Piston ring - fzr250 86 2kr

[Shak]

Hi guys, been browsing these forums for a while now and some great reads here.

Got the bike about a year ago but haven't had time to really fix it, I keep getting a bogging at 8000 revs (struggling to higher revs), Sealed up the air intakes (with initial thought of leaks)

I have been told by a compression test that I need a piston ring replacement by my mech, but he quoted me up to 1000$ for this job.

Im new to bikes and low experience but have reasonable knowledge of how the engine works. good at following guides.

Is this a job for a newbie lol.. and is that a reasonable price for a piston job?

Any help would be great :)!

[hayd3n]

is the bike smokey?? did the mechanic mention valve clearances?

[Shak]

not smokey at all, always starts no problem.

He txted me that number 3 piston has bad compression and it requires new piston rings.

he told me in person when i went to pickup the bike (this even happened about 4 months ago) that he only did a compression test .

[Shak]

Currently just looking into getting new spark plugs. Any specific ones I should look at for this bike?

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[Paul in NZ]

Do a leak down test... Those things are a bit hard on valves as well as in the modern fuel clags the whole mess up...

See if you can find my FZR 400 thread - as I did the top end on it, loads of pictures there..

Here

http://www.kiwibiker.co.nz/forums/showthread.php/49874-fzr400-exup

[Shak]

Will check. Thanks

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[The Reibz]

Run NGK-CR8E plugs.
You may have CR9E's already in it but my 3LN ran alot better with the slightly hotter plug. Careful when you put them in, the ali in that head is really soft. I had to retap all mine to get the plugs to go in.

There is a Valve clearance walk through on FZR250.com. Its not that hard to do.
Piston rings will require a full strip down of the bike and is a engine out job.

[Shak]

trying to find the walk through, if anyone comes across it can you please link me.

[Shak]

also the spark plugs were already cr8es so thats ruled out

[Shak]

293783

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[Shak]

I managed to get the airbox out. When I lifted it I saw that one of the intake pipes pretty much just pulled off. And also there was no seal between the bottom of the airbox and these pipes going to carb. (Arent these meant to be a sealed pipe?)

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[hayd3n]

I managed to get the airbox out. When I lifted it I saw that one of the intake pipes pretty much just pulled off. And also there was no seal between the bottom of the airbox and these pipes going to carb. (Arent these meant to be a sealed pipe?)

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everything should be well sealed , learn how to check the valve clearences :)
is the bike burning oil???

[Shak]

Yeah I need to find the correct guide for valve clearance. There is no smoke what so ever.

I can rev well over 8000revs when on neutral.

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[The Reibz]

here you go chap. Don't pay any cunt to work on these bikes (most people won't touch them anyway) your going to get over charged.

http://fzr250.com/viewtopic.php?f=20&t=3456

[Shak]

Excellent. Thanks alot! I was also told by my friends dad to check and make sure the carb jets are clean. Will do that as well and he also advised that engine maybe running out of life ( from the point that one of the pistons compression was about 20/40 lower than the others). Is he on the right path?

Thanks for all the help so far. Gotten a fair bit into the task and learning alot along the way! :)

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[The Reibz]

YOu will probably find the problem lies in the head and carbies.
Give them a really good clean and replace the main jets and pilots if you can. It will run a bit nicer on shit that isnt 28 years old.

Don't spend to much money on this bike though. They aren't really worth it because spares are way to hard to get now

[Shak]

ahh im stuck, in the process of cleaning the carb but the screws are worn out.. :facepalm:

wd40 is not helping either..

[hayd3n]

ahh im stuck, in the process of cleaning the carb but the screws are worn out.. :facepalm:

wd40 is not helping either..

sounds like you need a impact driver

[Shak]

yeah will have to source one i guess.
on another note, i need to seal my engine intake to carb rubbers, these are suspected to be leaking,

i got some hylomar universal blue, just a coat on the whole outside rubber area and near the seals should be sufficient? thought i should confirm this before i go ahead with it :sweatdrop:

These cost 120$ each at red baron

[Shak]

293828

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[The Reibz]

Those intake rubbers dont look bad at all. Have seen much worse than that. Don't buy anything from Red Barron. Serious, don't buy anything from them...

