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+--- Thread: Slight misfire - plugs? (/showthread.php?tid=74879)
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Slight misfire - plugs? - aquilaalba - 05-02-16
Hi all, just a bit of misfire, was there since I had the bike, was told that the plugs were done and that did not change anything. I will 'drain' water from carbs later on, but just checked the plugs and they are CR9E instead of CR8E, could that potentially cause the problem, or will it be rather something else? They do look fresh-ish, but considering what was done to the cooling system I wouldn't take their newness for granted... Also will check and clean air filter (K&N). Carb cleaning and balancing will be done later on, but for now was planning to change oil, do filter clean, plugs. Any other issues it might have? Did check the TPS and it was out, but all right now. Fresh fuel ticked. Also, it tends to stutter sometimes at low revs and in low gear - it normally happens only when it warms up, same with the misfire, less of a manifestation on cold engine. I should have start with this part, shouldn't I?
Re: Slight misfire - plugs? - bandit - 05-02-16
If your gonna change the plugs (which I would) you are correct they should be CR8E the 9 is not the correct heat range for your bike.
http://www.ngkpartfinder.co.uk/partfinder.php
Re: Slight misfire - plugs? - darrsi - 05-02-16
Check the TPS again out of curiosity and see if it's still in the correct position.
I've had two that have broken down on me rather than just stopped working completely, so they can misbehave and cause low rev issues without being obvious.
Balancing the carbs does do wonders for low rev problems too, but everything else has to be functioning okay as well before doing it otherwise it all gets a bit messy.
I did it last year with a slightly blocked up K&N air filter and it threw it right out of sync because of air flow issues, and the difference was really noticeable when I did it again after cleaning the filter.
Re: Slight misfire - plugs? - Bretty - 05-02-16
"low revs in low gear" ?
I thought I had a misfire when my bike started jumping out of second gear, a sign my gearbox was on the way out!
Are you sure it misfires through all of the gears at about the same point in the rev range and throttle position?
I nearly overhauled my entire engine before I realised my issue was mechanical.
Re: Slight misfire - plugs? - aquilaalba - 05-02-16
It judders and gets lumpy when I move off and will ring too low revs in, as soon as it passes 3000 it moves off smoothly, but going in 2nd uphill after slowing down can bring that as well, it seems gutless for a second, until it goes a tat faster and then it's gone. Misfire is there on tickover, less obvious (less misfiring maybe) at higher revs. Bear in mind this was a bike that was standing and half of it was mocked up, only now managed to restore it to roughly running condition. Will change the plugs later on and let you know. It might be the case (only pulled one plug out so far) that it's got different plugs, etc. Wouldn't be surprised...
Re: Slight misfire - plugs? - BBROWN1664 - 05-02-16
3000rpm on a small engine is very low really if it is under load. Try changing down a gear.
Re: Slight misfire - plugs? - Frosties - 05-02-16
(05-02-16, 04:16 PM)aquilaalba link Wrote: It judders and gets lumpy when I move off and will ring too low revs in, as soon as it passes 3000 it moves off smoothly, but going in 2nd uphill after slowing down can bring that as well, it seems gutless for a second, until it goes a tat faster and then it's gone. Misfire is there on tickover, less obvious (less misfiring maybe) at higher revs. Bear in mind this was a bike that was standing and half of it was mocked up, only now managed to restore it to roughly running condition. Will change the plugs later on and let you know. It might be the case (only pulled one plug out so far) that it's got different plugs, etc. Wouldn't be surprised...
Could be pilot jets if its also lumpy on idle. Above 3k rpm the main jets kick in. Just my 2p.
Re: Slight misfire - plugs? - unfazed - 05-02-16
:agree
If it clears above 3000 revs I would as frosties said check the pilots jets as they could be partially blocked especially on carbs 3 & 4 and the the number of turns on the pilot screw, for the 98 to 01 it should be 2 turns out. The pilot jets have a star web inside which is easily blocked and not easily cleared.
I found that putting them into good quality cellulose paint thinners for an hour and blowing then through with an air hose usually does the trick, but if not repeat the process.
On a few occasions I have had to resort a thin brass brush bristle to poke them out. Brass on Brass jets does not damage them.
If you have a lazer heat detector aim it at the pipes to give you a good indication of which cylinders have the problem as they will be cooler than the rest.
Check the resistance of the leads from plug cap to plug cap and they should be around 20Kohms they should not really be more than 20% difference in Resistance between the 2 &3 pairing and the 1 & 4 pairing. over 24Kohms will cause problems.
If there are large discrepancies, check the individual caps
Re: Slight misfire - plugs? - aquilaalba - 07-02-16
Thanks for invaluable advice, it seems that 2 and 3 are misfiring - hence I need a coilpack, I suppose. Brand new plugs in place, didn't change much. Looking for 2-3 coilpack then. Will report on findings after replacing it. Anyone's got a spare laying around?
Thanks!PS: I'm surprised I still carry on resolving problems with it, but if I'd gone this far I recon it stays with me forever. Oil's next.
Re: Slight misfire - plugs? - aquilaalba - 08-02-16
Coil pack on it's way, this should sort it.
Re: Slight misfire - plugs? - aquilaalba - 11-02-16
Ze coil pack has landed... Quick question, though. Considering everything on this bike was upside - down and back to front, could cables going into coil pack be swapped and cause misfire? Thanks.
