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Discussion Starter #1
Hi everyone, hope you are all safe and well !!
So my bike has been has been stood for a few years before I bought it and has recently been suffering from a miss fire in cylinder one, read the other threads on the forum to check coils, carbs, pilot jets etc to no avail, as is said by the people in the know “the easy bits first” what’s annoying is that when I took my bike in to have the carbs balanced after having it cleaned I got them to do the plugs whilst they was in there and thought nothing else about the plugs, because I would like to think that if there was oil on the plugs they would have said something then and saved me all the hassle of going down paths that I didn’t need to be going and it was only 5 months ago and I have ridden about 150 on it “tops” can it happen as quick as that ? also I don’t have creamy build up in the oil or in the coolant I changed the oil and it was very black there’s no white smoke or blue smoke, it does smell a bit rich, so I’ve changed everything again, oil so I could have look at it again no cream residue just very black also I did the fuel and air filter and the plugs again, another question is should I start again to see if the new plugs have made difference ? and what would be the next step ? and could it be as terminal as I think? Just to add the bike has done 7600 miles.

Anybody with input would be amazing or anybody experienced anything similar and any idea on costings or recommendations for places to go etc would massively appreciated !!

Kind regards

Jony
 

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Hello Jonny- I sense some desperation in your post and it doesn’t read well, understandably. Ive the same bike, since new and it’s got considerably more miles than yours, but low considering I bought it from new in 2001 (27,500mls). I’ve had the carb problems, generally caused from leaving is with fuel in it or even worse- drained carbs and 5 months later, carbs all over the place. Anyway, none of this is what you described- but you don’t say why you got the carbs balanced? A misfire is generally an electrical issue- if a plug is gapping due to oil-fouling, then this will do it. I can only imagine your bikes been sitting idle for years. How does it start? How does it idle? I ended up buying a set of 2nd hand carbs which actually solved all my issues. It doesn’t like been left unused and with Covid- I probably face the same poor idling issue later in 2021 when I get to ride it again.
Black oil makes me think blow-by. But it’s a guess and shocking that someone would leave a bike withhold oil in it- if its age. Does the oil discolour?

You are right to approach this carefully As it could be a number of things
 

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Discussion Starter #3
Hello Jonny- I sense some desperation in your post and it doesn’t read well, understandably. Ive the same bike, since new and it’s got considerably more miles than yours, but low considering I bought it from new in 2001 (27,500mls). I’ve had the carb problems, generally caused from leaving is with fuel in it or even worse- drained carbs and 5 months later, carbs all over the place. Anyway, none of this is what you described- but you don’t say why you got the carbs balanced? A misfire is generally an electrical issue- if a plug is gapping due to oil-fouling, then this will do it. I can only imagine your bikes been sitting idle for years. How does it start? How does it idle? I ended up buying a set of 2nd hand carbs which actually solved all my issues. It doesn’t like been left unused and with Covid- I probably face the same poor idling issue later in 2021 when I get to ride it again.
Black oil makes me think blow-by. But it’s a guess and shocking that someone would leave a bike withhold oil in it- if its age. Does the oil discolour?

You are right to approach this carefully As it could be a number of things
 

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Discussion Starter #4
Hi Pat.. Merry Christmas

Thanks for your reply!!

Ok, so I got the carbs balanced after they got sonic cleaned I was told that it made sense to do it and it wasn’t a huge expense and surprisingly they was a quite a way out good news there, thought that might do the trick... nope still really rough and the idle is I think high at 1.5 also when the choke is on it doesn’t get above 3k and drops down to 1.5 and that’s where the misfire happens, so I changed the coils and swapped around the caps.. I slapped myself and realised that the coil runs two cylinders and only cylinder 1 isn’t working so it’s my thinking is that it isn’t the coil ?
The oil has darkened, forgive me if have misunderstood the question.
What do you mean by blow by, I think what you mean is the oil has been overfilled possibly or the piston rings or a head problem as it’s only one cylinder again only guessing “help” ? The oil was changed last year , I can tell because it had an hi-flo filter on it and also the oil smelt a tiny bit of petrol..

Also what do you think about starting it again to see if the plugs have a difference?

