i now have 118-124 across the board i.e. all in between that range, so an improvement, if just a little one.


I spoke to a local mechanic, an MOT Tester, and he said it would run on those pressures, and its not too bad considering age, i don't know. It does fire up, and today once it warmed up i took it up and down a private road, and it rode fine, seemed to have power etc


I can get it to start, but it needs, when cold full choke and a whack of throttle, then its touch and go until it warms up, he did say to check fuel lines and carbs as well as it could be fuel starvation.


I am not sure which way to turn, do i do a leak down test, are my pressures significantly bad, i know compared to the manual they are about 50 PSI off minimum, but those with experience in seeing compression in FZS1000's are the values i have massively low.....


If so then i will just park the bike for now, have my 600 going through MOT once i have calipers sorted, so i can live without, but am keen to diagnose and fix, its a busy month however, fuel pump on my MG ZT has just died so other priorities.


Thanks


Anutz

[ram]

is the compression gauge a decent one? can you check it against another to make sure its reading correctly?

[anutz]

Its an un-branded one that cost 40$, but i do have a Gunson one, just not the right adapter, so may look for the right diameter one


Maybe if i am lucky it will be off by 60PSI and all they cylinders are fine 

[anutz]

Its an un-branded one that cost 40$, but i do have a Gunson one, just not the right adapter, so may look for the right diameter one


Maybe if i am lucky it will be off by 60PSI and all they cylinders are fine 

Just ordered an 12mm to 10mm adapter for the Gunson so next week should be able to test with a 2nd gauge....

[tommyardin]

Tommy posted the compression figures from the 600 , these are the ones from the 1000
Dont know why it came out sideways , bloody camera phones

Sharp thinking Graham, as I thought anutz was talking about his FZS600

[tommyardin]

Another one for valve clearences    ....re-grinding the valves would help your compression figures aswell....


had my X7 rebored a couple of yeasr ago...£50 per cylinder + new oversized pistons and rings , dont think thats your problem though  .....


tommy , showing your age there buddy      ..those old bikes would have been "overhead valve" engines , valves operated by a push rod from the cam located close to the crank , these new fangled motor cycles have the cam on the top and driven by a chain...called "overhead cam" engines.....still important to check valve clearences on the fazers after head removal....

Are not all modern motor cycle engines overhead valve? the really old motorcycles like my original BSA M21 was Side Valve, the BSA Super Rocket (1961) was Overhead Valve with under slung cam shaft running push rods .

If the valve settings are tight it will cause the seats on the valves to burn and also the seating in the head, they will require lapping/grinding in or replacing if they are badly burnt.
I will side with the others in here that said valves causing the lack of compression as the bike has done low mileage, if the bores still had any sign of honing in them they are not worn, plus the piston rings are under a lot of compression in the bores and will take up a certain amount of wear ,as long as the wear is uniform and the bore are not slightly oval, the usual sign of bores being worn is piston slap and a small amount light blue smoke when running, if the bike gives out a big puff of blue smoke when it first start but stops smoking after a few seconds it can point to unseated valves and/or worn valve stem/guides.


But as Red said my knowledge is of older machines, but the principles of the combustion engine remains the same, just much more refined.


As someone else pointed out a teaspoon or two full of clean engine oil down each plug hole will determine if its bores, all the plugs out to start with, oil down each bore one at a time as you test it with the throttle against the wide open stop, if there is no marked improvement in compression then it points to the valves or a head gasket blowing between cylinders.

[red98]

Another one for valve clearences    ....re-grinding the valves would help your compression figures aswell....


had my X7 rebored a couple of yeasr ago...£50 per cylinder + new oversized pistons and rings , dont think thats your problem though  .....


tommy , showing your age there buddy      ..those old bikes would have been "overhead valve" engines , valves operated by a push rod from the cam located close to the crank , these new fangled motor cycles have the cam on the top and driven by a chain...called "overhead cam" engines.....still important to check valve clearences on the fazers after head removal....

Are not all modern motor cycle engines overhead valve? the really old motorcycles like my original BSA M21 was Side Valve, the BSA Super Rocket (1961) was Overhead Valve with under slung cam shaft running push rods .












tommy , interesting thought that , yes , all modern bikes are  OHV.......two basic types of internal combustion engines refered to as...overhead valve and overhead cam...OHV , OHC.... but  as you have just spotted they are both OHV engines with exception of the side valve engine , these engines have the valve upsidedown within the block alongside the cylinder bore , so no moving parts in the head just the spark plugs and for any harley fans
   known as "  flat head " think all engines are now OHC but could be wrong........OHV , OHC are a bit misleading when you think of it like that , all to do with the positioning of the cam , OHV engines have the cam at the bottom of the engine driven usually by a chain and using pushrods , as you mention , to link to the valves , instead of the cam chain on  OHC engines......old terms to describe the two different engines which are years old but a bit misleading.......well spotted tommy   

[ram]

Its an un-branded one that cost 40$, but i do have a Gunson one, just not the right adapter, so may look for the right diameter one


Maybe if i am lucky it will be off by 60PSI and all they cylinders are fine 

im sure it wouldnt be that far out but wishfull thinking. still sounds like valves though.
if it turns it to be valves burnt then it might be cheaper to find a good used head than to have them recut and replaced

[anutz]

looks like i best get my hands on the kit to do a leak down test then...

