I haven't a Clue! £1800 spent and it's still not fixed 🤬 Yamaha V-Max.
ฝัง
- เผยแพร่เมื่อ 28 มี.ค. 2024
- (Part 2) The continuing saga of the Yamaha V-Max that has apparently been fixed by the local dealer, it hasn't. what a complete disaster. It gets worse before it gets better. Did I make a mistake? 😕
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I burst out laughing when you declared you hated motorbikes today. You've made us realise that even the best get challenged occasionally. Looking forward to the final instalment
Best technical motorcycle channel on TH-cam, love the explanation of how it all works. 👍
I have to agree.
Ditto
If I remember correctly the previous tech fitted a new ECU ? The old adage of “ just because it’s new doesn’t mean it works “ seems to fit rather well in this instance.
I wonder if Jim could borrow the ECU off the other VMax he worked on (known working) and try that IF he thinks it's the ECU.
@@stuartmetcalfe547 But if there is an electrical problem causing the ECU to be fried it will just fry the other customers ECU
Just found this channel! I'm loving the logical analysis and the engineer/mechanic turn of phrase!! The only sort of reality show for me, crack on.
Went down a rabbit hole with something similar years ago by a broken valve spring. It had broken right on the last coil. A compression test gave a misleading healthy reading, as it’s only cranking at around 200 rpm on the starter, but an increase in rpm like at idle or more would result in a misfire due to valve bounce. Only found it when I took the bucket off!
Interesting 👍 🤔
Waiting for the final installment of the V Max saga. Love the channel.
The hate you feel, is your feeling, just befor you solve the problem, and the love comes back. A Mechanics love , resembles waves on a beach. the wave is out at the moment.
Love all the technical info on this video.
Enjoyable watch. 👍
We had similar problem with a customers !999 Vmax, After carb clean new plugs, Carb Balance and set-up it still was not running on cylinder #3 and intermittent on #4 after, Lots of head scratching finally valve clearances checked and corrected it ran fine.
Well that sounds like something worth checking then.
Would you not see a valve issue, even a clearance or lift issue in the compression test? Seems like a strong 150psi would be fairly insensitive to misfire at idle?
@@BrianjSiehrif the valve only just seals when cold it could expand when hot and lose compression.
That was a great explanation of how a cv carb works..... Air pressure, velocity and vaccuum.... Wow I am no good at complex explanations but that was great..... like the videos... great.!!!!!
That’s the beauty of Flatslide carbs with accelerator pumps over CV carbs
“I fucking hate motorbikes today” definitely a catchphrase in our workshop 😂
Great video. I used to be a recovery driver and have some experience in V-max ignition and generator problems. I was never able to sort them ! 😪
Oh and just to add I love your stuff. Really enjoy watching and found myself looking forward to the upload bell going off at lunch today. Cheers from an interested amateur who, as he's got older, had learnt the extent of his capability and stops before XXXXXXX things up and ask!
Brilliant explanation of the throttle / diaphragm in a carb 🎉
I'm sure I'd be checking the crankshaft and camshaft position sensors next. if you had
diagnostics software it would help. Good luck.
I was suggesting same thing as it sounds a little off.
That's about 10 quid of 638 you spilt on the bench! Just the best video Jim.
I'm new around here. Really impressed with the thoroghness of your work. Attention to detail on the carb rebuild is astonishing to my eyes. Based on what I've seen so far you will get this bike sorted.
Not long found your channel, really enjoying your back catalog.
And yes I swear as much while working on bikes and cars 😅😅😅😅😅
shavings on pick-up coils.
also it's possible to switch rear coils on v-max. not the hi-volt leads, but supply connectors.
Very well may be the cause.
Found your channel a couple of weeks ago, being in my 63rd year I grew up with points condenser ignition. Then CDI came along (brilliant) never got involved in later EFI🤔 but find your posts of great interest & am learning a lot. Love the format also the thinking out load waffling 😂 like myself your like a dog on a bone & never give up until the EUREKA moment materialises. Can't wait for the next post. This Vmax isn't playing ball at the moment but the carburation work was the absolute 1st issue to be addressed 100%. Awaiting the next chapter 😮
I have a 1978 XS750 I got it in 2014 as a basket case and It has been a fucking pain for ten years, 3 years ago it wasn't going too bad, then we moved house and it has sat doing nothing and I thought I will give it a run, one of the carbs has been flooding, one of the fuel taps has been leaking, I cleaned the carbs reset the float chambers put it all together expected it to run lovely, like that Allen Millyard, everything goes Nice for him, and Tracy bakes him a bun, not mine, mine is Shit ! I have a 3 cylinder single, then a twin, I check exhaust temps and I have one cold one, change the plug, intermittent firing, thinks ! perhaps valve is sticking take off rocker cover breaks gasket, shit ! looks down plug holes all valves seem to move, forgotten about compression tester till I saw your report, so just wanted to say, your'e not completely alone. Have a nice day.