Hope that’s enough Pat and I really look forward to your reply

Kind regards
Jonny
 

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Did you have the valves adjusted before you synced the carbs? Have you popped the plug out of #1 and taken a look at the cylinder to see if the cross hatching is present or done a compression or leakdown test? If no, do a valve adjustment, then compression and leakdown and then resync. It also sounds like you may need to trim the air fuel. Running rich can cause carbon buildup and will make the engine run cooler. When I do carbs I usually adjust air fuel until she stumbles then turn the screw the other way until she stumbles and then split the difference. If she doesn't stumble on the turn out, I move to a larger pilot.

I wish you could just bring her by the shop so we could take a look and get you sorted. Such is life though i suppose.

Good luck bud.
 

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Discussion Starter #7
Did you have the valves adjusted before you synced the carbs? Have you popped the plug out of #1 and taken a look at the cylinder to see if the cross hatching is present or done a compression or leakdown test? If no, do a valve adjustment, then compression and leakdown and then resync. It also sounds like you may need to trim the air fuel. Running rich can cause carbon buildup and will make the engine run cooler. When I do carbs I usually adjust air fuel until she stumbles then turn the screw the other way until she stumbles and then split the difference. If she doesn't stumble on the turn out, I move to a larger pilot.

I wish you could just bring her by the shop so we could take a look and get you sorted. Such is life though i suppose.

Good luck bud.
Did you have the valves adjusted before you synced the carbs? Have you popped the plug out of #1 and taken a look at the cylinder to see if the cross hatching is present or done a compression or leakdown test? If no, do a valve adjustment, then compression and leakdown and then resync. It also sounds like you may need to trim the air fuel. Running rich can cause carbon buildup and will make the engine run cooler. When I do carbs I usually adjust air fuel until she stumbles then turn the screw the other way until she stumbles and then split the difference. If she doesn't stumble on the turn out, I move to a larger pilot.

I wish you could just bring her by the shop so we could take a look and get you sorted. Such is life though i suppose.

Good luck bud.
 

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Discussion Starter #8
Did you have the valves adjusted before you synced the carbs? Have you popped the plug out of #1 and taken a look at the cylinder to see if the cross hatching is present or done a compression or leakdown test? If no, do a valve adjustment, then compression and leakdown and then resync. It also sounds like you may need to trim the air fuel. Running rich can cause carbon buildup and will make the engine run cooler. When I do carbs I usually adjust air fuel until she stumbles then turn the screw the other way until she stumbles and then split the difference. If she doesn't stumble on the turn out, I move to a larger pilot.

I wish you could just bring her by the shop so we could take a look and get you sorted. Such is life though i suppose.

Good luck bud.
 

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Discussion Starter #9
Hi there 120.. Merry Xmas to you my friend

Unfortunately not, could you explain because I’m a nube at this as my son would say.. would that explain why the there is oil on the tip of the spark plug and the cylinder isn’t working? Having read some other threads I think you are spot on with regards a compression test/leak down I think that’s my next move.. regarding the valve clearance should.. sorry, should I do it in that order clearance then comp/leak test or the other way round, I’m trying to save money that’s all ? As for carbon buildup my plug was wet with oil, I so wish it was carbon build up, having researched what you said about tweaking the air/fuel tap would that reduce the idle/tick over ? 1.5 is it quite high?
if you could let me know the most economical way regarding the compression test and valve clearance order that would be amazing, my thoughts are test first and then I can go from there or would a valve clearance being explain the oil ?

kind regards

Jonny
 

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Ok, the 'oil's is probably unburned fuel because the cylinder is rich. Having taken it to a shop for a tb sync and having had this issue I'd steer clear of that shop or ask them if they warranty their work. Before you do a tb sync you need to lash the valves so that everything is indeed balanced. It is actually in the manual. After you lash the valves you can do a compression and leakdown test on the cylinders and resync the throttle bodies.

If it flunks the leakdown you need to get a little deeper into the top end and you may need to oversize and rering, so new wrist pins etc. You will also need to check the valve seats and it is a good time to remove carbon deposits in the head. You may need to lap the valves. Also make sure you use the appropriate assembly lube and follow the steps outlined in the service manual.

Or, find a reputable shop. Or, talk with the shop that has done the work thus far.

Just my .02, for what it's worth.
 

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Hi Pat.. Merry Christmas

Thanks for your reply!!

