fuel shutoff, replumbing, & individual filters

[Mike Hart]

Man, I don't believe it, my plugs are still bone white, well 3/4's bone white, one tiny spot of the lightest tan or grey.

Had the bike to redline in 3d gear several times today felt really good, though maybe the slightest dropoff in pull after 8000 rpm, maybe.

Back to the jet store for bigger mains yet. The pilots sure helped out though, just not enough.

[JP]

Sure your floats are set right? Big jets won't do much good if the bowl is empty (or nearly empty). JAT

[Ken Talbot]

Hey, Mike, I was looking back through some of the stuff from the old tech tips area, and came across some of Blaine Hoopes' material:

Q: What does the pilot air jet do and what effect does changing to a larger or smaller size have?

A: Pilot air jet bleeds air from the intake bell to the pilot circuit and dilutes/atomizes the fuel before it reaches the 4 holes in the carb throat. Larger pilot air jet gives leaner mixture to pilot circuit and will deliver more mixture so idle speed will increase, smaller pilot air jet gives richer mixture to pilot circuit and will deliver less mixture so idle speed will decrease.

Those 50 'pilots' you have just put in - are they the jets Blaine was talking about and maybe do you need to go the other way? I'm getting real confused and maybe grasping for straws, but there's gotta be some real basic reason why your system just won't richen up...

[ratbyk]

Airjets/Pilot jets

Ken, the jets you are refering to are 2 different jets. The air jet sits in the mouth of the air horn. The larger this one is -the more air that goes to the pilot. This leans out the mixture through mid range.
The pilot sits under a threaded in cap. This sits within a tube or pedastal close to the main jet. The larger this one is the more fuel it will flow, mainly during mid range.
Ken/Sooke
78E Ratbyk

[dasuchbe]

Hey Mike, what kind of exhaust are you running. I have really enjoyed the info in this thread. I am considering doing the same thing to mine. So I was thinking I should be able to use the similar jetting to smooth mine out. I mean I know I will have to experiment with it but you have definately done some cool stuff here.

[TopCatGr58]

Pilot fuel Jets access?

Hey there Mike,
Or anybody else that wants to answer. It's been a while since I have taken apart my carbs, and before my trip to NC from Va. I am going to get a set of 3 sizes richer mains(117.5) and one size up Pilot to 45.0, (thanks to Mike's pioneering work and I'm running Indy filters and 4-1 pipes with 110 mains=white plugs)but I can't remember about how hard it was to get to them. I am not going to remove my floats, have a couple of pins that are stuck, fixed one post, don't want to risk breaking another, and I know the needle valve is under the float.

I remember the mains were easily accessible, are the pilot's in the similar location near the front of the carbs, away from the float, and should I be able to replace them without removing the float? Sorry for dumb question!

[kenkrieger]

The pilots are in front of the floats,, no need to play with the floats.

[Mike Hart]

G'mornin folks, thanks for all the replies.

JP, yes the floats are good - see page 4 of this thread for photos and explanation.

Ken T - I went up on fuel pilot jets, not pilot air jets. Yes, it is pretty bizarre why I haven't gotten it to richen up yet, I was stunned yesterday, was sure I was going to see plug color. The motor feels like I'm getting closer.

Ken D - yes, except in later models incl XJ the pilots are not capped, they are right there to get at w/ screwdriver.

Dave, I'm running stock exhaust.

TC, the only thing pioneering about this is that it is on an XJ, plenty folks have done this on XS's, but if anyone has done it on an XJ, I think they might have chimed in by now and set me straight The pilots are easy to get to, in a 'tower' right next to the main jet. Older models run capped pilots, later models are uncapped. (iow, there are different mixture passages in that circuit)

The XJ runs great, sounds great, starts and idles better than ever before - but I sure want to see plug color, don't want to be burning up pistons and valves.

