1981 GS850G, needle jet circuit help? Bike won't rev past 3k or so

[Zaos]

The pod filters are still in the mail, for now I just have a piece of cloth covering the inlets.

Got the bike to rev to 5k, pilot jets were WAY off in the kit. It wanted the idle mixture out 4 turns.

Now right about when it hits 5k it after fires, that's too rich right?

[Brian randell]

Diaphragms check

[QUOTE=Zaos;2595768]Hey everyone! Honestly I've been trying but I can't seem to figure it out. Some background info.

Using an old aftermarket exhaust meant for a gs750 on the gs850

New carb seats
New carb o rings
Adjusted float bowl heights
Installed a rejet kit

I've tried shimming the needle (only one c-clip position) but nothing I've done seems to have changed much. The plugs in the bike currently are BR7ES as it's the closest thing the nearby parts store had. The bike idles and cold starts (with choke) perfectly fine, just no throttle!

The plugs were new (I installed them), but are already gummed up and black. Could it be because they aren't the B8ES that's needed?[/

[Tom R]

So just so I'm on the same page (bottom being the bottom of the needle) is there anything below the c clip? Any washers or spacers? And above it go the adjusted spacers right?

The kit said to put it below the c clip, and made no mention of removing the original spacer. Looking back your way makes way more sense.

Below the clip is a thin metal washer and a spring. Correct, you replace the plastic washer above the clip with something thinner... the spring and washer below the clip stay in their original position.... this pushes the needle up and allows more fuel. As others have stated, not much point in trying to tune without the filters installed. Which filters did you order?

[rphillips]

Nope, not the plugs, one heat range, especially with NGK, will never ever be noticeable. If I remember correctly, one heat range from NGK equals 3 heat ranges from AC, Champion, or Autolite, thus one range for the NGK equals 1/3 of one heat range for the others. & you will never know the difference in one heat range, as far as how the eng runs. Wish I could help, & good luck.

[Zaos]

Hey everyone thanks for the awesome tips honestly, HUGE help!

I went through the carbs one more time to clean them up and they all looked fine. Rechecked the float tolerance and they were ok.

Amazingly, I replaced the BR7ES with some (as required) BR8ES plugs and the bike actually revs like hell now! I wouldn't have thought that would make a difference, but here we are!

Theres a flat spot around 4.5-5.5k and the bike backfires a bit when revving it up high, but at least it gets there!

I ordered this set exactly

https://www.ebay.com/itm/191523200960

They are cheap, and I figure any leaks that they have between housing and filter I can fill with some silicone?

Once I put the filters on (coming apr 8th) I'll keep everyone posted in case the thread helps someone else down the road.

A good thing to note is that the kit was explicitly wrong then with where to put the shims.

[Tom R]

Those filters are just steel mesh....I guess they’ll keep bugs out. Those filters have been known to cause headaches because that inner ridge blocks an air jet or two; so check that. I’ve neverUsed them, but a lot of people have and usually recommend against them. APE Racing pods are lower priced than the k&ns, but work well.
against those, I’ve

[rphillips]

Very embarrassing !! I owe you an apology. Never meant to mislead anyone. That being said, I've never seen one heat range make any noticeable difference. I'd have thought you could have put any, available heat range in there & it would have not made the difference you're seeing. Glad you got it going & hopefully the filters will work well for you also. Looks like you're getting there. Keep it up.

[Steve]

I ordered this set exactly
https://www.ebay.com/itm/191523200960

May I make a suggestion?

While you are waiting for those "filters", fold a shop rag in half, drape it over the carb intakes. Use band clamps or zip-ties on the outer carbs to hold the rag in place. Proceed with all your jetting and tuning.

When the "filters" get there, toss them in the trash can. Your shop rag will provide better filtration and predictability for tuning.

.

[Grimly]

It most certainly wasn't the move of one heat range that made a difference - more likely the old plugs were fouled, defective, or counterfeit.
I've had the exact same experience of an engine burst into life with new plugs, where with the old plugs it was a pig to start, even though they looked fine.

[Big T]

When the "filters" get there, toss them in the trash can. Your shop rag will provide better filtration and predictability for tuning.

.

Couldn't agree more. Being cheap doesn't agree with CV carbs. Your bike will never run well with those.

[bwringer]

They are cheap, and I figure any leaks that they have between housing and filter I can fill with some silicone?

Nope. RTV silicone will deteriorate in the presence of gasoline vapor. Even the intake side gets enough vapor to make RTV fall apart.

[Rob S.]

APE pods look and perform comparable to K&N, and are half the cost (still about $75).

[Zaos]

So the filters came in, and the bike revs and drives just fine. I dont notice any hesitation or backfiring at all while test driving it.

Honestly I just wanted some cheap filters to test the bike, I still have some work before it's totally done.

Could you guys link the ape pods? Cant really seem to find em, though I might just be blind!

Unrelated, but does anyone know where to get a vacuum hose from petcock to carb? All the sizes I'm finding have way too big of an outer diameter to fit.

[chuck hahn]

single layer of red shop rag is sufficient..two may be too thick and actually induce a bit of choke. I use 1 layer when tuning with the airbox off..basically youre tricking te carb to think its getting the engineered in amount of required...let me say that again... REQUIRED restriction to operate correctly.

[cowboyup3371]

Vacuum and Fuel are best bought from the dealer