[Fazerider]

The internal volume of the adapter, hose and anything else ahead of a non-return valve will reduce the compression reading. That includes any portion of the plug hole that the spark plug would normally fill that the tester adapter does not, i.e. if the plugs have a long threaded portion and the tester adapter does not you will get a low reading.
The volume of the cylinder with the piston at TDC is only about 20cc, if the tester adds even 10cc that’ll reduce the reading by a third.

[anutz]

Will bear that in mind.


Main thing i am bothered about now is not the reading but where the leaking is...


Have a leak down kit on the way, so with the air compressor i have, should be able to find the culprit...

[tommyardin]

Hi Anutz,
Keep us informed on what you find, and as Fazerider said if the end of the compression tester dose not completely fill the plug hole length then it will show a low compression reading, but they still should be all around the same reading, it is best down with all the plugs out because the other 3 pots under compression when testing will stop/slow the engine from spinning at max speed especially if the battery is a wee bit low.
Try it with 10ml of oil in each barrel after the initial test.

[anutz]

Will do...


Have a Air Compressor that will provide 150PSI, well above what i need, and i have the leak down test tool, just need a 1/4 inch BSP Male adapter now that i should get today i think, so will post some pics/video when i do the tests etc...

[anutz]

Update

Got my hands a compressor and leak down tester...

All pistons were sound, 10-15% leak, only out of bores, no hint of any noise else where

So, I put it back together and re-checked the clearances...

It still is hard to start, but once it starts and warms up, then its fine i.e. no hesitation, and power on tap, so I'm a little miffed...

It just seems to need a right old handful of throttle and then screams into life, engine is smooth, no strange noises, really is fine, timing is 100% spot on, I think the low compression readings were not that low

Speaking to an MOT tester, who has a fzs1000, he has seen a few with readings like that, and they have had no issue, but who knows...

So for now, its summer and I think after a full ride out tomorrow it will do...

I am going to turn my attention to a carb rebalance and changing fuel filter tmrw, don't really want to mess with carbs if it runs well now...

Would love to figure it out

The Leak down test stuff was intresting, and the kit cost me 150 all in i.e. compressor, leakdown tool, decent adapters for coupling....so not been a bad learning thingy

Will have a look at how much the compression tester encroaches on the compressed cylinder volume as sonmeon said that can throw of readings mayde that's whats happened to me...

[PieEater]

It just seems to need a right old handful of throttle and then screams into life, engine is smooth, no strange noises, really is fine, timing is 100% spot on, I think the low compression readings were not that low

Sorry to ask the obvious but have you checked the EXUP is working 100%?

[anutz]

yep that's all fine and dandy - one of the first jobs I did, moves freely and at the right RPM's as well....

I have not looked at the carbs or fuel supply at all, and need to check the air box/filter, but not much else I can think of...

And if it runs fine, I am at the point where as long as It can start i.e. not leave me stranded, I will be happy....its too nice to have it not out on the road at the moment

[unfazed]

Maybe it is your starting technigue.
Compared to the 600 the 1000 is a cold creature.
As standard they need full choke and a bitt of throttle to start when cold, then needs a few minutes to warm up and sometime ride off with half choke for a mile or two, whereas the 600 just needs a bit of throttle and will ride away immediately.

[anutz]

So been out, riding past 2 days, and its got power and seems ok, however literally put the bike away an hour ago, go to turn it over to check some things, and withing 5-6 seconds the battery is buggered, relay clicking like mad.


I have ridden for an hour or so before coming home so it should be charged i would think


I measured the voltage ant its 12.4 ish, so seems fine, but as soon as i touch the started, drops to 0v very quickly...


was reading around about electrical gremilins, http://foc-u.co.uk/index.php?topic=15299.0


I wonder if this is all due to the battery not having the ability to turn the crank over, and supply good sparks etc


Not tested the voltages of the reg/rec or the battery when it runs, as waiting for the damn thing to charge, if it ever will


how can it read 12.4v and then not work i.e. drain to 0v when i touch it..????