Ok, so I got the carbs balanced after they got sonic cleaned I was told that it made sense to do it and it wasn’t a huge expense and surprisingly they was a quite a way out good news there, thought that might do the trick... nope still really rough and the idle is I think high at 1.5 also when the choke is on it doesn’t get above 3k and drops down to 1.5 and that’s where the misfire happens, so I changed the coils and swapped around the caps.. I slapped myself and realised that the coil runs two cylinders and only cylinder 1 isn’t working so it’s my thinking is that it isn’t the coil ?
The oil has darkened, forgive me if have misunderstood the question.
What do you mean by blow by, I think what you mean is the oil has been overfilled possibly or the piston rings or a head problem as it’s only one cylinder again only guessing “help” ? The oil was changed last year , I can tell because it had an hi-flo filter on it and also the oil smelt a tiny bit of petrol..

Also what do you think about starting it again to see if the plugs have a difference?

Hope that’s enough Pat and I really look forward to your reply

Kind regards
Jonny
Im still a bit confused over why you got the carbs sonic cleaned . It makes sense to have them balance- they do go out of sync and it causes each cylinder to run differently due the different flow-rates entering them.
The bike should tick over correctly after sync'ing, otherwise someone didn't do their job properly. You cant sync carbs off the bike-you can adjust for initial running, but theres carbs are CV types and rely on fuel and air flow being unrestricted and correctly metered. in sort, they are buggers when they get blocked and in some cases you will never get them working correctly- as I found out and replaced mine (for £100)
Coils- I cant comment as Ive not played with them. Generally as 4 cylinder has 2 coil packs that share leads as the bike only fires at one cylinder at a time.
Ive not run mine up since early October, but it will start at about 2.5k and increase reves after about 30 seconds, then I drop the chock down until it will tick over at 1100. I then usually head off on it choke fully off. My bike does smell of petrol when its cold- a rich mixture.
By blow by- Im assuming your oil is bing contaminated by combustion leaking past either rings or head gasket/valve stems.Ive read on here before that the valve that is on the front of the cylinders- I cant remember the acronym- but its something to do with emissions, can get blocked and require dismantling and cleaning. Im always nervous about doing something just because someone said it was a good idea, but I am not convinced your problem isn't carb-related. Do you know that the carbs are fully seated on the inlet stubs? They are very difficult to bed fully if, as most cases- the rubbers/stubs have gone hard.Ive smeared a little vaseline on my carbs when fitting them to the inlet stubs.
 

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Discussion Starter #12
Im still a bit confused over why you got the carbs sonic cleaned . It makes sense to have them balance- they do go out of sync and it causes each cylinder to run differently due the different flow-rates entering them.
The bike should tick over correctly after sync'ing, otherwise someone didn't do their job properly. You cant sync carbs off the bike-you can adjust for initial running, but theres carbs are CV types and rely on fuel and air flow being unrestricted and correctly metered. in sort, they are buggers when they get blocked and in some cases you will never get them working correctly- as I found out and replaced mine (for £100)
Coils- I cant comment as Ive not played with them. Generally as 4 cylinder has 2 coil packs that share leads as the bike only fires at one cylinder at a time.
Ive not run mine up since early October, but it will start at about 2.5k and increase reves after about 30 seconds, then I drop the chock down until it will tick over at 1100. I then usually head off on it choke fully off. My bike does smell of petrol when its cold- a rich mixture.
By blow by- Im assuming your oil is bing contaminated by combustion leaking past either rings or head gasket/valve stems.Ive read on here before that the valve that is on the front of the cylinders- I cant remember the acronym- but its something to do with emissions, can get blocked and require dismantling and cleaning. Im always nervous about doing something just because someone said it was a good idea, but I am not convinced your problem isn't carb-related. Do you know that the carbs are fully seated on the inlet stubs? They are very difficult to bed fully if, as most cases- the rubbers/stubs have gone hard.Ive smeared a little vaseline on my carbs when fitting them to the inlet stubs.
Hi Pat,

hope you had a good one !!!

The bike was running rough and at that point I didn’t check the cylinders to make that all 4 cylinders were firing and thought rough must be the carbs so I thought immediately it was carb related and then the carbs were removed and cleaned and then balanced and new plugs went in,
With regards the carbs being seated properly I will remove and apply a little bit of Vaseline as recommended.. thanks I will try that !! Also I will try the idle tap on the left hand side of the tank to play around either air/fuel mix to try and drop the tick over, the thing that is worrying me is that if it is head related am I doing more damage by eliminating the fuel side first ?
Blow-by I get it now thanks Pat, would that explain the oil being on the head of the plug or that one carb not working properly would force oil into that cylinder?