Go to youtube and search how to extract a stripped screw. Those carb bolts are always a bitch to get out. I had to drill and extract 3/4 of the ones on my 1000. Get a pack of good stainless fasteners from bunnings and replace them all.
Replace all the shit bolts that you come across. 25 years isn't nice to them.

[Shak]

great :) i gave it a coat anyway as i saw very large cracks under the metal ring.

my rubbers from airbox to carb though has really hardened up, barely fits onto the carbs. I think a new set is require for these, got quoted $32 each for these though from redbaron (much cheaper than 120!)

any other recommended places to try? have been hunting on trademe as well.


came across this for carbs as well

$55~ seems ok?

http://www.litetek.co/Carb_Kit_Yamaha_FZR250_2KR.html

and yes will def replace those screws

[hayd3n]

yeah will have to source one i guess.
on another note, i need to seal my engine intake to carb rubbers, these are suspected to be leaking,

i got some hylomar universal blue, just a coat on the whole outside rubber area and near the seals should be sufficient? thought i should confirm this before i go ahead with it :sweatdrop:

These cost 120$ each at red baron

sounds good :) as its on the suction side it should seal it up well

[The Reibz]

Bro leave those intake rubbers in a bin of boiling water before you refit them. It will soften them up enough to get them back over the carbs

I got a set of 3ln intake rubbers which may fit. Let me know if you want them

[Shak]

Ok il give that a go.

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[The Reibz]

Offer is open for those intakes if you want them. They aint the best but they are alright, I know how hard it is to find shit for these bikes.
Fuck they are awesome when they run properly though

[Shak]

Thanks. Hm mayb might be a good idea to replace them if yours are already soft.

Most likely mine are just going to get hardened again after I put them on and crack.
What would you like for them. Il pm u :).

Yea definitely going to try my best with the limited knowledge I have lol hopefully enough to get it going decent :D

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[Shak]

There is a screw under the tip of the driver in the carb. Its fully clogged. Just wanted to check if that is just a holding screw? Il post more pics to confirm. the guide im using is off a fzr400 and that screw wasnt mentioned (the carb was slightly different)

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[Shak]

293896

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[The Reibz]

Pretty sure thats the idle mixture screw. Well thats where its located on my 1000

[Shak]

that means if i take it out il have to screw it back with the same amount of revolutions.. this is going to tricky, research time..

[The Reibz]

3 turns bro. Turn it all the way in, loosely because these are delicate springs and screws. Grip the screwdriver with your fingers only
Then go 3 full rotations out. If its still a bit rich at idle when you get it going again go another 1/2 turn in.

[Shak]

Swt. seems it was set at 3.5 turns. Will have to see how it goes when started.

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[Shak]

Carbs all cleaned up. B4 I started I noticed when I pushed the rubber runners they got stuck up there. But after the clean it is now smoothly coming back to start position :D.

Wondering if this was the primary cause of the reving problem.

Should I do the valves check ( which means radiator out etc) or i put this back on and test it out before I move further?

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[Shak]

http://img.tapatalk.com/d/14/02/21/yzemavab.jpg

Hmm thinking about just checking valves since its all open. Keen to do it but need an opinion on whether to test the carb first :)

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[The Reibz]

Do the valves man, hard work has already been done stripping it down. Won't hurt to change your coolant either

[Shak]

Yup sounds good. Will Learn more from it too

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[Shak]

294128
A bit of help pls lol. Is that the crankcase end? Says to allign t mark with it but there is no mark. Also says while piston #1 is at tdc compression

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[Shak]

http://img.tapatalk.com/d/14/02/24/yne8yde6.jpg

P#1

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[Shak]

Also any recommended place to get a new gasket ? Current one seems abit aged..

