Author Topic: Newbe with v75 problem  (Read 20329 times)

Offline Kiwi_Roy

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Re: Newbe with v75 problem
« Reply #30 on: December 12, 2014, 03:00:01 PM »
Yep done that,and timing looks pretty close (thing is with the pick up plate it doesn't make sense for one side to time correctly and not the other).....need to borrow a strobe light I think (hadn't used mine for 20 odd years and now it doesn't work).

If it was a BMW Boxer it wouldn't matter since the cylinders fire every 360 degrees
Looking from the front
The RH (shift side) cylinder fires at TDC (lets call that zero degrees) the other cylinder (brake side) should fire 270 degrees later when that cylinder is at TDC
Now if you have the timing crossed over with the first RH cylinder firing at TDC (zero degrees) the other cylinder will fire not at 270 but late at 450 degrees (BDC with the exhaust valve opening)

I'm sure this happens with old loops all the time after an engine rebuild.

Please post a picture of the pickup plate with the running cylinder in firing position.
How is the pick up plate driven, at half speed from the camshaft?
Carl's drawing shows of the 94 V35-75 shows 4 evenly spaced lobes on a CW rotating wheel, is that what's really there?


BTW, I do realize the spark doesn't occur at TDC but just before, I'm just trying to get my idea across (not very well), I'm assuming the previous owner pulled it apart, mixed the wiring and it never ran since.

« Last Edit: December 12, 2014, 03:09:58 PM by Kiwi_Roy »
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Re: Newbe with v75 problem
« Reply #31 on: December 12, 2014, 03:29:10 PM »
KR , I think you may not be thinking this through . If the "wires" are crossed , neither cylinder will fire at the correct time . Crossing the wires would cause one cylinder to fire way late , and the other way early . Unless of course the timing could be so dramatically altered that one cylinder could be made to fire at the correct time , which I don't think is possible . Am I missing something here fellas , if so , the apologies all around .

  Dusty

Offline Kiwi_Roy

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Re: Newbe with v75 problem
« Reply #32 on: December 12, 2014, 05:50:56 PM »
Not so, it might be possible to move the plate enough to get one cylinder to be spot on, the other of course would be miles out, Besides it's more likely than a cam worn away to a point it will not fire.

I think the next step is to put each cylinder in firing position and see if the ignition lobe lines up with the timing sensor.


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Offline Chuck in Indiana

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Re: Newbe with v75 problem
« Reply #33 on: December 12, 2014, 05:58:46 PM »
Not so, it might be possible to move the plate enough to get one cylinder to be spot on, the other of course would be miles out, Besides it's more likely than a cam worn away to a point it will not fire.

I think the next step is to put each cylinder in firing position and see if the ignition lobe lines up with the timing sensor.


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Absolutely. To the OP. There's nothing magical here.  ;D You say you have compression, fuel, and spark at the right time. If so, it will run. It can't help it.  ;) I know, it's easy to think, "I've done everything.." but *something* is amiss. *Probably* it's ignition timing on the cylinder that isn't running. It *could* be a lobe wiped off the cam. Check the lift at the pushrod, do what KR said,  and get back to us.
Chuck in (Elwood) Indiana/sometimes SoCal
 
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Re: Newbe with v75 problem
« Reply #33 on: December 12, 2014, 05:58:46 PM »

oldbike54

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Re: Newbe with v75 problem
« Reply #34 on: December 12, 2014, 05:59:00 PM »
Not so, it might be possible to move the plate enough to get one cylinder to be spot on, the other of course would be miles out, Besides it's more likely than a cam worn away to a point it will not fire.

I think the next step is to put each cylinder in firing position and see if the ignition lobe lines up with the timing sensor.


Sent from my shoe phone!

Well , the OP never said the offending cylinder was not firing . From my experience it is hard to move any timing plate enough to compensate for 90 degrees of timing woogity . Maybe 20 degrees is possible . Once again , if I am missing something , apologies . Does anyone know for sure about this ignition system ?

  Dusty

Offline Kiwi_Roy

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Re: Newbe with v75 problem
« Reply #35 on: December 12, 2014, 06:33:25 PM »
Well , the OP never said the offending cylinder was not firing . From my experience it is hard to move any timing plate enough to compensate for 90 degrees of timing woogity . Maybe 20 degrees is possible . Once again , if I am missing something , apologies . Does anyone know for sure about this ignition system ?

