Different pilot jet sizes

[dbeardslee]

Half the time the el-cheapos are the best. I might have to pick one up - then I can stop borrowing my brothers . When you check the timing, you'll usually get better results if you hook the timing light to an external power source - like a battery charger or a car battery (not in the car, at least not while the car is running.) You want to plug the vacuum advance and keep it at 1100 rpms if you're setting/checking the timing, but if you want to see how far it's advancing, then don't (duh ).

[blade]

Well, I put the new plugs in, NGK BR6ES instead of the br8's the PO had in.
I took it for a ride and now I have power, lots of it and all the way through the rev band. I am happy that the jet change, the emulsion tube clean and the plugs change have fixed the 4-5k rpm problem.

On a side note I am getting a over run on the rpm's sometimes when I cut the throttle.
I think it is because of the leaky vacuum on the petcock is sucking fuel into the #4 cyl.
I am going to do the vacuum bypass mod and block the prime so I will have an off position. Hopefully that is why I am getting the over run.
I think it is, because after I get on the throttle there seems to be a lot of fuel going to #4 from the petcock, when I release the throttle after a while the fuel disappears from the vacuum tube and the rpm's return to normal.

[blade]

Half the time the el-cheapos are the best. I might have to pick one up - then I can stop borrowing my brothers . When you check the timing, you'll usually get better results if you hook the timing light to an external power source - like a battery charger or a car battery (not in the car, at least not while the car is running.) You want to plug the vacuum advance and keep it at 1100 rpms if you're setting/checking the timing, but if you want to see how far it's advancing, then don't (duh ).

Thanks for all the good advice, I am glad I can go back through the posts because it would be hard to remember everything.

[psycoreefer]

yup, fix that vacuum line pulling fuel, that would really be throwing #4 off. Also if you didn't you should do a vacuum synch on the carbs, will make it much smoother.

[blade]

yup, fix that vacuum line pulling fuel, that would really be throwing #4 off. Also if you didn't you should do a vacuum synch on the carbs, will make it much smoother.

I am glad yo think so too. Does that make sense that the over run would be associated with the leaky vacuum?
I haven't done a vacuum synch yet, but I did synch them with a thin wire to get them close. It seems pretty close to me, but I won't know till I do a vac synch.

[blade]

oops double post

[dbeardslee]

When you say over run, are you saying gas is coming out of the carb bells? That's a sign of two things - one, your octopus isn't shutting off the fuel flow, and two, your fuel valves aren't sealing in the carbs.

[psycoreefer]

I think he's saying when he shuts the throttle the RPMS remain "high" for a little while before coming back to idle, could be caused by the extra fuel, a vacuum leak, or out of synch carbs.

[blade]

I think he's saying when he shuts the throttle the RPMS remain "high" for a little while before coming back to idle, could be caused by the extra fuel, a vacuum leak, or out of synch carbs.

Yes, that is what I meant.
I am quite sure it is not the carbs being synched because when I unhook the vacuum tube and block off the hole on the #4 carb manifold I don't have the over rev problem.

[blade]

I took the petcocks off and did the vacuum valve mod. Next I removed the vacuum tube to #4 carb boot and put tube between the two petcocks to each vacuum port. I capped the #4 car boot.
I took it for a ride and it does seem better but at times it will hang at around 3k rpm when I pull the clutch in and take a while to return to idle.

I checked the throttle cable where it meets the carbs, it is fully seated, when I twist the throttle and it snaps back fully with a little slack in the cable.

Tomorrow I am going to borrow a friends vacuum synch. Hopefully that is where the problem is. After the synch I will adjust the mixture screws.

I have noticed that at idle I can smell gas coming from the exhaust pipes, it is not a very strong smell but I did notice it. I have read some other posts that say it is normal as the xs's run rich at idle but I didn't know what to think. It could be from carbs being slightly out of synch.
It is running great apart from the idle/rpm issue.

I really want to ride it more but I am nervous about doing some kind of damage to the engine.

[petejw]

sometimes if the rpms rise when you
are cutting the throttle, it could mean that
your running lean, depending on the throttle position
and the rpm, will determine what circuit your running lean in.
what settings did you end up using?

[blade]

Hi petejw

I ended up with 145 mains, 45 pilot and about two turns out on the mixture screws. Maybe I will need to turn the mixture screws out more?

[petejw]

what are your floats set at?
are you running an air box?

the mains and pilots seem ok

[dbeardslee]

Pete - he must be talking about the F with the stacks, pods, and 4/2.

[blade]

what are your floats set at?

I have not checked the floats yet.
What height is recommended for my set up with the 79?