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[Shak]

http://img.tapatalk.com/d/14/02/24/yjuzu5yv.jpg

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[The Reibz]

Blue RTV Silcone. You won't find new ones anymore. Unless you dont mind waiting a year for Yamaha to order you one...

[Shak]

70$ is way too much for one im guessing and not worth it? 5 days from good old baron lool. Ok silicone it is. Also any idea on the position post :)?

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[ducatilover]

Your manual should show you where all the timing marks are.
Is it still bogging down at 8000?

[Shak]

Dont have a fzr250 manual (no english version) so using a fzr400 manual. Still haven't put the bike back together since I opened it up. Will do some research tomorrow and measure the valves.

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[ducatilover]

You'll probably find the exhaust side valves are a bit tight.
I would like to know what the compression test results were and how he determined it was rings

[Shak]

From memory all he said was #3 piston was low (80 I think and 110 for the rest) concluding it to a bad piston ring.

Ok il post up the valve results tomorrow

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[ducatilover]

It should have a shit load more than that, unless he did the test cold.
If so, fire him, new compression/leak down test and consider checking the emulsion tubes and needles for being worn

[Shak]

Haha are these things easy to do (im a newbie). So far I have done a full internal clean of the carbs and moved on to the valve clearances atm. I guess if there are youtube videos out there. Il do some research and try it out

And yes I never went back to him lol

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[ducatilover]

Google is your friend :niceone: All easy to do. If you have eyes like me, you will need a magnifying glass to check needles and emulsion tubes correctly.

[Shak]

Ok after valves il move on to the tests you suggested. Thanks! :)

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[The Reibz]

Bro the TDC marks are a real cunt to find. I can't actually remember where they are to be honest but the easiest way to set TDC without them is to take put a long handled screw driver down the spark plug hole for number 1 cylinder and turn the motor over until the screw driver reaches the maximum height. Thats TDC

Alternatively you can line up the marks on the cam if you have the valve cover off

[Paul in NZ]

Bro the TDC marks are a real cunt to find. I can't actually remember where they are to be honest but the easiest way to set TDC without them is to take put a long handled screw driver down the spark plug hole for number 1 cylinder and turn the motor over until the screw driver reaches the maximum height. Thats TDC

Alternatively you can line up the marks on the cam if you have the valve cover off

While remembering that the piston will be at the top of the stroke twice in a cycle... TDC is when both valves are closed or close to it...

[Shak]

Hi guys so these are my findings. Im not sure if I did it correctly but did to best of my knowledge. I used the screw driver method.

So when at peak (screwdriver) the lobes were facing outwards. This according to the markings and book was tdc. I then measured the gap under the lobes. (when facing out)

Then for the second I did the same (screwdriver peak and lobes facing out) and so one.

something interesting about the 3rd piston was that I could with some effort fit the biggest guage as the piston moved lower as I inserted the guage (unlike the others).. ?? Is this normal?

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[Shak]

294214

294215

Ami logo side is intake
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[Shak]

294214

294215

Ami logo side is intake

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[ducatilover]

Hi guys so these are my findings. Im not sure if I did it correctly but did to best of my knowledge. I used the screw driver method.

So when at peak (screwdriver) the lobes were facing outwards. This according to the markings and book was tdc. I then measured the gap under the lobes. (when facing out)

Then for the second I did the same (screwdriver peak and lobes facing out) and so one.

something interesting about the 3rd piston was that I could with some effort fit the biggest guage as the piston moved lower as I inserted the guage (unlike the others).. ?? Is this normal?

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Clearance is only to be measured at TDC, otherwise you'd be using a degree wheel or a DTI gauge to find where to set them
And yes, lobes facing outwards is correct, but the screwdriver method is very inaccurate, plus or minus a few degrees can make a significant difference considering the base circle on an FZR cam probably covers near 60degrees between valve completely closed and fuck all valve lift, and with the lobes facing out you are at the extreme end of those areas.