Postman having a guess , Wiring loom , Ground and earths . Check alternator and all voltages . Air leaks.
So proud, actually said timing before you did on the video. Excellent fault-finding process. Thank you for sharing!
I had something like that on a BMW K100, Turned out the H.T. Leads were breaking down,
I fitted a cheap set for a Car = Fixed !. Good luck, Bill.
I was thinking ht leads caps and yet more new plugs , check coil output voltage , ie get the apprentice by the ear and grab one when its running , if nowt else the "dance" is mood lightning .
You will sort it Jim,your awesome.looking forward to your 3rd episode.
Always start with a compression test. Check for blow by with the oil filler cap off.
Squirt some oil down each bore. Throw it all together see if it wants to go. Piston rings go sticky over time.
Compression should be 180 psi each cylinder. Less than this bore is likely to be worn.
Squirt easy start into the intake when turning it over see if it starts.
Check plugs for sparking gap at .8mm 25thou..
Old bikes ignitor box fails might start sometimes and not others.
You explained the throttle theory very well! Greetings from Sweden!
try swapping the coils over ,had similar problem with a virago , a strobe light on the ignition leads lead me to this, feel your pain ,best of luck
Hi Jim loving your content just going through your back catalogue, the way u talk about yourself in the 3rd person is so funny and giving your self a bollocking 😂 brought back so many memories from when I was 17 and got my first bike a DT 50 loved it. Please keep up the great content you don't only educate and make people laught but more importantly you take people back to a different time and all the memories flood back 😊
Love your honesty. Keep em coming
Jim…Had a similar issue with an MX5 Mazda….it was behaving exactly the same as this VMax. The ECU was removed and sent away for testing….The ECU was returned NO FAULT FOUND . After messing about for some considerable time with sensors and the like. I had the ECU examined by a third party company who identified a burnt out component and solder link on the printed circuit..Replaced the ECU and problem solved.????Hope this helps 🤞
Thanks Mate, I'm thinking along the same lines, I think the recent swap to another ECU may have built in another problem 🤔
@@SuperbikeSurgeryTVMore than likely.
I'm in the trade and enjoy your videos on a weekly basis I have the vaccumate ts-72 digital pressure transduced type aswell as the carb-tune pro I find with the digital type checking valve overlap i.e and also other symptoms of a after-fire/back-fire without the potential need to preform a cyl leak down test saves a huge amount of time. I find I can pull the sync closer together with the mechanical type rather the vaccumate after a clearance job to ensure equal vaccume is being pulled following a compression test to confirm. Maybe its a weighted resistance giving a better balance rather than a transducer having to cycle a million Hz. I'm waffling now. 😂
😂👍
Not in the trade. Swap the HT leads plug caps and coil packs front to back and if the issue jumps to the front. Bingo. Its one on those components.
The ecu has been swapped and problem remains. Wiring form the ecu connector down to the coil packs could be faulty/dirty spark.. that 3 different thing to look at.
You will work it out looking forward to the result. Thanks for the video.
£1800! That's £1800 more than I would spend on a V Max. They look like a cross between a tea trolley and a pinball machine......and handle like one.
Very interesting, extremely watchable. Looking forward to seeing how you sort this one.
Thanks for sharing this depsite the bike mugging you off 😉 I find it reassuring that the best of the best don't get it right first time everytime! Roll on episode 3
great video, many thANKS, I just had my vmax carbs off to replace the rubber boots under the carbs, they were cracked right through, night and day with the new ones in.thanks for explaining the slide system, big help now i understand it. i had same symptoms as you, it was air leaks through the inlet rubber boots, its cured now
This (30th March) is out of order in the 'Unfixable VMax' playlist - it's #1 and should be #2 (#2 is currently 23rd March).
Great video cards sorted can't wait for the next one
Wow how difficult can it be, very difficult and complicated, but you are doing a really good job
Great couple of vmax videos.cheers.
