(ex) V65 Florida no start after changing headgaskets

[Tinus89]

Hi all,

 

I have a V65 Floriday which I converted to a scrambler. Different exhaust & pod filters. Yes, I know they are bad for performance.
My experience tuning carburetor bikes is very limited, so I may not have set her up correctly. 

 

After the rebuild, I stepped the main jet from 105 to 115. With adjusting the needle heights up (more fuel) the throttle response improved, so I went up in size to 128 an tried the same.
Again improvement, so I went up to the next size I had available (145). With the needles all the way down, the throttle response was perfect. Quick and without hesitation.
Tried starting her cold the next day, no issues.

 

I then changed the head gaskets (both were the cheap version & wheeping) and since then, I cannot get her started anymore. I have not touched any of the wiring in the process.
The bike is equipped with Carmo Electronics electrical ignition and "wants to run" (plopping in the exhaust). Sometimes during starting the starter suddenly stops as if she tries to fire whilst on it's way up on the compression stroke.

Checked/adjusted:
- Spark (good strong on both sides)
- Spark timing (created mark on flywheel as flywheel appears to not be installed in the correct orientation) for RHS TDC - +/- 7deg, checked with strobe OK
- Went back to jet size 128, 115 and eventually 105 (original)
- Changed spark plugs for new
- Compression both sides 13.5bar
- Switched spark plug leads left/right (no "trying to run" anymore when switched)
- Adjusted mixture screw anywhere between 1/2 turn and 4 turns (manual states 1,5 turns out)
- Adjusted idle screw up/down
- Emptied float bowls & tried to start her with brake cleaner, same result (only popping, no running)
- Removed air filters, no change

After AudioMick's response:
- Checked & adjusted (only minimal change required) valve clearance after head re-torqueing.

Observations:
- When I remove the carburetors, there is some stagnant fuel in the inlet
- Sometimes the spark plugs are wet, sometimes not
- When I open the throttle or the choke, she "does not want to run", popping in the exhaust goes away like she gets too much fuel
- It is almost like the new headgaskets have changed something, or the ignition timing is off
- Sometimes she fires against the starter motor, so the starter stops briefly. 
- Sometimes she fires in the inlet, but only a little bit (no loud bang or backfire)

 

I am at a loss, so are some of my friends who have been trying to help me. What am I missing? Could the head gasket replacement have gone wrong?

 

[audiomick]

You did reset the valve clearances after changing the head gaskets?

I only ask because you didn't specifically refer to that.

 

That is also on the route of checks I would make in your situation, i.e. go through and check (again) the valve clearances and ignition timing, and make sure all the wires are plugged in where they belong. Even if you didn't deliberatly do anything to them, something may have inadvertently become loose.

Given that the bike ran with the bigger jets before the heads came off, I reckon you could leave them in.

Anyway, once the basics are all checked again, then you can start looking for more complicated faults.

[Tinus89]

1 hour ago, audiomick said:

You did reset the valve clearances after changing the head gaskets?

I only ask because you didn't specifically refer to that.

Excellent question! Yes I did, and the adjumstment required was only minimal (set to 0.15 / 0.20mm). Updated the opening post as well.

[gstallons]

Have you gotten any closer to getting the bike running ?

[MartyNZ]

Retorquing the heads alone shouldn't stop it from running. Could the ignition timing slip somehow? Does it have points needing adjustment and tightening? Or does it have a sensor that has picked up some metal particles?

[audiomick]

My opinion, based on my V35, which is basically the same in the pertinent points

27 minutes ago, MartyNZ said:

 Could the ignition timing slip somehow? Does it have points needing adjustment and tightening? Or does it have a sensor that has picked up some metal particles?

First question: no. The timing sits on the end of the camshaft, assuming it still has the original contact breakers. In the first post, an electronic ignition was mentioned. Where does it get its timing from? Is it on the end of the camshaft? Does it still use the mechanical advance mechanism, and if so, is that clean and properly lubricated?

Second question: an electronic ignition was mentioned, so probably no points.

Third question: what sort of sensor does the ignition have? If it is a "Lichtschranke" (what the hell is that called in english?), i.e. a thing that works with a light beam that is interrupted by something to show the pulse, is the sensor clean?

 

EDIT:

incidentally:

On 2/22/2024 at 11:52 AM, Tinus89 said:

- Spark timing (created mark on flywheel as flywheel appears to not be installed in the correct orientation)

 

The flywheel on the small block models can be installed in three different orientations, 120° apart. Obviously, only one is right. That the timing marks don't line up is far too common to be funny.

 

[Tinus89]

On 2/23/2024 at 6:44 PM, gstallons said:

Have you gotten any closer to getting the bike running ?