Re: Slight misfire - plugs? - aquilaalba - 11-02-16
Right, cables on the coil packs seemed to be wrong way round, red (well, red/black) cables should go towards the footbrake side (sorry, thought this will cause least confusion), orange and white should go on the opposite. On coil pack no1 it seemed ok, as red was on the right side, but on 2-3 coil pack it was other way round. Had swapped the cables, might have been a bit better? Swapped coil pack and it doesn't seem to be better? Unless someone redo the cables and it should be wrong way round... What is the correct sequence of the cabling going into coil pack? Will try to swap them round and see. Checked the schematics and it doesn't indicate where which cable should go, thought it'd specify that. This bike is starting to really annoy me, it might be easier to strip the b*£$%rd and start from scratch... Not bike's fault, it's the muppet who's been putting it together last time...
PS: Cylinder sequence 1-2-3-4 goes from the clutch / gear lever side (left side of the bike), right?
Re: Slight misfire - plugs? - Frosties - 11-02-16
Don't dismiss the pilot jets just yet fella
Re: Slight misfire - plugs? - aquilaalba - 12-02-16
Misfire is still present past 3000 rpm, will have to strip carbs anyway and sync them, but will need Carbtune or similar and won't be able to justify it at present...
) Seems more like an electrical issue, will swap cables tomorrow on 2-3 again, as it was, maybe someone altered the installation? It run a tat nicer methinks... Will post a photo of what it looks like tomorrow.
Re: Slight misfire - plugs? - Gnasher - 12-02-16
(05-02-16, 11:51 AM)aquilaalba link Wrote: I will 'drain' water from carbs later on
Is there water in the float bowls have you looked? If so this would indicate that you have a problem with the tank and that will lead to blocked pilot jets!
(05-02-16, 11:51 AM)aquilaalba link Wrote:
but just checked the plugs and they are CR9E instead of CR8E, could that potentially cause the problem
No you can fit either the 9's are slightly cooler than 8's you wont tell the difference is normal everyday use in the real world.
(05-02-16, 11:51 AM)aquilaalba link Wrote:What has been done to the cooling system?
but considering what was done to the cooling system I wouldn't take their newness for granted
(05-02-16, 11:51 AM)aquilaalba link Wrote: it normally happens only when it warms up, same with the misfire, less of a manifestation on cold engine.
This is typical blocked pilot jet symptoms as has been said. A simple way to find out which ones ride the bike for a mile, stop, get some water in a spray and squirt the downtubes one at a time those that dont hiss are missing.
(05-02-16, 11:51 AM)aquilaalba link Wrote: I should have start with this part, shouldn't I?
Yes
As for the coil pack being faulty this is the last thing to check, I've been working on these bike since they were introduced the coils are very very reliable. The polarity is marked on the case. A very quick and easy test is to swap the packs over if the problem then jumps it's the coil, that said it's possible the lead is the issue as these do degrade over time mainly at the point where they enter the plug cap. Again very simple unscrew the cap trim off about 10mm and refit the cap.
I dont believe your issue is electrical it's already been said check the pilot jets!
Re: Slight misfire - plugs? - aquilaalba - 12-02-16
Will have to strip the little bugger sooner than expected then, as for the issues with the cooling system - here's my previous post:
http://foc-u.co.uk/index.php/topic,18921.0.html
As for the plugs / coil pack - both replaced and it's still the same, guess I'll have to spend some money on a carburettor tuner - clocks or Carbtune, not sure yet - any of them better / easier to use? As for draining water from the carbs - I was told that was the problem on my old Diversion XJ600S - thought it might be the case, tank flange / water drain pipe on Divvy was blocked and on this one it has been cleaned and is free to drain water from tank cap surroundings, so shouldn't be an issue. Lights were messed up a bit, but this has been sorted (again, previous post). Getting there, although it takes time. Will check coil pack's polarity and check voltage on the contacts, just to double check, but as you've said - most likely the jets need sorting out. Learning all the time... bit slow though. Saying that, six months ago I did not know nothing on the subject of bikes and now keen to do a lot more than I'd expect, had some success even few times, so plodding on!
Re: Slight misfire - plugs? - Frosties - 17-02-16
Any news fella?
Re: Slight misfire - plugs? - aquilaalba - 18-02-16
Only finished it today - swapped the 2-3 coilpack, not much of a change, but bit better. What was bothering me was that on the schematic drawing it was showing same side of coil connected to same wires, when on the bike it was connected differently on both. After Gnasher said it's polarity is marked on the case I've checked voltage going in and connected wires the proper way... This (there was hell of a difference right away) combined with draining (well, most of old fuel came out) the tank and filling with fresh premium petrol gave a nice result. Runs lovely (well, still need to clean the carbs, do oil and balance carbs afterwards, but a lot better). I've been riding around 8 miles today and what a difference... Still few things to sort out but already (finally) feels like a lovely bike! Thank you all, as I'd be stuck without your help. Much appreciated. Will see what comes next. Only annoying bit is that the latch for the seat won't shoot out, stays unlocked constantly but will take it off and investigate. Oh, and fuel gauge shows empty now - despite putting 5l or more from the canister... Never mind that, rides like never before!
Re: Slight misfire - plugs? - Gnasher - 18-02-16
Result........
The Fazer is a really good package (except for head lights on earlier models) and in my opinion still not bettered.
The fuel light assuming it was working as you didn't mention it could just be you've not reconnected the plug.
Re: Slight misfire - plugs? - aquilaalba - 20-02-16
Checked the connection, sprayed with WD40, checked again, still not working properly, level might be low though. Problem is that I've checked the expansion tank today and it is empty. Passed (finally) MOD2 yesterday, so can finally properly test the bike on normal roads and give it a good run whilst watching coolant level. It might be that there was air in the system and it is now properly filled with coolant (well, better than it was), will add coolant to the expansion tank and see if it settles or is leaking somewhere. Feels definitely better. Will post as soon as I got any update. Will probably go tomorrow with a Divvy to the workshop and swap for Fazer to see how it runs. Ended up passing the MOD2 on my old Diversion and not the Fazer as leak (well, empty expansion tank) was spotted day before the test.