Tuning after a Dynojet Stage 3 kit

[gmoore1785]

I finally got the stage 3 jet kit on the 1982 GS650G. I'm running pods with stock exhaust (4 into 2). After getting the kit together it fired right up. I had one little pop through the carbs at first, no more after that. I noticed a very faint steam/smoke from the engine after letting it idle for about 5 minutes. It appears to get hot a lot faster than it used to. I pulled plugs 1 & 2 after a quick test ride and noticed they were a little white on the tips.

http://imgur.com/J8GlDXk

http://imgur.com/49RUKFW

These plugs were brand new before the test ride. I got it up to 4th gear maybe about 55mph.

I put the air screws at 2.5 turns out and put the needles on the 3rd clip setting. It ran better than it ever has before but I wasn't sure if maybe it was too hot. Any insight on the matter would be appreciated. After 3 months of tinkering I wouldn't have gotten it to this point if it wasn't for this forum.

-G

 

[kdo58]

on my 850 i ran stock pilots and turned the screws out 4.5

 

[gmoore1785]

So turning them out another turn will lean it out even with the stage 3 kit?

 

[tom203]

Hopefully out will enrich , go here do some reading courtesy of Basscliff's . You do not want this thing running too lean

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

 

[gmoore1785]

I ended up at 4 turns out on the mixture screws. I don't have an RPM gauge so this has been tricky but starting at the top end I have two options for main jets so I went with the smaller of the two in the Dyno kit (155). Now for the midrange, again I just stayed with the Dyno setting on the 3rd clip. Low end: float height is at stock setting.

With this kit the bike starts right up with a very little amount of choke needed. Taking off from a stopped position is like day and night compared to what it used to be like with no Dyno and just 127.5 mains instead of stock 110's. I took a look at the plugs last night and they were closer to the tan color I want but still were hot as hell with a little white. So maybe another half turn for the mixture screws. But as far as I can tell it's running well.

 

[almarconi]

Didn't see it mentioned but did you check your petcock to make sure you are getting enough fuel flow? If it has a fuel filter I would get rid of it.
For your engine, I would use the dynojet 160 with stock exhaust and 165 with an aftermarket one. The 155's are probably a better choice at higher
altitudes, you don't say where you are located. 4-1/2 turns out from lightly seated should be about right.

 

[gmoore1785]

I rebuilt the petcock this year, but one of the 4 screws on the square shaped pieces is stripped and continues to turn. I put some stuff on it to stiffen it up but its stripped. Will that mess up fuel flow? It looks like the vac tube connects to that part.

To follow up about how it just rode: I just took the bike out for a ride on the highway. It was riding well at first, after about 10 minutes or less it would be very hesitant when taking off from a stop. Eventually it would just die at every stop light when I went to take off from 1st. I pulled the choke out and got it into 2nd gear and it went through the gears sort of alright enough to get the bike to my brother's house which was near.

I'm in Peoria, Illinois. Again, 155 mains, 3rd clip position, foam pod filters, stock exhast, air screw 4 turns out (I tried 4.5 turns out and it wouldn't start).

Here are my plugs after this last ride:
http://imgur.com/GE99PjV
http://imgur.com/tQhdbrW
http://imgur.com/ypqVB2C <<<<this one is number 4 on the bikes right side, its pretty white looking
http://imgur.com/2lwGzSp

If anyone has anymore input I would appreciate it. I know I may troubleshoot the 160 mains that came with the dyno. The bikes starts with no choke basically.
Hopefully this post isn't buried, I know someone on here has been through this similar problem.

 

[Steve]

Pictures of the plugs are pointless unless you also describe what was happening two seconds before the engine was shut off. :-k
The proper way to check the plugs (also called "plug chops") is to HOLD a particular throttle opening, which depends on which circuit you are checking. For the pilot circuit hold about 1/8 to 1/4 throttle (less is better) for about a minute, if you can. Hold the throttle as steady as you can, do not shift. When you are ready to check the plugs, pull the clutch, hit the kill switch, coast to a safe place to pull the plugs. To check the needle (mid-range), hold about 1/2 throttle for as long as you can. The bike will try to run away with you, so find a hill and use a higher gear. You are checking throttle opening, not engine speed. To check the main jet, use a higher gear (3rd? 4th?) and that same hill. Hold the throttle wide open. When you get near the redline, use the same "clutch, kill, coast" routine and check the plugs. If you did a full-throttle run then putted around a corner to find a safe spot, you are checking the pilot circuit, not the mains, even though you just did a full-throttle run. The LAST thing you did was putt around the corner, so that is what shows on the plugs.

Again, 155 mains, 3rd clip position, foam pod filters, stock exhast, air screw 4 turns out (I tried 4.5 turns out and it wouldn't start).

First of all, you don't have "air screws". Suzuki calls them "pilot screws", they can also be called "mixture screws". Turning them OUT adds a pre-mixed mixture to the general air flow (making it richer), turning them IN will reduce the mixture (making it leaner).

I find the choices here interesting. Stock mains are Mikuni 110. For a pipe, you would add 3-5 sizes, depending on how much the pipe flows. For pods, add another 4-6 sizes, so your pods and a pipe should add 7-11 sizes to the main. 10 sizes up would be a Mikuni 135. Dynojet numbers their jets a bit differently, their equivalent is a 144. What jets were provided with your kit? It appears that the 155s were the smaller ones. (I was not aware that Dynojet used anything but even numbers. ) They are equivalent to Mikuni 145, which might be too big.

One other thing that might need to be meintioned: check your float heights. It's actually better to check the actual fuel level, but you can start with the float height. It is common to measure from the wrong part of the float, which will make about a 5mm difference. Some of the conflicting results you are getting might be due to that. The proper place to do your measurement is the BOTTOM of the step on the float. If you look at the side of the float, it is basically an oval with a block on top where the brass hardware is mounted. You measure from the bottom of the step, which is the top of the oval.

.

 

[gmoore1785]

right before I turned it off I was on my brother's hill of a driveway in 1st gear, throttle pulled almost halfway. Thats what the plugs should be conveying. It rode well until it was warmed up, then it would die when taking off from 1st gear.

The Dyno kit comes with 155 mains, and 160 mains if you have pods. I went with the smaller of the two. They told me it wouldn't really matter if you have the stock exhaust, but an aftermarket exhaust would be an improvement.

I'm starting to think maybe the sweet spot for the mixture screws was more like 3.5 turns out, not 4. I supposed I should do a plug chop first like you just explained. The very last thing I wanted to mess with was the exhaust but If I have to I'll research what has to be done.

 

[gs11ezrydr]

I have been told but not confirmed that after 3.5-4 turns out on the mixture screws it does not make any difference because the screw has opened up the passage as far as it can go. Usually if you have to go over 3.5 turns out with the mixture screws a pilot jet change is needed and turn them out 2-2.5 or as needed. Just hear say.

 

[gmoore1785]

I'm probably going to take the bike to a shop and just be done with it. I'm running into more problems. I put on a new valve gasket in the spring and it's been leaky so I finally just bought an OEM gasket and put it on today. I broke one bolt and sort of stripped another. The two bolts are near each other but the top valve cover is on tight. Is this going to be an issue? I really don't know. Does any air get sucked in/go out through there? I wouldn't know.

I went out riding with it like that today. It rode and ran. Just feels a little weak at take off. I was told to check float heights, so that'll be next. I'm hearing the idle stay up after revving it though.

But if anyone knows if I'm screwed without one of the valve cover bolts in there, let me know. It's not a corner bolt, it's more in the center of the top cover, if that helps.