  Dusty

No, I think he said it was backfiring, this made me wonder if it was sparking with a valve open.
Remember it was bought as a non runner so who knows what the previous owner did to it.
I'm sure we will know soon.
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Offline Chuck in Indiana

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Re: Newbe with v75 problem
« Reply #36 on: December 12, 2014, 06:43:31 PM »
If it is a Motoplat, I'm clueless. I''m 99% sure that a Digiplex wouldn't do this.
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Re: Newbe with v75 problem
« Reply #37 on: December 12, 2014, 06:44:18 PM »
No, I think he said it was backfiring, this made me wonder if it was sparking with a valve open.
Remember it was bought as a non runner so who knows what the previous owner did to it.
I'm sure we will know soon.


Had that same thought . But he also stated it seemed as though the valve timing was a bit off . Yeah , hopefully we will get some baseline compression/leakdown readings , and some some idea of where the timing is .

  Dusty

oldbike54

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Re: Newbe with v75 problem
« Reply #38 on: December 12, 2014, 06:46:50 PM »
If it is a Motoplat, I'm clueless. I''m 99% sure that a Digiplex wouldn't do this.

Does the digiplex use one trigger with two pick up points ?

  Dusty

Offline Chuck in Indiana

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Re: Newbe with v75 problem
« Reply #39 on: December 12, 2014, 06:59:28 PM »
Does the digiplex use one trigger with two pick up points ?

  Dusty

It is the earliest of the computerized ignitions. Has a flywheel position sensor, and uses vacuum for advance.
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Re: Newbe with v75 problem
« Reply #40 on: December 12, 2014, 07:41:36 PM »
It is the earliest of the computerized ignitions. Has a flywheel position sensor, and uses vacuum for advance.

Thanks Chuckie .

  Dusty

Offline Kiwi_Roy

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Re: Newbe with v75 problem
« Reply #41 on: December 13, 2014, 03:32:06 AM »
I think we need the OP to give more details on the ignition system or at least some pictures until then we are grouping in the dark.
We know it's low milage, 19,000
The compression is good
It's backfiring through the carb

I tend to focus on electrickery as the cause of the problem because that's what I know best, I'm probably out to lunch but backfiring through the carb would occur if it sparked with the inlet valve still open, says the valves are ground in, could it be the tappets too tight?

Chuck, how does the flywheel sensor determine which coil to fire.
Would it be possile to put the flywheel in the wrong spot in relation to the crank thus throwing the sensor target out of position?

Simj26, please provide more details / pictures of the ignition system
« Last Edit: December 17, 2014, 05:40:38 AM by Kiwi_Roy »
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Re: Newbe with v75 problem
« Reply #42 on: December 13, 2014, 10:09:14 AM »
Hey KR , take me with you . To lunch that is  ;D

  Dusty

simj26

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Re: Newbe with v75 problem
« Reply #43 on: December 14, 2014, 02:14:31 PM »
Once again Chuck makes the most pertinent query for the most probable suspect.  ;-T

92 V75. I'm guessing it is a faired Strada.

Do you have a couple of modules like this, probably under the seat?



If so you have the motoplat system. Quite sensitive to poor earths. Clean and check ALL connections. If that doesn't work then swap over the modules and see what happens.

You're lucky. I normally don't help Triumph people.  :P
Yeah, mines like that but the boxes are plain no ribs. Already tried swapping all of the ignition components over with no improvement (I have a good spark both sides already)

Offline rodekyll

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Re: Newbe with v75 problem
« Reply #44 on: December 14, 2014, 02:23:08 PM »
simj --

We've asked for data and are getting none.  We can't help you unless you also get involved.

simj26

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Re: Newbe with v75 problem
« Reply #45 on: December 14, 2014, 02:26:17 PM »
Thanks for all the replies chaps ;-T  
Been away for a few days, but I'll try to have another look at it tomorrow and provide some more information then hopefully . :)  

Offline Chuck in Indiana

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Re: Newbe with v75 problem
« Reply #46 on: December 14, 2014, 04:02:05 PM »
Quote
Would it be possile to put the flywheel in the weong spot in relation to the crank thus throwing the sensor target out of position?

I would think so. It's one of the reasons I asked what kind of ignition it uses. I'm totally clueless (my normal condition)  ;D about the Motoplat, though.I don't even know how it's triggered. I'll look in Guzziology for some clues.  I'd still like to see some compression figures, along with assurance that it is sparking at the *right* time. Just some basic things.
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Re: Newbe with v75 problem
« Reply #47 on: December 14, 2014, 04:17:53 PM »
I would think so. It's one of the reasons I asked what kind of ignition it uses. I'm totally clueless (my normal condition)  ;D about the Motoplat, though.I don't even know how it's triggered. I'll look in Guzziology for some clues.  I'd still like to see some compression figures, along with assurance that it is sparking at the *right* time. Just some basic things.

