Performance Problems continue, new parts didn't fix anything

[dwitgoldwing]

Well, fine GL1200 people, I'm here to say that my new Carb Slide diaphragms,
and reinstalling the OEM carbs tops did absolutely nothing to improve my
performance issues.

I would like to know if we can come up with a clear, concise, protocol for checking
ALL the areas of performance on our bikes and get these things running right. It would be good to make a very detailed checklist from A to Z to get the engines running properly

If you watch most of the Youtube videos of GL1200 bikes, none of them seem to run very well. So I'm hoping we can get these machines running as well as possible.

Since so many people fuss at me about my top speed issues, (I like to ride fast
sometimes), I will just say that my '86 GL1200 runs like absolute crap
at rpms above 4500 when in 4th and 5th gear, (and riding "aggressively").
Yes, if I ride like an old man on Sunday and just putt around and don't go
above 50 mph, I guess I could put up with the crappy performance of my 1200.

The thing is, my 1200 is what I like ride to work and I want the thing to run RIGHT at all speeds. I have way too much time, money, (over $14000 and counting), and emotions, (lost a marriage in part thanks to my GL obsession), to give up now. I do sense an under-current of "just get a different bike" from most people today, (not GL1200 riders), because we live in a "get a new one" society. I really am linked to my 1200 like NO OTHER BIKE I've ever owned. I have not had this much connection with my GL1800, Ninja 250, CB350, dirtbikes, four-wheeler, Odyssey, snowmobile, or even my trusty Jetta TDI diesel, (which I love). Most mechanics in the area aren't much help when it comes to getting my 1200 to perform correctly, (they don't really want to mess with it), so I do all my own work, (plus I can't afford mechanic's bills).

A bit of history about my bike may help with trying to find some solutions.
I bought the wrecked bike off ebay about 6 years ago. The guy I bought it from
bought it from another fellow who "flipped" it, and that's about all I know what happened to the bike. The engine appeared to not be damaged, and I have put on 17000 miles since I bought it, (I know, that's not very many miles - trying to change that). Two years ago, I took my bike into my friendly mechanic who has a LOT of experience with 1200s and he changed the belts, synched the carbs, checked over the engine and he thought it was running fine, (but never did take it out on the interstate
and test it under full-throttle).
Let me back up and say, that over the years I cleaned out/coated the fuel tank, changed all the lines, hoses, etc. have tried several different spark plugs, changed coils, changed carbs, cleaned carbs 7 times, completely rebuilt carbs twice, adjusted floats to within .003", adjusted butterflies to identical settings with gauge pin, synched carbs MULTIPLE times, (with mercury sticks and dial guages, changed intake "O"-rings each time, installed brand new regulator, gone through 3 brand-new AGM batteries.
Friday night I installed new Carb slide diaphrams, and put original carb tops back on, (aftermarket chrome were suspect), and carefully synched the carbs, bike still runs like crap above 4500 under load in 4th and 5th gear. It's actually worse with the new
diaphragms, so I wasted $167.

Are there other adjustments to the bike that I'm not aware of? Cylinder 2 is quite jittery
when I'm doing the carb synch and I'm wondering if there is some kind of hidden damage. My mechanic friend didn't find anything wrong with the engine but at the time
he was loaded with work so who knows how much attention my bike really got.
I did a compression test last year and shared the results with our moderator, Vic, and it appears that the compression is OK. I guess I need to do a leak-down test, and
several other tests to see what's going on. I'm wondering about valve timing, and other things. Does the little valve body under the carbs have much to do with performance? How do you know for sure if it's carbs or timing, or ?

Is there a diagnostic machine that we can hook up to our 1200s that would tell us what is wrong with performance? I am near a company that sells bike dynos and am going to schedule a time to dyno my bike.

I have a friend in Michigan who has an '85 GL1200 and I want to help him get his running well so we can have a "Wild Hogs" type ride next year with our other 2 friends from high school. I would like to make it a priority to get all our 1200s running great so they don't end up in the junkyard or on ebay for parts. I mean, come on, there are guys riding '47 Harleys and still going strong, you would think we could keep these 1200s going for a long time, (granted the 1200 is a WHOLE lot more complicated bike)...

O.K. hopefully I will get some responses, that are actually helpful.
Thanks, in advance,
Don W., Winchester, KY

[Guest]

I am going to toss out a guess and say maybe it is your shift sensor, based on the fact that it runs poorly only in fourth or fifth gear.

