GS1000 “Skunk” update/inquiry

[DeegzARG]

Hi folks. It’s been a while since posting anything about the gs1000. 
 

Last week I sent the bike out to a mechanic to check the valve clearances and to install a dyna s ignition system. I elected not to have him tune the carburetor as he said it would be a full days work and I didn’t want to spend too much money at the time. When he did the valve clearance and electronic ignition the bike had k&n pod filters. I got the bike back and it wasn’t running 100%. It was running about 75% of its full potential. Small things like slight popping, idle would hang a little high then come down, if I tried twisting the throttle too fast it would want to stall. Small stuff. 

I thought maybe putting the original air box was the solution. I may have been wrong because the bike seems to be running worse. I didn’t have as much time as I wanted to play around with the carbs but it didn’t sound that great when it started. 

Sorry for the long post but I’ll get to my question….. if the mechanic installed the dyna s ignition with pod filters would me switching back to the original air box throw everything out of wack? Or can I go back and forth between pod filters and original air box without a worry? 

Settings with pod filters: 130 Main Jet, 17.5 Pilot Jet. 2.5 turns out for both air and fuel mixture screw, tried both 4th and 5th clip position on needle and 5th clip position was more responsive  

Settings with Airbox: 95 Main, 17.5Pilot, 7/8 turns out on fuel screw, 1.5turns out air screw, 3rd clip position on needle

Any help is appreciated!!

Best,

Carlos

[Gixer1460]

Did it have pods or are these a new addition? I'll assume the latter - if so, carbs particularly CV types, don't like to play with pods without a fair bit of work - they ain't plug and play! If all he did was what you said and bike runs bad with std airbox and STANDARD jetting then something else is going on!  Possibly he screwed up the valve clearances ? Did the bike have points or electronic ignition with ATU? Has the ATU not been used?

[gs7_11]

Did he fit air corrector jets as well as change the mains, maybe?

You need a baseline...go back to completely standard and start from there. 

[simesman]

It sounds to me like he has good old VM slide carbs with those standard jet sizes.

[DeegzARG]

Thank you guys a ton for the responses. I really appreciate the help!

I tried going back to the stock air box with all the stock jet settings and the bike did not run well at all! I tried playing with the fuel screw and air screw and it didn’t make enough of a difference to have the bike running well. (Settings 95main, 15pilot, 3rd clip position for needle, 7/8 turns out on fuel screw,1.5 turns out for air screw)

The changes I made after trying the factory air box was back to the k&n pod filters, 115main, 17.5pilot, 3rd clip position, 2out fuel screw and 2 out air screw. Ran better than stock but still seemed to be starving for gas especially when you open throttle quickly. 

Next change was k&n pods, 130main, 17.5pilot,4th clip position, 2.5 turns out on fuel screw,2 turns out on air screw, also new spark plugs(b8es)NOW this made all the difference in the world! Bike idles perfectly and I took it for a quick spin and the bike is night and day! I don’t want to jinx anything as I still have to test the bike when it’s cruising and I’d also like to check the spark plugs but the bike is running the best it ever has and pulls so hard now. Almost a completely different bike. 

I’m going to do more testing these couple of days and keep you folks in case anyone needs this information in the future. 
 

Thanks again folks!

 

Carlos
 

 

[DeegzARG]

UPDATE - I had the bike at my work shop for the last couple of days testing it in the area, taking it out for a spin to make sure it ran well. It was running perfectly! I decided I would bring it home and enjoy it this weekend. It was about a 35min ride and half way through the ride the bike just started running like garbage. 

it started idling too low and did not have any power whatsoever. It stalled a couple of times and was running “rough”. I thought maybe the fuel was running low so I pulled over at a gas station and the tank was about 75% full. 

I guess I can pull the carburetor off again and pull it apart to make sure I don’t have any clogged passages. If it’s something to do with the dyna ignition that’s kind of out of my wheelhouse as I don’t feel confident messing around with that. If it was running great for the last two days would the dyna s ignition be a possible issue?

this was so disappointing because I spent so much time last weekend “dialing” it in and it was running incredible. 

any ideas why this may have happened? What would be the next steps you folks would take? Any help is appreciated 

Edited September 6 by DeegzARG

[TonyGee]

check all the connections to the Dyna first.  