Chuck, the 'plat runs from pick ups in the normal small block location on the front of the camshaft. Timing is set in the normal manner. All the one's I've worked on are so but being a 'Police' model they sometimes had special requirements. I need one of your shrug smilies.

The flywheel can be put on incorrectly but both sides would be affected and due to the number of crankshaft bolts it would be way too far out for both sides for it to function or fire on one side if the sensor was located there. The PO should be able to see if the timing marks and good side ignition line up.

If his modules are a later version then I'm not sure if the pick ups are set independently or are set 'teamed.'

I'll go back to my original suggestion about connections and earth points. They need to be immaculately clean. Might not be the problem but it needs to be eliminated.

The 'plat often gets a bum rap. Its not my favourite system but will often run faultlessly for years. I've been told the pick ups are analogue rather than digital senders. The modules are known to fail but like twin engined aircraft that is only logical. 2 engines means twice the probability of a failure. The good things about this system is that you can limp yourself home on one side and the advance system is incredibly smooth, unlike the mechanical system.

Rod

Offline Chuck in Indiana

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Re: Newbe with v75 problem
« Reply #48 on: December 14, 2014, 05:06:34 PM »
We didn't get the Motoplat small block over here as far as I know. Guzziology just has a small paragraph about it. Dave mentions lining up a line on the pickup plate with a mark on the engine case at about 11 o'clock. He says the left line is for 350s and the right for 650s and 750s. Then, he says the later versons of the pickup plate won't have any marks at all.  ;D In that case, just line up the pickups at about 1:00 and 7:00 to get it started, and time it with a timing light.
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Re: Newbe with v75 problem
« Reply #49 on: December 14, 2014, 05:18:12 PM »
Has anyone mentioned that this might be a leaky *Thrunge grommet* , or a bad *dust excluder* , OK , yeah , you're right , going to my corner now  :-[ 
OK , so this is an Eyetalian model , what kind of ignition system does it have ? If both sides are sparking , is it even possible that only one side is in time ? OP swapped components side to side , no change , which still leads me to believe this is a valve lift or timing issue .

  Dusty

Morizzi

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Re: Newbe with v75 problem
« Reply #50 on: December 14, 2014, 05:50:53 PM »
Has anyone mentioned that this might be a leaky *Thrunge grommet* , or a bad *dust excluder* , OK , yeah , you're right , going to my corner now  :-[ 
OK , so this is an Eyetalian model , what kind of ignition system does it have ? If both sides are sparking , is it even possible that only one side is in time ? OP swapped components side to side , no change , which still leads me to believe this is a valve lift or timing issue .

  Dusty

I think you've hit the grunge grommet on the head there Dusty.  ;-T I stand aside to your lateral solutions!  :D

Chuck, I'd bet my bottom dollar you've got some of them over there. Early carb Nevadas would be the first place I'd look. I just can't see Luigi not sending you some or changing just for the USA. small blocks after all were a big hit in Europe so the US was a small market for them on these.

There were 2 different static timings for the older small blocks. 5 and 8 degrees off the top of my head witht eh smaller ones being the lesser. Can't be bothered to look it up and I've marked my flywheels to suit.

Its a Kettering system still so any disruption to the current to the coil will generate a spark but not when you want it. This can be on the +ve or -ve side. As the power to the coils is usually in parallel and one side is working fine then this is unlikely but a dodgy connector/ion to the coil can still cause this. This does remind me to ask: Does this model have an electronic or mechanical tacho? If electronic does it wave around when misfiring? May be a case of the tail wagging the dog.

The modules control the advance on a 'plat. They do this by controlling the earth circuit from the coils which is why good connections to earth are essential.

All this aside I'm starting to run with the thrunge grommet theory.  :D

I need answers to my questions as do others. I'll bow out now until we get some material feedback.

Rod

Offline Chuck in Indiana

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Re: Newbe with v75 problem
« Reply #51 on: December 14, 2014, 05:59:26 PM »
I should have said we didn't get the the Motoplat 750 small blocks. Probably Guzziology wouldn't have said anything about them at all if we didn't get *any*.  My bad. Again.. ;D
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Offline Kiwi_Roy

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Re: Newbe with v75 problem
« Reply #52 on: December 15, 2014, 03:38:32 AM »

Its a Kettering system still so any disruption to the current to the coil will generate a spark but not when you want it. This can be on the +ve or -ve side. As the power to the coils is usually in parallel and one side is working fine then this is unlikely but a dodgy connector/ion to the coil can still cause this. This does remind me to ask: Does this model have an electronic or mechanical tacho? If electronic does it wave around when misfiring? May be a case of the tail wagging the dog.

