The saga continues I have a 1987 gl1200 that backfires thru the exhaust here ALL of the things I did to it,
1st had a water pump go bad and burn a head gasket,replace both along with new timing belts and cleaned carbs using spray carbs cleaner
2nd had a bad power wire to the coils and cdi ,No spark, Did a coil mod.se attachment still no spark, Thought it was a bad pulse generator,replace them no luck so replace cdi with a used one still no luck then found bad wire, replace it and it runs
3rd now that it runs I had a bad backfire pulled carbs off and the air cutoff valve was bad could see light trough it order Randakk's Cycle Shakk Honda GL1200 Carb Overhaul Master Kit
http://randakks.com/products/randakks-ow...erhaul-kit
4th clean everything old school with pan of hot 100% lemon juice now run only with the choke on
could it be the slow jets HELP
You double checked your timing? When a new problem develops it is often from the last thing you touched
Unfortunately there are many things on the GL1200 that could cause backfiring through the exhaust.
1- a bad igniton switch or kill switch circuit
2- faulty pulse generators
3- worn out spark plugs
4- worn out or defective spark plug wires
5- defective resistors in the spark plug caps
6- leaking ignition coils or weak coil output
7- incorrect ignition timing
8- incorrect valve timing
9- leaking exhaust valve(s)
10- fuel mixture issues + + +
For an engine to run properly all these and more requirements must be met. I suggest that you perform a proper compression test and make sure everything is right inside the engine then work your way down the list from there. Wish I could make it easier for you, but, I would have to follow the same procedures if I was working on my own bike with the same issues as yours demonstrates. Don't be intimidated by the list as folks here will help you walk through it all and help you get your bike running the very best that it possibly can. Good luck and don't hesitate to ask lots of questions if you are not sure about anything.
all which has already been mentioned, and, make sure the coils are connected to the correct cylinder.
Somewhere in this forum I recall reading how one or two of the service bibles we reference to keep our bikes alive, has the wiring from the coils to the spark plugs incorrectly written.
Also, if this is getting frustrating and a bit overwhelming, make a list of what you feel you need to try. List it from easiest to more difficult or (as I do) from 'things which don't need replacement parts' to 'things which required replacement parts'. No point in buying parts you don't need.
Also, the list allows you to take notes and document what worked and what didn't work to be used as a reference so you don't repeat something which didn't work.
my .02
Good Luck and come back with all your questions, comments and concerns.
I'm having similar problems with my '84 aspy not staying on without the choke, will have to go thru above list also. Later.
These carburetors can be baffling which is why there are a few SINGLE VW CARBURETOR intake manifold designs available.
But, don’t despair!
There have been many minds dealing with the short comings of these carburetors and all the answers to getting YOUR carburetors running perfect are available.
This forum, Randakk, Steve Saunder, to name just a few, have all dealt with the same issues you are.
Understanding the inner workings of these carburetors is too extensive for one written response. Please familiarize yourself with past posts so you can get a good understanding of how to remove, disassemble, clean, reassemble and adjust these carburetors.
You state you cleaned everything old school with pan of hot 100% lemon juice and now it runs only with the choke on.
First, these bikes don’t have a choke on them. A choke restricts the amount of air flow.
These bikes have an enrichment circuit. Additional fuel will flow into the carburetors/engine.
The ending result is the same, restricting air flow (choke) increases the fuel to air ratio just as increasing the amount of fuel (enrich) will increase the fuel to air ratio.
If the engine will only idle with the enrich lever on, and then runs like a raped ape when given some throttle, most likely the primary jets have blockage.
There are miles of passages in these carburetors, some passing air, some passing fuel, neither will function as designed if there is the smallest of blockage.
The primary jets contribute 20% of the fuel needed to run the engine when the secondary’s come into play, so the primaries must be clean.
Use caution when choosing a cleaner as today’s chemicals may damage yesterday’s rubber materials.
Remove and clean the primary jet, then look through it, you should be able to see daylight. Then replace the jet.
Use caution as these parts are made of soft metals and don’t require the torque of a cylinder head bolt.
When testing the performance of the engine while on the bikes center stand, please resist the urge to whack the throttle open.
Once the engine has reached its normal operating temperature, slowly open the throttle.
As you do this, watch the tachometer and listen to the engine. The rpms should rise up in a relatively smooth rate with no hesitations or flat spots.
It takes practice and a good ear to ‘feel’ the engines rpms.
There are primary and secondary jets, air passages for the float bowl and the needle piston. The needle piston needs to be able to float up and down without hesitation or snag.
There is alot going on inside ONE carburetor, and it all must work correctly or performance suffers. These bikes have FOUR of these carburetors, AND the four need to work as one unit.
Yea, it is complicated and a lot of work to get a bad set to function as they should.
-But, it is worth the time and effort!
It took me two years of spare time to resurrect the bike I bought from the original owner’s son, who kept the bike two years AFTER his Dad had passed away. It was covered, outside and needed some Love.
She has now taken me almost 40,000 miles since I put her on the road again.
After a ride, I glance back at her as I am walking away, I swear I see her smiling.
Good Luck.
Ask questions.
Walk away for a while if you need to.
You WILL solve the problem you are having.
-Ride On
I'm 100% sold on soaking carbs in Pine Sol, melts grease, varnish, corrosion. Is 100% safe for rubber and plastics and you just wash them off with water after the soak. Some dilute it 50/50 but I always use it straight. 24 hours is usually all it takes to clean most banks, if after hosing them off they need more soaking you just dump em back in for a few more hours. The only down sides I have found is that it is a water based cleaner so you may get some slight rusting if left to soak for too long and once all the oil has been stripped off the aluminum they will start corroding too so it's important to blow them completely dry and give them a wipe down with some light oil like WD-40. Any staining of the aluminum will show it's self too. When done I pour it back into the container and will use it several times before I throw the sludge out. If it jells up add a little water and it will thin back out. Wear gloves when working with it because it will dry your hands out bad from stripping the oil out of your skin. Plus it makes the shop smell nice.
FIXED
DON,T trust Clymer Manual it tell you one coil fires 1&3 Cylinder other fires 2&4 WRONG One fires 1&2 other Fires 3&4 only way a found out went to a shop and they had a 86 gl1200 and it was wired the right way change mine and DA DA it run right, Got carbs synce run like a Rape Ape now
Thanks to everone who help me with everthing