Nope, no luck.

On 2/23/2024 at 11:50 PM, audiomick said:

My opinion, based on my V35, which is basically the same in the pertinent points

First question: no. The timing sits on the end of the camshaft, assuming it still has the original contact breakers. In the first post, an electronic ignition was mentioned. Where does it get its timing from? Is it on the end of the camshaft? Does it still use the mechanical advance mechanism, and if so, is that clean and properly lubricated?

Second question: an electronic ignition was mentioned, so probably no points.

Third question: what sort of sensor does the ignition have? If it is a "Lichtschranke" (what the hell is that called in english?), i.e. a thing that works with a light beam that is interrupted by something to show the pulse, is the sensor clean?

So the classic point system has been replaced by Carmo electronic ignition. The mechanical advance is gone, there is an electronic pulse generator on the end of the camshaft like this one:

 

 

I do suppose this could have become contaminated, because the storage location of the bike is also used for other stuff (occasional spray paint, metalwork) so I could clean it up properly.

[audiomick]

Ok, so if that is all in good working order, correctly set up, and clean, it should just work. Given that the bike was running, as I understand it, before the head gaskets were done, I think one can assume that the system is basically ok.

You mentioned in the first post that the "plopping, wants to start" stopped when you changed the plug leads, if I understood the post correctly.

 

I can't see any reason why the pickups would have "slipped" during changing the head gaskets. Did you even have the front cover off? Maybe to get to the Allen head screw through the alternator to turn the motor over whilst checking the valve clearances? If it was off, have a look in there again to make sure the wiring still looks ok.

More likely: you would have had the tank off to do the heads, I expect. The coils are under there, aren't they? Have a good look there as well, in case there is a wire off somewhere. Although you did mention in the first post that there is spark on both sides.

 

A very silly thought just went through my head: you have checked the kill switch, that it isn't switched off?

The way I've wired mine (with Silent Hektik ignition), the kill switch switches the +12V to the coils off, so it wont spark if the switch is off. I can't actually imagine how yours could spark with the kill switch off, but I'll let the question stand...

 

Another thing: you mentioned have set the static timing

On 2/22/2024 at 11:52 AM, Tinus89 said:

for RHS TDC - +/- 7deg

Hopefully you mean "+7°", i.e. 7° before TDC rather than +/- 7°.

You set that for the right cylinder. The workshop manual says to set the static timing for the left cylinder first, but that is for points.

Page 124 ff.

https://guzzitek.org/gb/ma_us_uk/V35V50V65_041983_Atelier(GB).pdf

The instructions for my Silent Hektik, on the contrary, say to start with the right cylinder:

https://www.silent-hektik.de/MG_PB5FH_39.pdf

Do you have set-up instructions for your system? On what basis did you set the static timing on the right cylinder?

Don't know for sure if that is really a potential source of error or not. I'm just trying to think of anything that might have slipped through the net.

[80CX100]

You don't say how you verified the spark,but are you certain that it's actually sparking & at the right time?

When I was having trouble setting & getting the points running right initially on my CX100;KiwiRoy recommended that I open everything up & rotate the engine manually as I watched the valve assemblies,points, etc,,, it really helped me to get it all working correctly & on the right TDC,fwiw ymmv.

While you're double checking all your grounds & contacts, verify the air gaps on any ignition sensors as well. 

I hate it when garage gremlins disconnect sh*t & phq things up. btdt 

Time,patience & a fresh set of eyes always overcomes in the end.

 

[audiomick]

2 minutes ago, 80CX100 said:

Time,patience & a fresh set of eyes always overcomes in the end.

Yes.

[audiomick]

I've started thinking about the carburettors. Did you have them off completely when you changed the head gaskets? I could imagine it might be possible to take the heads off without removing the carburettors, but it would be more trouble than it is worth, I think.

So: the carburettors were most likely shaken up a bit, and maybe lay on the bench for a while on their sides or something. Maybe some gunk out of the float bowls found its way into a passage somewhere, or maybe the needle valves aren't closing properly anymore (because of gunk on the seat...).

Are you absolutely sure that the throttle cables and choke cables are correctly connected, have enough play in them, and operate correctly?

Incidentally, how do the seals on the choke pistons look? I can't see them causing your problem, but they get old and don't seal properly. I've even had one instance where the choke piston were out, and didn't seal properly when they went back in, even though the rubber disks that make the seal were not all that bad. Havin said that, when the chokes aren't sealing right you tend to have problems getting a stable idle rather than the bike not starting at all.

Going by your description, I'd more likely suspect the needle valves not sealing properly and therefore the carbs flooding, or something in that direction.

