Thread: Keihin jet opitions
02-26-2010, 04:13 PM #1
Keihin jet opitions
I have a 96 ZXi 1100 and need some suggestions to make this run efficiently. I just got the new motor in yesterday and some Boyseen Power Reeds. I will also be running OP F/A on this as well. I have already cleaned and rebuilt the carbs with a Jetlyne kit and replaced all the lines so the carbs are ready to go with one exception.
What would be the best jets to use with these mods I have added one or will the stock ones work fine?
Other mods not engine related is a Solas Concord 12/18 impeller, R&D Intake grate, and a Shred-Master Ride Plate.
02-26-2010, 05:48 PM #2
if you didn't change your engine size, you should need new jets.
you have to be carfull with what carbs you have as some keihin carbs are air to fuel mix, not fuel to air adjusters, (ie closing the jets increases the fuel to air mix instead of the otehr way around)
02-26-2010, 07:29 PM #3
So you are saying since I didn't change the size of the engine I shouldn't need to rejet? If so I thought this was the case but someone was telling me differently and I just wanted other suggestions
I have the CDK II carbs Non CV.
02-26-2010, 11:24 PM #4
check you piston wash and it will tell you how each cylinder is running
02-27-2010, 03:58 AM #5
Brand new stock 1100 CC motor from SBT. Just looking for a simple yes or no answer if I need to install different jets with the engine mods I listed above.
02-27-2010, 12:13 PM #6
it would be nice if there was one. Should you ? NO, might you ? Yes. You will need to monitor how the ski is running. Plugs, wash, etc.
What happened to your old motor? you seize it or blow a piston?
02-27-2010, 02:13 PM #7
One thing people often do is when a motor blows they figure well I will rebuild and mod at the same time. Well for some experianced people this can be fine for the rec rider who tunes a little here and there maybe not so much.
Now for your ski you added a intake grate which means more load...
And also added flame arrestors so more air.
added a prop which might be more load.
Most of the above means you will need a little more fuel overall.
Now it's been a while since I worked on those carbs but I dont think they have high and low fuel screws. If they do then a rejet will not be needed.
If they dont have fuel screws then a jet change should be done to be safe.
If there are fuel screws then just go out about 2 turns from stock to be safe and bring them in after break in and get it running right.
If there are not screws go up one jet size on the main.
hope this helps.
For future tips on modding just do one thing at a time. Like in the future if you want to add carbs and a head....do the carbs first and get it running right then add the heads.
02-27-2010, 02:51 PM #8
I have not rode this ski since I bought it and the motor is not even in the ski yet. I heard I needed to re jet because if the mods I have done to the motor but I haven't changed the displacement and never heard of doing that unless you had changed the displacement. I was needing to find someone to tune my carbs once I got this built and that is when I received a PM about it and just wanted some suggestions. So I don't know how this ski runs to be honest because the motor is not in it. If I needed to re jet I wanted to do it while I still had the carbs out.
Johnny5, yes it does a high and low screw so then I won't need to re jet correct? I didn't think I would need to.
The only mods on the motor is the Reeds and the F/A for obvious reasons. I have all the other parts like the ADA head and the other listed but I wasn't going to put them on until I got the ski running. I wanted to test the ski with the factory parts so I could see what the difference was when I put the grate, ride plate, and impeller on.
02-27-2010, 04:06 PM #9
Yes if you have fuel screws then you should be fine. The only reason for needing more fuel is the airbox is gone and flame arrestors have been added which add more air and tend to lean the mixture a little so then more fuel needs to be added but not enough for a jet change but enough to where a 1/2 turn or full turn out may be needed.
Now a jet change would be needed for porting or after market pipe or alot more compression and timing or other mods but for FA's and a pump gas head you will probably be fine. But better to go rich then lean so if it;s a little smoky and bogs a little at least you know you have enough fuel.
A tach really helps for tunning and can be cheap insurance when you start adding mods.
But keep an eye on you plug readings to see how brown or black they get grey is not good along with white. Piston wash on a pretty stock ski is more then likely not needed.
Keep us updated
02-27-2010, 06:52 PM #10
Will do thanks for the feedback. I didn't think I would need to change them. I was going to have someone tune them for me as I am not sure how far off these are from stock settings or what the stock settings these needles should be set at. It does have a tach so that should help like you said. Now if this was a car, no problem I could do this, but not real sure on a ski so would rather have a expert do it.
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