Or something.
I'd use the screwdriver method and look around either side of the engine to find the timing marks, often they're on a trigger wheel

[Shak]

When the screw driver was at peak I saw the t mark was inline with a notch on the outside case (generator cover) . I used that to line up.

Also to confirm. Every piston (the one iam measuring) has to be at tdc when measured? Piston 3 had me concerned when I was able to move it lower with the feeler guage when measuring

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[ducatilover]

When the screw driver was at peak I saw the t mark was inline with a notch on the outside case (generator cover) . I used that to line up.

Also to confirm. Every piston (the one iam measuring) has to be at tdc when measured? Piston 3 had me concerned when I was able to move it lower with the feeler guage when measuring

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Yep, do each one at TDC.
Or any cam poking outwards, you'll find when #1 is at TDC, you will have the intake closed on either 2 or 3, and exhaust open on the other of the two. But for simplicity, TDC every time as Yamaha tell you to.

[Shak]

Cool that's how I did it. I guess some shims needs changing. Ahh I hope this fzr400 manual is same for mine..

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[ducatilover]

Probably not :crazy: but it may be similar enough...

[Shak]

also guessing that i cannot use the shim measurement chart from the 400 manual..?
any recommendations on the best place to buy shims are? (not kits as they are 100+) i can just find out what shims i need and purchase them only?

[ducatilover]

Bike shops tend to exchange shims
Shim chart from the 400 manual will work, although a micrometer and some very basic math will too

[Shak]

Ok I remeasured making sure timing marks are in line. Here are results.

Do I try and forcefully fit the largest I can? Or fit the largest guage in with little effort into the gap? Because I was able to fit larger sizes with some force. 294238294239

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[The Reibz]

fit the largest guage in with little effort into the gap

This... Well thats how I have done it. Others might disagree

[Shak]

ok thats what i have recorded on there, apart from piston 3 it should be .014 or even .012

[Shak]

http://img.tapatalk.com/d/14/02/27/equ6uhe4.jpgWas about to change shims but decided to remeasure again and not too forcefully.. results seem ok as they are within the range. 294253

Sry for bad image. Thats .006 (smallest guage i have) all for intake and .010 and .012 for exhaust

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[Shak]

It should have a shit load more than that, unless he did the test cold.
If so, fire him, new compression/leak down test and consider checking the emulsion tubes and needles for being worn

I checked the tubes while cleaning out the carb. They seemed in good nick.

About the leak down test whats the best way without taking engine out? Youtube clip I saw was an engine out job

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[Shak]

Ahh I see. I need to buy a leak down tester kit for the bungs etc lol.. any mobile testers? I might have to ring around.. :confused:

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[The Reibz]

Bro if you need to run a compression test then you can borrow my tester. I got no idea on leak down tests as I have never done one, when I rebuilt my falcon motor a compression test was all I needed to tell me that the head gasket was fucked.

I can bring my tester over on saturday if you want (weather shit so fishing is off) along with those rubbers. I don't think I have a 10.2mm adaptor for it though. A couple of the boys on here have borrowed it and it hasn't fit their bikes.

[Shak]

Bro if you need to run a compression test then you can borrow my tester. I got no idea on leak down tests as I have never done one, when I rebuilt my falcon motor a compression test was all I needed to tell me that the head gasket was fucked.

I can bring my tester over on saturday if you want (weather shit so fishing is off) along with those rubbers. I don't think I have a 10.2mm adaptor for it though. A couple of the boys on here have borrowed it and it hasn't fit their bikes.

that would be awesome, only thing is im not too sure how to exactly do the compression test my self, i had a look at some vids on utube though. are you able to guide me? make sure im doing it correctly? if your free that is, and i have a cricket game at 12 so will have to be done by 11am.. or another day is ok if you cant make it.

il keep reading on the compression test though

i might be able to get a 10.2mm adapter

Thanks again!