[ratbyk]

Mixtures

Mike, if you are so-so close on your jetting right now, why don't you simply raise the float level a mm. This would richen up all circuits at the same time. It would likely give you a little plug colour and reduce the possobility of burning anything.
Also, go for a longer run before pulling the plugs. Give the engine a chance to get some colour on the plugs. I think this would give you a truer indication of what is happening in the combustion chamber than these quick wide open then chop itoff runs. I doubt that you can ever ride on the street at wide open throttle long enough to worry about burning anything when the mixture is so close.
I bet that if you do this your plugs will have some colour on the center electrode insulator and that the outer circle/next to the threads will be dark/black.
Ken/Sooke
78E Ratbyk

[Mike Hart]

Thanks Ken, I already set the floats as rich as they can go (see pg 4 of this thread). Any richer and I'm asking for trouble with the needle valves not closing. At one point, I was doubting my float work, but I rechecked, and yes, I raised the level (lowered when upside down).

Yesterday's run was 60 miles, short chop-off runs and 'average' runs see the plugs exactly the same.

[strom]

OK, a question.

I started the bike, and when it ran, it ran quite hot. I know this is an air-cooled engine, but still.
It managed a normal start about twice. Other times it doesn't start at all, just hangs in the 500rpm area, all cyls firing. And that's when throttle half way-fully open. It stutters a bit if choke is on and no throttle.
First I thaught fuel... bypassed the filters and no change. Next I thaught weak battery from all that starting. Recharged, still the same. Now I'm in the middle of cleaning the carbs and nothing special comes up. The gas was drained before they let it sit for 6 years.
Anyway, now I'm thinking ignition timing. I gotta set the air gaps, between the pick up coils and advancer, whatever that is.

Any ideas?

LP

[Mike Hart]

Local Suzuki dealer is swapping jets for me, I got one set from them, today they swapped and will keep swapping for me til I get it right.

Also, the local MotoGuzzi shop has a gas analyzer, their guy says for me to call him one day so he can warm up the machine, he'll sniff the exhausts for me for free so I have CO and Hydrocarbon numbers for some hard data.

BTW, I was looking at jet prices on the internet - Cycle-recycle http://www.crc2onlinecatalog.com/Index_Main_Frame.htm wants $3.25 ea, plus $6 shipping; Bikebandit (bandits indeed!) wants $7.80 each~!!!!! That's the highest price I've seen anywhere, I thought the Suzuki shop was steep at $6.25ea.

The saga of the search for plug color, to be continued...

ps hey Strom, your post will get lost in this huge thread. Set the air gap, I think you answered your own question.

[Rick Wood]

Jetting ???????

Mike,

Here is some Info on my Hook-Up, After putting in a Big Bore Kit & and Mac 4-2 pipes W/ K&N individual filters I knew that I would need to rejet . So my thaught was Jet Kit I did have some second thaughts after your slam on the Allxs11 list of DynoJet but I already had the jet kit. After my Re-Build of my engine. I tore into the Carbs the diaphragms were in rough shape so I put in new one's from Cycle-re-Cycle and Triple cleaned the carbs. When they were all apart I found a good cleaner was to use Mag Cleaner with a brush (Made them look like new). But back to the jetting the DynoJet kit you change the

Pilot Air Jet DJ190
Fuel Needle DJ640 (The Stock Needle could not be adjusted)
(The DynoJet Needle has 5 Slots )
Main Jets DJ138

And you have to drill out the Air Passage in the slide

Here is the link for those that are interested
http://www.dynojet.com/pdf/4101.pdf
DynoJet

At any rate the bike runs great. BUT (White Plugs) (Very little Color)

One of the guys I work with race's Snowmobiles he tolded me that if you have any color at all you should be in good shape (But he Re-Build his Race Engine's about 4 or 5 times a year.

DynoJet Instructions say to put the E-Clip in the second noch down. I moved mine to the third (Middle)

Don't have any answers (Just Input)

[ratbyk]

Float Height

Mike, another idea on raising float height. I don't know about the XJ but on my XS under the needle seat is a thick fiber washer. If you replaced this washer with another, say 1 mm thinner then you could achieve a mm rise in float height without changing any of your present settings.
Tricky ah what!
Ken/Sooke
78E Ratbyk

[Mike Hart]

Pretty sneaky, Ken! The later models don't have the thick fiber washer though, IIRC.