Top end query;

[petejw]

Hi Mindwebs,
the only thing i noticed is that u stated u had
exhaust restrictions to help ur low end power,
this could cause a top end reduction, what exactly
are the exhaust restrictors? how are they fitted and in what
way does it restict the exhaust?
are you running the stock air box?

[MindWebs]

This is my restrictor valve, not real fancy. a round piece of stainless steel
tig welded to a S.S. bolt.
Pic is valve fully closed


this pic is valve fully open


this are installed in the pipes just BEFORE the mufflers and i have played with them at all settings..

i have them set to a 35 degree angle now.. (approx)
it seems to help with the dead spot.

I'm running the factory air box, yes.

[petejw]

so when u say u have it fitted at a 35 degree angle,
does it stay that way or does it open or close from exhaust pressure?
personally i wouldnt use it, id try and fix the flat spot
even with open pipes if its tuned correctly u shouldnt be getting
any flat spots.

[MindWebs]

I am running harley touring pipes.

these are not tuned for our bikes.

the flat spot is not as carb issue it's the fact that the jap's are smarter then i am and tuned the factory exhaust to produce maximum horsepower from the engine.

my original mufflers had 4 inch holes in the bottom of them from rusting.
i went the cheap route (HD) and now i have to "tune" this exhaust.

GSXR's have an electronicly controled restrictor valve in they're exhaust.

mine is a bolt. you tighten it where you want it.
there is a slot cut into the end of the bolt that shows me where i'm setting the plate.

[petejw]

i understand what ur saying but there are
many running around with after market pipes,
you still need to set the carbs up accordingly,
i still think that restriction could cause you problems
at the top end.


some harleys have the butterflys in the exhaust as well
but they open and close and arent fixed in 1 position.

[MindWebs]

you have a very valid point.

i don't know if the restiction is causing problems.
it could be.

but the restrictors went on with the touring pipes 1 month ago.
i've never (3 years of driving it) gone faster then 108(MPH)

the sportster pipes i had on there didn't give me the flat spot but i also welded a washer in the end of that, to change noise pitch.

[jmnjrpa]

Peter,

If I had done all you have I would be pissed! Your case has me leaning toward fuel or air starvation. Can you redline in any or all gears? What is your compression? How have you got your valves set? What accessories (faring, etc...) are on the bike?

Does the bike run better in winter or summer? Your temp variation is not extreme.

With three years good use on it you can rule out most of the list. You will have to concentrate on items that remained constant.

May sound a little out there but has this frame ever been wrecked?

[XSokieSPECIAL]

check the air in the tires? He He He LOL Couldn't help it!

Seriously, stick a couple Roman Candles up the pipes and I bet your problem is solved! OK, OK, I'll sign off.

John......you've been watching old roadrunner cartoons again. Haven't you?


BEEP BEEP.................Heh heh heh

[jmnjrpa]

Love em!

Gotta admit they could give your butt a sparkle! LMAO

[XJOK2PLAY]

Wow...first its farm animals....now its shoving roman candles up his....pipes...yeah ...pipes. Well, this is Oklahoma now isn't it.

Hey, Bud!!! Look out!!! LOL

Don't make us have to dig in the joke bag for stories about those who live in Ohio......... hehehe


Besides, there's nothin' wrong with a little 'creativeness' when it comes to 'alternative forms' for making HP, is there???? HP is HP....

Ya gotta do whatever it takes to achieve ultimate power...
you know... "220 volts...221 volts... uhhh, whatever it takes!" (Quote from the movie Mr. Mom, and the infamous 'chain saw in the kitchen' remodel scene... one of my favorites...)

[Ivan]

I wonder how much the current stuff they try to pass as gasoline has to do with all this. I had to richen up my 81 carbs through the whole range, pilot jets, raised the needles, float levels, and bigger mains to get it snorting like the angry bull it is. On my 79, the PO said he had jetting done on it. It runs like a scalded cat so I haven't messed with it, but it gets around 26mpg, which would make sense with as much water and alcohol as they have in the gas around here.

Maybe you guys could try some octane boost or even a few cups od diesel fuel in the gas to try and negate the alcowater and boost the BTUs per gallon a bit and see if that makes a difference. Just a thought.

[cywelchjr]

I wonder how much the current stuff they try to pass as gasoline has to do with all this. I had to richen up my 81 carbs through the whole range, pilot jets, raised the needles, float levels, and bigger mains to get it snorting like the angry bull it is. On my 79, the PO said he had jetting done on it. It runs like a scalded cat so I haven't messed with it, but it gets around 26mpg, which would make sense with as much water and alcohol as they have in the gas around here.