[DeegzARG]

One change that I made recently was remove the in line fuel filter. When I got the bike it had been sitting with gas for so long the fuel rusted pin holes through the tank and we repaired the tank the best we could and installed a pingle fuel valve. Removed the vacuum. Could tge fact that i removed the filter be causing the issue? I might pull the carbs apart again and install an in line fuel filter and give that a shot. Hopefully that’s the issue. 

thank you

[Dezza]

Sounds like you have got cack in your carbs. Was the filter mesh still on the Pingel tap? They're easily displaced.

Edited September 6 by Dezza

[Reinhoud]

You need an AFR gauge with O2 sensor, then you can see what you're doing instead of guessing.

Or take it for a dyno run 

[ral]

Dyno set up all day long is the way to go, you won’t regret getting the set up bang on.

[DeegzARG]

Hello everyone

Just wanted to post some information on the progress of the bike. I went back to the stock 15 pilot jet but kept the 130 main because I don’t have a smaller main. When I get a chance I’ll put a 120 main and see how the bike runs. The biggest improvement is putting b6es spark plugs instead of the recommended b8es. The bike has been running fairly well. Only issue I’ve noticed is when I’m cruising over 80km it hesitates a little, it doesn’t want to run smooth. If I twist the throttle all the way then the bikes comes alive and runs smooth. It’s at about 50-75% throttle that the bike runs a little rough. I haven’t been messing around with it too much because it’s so much fun for city riding not so much for highway riding yet. 

Any idea why this may be? Would doing a carb sync help with the issue or should I play around with the fuel screw and air screws?

Thanks again!

Carlos

 

P. S. I’ll definitely look into someone that does dyno tuning. That would be ideal

[Gixer1460]

If the carbs are running rich and the plugs are fouling then a move from 8's to 6's will improve running BUT they are running very hot in comparison so if you get a bit of power and revs on, you could melt the tips off which can damage pistons! The recommended plugs are really the best ones if the tune is corrected, and the best way of doing that is the dyno - costs a bit but its quicker than 'road tuning'.

[gs7_11]

You don't need a dyno tune if the bike is stock, nor hotter plugs.

Just get the carbs properly  sorted out with the stock jets. If it's all standard and not running well there's a FAULT. Fix it.

Your carbs are probably dirty with blocked passageways, or have incorrect float heights, or leaking float valves, or the wrong jets.

You definitely need some sort of fuel filter by the sound of it.

Edit:

There's some good discussion of thorough carb cleaning on this thread:

Carb Clean Tips

Edited October 21 by gs7_11

[DeegzARG]

What’s involved when dyno tuning a vintage motorcycle? I’m a newbie when it comes to this kind of stuff

[Gixer1460]

No different to dyno'ing any other vehicle - best if its actually running, sufficient fuel, oil water etc. Tyres at recommended pressures and everything fixed so that it won't fall off. Obviously for an older vehicle the rpm's won't be as extreme and a good operator should have some reasonable mechanical sympathy - after all if over reving it puts a rod out - he'll have to clean up all the oil and mess LOL!

[DeegzARG]

Appreciate the help Gixer1460!

 

im really debating whether I should go back to the stock air box and get the bike running the best I can that way. I’ve always got the pod filters and can go back to them anytime in the future. 
 

what do you folks prefer? Stock air box or pod filters? The bike is pretty much stock other than the hindle exhaust and the pingle non vacuum fuel valve. 

Edited October 22 by DeegzARG

[TonyGee]

always best to run an airbox as it makes life so much easier, but sometimes on a build theirs no room for one or if its a tuned motor.  if you are after a good standard running bike stick with the airbox. 

[DeegzARG]

Are there any performance benefits when the only change has been a 4-1 exhaust?

i haven’t touched the motor or made any other performance mods

[andyroach]

On 9/20/2024 at 11:20 AM, ral said:

Dyno set up all day long is the way to go, you won’t regret getting the set up bang on.

I agree completely with this. I have had Dyna's on my road bikes and my race bikes and they always ran better than with points.

But, twice I have installed new Dyna systems, complete with coils and leads, and after a short while the ignition black box has died. Once was on a trip to the UK from Spain and I just made it to my mates house as it died. It had been running rough for a few hours, then stalled and it was dead. no spark, nothing.

Dyna replaced them both without any argument. one I had bought when I first started a build that went on for nearly 2 years, but they didn't question it at all when i told them. They just sent me a new one.

Customer service like this is hard to find these days, so I think a quick "HOORAH" is in order.