Help with bike lying up

[Suzuki boi]

Thanks lads
Swapped the map sensor with the ambient temperature sensor and still the same.
Managed to get the bike to idle for awhile,be it having to constantly blip the throttle to stop it cutting out and the white smoke is fairly gone so must of been a build up of condensation.
I noticed it's constantly,yes constantly backfiring on when I turn the throttle a small bit(low revs,revmeter still not working so not sure of exact revs)
Tried sourcing the rev/odometer problem but no luck, all cables in good nick.

I notice that cyclinder 2 header doesn't get as hot as the other 3.
On idle I can't touch cyclinder 1,3 or 4 but can hold onto cyclinder 2,s header.
Swapped plugs around,swapped injectors around. Still issue with header happens .
Swapped ignition coil from 3 into 2 but still the header doesn't get as hot.
Wtf
Now I'm thinking low compression? No idea

[KiwiCol]

swapping plugs, coils & injectors is good diagnosis work. What's left? only mechanical issue in cyl 2. I'd say probably valves, maybe a burnt exhaust valve. 
Others with more knowledge than me will no doubt be able to diagnose more accurately.

@grog @seth @Blubber

[Blubber]

Can it be false air drawn into nr 2?

Maybe a worn o-ring between the head and the rubber manifold , a.crack in the rubber manifold,  nr2 out of sync / balance. One of the rubber hoses towards the MAP pressure sensor porous?

Valves can stick, close badly due to carbin built up but this engine isn't known to do so.

[Suzuki boi]

Also forgot to mention.
When I took the plug out of cyclinder 2 ,it looked fairly new,as in now soot or black on the tip.
I took the plug out of cyclinder 4 it had soot on it so was doing its job.
Also if I open the throttle header number 2 gets fairly hot,hot as in I can't touch it.
So seems to only get hot when revved but only warm when idling !
Also tried the bike without a coil in cyclinder 2 and bike doesn't seem to run any different.
Pull coil out of cyclinder 4 and bike won't even idle.
And doesn't seem to be any backfire when I hold the revs high 
Bike is really killing me at this stage.

[Suzuki boi]

swapping plugs, coils & injectors is good diagnosis work. What's left? only mechanical issue in cyl 2. I'd say probably valves, maybe a burnt exhaust valve. 
Others with more knowledge than me will no doubt be able to diagnose more accurately.

@grog @seth @Blubber

Ye was really hoping it was just something as simple as an ignition issue but nope

[Suzuki boi]

Can it be false air drawn into nr 2?

Maybe a worn o-ring between the head and the rubber manifold , a.crack in the rubber manifold,  nr2 out of sync / balance. One of the rubber hoses towards the MAP pressure sensor porous?

Valves can stick, close badly due to carbin built up but this engine isn't known to do so.

Checked all hoses by the throttle body and they all seem ok
Anyway to test if nr2 is out of sync?
Or to see if there's a crack by the manifold head?

[Andre]

Ye was really hoping it was just something as simple as an ignition issue but nope

Could still be an ignition issue.
May be a poor connection between spark plug cap and spark plug. Switch #2 and #3 spark plug cap and check temperatures again at idle.

To check for vacuum leaks ("crack in manifold") do the age-old test for vacuum leaks by spraying carb cleaner (I used cigarette lighter gas) on suspected areas and see (in your case hear) if rpm picks up in idle.

To test for TB sync see the service manual starting at page 4-66 (can download it from the download section)

[KiwiCol]

swapping plugs, coils & injectors is good diagnosis work. What's left? only mechanical issue in cyl 2. I'd say probably valves, maybe a burnt exhaust valve. 
Others with more knowledge than me will no doubt be able to diagnose more accurately.

@grog @seth @Blubber

Ye was really hoping it was just something as simple as an ignition issue but nope

What about the lead itself? When you said about the colour of the plug, it sounds like it's just not firing.  You have done everything else, what about the actual lead?

[Suzuki boi]

Ye was really hoping it was just something as simple as an ignition issue but nope

Could still be an ignition issue.
May be a poor connection between spark plug cap and spark plug. Switch #2 and #3 spark plug cap and check temperatures again at idle.

To check for vacuum leaks ("crack in manifold") do the age-old test for vacuum leaks by spraying carb cleaner (I used cigarette lighter gas) on suspected areas and see (in your case hear) if rpm picks up in idle.

To test for TB sync see the service manual starting at page 4-66 (can download it from the download section)

Swapped 2 and 3 and no difference.
Got the multimeter out and tested the coils with the leads and all reading 100%.
Checked the throttle body sync pdf and need a set of vacuum gauges. Will need to order some on Amazon so.
Wil get some more carb cleaner and spray it all over .
One other thing I tried.
I disconnected the plug lead from cyclinder 1 and the bike didn't sound much different.
Plugged cyclinder 1 lead back and disconnected cyclinder 2,the same thing,bike sounded the same.
Now when I disconnected cyclinder 3 the bike would just about start but wouldn't idle
The same with cyclinder 4.
So to me there's an issue with cyclinder 1 and 2. Even tho cyclinder 1's header gets hot.
The only thing that has the 2 cyclinders connected in anyway is the throttle bodies.
So syncing could be the issue

[Suzuki boi]

swapping plugs, coils & injectors is good diagnosis work. What's left? only mechanical issue in cyl 2. I'd say probably valves, maybe a burnt exhaust valve. 
Others with more knowledge than me will no doubt be able to diagnose more accurately.

@grog @seth @Blubber

Ye was really hoping it was just something as simple as an ignition issue but nope

What about the lead itself? When you said about the colour of the plug, it sounds like it's just not firing.  You have done everything else, what about the actual lead?

Swapped the leads 2 and 3 around and made no difference

[KiwiCol]

Ok, no go there.  Is there any power being supplied to coil 2?  I know you swapped the coils & problem persists, so not the coil, but it could be the power supply to coil 2. 

[Andre]

Would do the carb cleaner first as it is the easiest.

Sync tool is good to have anyway. Not sure if it is meaningful if 1 cyl. is not running correctly for other reasons than being out of sync.

Ok, you used a multimeter. But did you measure PEAK voltage (manual 7-22). Need an adapter for that. Costs dearly but can be made cheaply DIY.

[froudy]

@Suzuki boi

When you do get some balancing guages use the Morgan Carbtune..They work a treat

https://www.carbtune.com/carbdtls.html

[grog]

Not really wanting to get involved, but. Have you actually checked spark at all cylinders? HEI tester required. Have read thread but gets confusing.

[Suzuki boi]

Thanks for the help lads.
Haven't been near the bike in awhile.
Got a compression tester to rule out compression issues.
Checked all power supplies and tried carb cleaner and no luck.
Compression test showed
Cyclinder 1 : 160psi
Cyclinder 2: 160 psi
Cyclinder 3 : 165psi
Cyclinder 4: 165psi
So compression not an issue.
After I had a good roar and shouting some foul language.
I looked back the throttle body as the issue must be somewhere there.
Low and behold I must of mixed up the 2 pipes,the one from the throttle body to the map sensor and the other pipe that goes to the pairs system
Makes sense why only the 2 right cyclinders were getting hot ,because they were the only ones getting air flow
Sorry lads it was my absolute f**k up
Now I'm off to try fix this rev meter and odometer