Jim, here's an idea . . perhaps the rear bank exhaust pipes have collapsed internals causing a blockage? Try loosening the flanges at the cyl heads and see if there is an improvement.
Or . . remove the pipes at the muffler flanges and see if that helps?
Other thing is, maybe the camshaft have worn lobes and not giving the valves enough lift?
Good luck mate!
An old Kiwi mechanic from Downunder
I used to be on a parts counter in the 90s and a rich dude came in with a sob story about a nitrous kit on a vmax .I must have sold him about every bering , gasket ,oil seal .and shell bering (pain to match ) this kept my till ringing for week after week .god knows how much he spent on it ....the lesson is don't try boosting a complex engine and expected it to last , unless your wallet is fat (I did my best to make it thinner) 😄
Bless you Jim, youll get there ! 🍻
It’s amazing to think that what you found with the carbs it’s the same. I had a similar problem with a Kawasaki GT 750 I stripped the carbs and got nowhere and believe it or not it was the bloody plug caps as 2 were faulty couldn’t believe it. You will find good luck
Mental!! Hope you get it fixed soon.
Hi Jim, I’m chasing the exact problem on my 1992 Vmax currently. Starts running like crap after a while. Been through carbs and everything else a dozen times and now thinking a fault in the charging system whereby the battery runs low and the alternator isn’t outputting enough amps to power the coils. Your slow cranking got me thinking and the Vmax is notorious for dodgy charging.
Check also the V-boost valve is shut fully at idle. I found mine sticking open due a miss directed hose inhibiting the actuator
Great video . I feel and share your frustration. I have a flooding carb on a Rebel 250. Carb been off 3 times . Cleaned to within an inch of its life . New float , float needle and seat polished . Tank is almost new and filter fitted . Still petrol pouring out of overflow . No idea what to try next . I too hate bikes at this point .
Loving this journey you’ve done everything right and managed to make me Laff
I would make sure its dark in workshop fire it up see if back two plug leads are arking
I think he would hear the 'click click click' if it was arcing... but good point!
Love the videos, I have a 89 vmax with a no spark condition on the rear pass cylinder. I’ve been beating my head against the wall trying to figure it out. With some help from more knowledgeable people I hope to fix it. Thinking mine is cdi related after multiple meter readings. Apparently there are 4 mosfets in the cdi and are prone to fail supposedly. Again enjoy watching and learning from your videos, thanks.
Fair play to you Chap.
Loving the Channel.
love the explanations , , thanks for sharing.
Great explanation of the Constant Velocity Carburettor... I think in Part 3 of this series we'll be watching valve clearances....😅
Jim I very much enjoy you sharing your thought process and diagnostics. Your explanation of slide operation from about 16:00 was very educational. Two thoughts occur concerning this: the vacuum operated slide sort of dampens or modulates throttle operation and might be useful if fuel emissions are a concern. Any chance you could swap in the old ECU? Looking forward to Part 3.
Had a similar issue with my XTZ 750 compressions showed ok but the valve clearances were too tight. Making it very difficult to start from cold and would misfire and foul plugs.
tons of top tips in this video!
Great content, and am enjoying the regular frequency.
I’m having a battle with the oil leak from the cam cover of my 07 ZX6R (garage def did not replace the gasket when the valve clearances were done, which I paid for!) - stripped one of the bolt holes which I believe goes into the cam-cover caps, when I attempted to sort the issue! Bloody fucking bikes!!!
I feel Ur pain I did a v max 15 years ago, vowed never to do another,the one I did had a different issue,it ran ok but when you were cruising at 70 ISH and wound the throttle on it would hold back then go,I spent 2 months on and off,had another guy look at it who also had it for a month,it was better but not spot on,the guy who owned it was ok so he had it back,trouble is the labour cost became stupid and u never got any where,I was lucky I was doin Dyno set ups at the time so i could do it on the Dyno ,at least I could run it with the tank off n stuff,had a thought might be worth checking exhaust it may have to much back pressure being the two rear cylinders,I think they have baffled downpipes,anyway waffling ha,love your vids,keep up the content bud,andy
Check trigger wires are not crossed to rear coils
It is always more difficult to fault find when someone else has “tried” to fix it. I would start by making sure all the connections from pickups to coils etc. are as they should be and check the timing. Then use a secondary ignition pickup and your scope to see if the plugs are actually firing in the cylinders and not outside because of a leak somewhere. If that is not the problem I would then look at the valve train. The compression test only confirms the valves are closing properly but it cannot indicate whether they are opening correctly.
