Looking for guidance

[DrDankNuggs]

I recently purchased a 82 gd650gl, It ran on starting fluid and that was enough for me to pull the trigger. I popped the carbs off they were not too bad clog in main jet and needle get. threw them in the ultrasonic and cleaned as shown in the guide here. popped them back on added fresh fuel but still have the same issue will run on fluid but won't fire with the fuel in the bowls.
I'm a small engine mechanic but new to motorcycles, Ive got two questions will the engine not run with the air box off? and does anyone have any suggestions where I should look next? compression valves ect. don't want to waste time poking around in the wrong area so any help would be appreciated.

 

[posplayr]

You can put a rag across the inlets of the carbs to create some vacuum on the inside of the carbs.

 

[DrDankNuggs]

You can put a rag across the inlets of the carbs to create some vacuum on the inside of the carbs.

Ok so does that mean that it needs the air box hooked up to run at all? I only didn't install it because I'm waiting on new intake o-rings, figured it would run without the box not perfect but I could at least get her to run a little.

 

[Rich82GS750TZ]

Just to expand on what pos wrote, Yes, the bike should run with nothing behind the carbs, but not well, because it’s just too much air. The rag will get you closer to a proper air/fuel mix. By “cleaned as shown in the guide here”, do you mean that the carbs were completely taken apart and all parts dipped in carb dip and all orings replaced?

Valve clearance should be checked/adjusted before any carb tuning can be done.

Before any of that, you could check if each cylinder at least has compression by removing spark plugs, put thumb over the hole and manually advance the crank (with a wrench on the big nut under the ignition cover, turn clockwise as looking at the ignition, never counterclockwise). Should feel suction and blowing out though the plug hole where your thumb is as you turn the crank. An extra pair of hands helps.

Others will have to instruct on properly checking compression, special equipment needed. Or use the search. Use advanced, search titles only.

 

[posplayr]

Ok so does that mean that it needs the air box hooked up to run at all? I only didn't install it because I'm waiting on new intake o-rings, figured it would run without the box not perfect but I could at least get her to run a little.

I assume since you posted your question becuase you don't want to wrestle that airbox on "just to see". If it was easy, you would have just done it.

Apparently it is not running; so the path of least resistance is the cloth.


As Rich clarifies, you will get a long list of recommendations from everybody else including the top 10 newbee mistakes.

 

[Rich82GS750TZ]

Top 10 Newbie Mistakes

 

[posplayr]

top 10 newbie mistakes

4) trying to run the bike without the airbox...or installing pods w/o rejetting. The air/fuel ratio will be drastically lean, which will not only cause running problems, but likely damage the engine by causing it to run hot. Installing a free flowing exhaust will likewise change the jetting requirements, but not as drastically as pods.
.

eom......................

 

[DrDankNuggs]

Definitely a newbie here so guess not surprising I made that mistake! I'm a power equipment mechanic I work on Briggs Kohler Honda Kawi, engines daily I can usually test run without a/f, but always make adjustment with a/f.

Since my first post I broke out the compression tester, found all 4 are within 7 psi ranging from 95-102 was relieved to see that! I took the carbs back out and am going to throw the air box back in then give it another shot.

I wanted to make sure I could get the engine running before investing in valve shims ect. hoping after I re-installed everything she's able to run on her one, then I'll check valve lash and order shims and whatnot then onto the fine tuning.

I appreciate all the input and help, I would definitely be cussing louder without it!

 

[Steve]

All the suggestions so far are good, but as usual, there is a bit more behind them.

1. Your bike should start and at least idle without the airbox. Posplayr's suggestion of a rag over the intakes is good. I have not figured out whether it restricts a bit of air or merely smoothes out the airflow over the jets, but the bottom line is that it works. It works well enough that you can actually ride around the block, but it's NOT good enough to do any jetting checks. Without the rag or the airbox, you can start the engine, but if you blip the throttle, it will stall.

2. Not sure what guide you read that suggests using an ultrasonic cleaner for the carbs. An ultrasonic cleaner might work in some cases, but when you are not sure about the carbs (especially when you saw that they had to use starting fluid), it's best to do them properly. That includes blowing them apart to about 250 individual pieces, then soaking the jets, the carb bodies and the float bowls in "dip". The favorite "dip" is Berryman's Carb Cleaner Dip, which you might have at work. The trick is to ignore the instructions on the can. The last time I read them, they said to dip the carbs for "15 to 30 minutes". Those instructions were probably written when the contents of the can could actually do the job in that amount of time, but the safety weenies have taken over and you now need to soak the carbs for 15 to 30 HOURS. Follow that with a blast of carb cleaner spray through the passages in the body, then blow it all with compressed air before re-assembly.

3. Even if your carbs are set up PERFECTLY, if your valves are not in adjustment, the engine will not start.

The clearance does change, and it always gets tighter. Eventually, there is NO clearance, which will soon lead to burning valves. Hard starting, especially when cold, is a classic sign of tight valves. Check them NOW. Because you have <some> compression and it's rather even, I would not suspect any burnt valves, but the numbers are a bit low. On a cold engine that has not been run for a while, they are not too bad.

4. With adjusted valves and clean carbs, the bike should start. Then you can check the charging system, which is another typical problem area. Easy enough to get that squared away.

5. Don't forget tires and brakes. Check the date code on the tires.
What color is the brake fluid in the reservoir? "Clear" is perfect. "Ginger ale" is acceptable. "Root beer" is past time to change.

.

 

[DrDankNuggs]

I did the main body of the carbs an jets in the ultra sonic (with carb solution) because thats what I use at work on a daily basis so I figured it would be ok.
I reinstalled everything with the air box this time it did at least fired on its own, didn't stay running but its a start. I looked into sourcing valve shims locally with no luck so I plan on measuring the gap and determining what size shims I need tomorrow. I also checked spark with proper tester its there but not quite as bright as I would have liked but one thing at a time will post results of valves tomorrow. Hoping for the best

 

[Guest]

Did you hold the throttle open for your compression test? Those numbers sound low.

 

[DrDankNuggs]

Took a little longer than expected sometimes life gets in the way, so to answer compression question no I didn't and I should know better I will retest and update with new numbers, but my valve numbers are.....
1: IN: .006/.152mm EX: .002/.051mm
2: IN: .0025/.064mm EX: .003/.076mm
3: IN: .002/.051mm EX .003/.076mm
4: IN .0025/.064mm EX .004/.102mm

Looks like some are ok and some are in need of new shims but I'm no pro so what do you guys think?

 

[Big T]

#1 intake is too wide. Go 2 steps on shim, or an X shim
Did you get Steve's spreadsheet?

 

[DrDankNuggs]

Not yet but I emailed him a few hours ago. I got my o-rings from cycleorings today so I'm going to redo the carb for the second time dipping this time instead of ultra sonic. I woulda figured sonic woulda been better than a dip but idk, waiting for a vc gasket & soon to be shims might as well do the carb again while im waiting.