Maybe you guys could try some octane boost or even a few cups od diesel fuel in the gas to try and negate the alcowater and boost the BTUs per gallon a bit and see if that makes a difference. Just a thought.

I think it is about 100% of it. Here's why I say this. I still have my 80 XS400 that I bought in 84 from my uncle (first owner) and I went through the tuning when I got it (it had been sitting for a few months so I had to (you guessed it) clean the carbs. Back then with clean carbs, that bike got 53 to 56 mpg, and that is with my fat a$$ on it. Roll forward to 2008, which I took it out of storage and rehabbed it to put it back on the road. I had to clean the carbs again (of course, and 3 times to boot, it's got the same carbs my 11 does) and all, AND I found that I had to go through several things to richen it up considerably (didn't end up rejeting, I was able to do it with a combo of raised fuel level in the bowls and turning the idle mix out a couple extra turns) and got it running pretty good and to where it was not horribly lean, and now on a good day I can get a max of 45 mpg with the same bike, same engine, same carbs, same rider (yes I am a few pounds heavier now, but not enough to make that big of a change). The difference is (and my mileage changes between winter and summer) the ethanol, which varies between 10% and 15% here in lovely Kalifornia. In the winter on my XS11 which is what I ride pretty much exclusively now I get around 26 to 27 mpg around town and about 36 mpg on the road. In the summer I generally get about 28 to 30 mpg around town and almost 38 on the road. I find similar result with my cars as well, and they are all fuel injected.

[TopCatGr58]

Hmmmmm Greg,

--------------------------------------------------------------------------------

Quote:
Check points should be: compression, shape of final drive (and mod), shape of middle drive, possible fuel restrictions, plug conditions, coils, valve clearances, wheel bearings, possible brake drag and maybe not last but not least atmospheric heat (heat alone can rob 10% of available HP).

Also +1 on your advance.

Scratch all that. I ain't no GURU.

Scratch all that. I ain't no GURU.

Hey Big John, at least you aren't Big "BAD" John!

In mine and many others eyes, you are already a GURU. We're talking the same thing. I was just showing him a possibly quick way to check the fuel restriction when he mentioned the Octy. The ignition is definitely high on the priority of things to check...many 'misses' and such have been cured with NEW ignition coils and wires and plugs. These are just some of the things he can check( seems to be a bit timid about getting in too deep into the engine), and by all means the health of the engine needs to be determined...ie. compression, valve clearances and such...but they require a bit deeper digging into the mechanics of the engine, and Greg didn't seem to be to anxious to do that at this time.

Didn't mean to appear to be stepping on any toes here!
Now I think I'll shove a bundle of bottle rockets into my seat to get that extra boost of power .....they have a more consistent power output vs. the pulsing of roman candles!
T.C.

[MindWebs]

fuel?

ok... i'll admit fuel is crap nowdays...

but my 250 ninja and my S1(250) can still hit 105-108mph
on that same fuel.

i know the ninja is about 38HP and the S1 is 28HP

the xs is what like 90 some HP?

i don't tune the carbs to a setting.
i set the carbs according to kens write up.
http://www.xs11.com/forum/showthread.php?t=13124

and have very good color on all 4 plugs.
compression is 145-160 psi

Frame wrecked? i have no idea...
i got this 11 from my uncle, he never rode it, he got it from another guy
10 years ago. very little history is known on this bike.

[XSokieSPECIAL]

Hey Big John, at least you aren't Big "BAD" John!

In mine and many others eyes, you are already a GURU. We're talking the same thing. I was just showing him a possibly quick way to check the fuel restriction when he mentioned the Octy. The ignition is definitely high on the priority of things to check...many 'misses' and such have been cured with NEW ignition coils and wires and plugs. These are just some of the things he can check( seems to be a bit timid about getting in too deep into the engine), and by all means the health of the engine needs to be determined...ie. compression, valve clearances and such...but they require a bit deeper digging into the mechanics of the engine, and Greg didn't seem to be to anxious to do that at this time.

T.C.

Yup......I'm kinda lazy when it comes to exploritory surgery.

The engine is most definitly mechanically sound. I HAVE checked it seven ways from sunday in that respect.

I'm sure the problem is somewhere in the tuning which is something I'm still learning with this engine.

In the lower gears I've tached up to 9K but in 5th 98mph is like the sound barrier.

I didn't notice this until I put the Mac side kick mufflers on. It may just be a back pressure issue.

I have 2 other sets of mufflers so I might do some swapping and see what happens.