Top end query;

[crazy steve]

I'll throw my .02 into this....

As a Harley owner also, I'm familar with their mufflers. As Doug said, jetting is affected by the amount of air getting into the motor; more air, bigger jets. Now, generally speaking, when changing only the mufflers on a Harley (or drilling the baffles for more 'sound'), no jetting changes are needed. You still have the restriction of the stock airbox, so the amount of air getting in will be unchanged. So jetting changes are unneeded with only a muffler change, and any 'fine tuning' can generally be done by moving the c-clip on the needle (usually down one notch).

Stock Harley mufflers, even drilled ones, are pretty restrictive; a freer-flowing muffler and AC change will gain you roughly 20% more power on a dead-stock Harley (no, that's not a typo) but as was pointed out, the pulses are much larger compared to a XS11. I'd try stock jetting as a 'baseline', then go from there...

'78E original owner

[XS1100_OEM4ME]

750f/d

I had a 1979 XS750 Special in 1979, gas was better IMHO but stock out of the box (with the 750R/D of course) she would do 126 mph no a cool day (below 80 deg. at least). So I dont think the 750R/D is not holding you up. It would get to 100 fast, then it took time, guts and road to get the next 26 mph. I did weigh 80lbs less in 79, now I have more gut and less gut's (LOL)

[MindWebs]

hmm..?

Very good advice, I will try to follow.
i will go back to stock jetting and work up from there.

i may have a gremlin some where yet...

it dawned on me that when i started this process, i had bright yellow flame at 6000 rpm and higher with the factory main jet and factory pilots.
137.5 mains and 42.5 pilots.

that should be rich.???

soo....

i think i need to do a bit more digging to find the culprit of this issue, before i continue with the rejetting. not sure if its and electrical or mechanical gremlin.

i've got alot to learn.. and i apreciate all the help!!!

at the moment i've got the 145 mains and 45 pilots loaded.
it seems driveable, i made the mistake of lowering the back presure valves to
30 degree's and wow.. does that mellow (weaken) the acceleration from 2k to 5k. i'll set it back to 45-50 where it makes the engine snap better.
so it seems that extra back presure is needed on the HD exhaust pipes.

hmm... i'll talk to the gents that wheel up to the xssesivly lost north rally and
have them look it over and see if they can find any glaring errors i've made.

i may have missed something simple and it's rate in front of my nose.

i'm still limited to 100mph, it refuses to go past that mark in any gear at any rpm. i tryed many combinations.

it simply runs out of power.

we'll see what they can come up with.

Thanks dbeardslee and everyone!!
I'll let you know in a few weeks what we find.

[nutwister]

Observation

I just read this thread from the beginning and it seems quite interesting that the original author has been banned and unable to contribute yet the thread still continues.

Anyone know what happend with xsokiespecial's bike?

[MindWebs]

the main reason it continues is that i believe we both have the same problem.

what the problem is... i have no idea......

is has eluded both of us as far as i know.

i only know what you're read here, last i heard he worked out problems in the bottem end.

i don't know if that fixed his issues......

but i don't have any noise in the cases, so it's doubtfull that would have been the problem.

I've been wrong before..........

[petejw]

ive just got hold of a cpl colour-tune plugs,
havent used them yet but found this site
on using it, hope it helps you out...

http://www.carbtune.com/

the instructions are under the colour tune plug pic.

[MindWebs]

I am starting to think about a new theory..

i'm wondering if valve stem seals might cause these issues..?

in my garage (incandesent lighting) i can see i'm burning oil, but i'm not seeing any build up on my spark plugs.

this leads me to wonder if the exhaust valves seals are leaking.

how that would rob horse power I'm not sure.....

as i said... it's only a theory.

next weekend i'll talk it over with the members that can make the Xssively Lost Fall 2010 (Minnesota) Rally
http://www.xs11.com/forum/showthread.php?t=28859

Later guys!!

Webs

[crazy steve]

I am starting to think about a new theory..

i'm wondering if valve stem seals might cause these issues..?

in my garage (incandesent lighting) i can see i'm burning oil, but i'm not seeing any build up on my spark plugs.

this leads me to wonder if the exhaust valves seals are leaking.

how that would rob horse power I'm not sure.....

as i said... it's only a theory.

