'86' V65 Magna build

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DG, I figured the lack of space would certainly cause some temp difference, but should it cause the amount of difference I have?  That front left almost cannot get above 200 deg.  while the front right will get around 300 deg. and the back two are near 500 deg.   The only cylinder that seems odd to me is that front left.  I can pull off of the highway after a 2.5 hour run at 80mph and comfortably wrap my hand around that #2 exhaust, and it's just barely above warm.

[reaperkeeper]

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When are you taking these readings? I understand you are at operating temp on the motor, but is it right after running down the road?  no idle time? or are you allowing the bike to idle for a few minutes after riding it before you take the readings.
500 degrees in the rear is WAY to hot for idle, your running lean back there, and yes, under 200 in front is to cold.

Some simple and easy things to verify:
coils: One for cyl 1&3 (rear two) and should have the white & yellow wire going to it.  One for cyl 2&4 (front two) with the white/blue wire going to it, both should have a ground wire (black I think) If these are mixed up that might cause your problem.

The rest would require the carbs to come out again, but if the coils are hooked up as described above then your problems is most likely in the carbs.
the carbs for the rear cylinders (1&3) have some different parts in them form the other two. There are different legnth springs (shorter) for the diaphragms, the diaphragm jet needles are thinner and the emuslion tubes are different as well as the jet size depending on what year carbs you have. The float level can be different also depending on year and can make a huge difference if set improperly at high RPM/speed- no rocket science here, just verify the basics.

Well I have gone way off track from what I wanted so........as I said earlier....call me if you want when you are ready......until then -  Enjoy the Ride!

[Greg Cothern]

I would suspect that some of the jets and springs etc have been swapped from front to rear cylinders.  The rear cylinder carbs have a stronger spring as the tilt of the engine puts the trumpets more in the air flow.  Also I believe the rear cylinders have a slightly larger set of jets.  Usually 2 higher, for example (dont quote me on the #'s cant remember, so I am simply throwing out an arbitrary set of #'s), if the front cylinders had 100's then the rear would have 102's.
If these springs and jets were inadvertantly swapped you will create a varied air fuel mixture that would result in some of your wildly differently temp readings. 
You have not mentioned your Pilot Jet adjustments???   I would start by turning them in to a light seat them back them out 2 1/2" turns, good place to start.  I tuned my Super Magna with the roll-off method.  IN as quiet of an area as I could get I warmed up the Super, and adjusted the idle high to 1200-1300 rpms, then opened the jet (counter-clockwise, richening) till I could tell/hear the rpms slightly fall off, then turned the jet in clockwise about an 1/8th of a turn.  On to the next carb.
I think you will find a closer reading. 

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I've tried really hard a few times to adjust the pilot screws like the book says, just like Greg described.  I cannot hear the difference in rpm when I turn the screws, nor does turning one pilot screw at a time even change the motor enough to know a stopping point to turn it back in 1/8 turn.  So what I did was start each screw at 2 1/2 turns out then run it in town and on the highway.  I then onece I parked it and let it cool, I pulled each plug and adjusted the screws according to how the plugs looked.  All four pilot screws are in different positions, but not by much.  Right now, all the plugs are a nice bronzed color with no carbon build up except for the #2.  It's a good color but has a little build up still.  I'm gonna have to get Reaper on the phone here soon and pull the carbs apart to figure it out.  I think maybe Greg migh be on to something with the swaped out jets and springs but I don't know.  I would be suprised if it were something that wrong because this bike is still the fastest bike I've ever rode.

[Greg Cothern]

It would still be fast!!!  LoL.

You can pull a front diaphragm and rear diaphragm and check, especially on the cylinders that are WAY OUT.

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Im gonna pull it apart this weekend, but here's a goofy question:  My bike is an 86, I have 83 Non-Cali carbs on them.  the main jets on an 86 are front-#115 and rear-#118 but the main jets on an 83 are both #140.  Is there a difference in the engine to where this difference could cause a problem?  Which jets should I try to set this carb to, the 86 specs like my motor, or the 83 specs like the carbs?