[The Reibz]

Its very easy to do. Pretty much you just turn the motor over on the starter and watch the compression build up on the gauge.
I got a feeling that cyl 3 has a sticking valve by what you have said. It actually takes a hell of alot of effort and abuse to fuck all 3 piston rings and for the amount of Km's your bike has done I would be highly surprised if it was a ring issue

[Shak]

http://www.youtube.com/watch?v=uj8YDwlILwY

this guy made it much easier.

(and i take all 4 spark plugs out? wont air escape from other pistons while testing?)

[The Reibz]

wont air escape from other pistons while testing

Yeah bro thats the whole point. That way you can tell if there is a leak between the headgasket surface from one cylinder to the other. Make sure the fuel is cut too.
its around $80 for a stanley compression tester at SCA, no idea where to get adaptors from

[Shak]

Ah right. Makes sense. I have a look. Saw one on trademe with adapter for 45 might be good to keep one handy for future as well. Thx


http://www.trademe.co.nz/motors/car-parts-accessories/tools-repair-kits/meters-testers/auction-698986384.htm

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[The Reibz]

yeah thats a good deal, but still, you need a 10.2mm adaptor to get into the fzr threads.
They are a small plug, hayabusa uses exactly the same plugs too.

[Shak]

Ok will have look into it :)

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[ducatilover]

Ok I remeasured making sure timing marks are in line. Here are results.

Do I try and forcefully fit the largest I can? Or fit the largest guage in with little effort into the gap? Because I was able to fit larger sizes with some force. 294238294239

Sent from my GT-I9505 using TapatalkYeah mate, should be a wee bit of drag on the feeler gauge but not tight/forced


I checked the tubes while cleaning out the carb. They seemed in good nick.

About the leak down test whats the best way without taking engine out? Youtube clip I saw was an engine out job

Sent from my GT-I9505 using Tapatalk Did you check very hard for ovality?
I need to re-cap I think :facepalm: already forgetting what the original issue was


that would be awesome, only thing is im not too sure how to exactly do the compression test my self, i had a look at some vids on utube though. are you able to guide me? make sure im doing it correctly? if your free that is, and i have a cricket game at 12 so will have to be done by 11am.. or another day is ok if you cant make it.

il keep reading on the compression test though

i might be able to get a 10.2mm adapter

Thanks again!
Righty-ho,
Comp test:
Remove all plugs and leads
Screw compression tester in to plug hole
Open the throttle wide open (you must do this)
Hit teh starter button and watch compression rise on the gauge 'till it stops, should only take a few seconds

Leak down test:
Remove plugs/leads
remove air box
remove rocker cover
remove radiator cap
Screw leak down tester in to spark plug hole
Put the cyl you are testing on TDC with the valves closed
Hold the crank with a powerbar and socket, or make a crank holding tool
Dump around 100 psi in to it

More than 20% of the air escaping means an issue is present, especially in a tight wee motor like that. Leakdown tester will have a gauge to tell you how much leakage is going on
Air coming out the intake/carbs = leaking intake valve
Air coming out the exhaust = leaking exhaust valve
Air coming out the head (now you have rocker cover off, or out the crank case breather) = shagged compression rings
Air out radiator filler/bubbles = head gasket

Small motors like yours are known for being very hard on exhaust valves, due to the heat they go through and the extremely small area contacting the seat, meaning they do not cool well at all, also the valves are so skinny (usually run a 3.5-4mm stem) they won't sodium fill them :no:
And the fact that everyone lets them get out of tune and chucks a gay exhaust on them, meaning they run lean as shit

I haven't gone to the start of the thread again, but I recall you saying it is bogging down at 8000rpm-ish? Because I could have thought it'd be a carb issue..