CHECK THE VALVES
I agree mate, the carbs were bolloxed.
You'll find the issue, it's just a shame it's a ball ache.
Think of it this way, as a bare minimum the carbs needed doing. And if it arrived to you in proper mechanical condition (carbs ok), you'd be starting your fault finding from now.
Hi Jim, check valve clearance first, then with a pressure transducer check cam and crank correlation waveforms for synchronization and drop outs
You wouldn't check the cam and crank correlation with a pressure transducer. You would back probe both the pickups and check their wave forms against a known good signal. The transducer would give you great indication of every stroke throughout its 720 degree of rotation taking a trigger from the ignition coil you could determine the actual time of spark in relation to crank angle also buffer the event and re evaluate over a cuppa tea later on rather than try to concentrate on too much at once.
@@thebiker2655 you right but if it's an old bike without pickups, how you test the synchronicity of the two shafts, or wear, perhaps with a gas analyzer, what you suggest?
Only a hobbyist, not an expert, but before I'd lose any more hair with this, I'd check the valve clearances on this bike Jimbo. If anything it should help with the difficult starting? Then maybe swapping about the HT leads ?
Keep on keeping on…..
I once put one of the coil + & - 12v connectors round the wrong way on a VFR750. It ran like this!
You’ve got this Jim 💪
Would you consider doing a video describing different carb features that someone may or may not have and differentiate from the basics that every carb would have?
Hi having worked on many varieties of carbs for all kinds of engines these are the first slides I have seen without a cutaway
Don't need a cutaway coz they don't completely bottom out on the carb body.
@munter10 again
Never seen slides that don't bottom out
Can you get the original ECU back? I reckon the carbs were always the issue and the ECU is wrong/faulty and has created another issue
Good call.
What I would find is testing the work with a fuel bottle causes a miss. Some systems need pressure in the fuel lines to force fuel into system rather than letting it flow in.
It always seemed silly to me, but once I'd connected tank and proper fuel clips, the missing sound would vanish and all would run smooth.
This makes the issue seem like its a carb problem when it is only a lack of fuel pressure in the system.
You normally find if the fuel tap on the tank does not have a free flow when turned open. Then your system needs pressure that seals and sucks fuel through the system rather than a drip feed. If that makes sense.
That's a humble pie for me too, i was gonna bet that rebuilt carbs would sort it !
keep at it lad ul get there keep up the great work
i'd be swapping the coils over next. if still the same then i think it's got to be the CDi unit or the pickups. it must be losing spark if it's igniting unburnt fuel in the exhaust.
I don't work on motorbikes but can you index the flywheel ? Put each cylinder to tdc mark the flywheel and hook up a timing light, fire it up and see if the spark event is approx at tdc on 4 cylinders if not then a direction to go in, sorry if this is useless info
We have a rule in our workshop. Never trust a part previously fitted by the owner or another workshop it is almost always the problem, be it the wrong part (wrong year) or fitted incorrectly.
We all have those days, but let it play in your head for a while and youll figure it out...
And the other idea based on ECU comments (although I think you said a new ECU had been ffitted) I had a dry joint in the ECU of a Ducati 996SPS. However it caused an intermittent fault when the ECU got warm so the symptoms seem different.
If an ECU has been fitted from new stock, I can't see that it is that.
I've seen ECUs be fine when tested but fail under load.
@warwickscram1656 yep. Similar to my 986SPS I think. Took a Ducati specialist some time to trace it and once dealt with, sweet as a nut. Stuart
@warwickscram1656 noting though that this Yamaha appears to have had 2 ECUs. Turned up at main dealer with an ECU fitted and the fault. The main dealer changed the ECU I understand (don't know with what) and the problem is, I understand, identical.
That would indicate to this amateur that it was unlikely to be the ECU.
Jim's the man though. He'll sort it. I'm just a dabbling amateur.
My Dad was an engineer and taught me to follow the "what has changed" principle and the "change one thing at a time" principle.
Which Jim follows too.
Love this channel.
Stuart
@@stuartmetcalfe547 I agree, this channel is great and makes me miss the days when a motorbike was in my budget (I'll get another when my kids grow up!)