Have a look at this topic for more information:

http://www.gl1200goldwings.com/viewtopic...h+5th+gear

[admin]

First, before we can do anything very productive at helping you we need a proper compression test reading of all the cylinders, then you need to do a complete check of the ignition according to the manual and we need a plug reading. Air filter and fuel filter must be clean and gasoline should be fresh. Sorry to put you through all this but anything less would be just guessing at what your bike's problems and I'm sure that some of the experts here will have more for you to check but what I've laid out is basic but necessary diagnostic steps to help solve a bike's running problems. Next we need a more accurate description than "runs like crap." Gets up to 4000 RPM smoothly then sputters and stalls indicates a possible fuel flow problem which would prompt a fuel pump test. "Run like crap" tells me nothing. Gets to 3500 and starts to backfire indicates possible ignition problems, resistors, plugs and coils need further testing. And so on, if you really want to diagnose the problems with your bike. And the biggest thing you need for diagnosing your bike is focus. Jumping from here to there on a whim is just a waste of time and money, you need to verify each system on your bike until the process of elimination has focused on the root cause of the trouble. Sometimes online forums can mix a guy up terribly because each man has a different solution but you just need to focus on one system at a time, fully and completely, until the problem gets resolved and you need to check and doublecheck all your results along the way. Obviously the problem is there, you have to find it by process of elimination rather than guesswork so choose your strategy and we'll work along with you, jump all over the place and I'm out because I know it will get you nowhere fast.


TIP: The ECU is one of the very most reliable components on a Gold Wing GL1200.. You can try another one to eliminate it but I have never never , ever seen or heard of one going bad, but I don't know everything.

[Guest]

Vic, I reread the post I referenced then changed my answer!

[admin]

Very good JettDirect. A bad shift sensor would lower performance somewhat but it would not keep a GL1200 from performing well at full throttle, high RPM as what it does is allow ignition advance timing to come on during cruise and light throttle situations in 4th and 5th gears.

[dwitgoldwing]

So shall I put in a new set of plugs and then ride the bike for about 500 miles to get
a good read on the plugs? I have tried to be methodical about my "fixes" rather than
just buy something new to try. I usually make one change and then
see how it affects the engine performance.
Many of the tests in the manual have been inconclusive. as to what the problem is.
The bike "should" be running fine, but it isn't.
The engine never has seemed to be pulling together evenly when under load and ridden
hard, (especially above 4000 - 4500 rpm). It is much more noticeable in 4th and 5th gear, but the lack of full power issue is there in the lower gears as well.


I did the brand new air filter, fuel filter, fuel pump, spark plug thing last year when I did the
compression test.

See attached compression test results.

I've even given thought to buying a different engine altogether because I'm not sure
about what hidden damage there was when a previous owner flipped the bike. I know the fairing and shelter and every piece of plastic was unusable, (but oddly enough the crash bars are original). I plan on working through this thing, but frankly each test says that everything is within specs. I guess I really need to get this thing on a dyno
to show the results.

Hmmmm.

[admin]

Sounds to me like you want to compare last year's test results with this years problems and diagnostics just don't work well in that type of environment. Without having your bike in front of me I cannot tell you what is wrong with it. You need to start with a clean slate and by process of elimination form conclusive results which indicate that each system is good or bad or marginal. I just can't see any other way to help you solve the drivability problem with your bike unless you just want me to randomly guess at what the problem is and to do so is just like saying that the problem is carbs, ignition, compression, plugged exhaust, plugged air filter, seized brakes or any number of problems.

Start here, take the bike for a ride down a lonely country road, get the engine hot and then run the bike up to where the problems are occuring then pull the clutch in and hit the kill switch simultaneously to stop the engine and let the bike coast to a stop then wait a few minutes for the heads to cool down and remove the spark plugs so we can get a reading, bring a camera to shoot them if you can't read them properly, but in either case give an accurate description of the working side of the spark plug to post here. Don't forget to number each plug as it comes out. Also describe how the engine ran, as accurately as possible, sparing no detail, just before you killed it. This will be step one.

[dwitgoldwing]

O.K. will do that procedure this weekend, (supposed to be 67°).