Bad valve stem seals rarely affect performance that much. If you have bad seals and guides, then you may start seeing some problems. With bad seals, the only time you'll see any major oil smoke is at starting when the bike has been sitting a while(when oil has had time to leak past the seals) and decceleration (closed throttle, so the motor develops a large vacuum in the cylinders and sucks oil past the seals). The rest of the time, oil leakage past the seals will be minimal and you'll see very little if any oil smoke.

Replacing just the seals can help with smoking, but if the guides are bad they won't last all that long.

'78E original owner

[MindWebs]

I talked to XSokieSPECIAL and found out the results.

he claims that it was bad rings that caused his lack of high speed.
His cure was to swap in a different engine.

Hmm...

not a bad plan if a person can come up with a cheap engine, he was lucky and got a few from the bob jones estate.

so..

i'll finish tinkering with my jetting and run'er till she blows.
i sideways joke i must admit... these engines do tend to burn a little oil.

also i've heard a few other accounts of 79's lacking top speed.
i believe that there may have been a bad batch of piston rings used in the 79 engines.

thank you, EVERYONE!!!
i think this has now finished this thread.

Good luck to one and all.

[XS1100_OEM4ME]

Yes Steve

Bad valve stem seals rarely affect performance that much. If you have bad seals and guides, then you may start seeing some problems. With bad seals, the only time you'll see any major oil smoke is at starting when the bike has been sitting a while(when oil has had time to leak past the seals) and decceleration (closed throttle, so the motor develops a large vacuum in the cylinders and sucks oil past the seals). The rest of the time, oil leakage past the seals will be minimal and you'll see very little if any oil smoke.

Replacing just the seals can help with smoking, but if the guides are bad they won't last all that long.

'78E original owner

Valve stem seals only cause oil burnning (that you can see) when at start up. That is when oil that has leaked past the "intake" seals burns off. The exaust seals, due to pressure instead of vacum, just push the oil back into the motor, IE, some EGR working to do away with it.

[dbeardslee]

also i've heard a few other accounts of 79's lacking top speed.
i believe that there may have been a bad batch of piston rings used in the 79 engines.

I've got a '79. I've had her up to 135 and she still had plenty left. If you suspect your rings you might try the wet/dry compression test. Warm the motor up to full operating temperature, and take a compression reading. Then put a small amount of oil in each cylinder (one at a time) and rerun the compression test. The numbers should remain pretty much the same in relation to each other. If you have one where the reading changes significantly in relation to the other cylinders, it's an indication of worn or broken rings. Unless you've got a motor with very high mileage, I would expect the rings to be OK.

As far as leaky valve seals, I agree with the others that it isn't likely to be the culpret as far as performance is concerned. That being said, it can be an indication that your head could use reworked. XS valves are pretty notorious for getting a lot of carbon build up on the valve stems, and if it creeps up the stems far enough it can cause your valves to stick. They also get a lot of crud in the ports. Whithin six months of acquiring mine, I pulled the head, cleaned the ports and the valves, lapped the valves, replaced the stem seals, and reshimmed. What I noticed was how much smoother it made the motor run - of course that was after the carbs were setup correctly .

[nutwister]

he claims that it was bad rings that caused his lack of high speed.

RINGS?

[MindWebs]

that's what he said....

but i guess he was a bit hammered at the time...
so maybe that wasn't it...

i was just relaying what i heard...

if you know something diferent please let me know.
i still have the same problem.

but my ambition to tear down the motor just to find out a minor issue that is keeping me from getting my divers licence revoked and me going to jail..
well...
i'm just not real antsy or pepped up to do an engine overhaul.

not to mention lack of funding for parts and repairs that are needed.

am i curious as to what the issue is, yes i am.
but i have no "need" to go past 110mph.

Later,
Webs

[jmnjrpa]

changed motor

I rode with Okie in the ralley last month. We had an 80 mile stretch that was held at over 100 mph (the whole group of 9). I would say that fixed his but I don't know yours has the same problem.