Pops and cuts out 3K.

[GTXS1100]

Im working on my last issue that i have. I cleaned the carbs out the other day and i was having this issue before. I did go ahead and install some larger jets since i have 4 k&n filters and open header. When i rev up the bike in the shop with no load everything is fine but when i get her out on the road in every gear it cuts out around 3k. I was wondering if any one had ran accross this problem and what they found. Or can anyone point me in the right direction. I Checked the timming too it seamed to be fine and the vacuum advance was working as well..

[DGXSER]

As may have been stated before, these bikes like/need some backpressure to operate correctly. It will take ALOT of trial and error to get tune the bike to work with that setup.

More than a few have tried to run open headers on these machines. Some have gotten some degree of success. Most if not all eventually go to some sort of exhaust. I recall Ivan using a glasspack on his for a while. He eventually had to give up on it and ponied for a decent exhaust system.

An option is to find some discarded Hardley mufflers. It seems the factory exhaust is one of, if not the first thing to go on a HD, and the perfectly good mufflers fit nicely and work well on an XS11.

[GTXS1100]

I was affraid of that since i hacked up the only set of exhaust i had. Ill have to try and come up with another set somewher.

[GTXS1100]

Something else i was wondering since my issue is at around 3k is it possible that my Main jets could be the problem? I may try putting my old Mains back in and see what happens.

[crazy steve]

No, don't go back to stock size jets; if anything, go even larger. Like Don said, these bikes don't run well with open pipes and can be very nasty to tune with them... very few (if any) have had success getting one to run without some backpressure.

[GTXS1100]

The jets i installed where 147.5
137.5 stock + (2.5*4) = 147.5
3jet size for individual filters
2jets for open headers
-1jet size gives me 4.
That is right, Right?

[GTXS1100]

I have 2 sets of stock mains. I can drill out one set what size drill bit should i use. Ball park ill order the right ones once i find out something close that works.

[DGXSER]

I have no idea what drill sizes match what jet sizes. I do not think the jetting recomendations cover the open header scenario you have set up. So again, your just going to have to play with it and see what works.

3k is where the mains start to kick in, around 5k is where the mains are about all in, enter the true power band at this point. If it runs decent up to 3k and then it seems to fall on its face, you may need larger mains. Even with this, you may still need to bump the pilots to 47.5 or so. the pilots still play a part even when the mains are brought in.

Reality is that a drilled out jet will not have the tapered opening and such of the factory jet, so even if it works right with the drilled jet, it is no guarantee that the same "sized" factory jet will work.

Like I said earlier, you can find slightly used Harley pipes for less than $50 on ebay from time to time. That will probably be the cheapest out for you.

[motoman]

Drilling out jets or soldering shut and re-drilling creates swirls that create a toilet-bowl effect. Have seen this done in the automotive world with mixed results, mostly bad results. Take DGXSER's advice and others and get some sort of exhaust with some back-pressure on system before doing any further jet changes.

[GTXS1100]

I dont realy think its an issue with the exhaust as much as it is an issue with the carbs. My pilots are jumped up to 45.0. It ran pretty good last year even with the exhaust the way it was. I was reading "Round Three?" and that sound like more of whats going on. It will be easer and Cheeper to do some playin with the carbs before i go tracking down a set of exhaust. Im going to make sure every thing is perfectly clean on the carbs so i can rule them out first. Thanks everyone.

[petejw]

id go smaller on the main jets,
try 142.5 thats upping them by 2 sizes,
id also drop back the pilots to stock 42.5
and go from there.
having the open exhaust will affect low and mid
range performance usually flat acceleration, but shouldnt
cause the flat spots u mentioned, have a look at ur plugs
to see if there fouling up, the plugs will give u a good
indication of whats going on.

[GTXS1100]

hey Pete i didnt shim my needels cus i couldnt get the little phillips screws to bust loose on one of them. You think that could have something to do with it. I was wondering about that. I thought i would put them back together and try it before i tryed any thing else.

[petejw]

hey Pete i didnt shim my needels cus i couldnt get the little phillips screws to bust loose on one of them. You think that could have something to do with it. I was wondering about that. I thought i would put them back together and try it before i tryed any thing else.

u shouldnt need to shim the needles if there not
adjustable, like i said drop ur jets back down and
see how u go from there.