[reaperkeeper]

Pop.

I am running the exact same set up you are, an 86 engine with 70A carbs.  The engine is a stupid mechanical assembly of parts.  It does not care, nor have anything built into it to limit its performace from year to year, timming is all the same, the difference is in the carbs!  If you have the 70A carbs and are running stock exhaust up to the collector, then use the 140s.  I have found, for me, at my location, with my atmospheric conditions and my set up that 142's all around work best.

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Thanks Reaper.  Tomorrow I'll pull them off and check out their gizzards.  Is there a way to identify what size the jets are?

[roboto65]

Yeah get a magnifer lens and should be numbers on them.

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Well, I just took the carbs out and pulled them apart.  All of the float bowls look very clean.  All of my main jets are the 140's and are all very clean.  The shorter jets all have the #38 on them.  I'm not sure if that's the correct size or not.  I took the springs and the jet needles out, and everything seems to be free moving and very clean.  The longer springs and the thicker jet needles were installed in the front two carbs just like the shop manual describes they should.  I'm not totally sure how to read out the float level (6.0mm, the manual reads) and I'm not sure what the book is talking about with "Venturi Dia."-Primary 12.0mm and Secondary 33.2mm.  Overall, it's looking like I'm not going to find anything blatenly wrong in these carbs to explain my bikes problems.  I do need to double check my coil wires.  Mine has the black/white wires attached to the (+) terminals on both sides, then on the right (-) is a yellow wire, and on the left (-) is a green wire.

[reaperkeeper]

Did you check the float valces???????????????
no type of damage is allowed, no rings, no cracks, nothing, they should look perfect!

Im not sure what is going on with your coils.  The book only shows two wires to the coils, and that is all I have gling to mine as well.  Black&white is ground, common to both coils, yellow goes to the coil for cyl 1&3, blue goes to 2&4.  Green is usally assosiated with a ground in my expierence. Where does the green wire go/come from?

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I haven't gotten to the float valves just yet, it was pretty late last night when I took them apart.  On my coils, the black/white are going to the positive side?  The one that I thought was green, is infact blue, sorry bout that.  Would those coils even work at all if they were wired up backwards because it sounds like mine are lol.  I'll get back into the carbs a little later.   Thanks for the input so far!

[reaperkeeper]

The wire diagram does not specify, but you are correct, it would seem it does not matter.  When you look at the float valves, please look up inside the valve housing where the pointed end of the valve plunger goes.  Its a small hole so if you have a magnifier and a bright light it helps.  the housings can be removed also, they have a screen on them if you do remove them.  Please feel free to call me if you want.

[ToolBoxPop]

I inspected the float valves really well, and they all four have a visible ring where they seat but I cannot feel an indentation so I think they are still good to go.  I got ReaperKeeper on the phone and we discussed what I was looking at with my carbs, and I noticed that one of the brass colored tubes that stems down into the float bowls directly next to the float valve was different than the others.  The #2 tube was open straight through to the carburetor intake.  And I noticed that the vacuum piston needle, when fed in from the top of the carb slides straight down that tube.  The other three tubes had a steel ball pressed into the end to block it off.  Reaper looked at a set of carbs at his house and found out that without that steel ball at the end, there was nothing metering the flow of fuel.  For a lack of any better ideas, I JB Welded the end of the tube closed.  Took the bike for a spin after syncing the carbs and holy cow did that bike come to life.  Flawless acceleration clean through rpms and pulls hard!  That is the fastest machine I've ever been on for sure!  For some reason though, that #2 exhaust still only reads about 190 degrees when the others run far hotter.  At least I'm making progress!  Thanks Reaper for the help!

[John Luttrell]

That's great news and a great find!  It sounds like the additional fuel was keeping the cylinder temps down in that cylinder.