Its confusing Pat what to do next, should I go down the carb route or should go down the valve clearance leak down test next ?

kind regards

Jonny
 

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Compression and leakdown first bro, like you say, chasing air fuel you'll be doing damage if something isn't right with the valves or the rings. Also, if you soak the intake boots in wintergreen oil and alcohol over night they will return to being supple as opposed to hard as a rock.
 

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Discussion Starter #14
Ok, the 'oil's is probably unburned fuel because the cylinder is rich. Having taken it to a shop for a tb sync and having had this issue I'd steer clear of that shop or ask them if they warranty their work. Before you do a tb sync you need to lash the valves so that everything is indeed balanced. It is actually in the manual. After you lash the valves you can do a compression and leakdown test on the cylinders and resync the throttle bodies.

If it flunks the leakdown you need to get a little deeper into the top end and you may need to oversize and rering, so new wrist pins etc. You will also need to check the valve seats and it is a good time to remove carbon deposits in the head. You may need to lap the valves. Also make sure you use the appropriate assembly lube and follow the steps outlined in the service manual.

Or, find a reputable shop. Or, talk with the shop that has done the work thus far.

Just my .02, for what it's worth.
Hi 120 hope you had a good one !!

sorry 120 is a throttle body sync the same as a carb balance? What you are saying is the plan would be to get the valve clearance done leak/comp test done and then go from there? Sorry 120 is lashing the valves a clearance check? Sorry.. and is un-burnt fuel black in colour?

kind regards

jonny
 

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I really need to quit saying throttle body sync when talking about carbs. A carb sync or sometimes carb balance, yes.

Compression and leakdown can be before and after valve adjustment or just after valve adjustment (valve lash). It will need to be done after adjusting regardless. Also when doing the lash you will be verifying the cam timing as it is part of the procedure, so that knocks that out of the way.

Unburned fuel will look like oil. The end of the plug will be black. It's unburned fuel though.
 

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Discussion Starter #16
I really need to quit saying throttle body sync when talking about carbs. A carb sync or sometimes carb balance, yes.

Compression and leakdown can be before and after valve adjustment or just after valve adjustment (valve lash). It will need to be done after adjusting regardless. Also when doing the lash you will be verifying the cam timing as it is part of the procedure, so that knocks that out of the way.

Unburned fuel will look like oil. The end of the plug will be black. It's unburned fuel though.
 

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Discussion Starter #17
I really need to quit saying throttle body sync when talking about carbs. A carb sync or sometimes carb balance, yes.

Compression and leakdown can be before and after valve adjustment or just after valve adjustment (valve lash). It will need to be done after adjusting regardless. Also when doing the lash you will be verifying the cam timing as it is part of the procedure, so that knocks that out of the way.

Unburned fuel will look like oil. The end of the plug will be black. It's unburned fuel though.
Hi 120,

it’s fine, it’s always useful to pick these bits of terminology up as you go along.. cheers 120 !!

So.. that’s the plan, please correct me if I’m wrong.. leak/comp test first, if it passes (please god !!!) then valve clearance
If it fails then head off without getting the valve clearance done ?

kind regards

Jonny
 

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Oh, I know the difference, my mind is just full of hayabusa and injected r1 from work last week. I know your machine has constant velocity carbs. I simply misspoke. Do the valve adjustment as that will verify timing. Do a compression and leakdown and that will let you know if you need to get into the jugs. Then re sync carbs.

Yes, the black wet plug is wet. Because it has fuel on it. Because it's rich. I'm 99.9% positive its fuel, not oil. Oil fouling generally happens with 2 strokes. If it were oil on the plug, you'd be getting gobs and gobs of smoke. Trust me. A guy snagged a control ring on an xr 400 he brought in last month and I thought it was an insecticide machine. If it were oil on the plug, it would smoke. A lot.
 

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Discussion Starter #20
Oh, I know the difference, my mind is just full of hayabusa and injected r1 from work last week. I know your machine has constant velocity carbs. I simply misspoke. Do the valve adjustment as that will verify timing. Do a compression and leakdown and that will let you know if you need to get into the jugs. Then re sync carbs.

Yes, the black wet plug is wet. Because it has fuel on it. Because it's rich. I'm 99.9% positive its fuel, not oil. Oil fouling generally happens with 2 strokes. If it were oil on the plug, you'd be getting gobs and gobs of smoke. Trust me. A guy snagged a control ring on an xr 400 he brought in last month and I thought it was an insecticide machine. If it were oil on the plug, it would smoke. A lot.
 
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