The modules control the advance on a 'plat. They do this by controlling the earth circuit from the coils which is why good connections to earth are essential.
 
I like this explanation, it would explain the bike going from a runner into a farting spitting machine without human input  ???
I think a timing light would be useful at this stage.
« Last Edit: December 15, 2014, 03:43:36 AM by Kiwi_Roy »
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Re: Newbe with v75 problem
« Reply #53 on: December 17, 2014, 03:11:16 AM »
Hello again. Took me a while to sort out how to work instagram....but this is a pic of the EI pickup
http://instagram.com/simonj6160/

simj26

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Re: Newbe with v75 problem
« Reply #54 on: December 17, 2014, 03:21:45 AM »
Oh yeah...it's an electronic taco working off the right coil, seems steady, no flapping about,but will check that again when I've put it all back together....tried disconnecting it...made no difference.
Checked the valve lift and there's no discernible difference between left and right cylinder.
 So of the two marks on the timing plate the upper one should line with the mark on the casings for the 750? I'll go back through the contacts and earths and check them again. ;-T

Offline Kiwi_Roy

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Re: Newbe with v75 problem
« Reply #55 on: December 17, 2014, 05:58:04 AM »
Hello again. Took me a while to sort out how to work instagram....but this is a pic of the EI pickup
http://instagram.com/simonj6160/

It appears to me as though the two round pegs correspond to the spark for left and right cylinders, I suspect they are magnetic.
I assume the rotor is fixed to a mechanical spark advance, is it possible to turn the rotor against a spring in the CW direction?
It should spring back.

The two wires we can see will be connected to a coil around each peg, they should be identical in resistance to ground. It's also possible there is some electronics in each of the blue plastic lumps in which case you might not be able to measure the resistance, try swapping the meter leads.

Put each cylinder in firing position (TDC with the valves closed) and I suspect you will find the ignition rotor lines up with one or other of the pegs.
Take a photo of the rotor with left then right at TDC

I note the zero mark is slightly off the pointer on casing.

Is it possible to unbolt the rotor and move it to a different position, if so how many different positions will it fit?

Please photograph the other ignition components and if possible a sketch of how they are interconnected.

I suspect an ignition strobe would illuminate the rotor adjacent to one or the other peg, it shouldn't show firing at any other point.


Please note:
I have never seen one of these systems, I'm applying simple logic based on past experience.
I haven't entirely given up on my crossed wiring out of position rotor theory :beat_horse
« Last Edit: December 17, 2014, 06:47:24 AM by Kiwi_Roy »
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Re: Newbe with v75 problem
« Reply #56 on: December 17, 2014, 07:57:01 AM »
Does it have a mechanical burrito ?  **C

  Dusty

Offline Kiwi_Roy

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Re: Newbe with v75 problem
« Reply #57 on: December 18, 2014, 04:10:52 AM »
Don't give up on us now  ;D

P.M. sent
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Re: Newbe with v75 problem
« Reply #58 on: January 05, 2015, 01:44:07 PM »
Only just got back to this (bike at the back of the shed while I get on with some other stuff)
The rotor has no movement, so not a mechanical advance and there's also no vacuum advance. My understanding is that the advance is controlled by the two ignition boxes.
 The thing that has struck me though is that the pick up plate and screws look an awful lot newer than the surrounding area......Recently fitted perhaps?
I'll have another bash at it as soon as I can lay my hands on a strobe......should give me an idea what's happening (or not happening ???)
 Thanks for the constant input chaps :bow

Offline Kiwi_Roy

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Re: Newbe with v75 problem
« Reply #59 on: January 06, 2015, 04:38:11 PM »
Only just got back to this (bike at the back of the shed while I get on with some other stuff)
The rotor has no movement, so not a mechanical advance and there's also no vacuum advance. My understanding is that the advance is controlled by the two ignition boxes.
 The thing that has struck me though is that the pick up plate and screws look an awful lot newer than the surrounding area......Recently fitted perhaps?
I'll have another bash at it as soon as I can lay my hands on a strobe......should give me an idea what's happening (or not happening ???)
 Thanks for the constant input chaps :bow
Recently fitted wrong perhaps  ???
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