Need help with jetting please

deecha · Posted: August 24, 2008, 3:48 pm Post subject: Need help with jetting please

I have a 1980 XS650G and I have attached some photos to help better explain what is going on. Let's start with what I have done with the bike since purchase, I put on the xs performance pod filters from mikesxs and I put some mufflers on to help make it run a bit more quiet. The jetting on the carbs are as follows pilot jet 45 and mixture screws out 1/2 turn and the rest is stock settings. I know my mixture screws need to be turned out more but it just does not want to run right the further I turn them out. As you can see in the pictures my spark plugs do not look the same. The one that is brown is the #1 cylinder and the other one is #2 cylinder. Valve clearance has been checked and is good. The threds on #1 cyl are jacked up but the plug still goes in and gets tight it does not strip. When the engine is running I can tell #1 cyl is not working as well as #2. If anyone can help me I would greatly appreciate it and if you would like more pics or more info please let me know thanks.

deecha · Posted: August 24, 2008, 3:52 pm Post subject: Re: Need help with jetting please

for some reason I cannot upload the photo of the other plug but it's running way lean on #2

xsjohn · Posted: August 24, 2008, 4:55 pm Post subject: Re: Need help with jetting please

2 (right) is always lean on these.....that where my needles come in.....have you checked the balance well.....and set the mix screws like at 2 turns out to start....and the floats have to be dead on.....like 27.5 mm......the stock needles are impossible to work with............

xsjohn

deecha · Posted: August 24, 2008, 5:38 pm Post subject: Re: Need help with jetting please

John, are you talking about the fuel balance or what balance are you talking about? I hate the stock needles they are a big pain in the ass. This winter I am going to rebuild the motor and get some of those needles from you.

xsjohn · Posted: August 24, 2008, 5:59 pm Post subject: Re: Need help with jetting please

Well you can't balance the fuel mix with the stock needles .....but you can use a 135MJ and a 45 pilot at maybe 2 1/4 turns.....and set the balance between the carbs...and my needles do help balance the mixtures for the hotter right cylinder......dicked with that till I should have been slapped..........

been having fun with my 2 head gasket thing.........still getting great mileage 57 or so and the thing is real mellow and still pulls 18/29 with my skinny ass on it maybe even better than before since I don't crank a bunch of revs........well at least till I want to......

Would you guys save the original head gaskets for me.........easier to bond them together...........would appreciate.........

xsjohn

deecha · Posted: August 24, 2008, 6:50 pm Post subject: Re: Need help with jetting please

Thanks for the info. Why does the right side run hotter? So you are bonding two head gaskets together? Does that make more hp or torque?

xsjohn · Posted: August 24, 2008, 7:03 pm Post subject: Re: Need help with jetting please

Think the consensus on the right is......it's the drive side and there is no place for the cylinder to dissapate the heat as easily as the left.........

2 gaskets lowers the hp a bit and at the same time advances the cam 2 degrees for a bit more bottom end torque.......now I can run the next hotter plug and use a bit more fuel and it seems to help pull my taller gears.....was getting 58-60 MPG now 56-57 or so..........engine hopefuly will last longer.........and it does run cooler.......just got bored and wanted to experiment..........harder to tune because it pulls more air down low and in the lower mids.......had to scratch my head with totally different carb settings........another learning experience for sure.......and the used cam chain is back to original adjustments......

xsjohn

deecha

Wow smart man, I am going to have to try that. So have you figured out any other ways to cool down the right side? How about if I run a colder plug on the right side?

xsjohn · Posted: August 25, 2008, 8:18 am Post subject: Re: Need help with jetting please

Was thinking it would be good to have a spare cam with 2 degrees retard for when 2 gaskets are used....chain wheel can be pressed off and repositioned just a half a bit retarded....that way the carbs wouldn't have to be changed much if at all and the cam would end up back in the stock position.......but as the chain stretches some more and the carbon builds back up it will be back to stock soon enough.....read some where that many cam builders build in a bit of advance in their cams so when the chain stretches it falls in .....just messing around you know....and then again chains are cheap so why mess with it anyway...does run somewhat cooler and more mellow.....after 62 thousand just wanted to try something different that could be put back if needed.......colder plug on the right wouldn't cool down the right cylinder........

xsjohn

deecha · Posted: August 26, 2008, 1:41 am Post subject: Re: Need help with jetting please

Very intresting, I like the idea with the cam sprocket I never even thought of that. I decided I would pull the engine on the bike and see what's inside and well I need new pistons and I will put some pics up of the pistons because the right side is jacked up a bit. I really appreciate all input and advice john you have definately helped me out a lot.

xsjohn · Posted: August 26, 2008, 7:58 am Post subject: Re: Need help with jetting please

Are you sure you need new pistons........what is your compression....... if you lift the barrels for no reason it makes it harder to get the thing to reseat and get good compression.....

xsjohn

deecha · Posted: August 26, 2008, 5:25 pm Post subject: Re: Need help with jetting please

The piston ring end ga was .020in for top ring on both sides second ring was a bit better and both around .018in the oil rings are at .035 and the piston on the right side has some scoring marks on it so I figured go one over on the pistons and rings.

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