Rejetting 82 GS1100GKZ- Jet sizing

[POE_333]

Hey guys. I just got my Dynojet kit in today. All is done except the main jets. The instructions say for a stock exhaust, use DS165 main jets. For aftermarket/mod'd exhaust, use DS170 main jets. When I went to pull the stock jets, I found that they are 170's. I am considering putting the DS165's in like the manual says, but the previous owner had installed 170's.. HMMMM... ( main jets are at the rear of the carbs on the filter side correct? Not under the float bowls right?) What do ya'll think?

By the way, I'm taking pics for demonstration if anyone thinks they might help for me to post them. I've been on a first name basis with the carb engineer from Dynojet for a while now.. LMFAO!

I also got my new tires in today! YIPPEEEE!!!!! Some pretty aggressive tires and hella cheap too! ( I got a mean discount from Bike Bandit for tickin me off so bad! lol)

Anyway, What do ya'll think about me taking the main jets back down to 165's like the manual? Or should I leave the 170's that are currently in there?

 

[Nessism]

The main jets are in the float bowl, those jets you are looking at are the air jets.

 

[POE_333]

Ok, so the instructions on the Dynojet kit are misprinted then? Or they sent me all air jets? They are calling for me to change the Main Jets, yet the jets I'm lookin at in the kit are the same size as the Air Jets. The jets in the float bowl are 107's and are a lot more robust looking. The kit is a 3103 that I ordered as per the advice I got from .. I think you.. lol.. Anyway. So I should change the 107's to 165's? Leaving the 170's Air Jets alone right? There is a DJ114 and a DJ118 set also included in the kit, but the instructions say those are for a stock air box. And they are all the same size form factor as well. I just don't want to have to do it twice. I'd rather look like a fool by asking then BE a fool for not asking.. lol

 

[POE_333]

Ok.. Now I feel dumb! the threads are different between the jets. SOOO.. I've got the 165's installed now. Only problem is now, that the bike revs to about 2500 with no choke.. Ideas?

 

[Nessism]

Ok.. Now I feel dumb! the threads are different between the jets. SOOO.. I've got the 165's installed now. Only problem is now, that the bike revs to about 2500 with no choke.. Ideas?

Sounds like an air leak. Did you replace the intake boot O-rings?

 

[duaneage]

throttle cable too tight? it happens. Should be 1 /16" of play before the cable tightens up

 

[POE_333]

Good call Duane! And yes Ed, I had replaced the o-rings last time I dug into the carbs. Next order of business is tuning.. God help me! lol. I'm thinking I need to tighten the air mixture screws down a touch bc when cold, it takes about 3-5 minutes to crank the bike. When I looked at one of the plugs, it was wet with gas. Or is there something else I need to check on first?

 

[doctorgonzo]

Have you adjusted the valves? Do you have good voltage at your coils? Are you starting it by NOT turning the throttle just pulling full choke? Where did you set the pilot screws initially, about 2.5 turns (I think that's what the dynojet kit recommends)?

 

[POE_333]

I haven't changed anything but the jet kit so far. I'm trying to make as few changes as possible before taking each additional step. The voltage is a lil low (12ish) at each coil but from what I hear should be fine. I have to tug the throttle a few times just a bit with about 1/4 choke on before it finally comes to life. And the screws are set at 2.5 turns out as instructed by Dynojet. Just making sure my dumb arse isn't missin anything too obvious.. lol

 

[doctorgonzo]

For a cold motor try starting it by putting petcock on prime for about 3 minutes, not giving it any throttle, and using full choke. I think that is the "standard" way to start. If you've never adjusted the valves, pretty good chance hard starting is related to that. Should be next on your list, getting the valvews adjusted. Carb tuning will be an exercise in futility until the valves are properly adjusted.

 

[POE_333]

OK I'm looking into the posting on valve adj now. Thanks!

 

[POE_333]

One question though.. What does the Prime position actually do anyway? Does it allow the vaccume from the carbs to pump the lil diaphram?

 

[doctorgonzo]

One question though.. What does the Prime position actually do anyway? Does it allow the vaccume from the carbs to pump the lil diaphram?

In the "On" position the vacuum from the motor running opens the petcock and lets gas flow. So in the "On" position when the motor isn't running no gas will flow. If you ran the bike 3 hours ago, or even 1 day ago, the carb bowls are probably full and it won't matter. If the bike hasn't been started in a couple of days there may not be enough gas in the bowls to start the bike. The "Pri" position lets gas flow with no vacuum from the motor, so you are "priming" the carb bowls, filling them up. DO NOT leave it in the prime position because if you do you may come back tomorrow to a huge puddle of gas under the bike.