[Shak]

awesome, very informative. thanks!

for leakdown test (do the test when engine is dry?) - also saw this with the soap trick http://www.youtube.com/watch?v=zdq7NRcUIp8

for compression test (do when all fluids are filled?)

and yeah was bogging around 8000rpm and making it very hard to hit 100kms

[ducatilover]

You can do leak down either wet or dry.
Soap test isn't really going to help on a 4 stroke

[Shak]

294286

Will pickup some oil. Filter and coolant and go ahead with these test.

Would you say its better to call in dave I think it was (mobile bike mechanic) and get him to do the tests. That way I dont have to buy the kits and it gets done correctly?

I wonder if hirepool have these bits for hire. ( just that I highly doubt il use these items more than once lol) probably next bike will be a bit newer :D

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[ducatilover]

Get the mobile mechanic man in, he'll be used to doing such stuff

[Shak]

Ahh totally fd up.. finally had some time and put the valve cover back on properly and the last bolt just seperated while tightening... going to need a screw extractor kit and a new bolt..
Grr 294671

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[SNF]

Ahh totally fd up.. finally had some time and put the valve cover back on properly and the last bolt just seperated while tightening... going to need a screw extractor kit and a new bolt..
Grr

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That's exactly what happened to me last time when I was going to check clearances, which I still need to do. The bolts go through the rocker and into the metal things covering the cams? - forgot technical name. I think we managed to twist it out in the end. I have a spare one if you need it.

[Shak]

Yes I do need one please. Would be awesome! Did u just use a plier to get it out?

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[DanielM8]

Yes I do need one please. Would be awesome! Did u just use a plier to get it out?

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Jeremym001 posted how he did it for FZR250 on your other topic:
http://www.kiwibiker.co.nz/forums/showthread.php/165070-WTB-FZR250-2kr-1986-valve-cover-bolt?p=1130690520#post1130690520

[Shak]

Hi guys, finally after months of no time got around in the break to get the bike started and found fuel leaking from the carbs..
Opened it up and tried to fix it but snapped a bolt inside... arr

Looking to just buy another set if anyone has one for me.

Let me know please as im working onit myself but at a mechanics shop and dont wont to keep it there for long.

did the comp test again.. was fine
So engine ruled out
Thanks guys

[ducatilover]

What was the bolt?

[Shak]

This is Not an image of my carb

but its the golden bolt from this pic (looks same)

http://img560.imageshack.us/img560/540/pax1.jpg

[ducatilover]

Was there anything under the others? looks like an emulsion tube to me and will be specific to your model

[Shak]

Yea it connects to the other side, this bolt holds a casing for the other side , the carb is at the shop but il bring it home tomorrow and have anothee look, I have a feeling I saw the needle from the diaphragm where the bolt snapped

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[ducatilover]

So the others had a tube with small holes in them?

[Shak]

Yea on the side of the bolt, under the snapped bolt is as described b4, the bolt has no holes

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[ducatilover]

That's okay then, as long as the emulsion tube is okay you'll be fine mate

[husaberg]

Dont have a fzr250 manual (no english version) so using a fzr400 manual. Still haven't put the bike back together since I opened it up. Will do some research tomorrow and measure the valves.

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Cool that's how I did it. I guess some shims needs changing. Ahh I hope this fzr400 manual is same for mine..

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I have a FZR250 manual i downloaded from the web somewhere..... PM ya email, i will post the link if i can find it.
I am guesing the bolt got there Shak?

parts manual is 3mb so Too big for KB

[Shak]

Awesome thanks! Shankman2010@gmail.com

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[Shak]

Got the bike running, goes really well, no more bogging, only if i accelerate quickly when going high speeds theres a slight miss.

ended up getting a new carb, full fluid clean out and sealed air intakes on both sides of the carbs :).

thanks for all the help guys! :D

[ducatilover]

Do skids my son

[F5 Dave]

and wheelies.


. . . although you might need a sharp rise in the road with a sudden falloff after