Awesome a Super bike Surgery Friday, been looking forward to this. Thank's to you I learned something new today about carbs, I had a mechanic tune a carb by changing the hole size in the slider and shaped the needle and at the time I had no idea how it would change things, who says you can't teach an old dog new tricks lol. Have you tried an exorcism, it could be possessed by an old dead Harley rider. Fcuking great channel.
That's not fair. I was just typing up to say get a timing light in case someone swapped the ignition wires to the coils then you answered 😂 you never mentioned if it ran fine off idle after the clean? If you're cracking out a scope, whats the trigger signal like? Keep up the good work jim 👏 👍
Check intake valves. May be tight.
Sounds like a coil. They controll the cylinders in pairs. If there are two cylinders missing try swapping the coils from front to rear and see if the miss changes. EDIT: didn't watch far enough
I was mechanic in a motorcycle shop, we did various bikes although I preferred Honda. Your bike is a puzzle,you have tried the normal things. My boss would be going mad at this time. We had 4 mechanics working together so we would discuss things like this with each other. Sorry I cannot help you.
It's sometimes frustrating when working alone. In a way it makes you a better technician as you have to think deeper and out of the box. Jim's thinking and attitude to work is that of a master technician.
@@thebiker2655 when I left shop I went self employed as a mobile for 15 years, although I was a mot tester for 30 years. This was easier and made more money than fixing bikes.
See if there is a water leak. I know theres compression but if the coolant nesses with it could explajn the wet plugs and no ignition.
VVT Issues perhaps? But that’s just a guess as you’ve explored most other avenues 😢
Might be worth checking the coils are earthing correctly. Also whats it like at higher revs like before, do the rear cylinders come back in again? I would look at the fuel pump to and clean all the ground points You can.
swap the ignition coils around see if the symptoms move cylinders
Could move the coils around just rule that out to, hate problems like this i know that frustration you are feeling, hang in there you will sort it.
That slow cranking sounds like a symptom of the main issue. I would try cranking it without sparkplugs on the unhealthy cylinders, if the crank speed becomes normal it would mean you have a "blockage" on the exhaust path. That can mean exhaust valve clearance out of spec or exhaust line blocked
Perhaps pop the camera down just to confirm the inlets are opening. or wires crossed to the coils? ayway looking forward to the resolution.
Just one last thing…You have your fuel supply set up there with an external fuel line. If you can ….put a separate line to each carb from 4 calibrated fuel containers and see if there is any difference in the amount each one consumes. ????Crazy I don’t know..What do you recon??
Something timing related maybe. Do relative compression test with ignition sync
Ah you came to the same conclusion. The test I mentioned is the easiest way to test ignition is on the right stroke. Take a plug out to see which cylinder is which and follow firing order. Or use an in cylinder waveform with an ignition event to sync up
The previous shop didn't bother fixing a crap set of carbs, so the accusation is still valid. Has the customer got the original ecu? Is it the correct part? Problem with the timing pickup? Or the rear cylinder head has been off and the timing chain is out of wack, not sure the engine would even survive that...
You've got compression, spark and fuel, so timing it must be
The only suggestion I can think of is spark timing. You have a good spark, but is it happening at the correct time?
If something was blocking the inlets around the vmax valve hence why balancing carbs was not going to well? Or air leak around the vmax valve body as there are so many rubber connections on an old machine
I had an old school mechanical throttle, you got used to getting it over 3000rpm before nailing it, if not you went nowhere fast
I wonder if the coils are grounded properly?
Had a similar issue with a GpZ550 and found it was a corroded ground connection with one coil.
Swap the rear HT leads or coil packs front to rear
This seems like a bad earth issue, or the timing is slightly out.
Some older bikes like to have the fuel system with a bit of pressure in it. As in the fuel tank connected up builds the pressure and forces fuel into carbs rather than just having a free flowing set up. Seems silly but in many years of builds its something i would notice now and then when testing bikes as you are.
Once i connected fuel tank and proper clips that intermittent noise your experiencing would go away from my builds.
The bikes always sounded like they were missing , and it was because a lack of fuel pressure.
You could try squeezing the fuel supply bottle to force pressure into system and see if that changes the miss...
Timing is a definite possibility. So is battery voltage. I see its a slow cranker but is this battery or starter /starter circuit related out of interest? If the battery is low voltage this can of course effect the ecu/ignition module causing all sorts or weird problems, including individual cylinder timing (as you say it has 4 separate pickups, so in effect 4 separate ignition systems)....
Check the valve clearance and timing marks it may have jumped timing!!