 

[POE_333]

OKIE DOKIE.. I got it now. Thanks for the clarification. I never understood what that all meant lol. I sure hope ya'll don't mind my ignorant questions. But if the bike had run pretty well before I changed the air cleaner to pods and rejetted the carbs, I might still need to adjust the valves just for that reason? Like I said, forgive my ignorant questioning, but I like to know WHY and not just HOW so that next time I might not have to ask so many stupid questions lol.

 

[POE_333]

Time for more dumb questions. To avoid my own confusion. I might still have to adjust the valves if my compression is good on every cyl? (approx 122psi- 4 psi total variance)

 

[doctorgonzo]

Time for more dumb questions. To avoid my own confusion. I might still have to adjust the valves if my compression is good on every cyl? (approx 122psi- 4 psi total variance)

Yes, per the manual (gosh trying to remember) every 4000 miles.. 6000 miles.. something in that ball park for valve adjustment. What happens is the valve is pounding into the valve seat, Over time it sinks deeper and deeper into that seat (we're talking hundredths of mm here). At the other end of the valve is the stem. Sitting on top of the stem is a shim. As the cam shaft lobe rotates it pushes against the shim on top of the stem and thus pushes the valve away from the seat at the other end. This is what opens the valve. Ok, now what is going to happen as the valve head wears deeper into the seat is that the clearance between the shim and the cam lobe gets smaller and smaller. A point will come where that clearance is zero. Then (whew, long winded I know, but trying to explain fully) the valve can't close all the way. The result is hard starting and poor performance. The even larger problem is that the valve dissapates it's heat by contacting the head. Once the valve no longer contacts the head when fully closed it can't dissapate that heat resulting in a "burnt" valve (and a head rebuild).

 

[Larry D]

Yes, per the manual (gosh trying to remember) every 4000 miles.. 6000 miles.. something in that ball park for valve adjustment. What happens is the valve is pounding into the valve seat, Over time it sinks deeper and deeper into that seat (we're talking hundredths of mm here). At the other end of the valve is the stem. Sitting on top of the stem is a shim. As the cam shaft lobe rotates it pushes against the shim on top of the stem and thus pushes the valve away from the seat at the other end. This is what opens the valve. Ok, now what is going to happen as the valve head wears deeper into the seat is that the clearance between the shim and the cam lobe gets smaller and smaller. A point will come where that clearance is zero. Then (whew, long winded I know, but trying to explain fully) the valve can't close all the way. The result is hard starting and poor performance. The even larger problem is that the valve dissapates it's heat by contacting the head. Once the valve no longer contacts the head when fully closed it can't dissapate that heat resulting in a "burnt" valve (and a head rebuild).

Trust him.......he's a doctor. I love those Dr. Pepper commercials.

Regardless of what mods are done, the valves are a regular maintenence item and must be checked/adjusted every 4000 miles or so.

 

[doctorgonzo]

Not even REALLY a doctor (heh), only have a Masters degree. I sang in a punk band for years and years here in Tennessee called "Doctor Gonzo" (I'm a Hunter S Thompson fan), and it's also my stage name as the announcer for the Nashville women's roller derby team, and as an MC for burlesque shows.

 

[POE_333]

Well alright then! Heck that's more then I'd expected to get.. Again Thanks! Working on cars for a few years I do already know the basics, but hey, I'll take all information I can GET! lol.. Only thing that you didn't clarify for my ignorance is that, on bikes, even with great compression (only 28k miles on the bike- it had better be! lol) the valves might be out of tolerance (stuck open due to lack of clearance) to cause such a problem as I am experiencing? I know that when the clearance is nil and the valve stem touches the cam, it can leave the valve open which causes a loss in compression (just like bad rings, ect) Please understand that I'm in NO way challenging ya'lls expertise on this matter, I'm only trying to compare what I know with what I don't and to convey this to those of you "in the know" so that I can perhaps narrow down the gremlins to look for.

 

[POE_333]

Alrighty then, I'll just shut up with the questions until I've done what I'm told.. (yes Dad).. LMAO.. Also, I'll assume that I'm going to need a gasket for the valve cover for this huh? I think I'm gonna buy the whole gasket kit as it'll be cheaper then buying the 5 gaskets I know I need already individually. DAYUM this is gettin expensive! lol