Let me ask you, as far as synchronization goes, would it just be best to
sync the throttle plates with a gauge pin, (or feeler gauge), and forget the
vacuum sync procedure altogether? My gauges jump around so much,
it's almost impossible to get a very accurate reading at idle. I made new
brass adapters on my lathe with the smallest drill bit I could use, (I'm talking
TINY), and yet the gauges still jump a bit.

I think I'm going to yank my intakes off and reset the butterflies
to match.

Let me know what you think.
Don W.

[admin]

The gauges will work far better than feeler gauges. To restrict the vacuum further just go to a pet/fish store and buy some restrictors to place on your hoses then you can get better readings.

Make certain that you use new o-rings on the intakes and check the intakes for leaks at all joints with raw propane from a an unlit torch, do it outside on a calm day. If there is a leak the propane will find it and cause a change in idle speed. This is critical.

[Ed Z]

To be of much help I need much more detail on the problem... You don't mention anything about the acual indications you hear, feel, see above 4000 RPM... There are so many areas to check into and more info is needed to narrow the field... You made mention of the "little valve body under the carbs"... Yes indeed the reed valves are important... Next time you have the carbs off, be sure to clean and inspect each of the 4... Also insure that the lines to each manifold is clean and clear of gunk... Do use new O-rings on each end of these hoses...

One thing to check on with the carbs is to insure each of the slide valves moves freely within each carb... They should drop like a rock down each bore... If any of them don't then some polishing the bores with 800 grit sand paper may be in order...

Without more detail though it is near impossible to sugest what direction to look in... Heck it could be as simple as a gas cap vent issue... Run it down to 1/2 tank or less and just twist the cap so it is just sitting over the opening and give the bike a short hammering....

[Tropicalsuns]

My gauges jump around so much,
it's almost impossible to get a very accurate reading at idle.

I have learned quite a bit with the guidance of this board. I also just spent about thirty man hours chasing drive-ability problems that turned out to be something simple. I changed out spark plugs that were new 50 miles ago and solved my problem. (I did not do this as I thought it could not be it as they were new) That's why Vic says focus one system at a time.

While I certainly can sympathize with your situation it sure seems to me that your not pulling on all four cylinders and your sync is way off.

I also know what you have invested in your bike.

Ditch the sync tool you have and buy this:

<!-- m --><a class="postlink" href="http://www.carbtune.com/">http://www.carbtune.com/</a><!-- m -->

This tool is extremely accurate and makes syncing a snap.

BTW both my 1200's run like new.....actually sold the one I was trying to fix yesterday.

[neoracer]

i have to agree with Tropicalsuns that you should invest in the Morgan Carbtune, i tried to do the sync with other dial type gauges and it just didn't work

the morgan is especially good when u do the "high" idle check at 3000 or in your case u could do it higher,(cringe)

what seemed close at idle was really apparently "off" at 3300 (cruise rpm's) plus it leads you to suspect a problem with the cylinder and/or carb on the one that just doesn't come in right

start from there and i feel it wil lead ya to finding and tracking down a persistent problem

they aren't cheap but than again if you spend $110 dollars and it prevents you from wasting another 500 in useless parts,was the price too high?

dragraced for years and watched people spend alot of money in parts and ended up selling them cheap when they thought they were no good.......problem was only that they didn't know how the do it a 10.00 on an 70 deg,40% humidity day is not the same as a 10.00 on an 85 deg , 80% humidity day but because they only went 10.30 on the hot day they thought the parts were junk,, :d :d bought quite a few of those junk parts from them,while they were going broke trying to go fast

you'll get it right,just dont waste your time and money doing it

[dwitgoldwing]

Thanks for the info on the Carbtune, I will order one right away.
Marty, did you go with a different spark plug than stock to fix your problem?
I've tried different plugs over the last 5 years and it never seemed to make a difference.

I will try to get the sparkplug readings done this weekend.

I'm putting in heated seats right now and can't wait to make my winter riding more comfortable, (heated grips are next).

Thanks,
Don W.

[SIR tricky]

I do find this incredulous but something to keep in mind.

The recommended replacement of the Spark plugs is 4000 miles.

I usually can get a year out of the NGK's and then performance starts to be affected but it is something I replace EVERY spring.

My bike will misfire on start up if the plugs are not changed prior to about 6000 miles

[Guest]

Don,

Do you have automotive alternater conversion on you bike. If not you maybe exceeding the wattage output of the stock stator and you will most likely destroy it.

Sorry off topic