EDIT: don't forget to check the filter behind the banjo fitting that the fuel line is connected to. They clog up sometimes, but once again, I would expect bad running and not revving out properly more than not starting at all.

[motortouring]

My first suspicion would still go to the ignition. It sounds like the timing is incorrect. 

Do jo have a stroboscope to check the spark while starting?

You probably wiggled the sparkplug cables when taking the heads off. Please recheck everything related to that, connection to the coils and caps and plugs.

For the carbs, is that PHF30? Or PHBH30?

Main jet is not important for starting. Only for full throttle. That is the last one to improve.

You could also share your question on the MGCN site, there are a few top experts on this.

[audiomick]

19 minutes ago, motortouring said:

You could also share your question on the MGCN site, there are a few top experts on this.

Or better yet, here:

https://gpiu.de/forum/

That is a German language forum run by Martin Hagemann. This is his home page

https://gpiu.de/

Martin is the recognised expert for the "small block" Guzzis in Germany. His English is not brilliant, but there have been a couple of queries in English on the forum, and he manages. And I look in there pretty much every day, so if there are problems in translation, I could help.

 

[audiomick]

25 minutes ago, motortouring said:

For the carbs, is that PHF30? Or PHBH30?

According to the workshop manual, it should be PHBH 30.

Page 30

https://guzzitek.org/gb/ma_us_uk/V35V50V65_041983_Atelier(GB).pdf

[Tinus89]

13 hours ago, 80CX100 said:

You don't say how you verified the spark,but are you certain that it's actually sparking & at the right time?

(...)

While you're double checking all your grounds & contacts, verify the air gaps on any ignition sensors as well. 

(...)

Time,patience & a fresh set of eyes always overcomes in the end.

As my flywheel mark is incorrect (due to orientation), I positioned the right cilinder at TDC compression stroke (so after the intake valve closes). I then marked the flywheel 7deg BEFORE TDC. The 7deg is based on the distance between the two marks (there are two for each TDC).
I then tried starting the bike whilst checking with a strobe light on the right cilinder. There was some scatter (starter motor working against compression) but the timing seemed correct.

I also checked spark with the spark plug out & against the block, nice strong spark.

Believe me, time & patience have been in abundance (> 2 weeks already), so therefore I am asking on this forum for the fresh set of eyes now:)

 

11 hours ago, audiomick said:

I've started thinking about the carburettors. Did you have them off completely when you changed the head gaskets? I could imagine it might be possible to take the heads off without removing the carburettors, but it would be more trouble than it is worth, I think.

So: the carburettors were most likely shaken up a bit, and maybe lay on the bench for a while on their sides or something. Maybe some gunk out of the float bowls found its way into a passage somewhere, or maybe the needle valves aren't closing properly anymore (because of gunk on the seat...).

Are you absolutely sure that the throttle cables and choke cables are correctly connected, have enough play in them, and operate correctly?

Incidentally, how do the seals on the choke pistons look? I can't see them causing your problem, but they get old and don't seal properly. I've even had one instance where the choke piston were out, and didn't seal properly when they went back in, even though the rubber disks that make the seal were not all that bad. Havin said that, when the chokes aren't sealing right you tend to have problems getting a stable idle rather than the bike not starting at all.

Going by your description, I'd more likely suspect the needle valves not sealing properly and therefore the carbs flooding, or something in that direction.

EDIT: don't forget to check the filter behind the banjo fitting that the fuel line is connected to. They clog up sometimes, but once again, I would expect bad running and not revving out properly more than not starting at all.

The carbs have stayed on the bike, I just loosened the rubber boot. They have been rebuilt with new parts 2 years ago & I have checked the jets are clear after the non-start issues. Throttle cables are OK & have free play. Choke pistons OK. 

Also, I tried starting the bike with the choke float bowls empty (and fuel shut off) whilst spraying brake cleaner into the carbs, but even then she does not want to run. Therefore I don't really suspect the carbs anymore.

 

11 hours ago, motortouring said:

My first suspicion would still go to the ignition. It sounds like the timing is incorrect. 

Do jo have a stroboscope to check the spark while starting?

You probably wiggled the sparkplug cables when taking the heads off. Please recheck everything related to that, connection to the coils and caps and plugs.

For the carbs, is that PHF30? Or PHBH30?

Main jet is not important for starting. Only for full throttle. That is the last one to improve.

You could also share your question on the MGCN site, there are a few top experts on this.

To me it sounds like timing as well, but I can't explain what has changed when changing the head gaskets.
I have checked the timing with the strobe light as indicated earlier in this message.

Carbs are PHBH30