performance question

[darrelldaltonga]

I have a 79 XS 11 and i'm not one to condone street racing but I have a friend that i ride with that has a 2007 Suzuki M50 which is an 800cc fuel injected bike From time to time when we take off we get on it and he just leaves me. My bike runs fine and has new rings carbs rebuilt and so on..What i'm asking is..is this normal performance for this bike or could i have problems else where
heres the bike
http://www.xs11.com/forum/showthread.php?t=22687

[CatatonicBug]

I see no reason why a suzuki 800 would be able to out-pull an XS1100. Are you giving it WOT off the line? How about speed-shifting?

[drooker56]

There must be something wrong cause I have pulled better on bigger than an 800 v-twin. Have you done anything with the ignition or had it tested? If you have rebuilt the carbs and the top end I would check your coils, wires, and plugs. I am sure you have probobly done this but its all I can think of I'm only a backyard mechanic and its taken me 2 years to work most of the bugs out of mine.

[darrelldaltonga]

I haven't done anything to the ignition but it runs very good and fires up fine. I've tried this scenario with two 800cc bikes and both times every time i get left the only thing i can think of is my pipes being short and not having enough backpressure but it shouldn't make it this slow

[drooker56]

I am running headers only, I have no back pressure either and everyone tells me it will run even better if i did. I am going to have a longer pipe welded in soon and have a large washer welded in to give pressure, I still want the sound. Hopefully you will get better advice than I can offer a lot of the guys on here are amazing. Good luck, its a hell of a nice looking bike!

[darrelldaltonga]

appreciate it...my bike doesn't have to be fast but if its supposed to be faster i want it to run as it should

[trbig]

If I'm reading right, that Suzuki is rated at @ 56 HP. V-twins are notorious for low end torque.. so yeah, they should be able to make a race of it to about 20-25 mph or so, but after you hit @ 3k rpm and up.. you should be smoking him.


Tod

[TopCatGr58]

Hey Darrell,

Like Tod suggested, the powerband for these bikes it 3K +! Are you dumping the clutch at 1500 rpm?? Is this a straight on start from dead stop, or a slight roll on? Try revving to 4k, and fanning the clutch some keeping the rpm up or at least above 3k until you can get fully into the clutch, and then you should be able to crank the throttle WIDE OPEN and walk away from him up to 7.5 to 8K rpm before you shift into second. Be leaning forward to help keep the front end down!
T.C.

[Ivan]

Backpressure just smooths out the low end. I ran a straight through exhaust (cherry bomb) off a 4 into one header and the top end was incredible. The trouble was that the low end sucked. There was nothing up to 3k and then it felt like getting rear ended.

Then I put Jardine spaghettis on and the low end is now much more manageable. I don't think it has anymore power or torque, but the pull is much more smooth. The did neck down the top end considerably. It definitely doesn't have the pull above about 7k it used to.

Also, when playing with V-twins, you have to remember that those single throw cranks have the mass of the engine all going up and down at the same time. If the rev those engines much above 4-5k, things start vibrating off. Important things, if they ever want to reproduce. So don't let your ears fool you into shifting too early. With a stock FD (not the 750) you should be able to pull in first up to about 40 mph then shift. With the 750 FD you can pull clear up to about 50 mph, then second tops out about 70 or 80. So by the time you are ready to hit third, they are in fifth and thinking about 6th if they have it...

[DGXSER]

Interesting you mention the rattle your teeth out thing Ivan. The other day I was behind a Hardly in the cage, a newer one, as in post 1990 I would suspect anyway. This thing sitting still had the entire bike shaking like a freaking shake table in a casting factory!! I'm talking everything except the wheels was bouncing. The guys arms looked like he had parkinsons or something holding onto the bars! It was a dresser and even the bags were shaking so hard, I wanted to pour some 'rita mix in and follow him for a stop or two and drink up! Amazing what some people will pay money for!

[fredintoon]

I haven't done anything to the ignition but it runs very good and fires up fine. I've tried this scenario with two 800cc bikes and both times every time i get left the only thing i can think of is my pipes being short and not having enough backpressure but it shouldn't make it this slow

Hi Darrell,
this bike is new to you and is your first XS11? Are you absolutely sure it's running on all four cylinders? Mine started to run exactly as you describe, seemed to run OK and fired up fine but a serious lack of go.
Did the ol' spit on the pipes trick after a run and sure enough, #4 didn't spit back. Fought with the ignition for a week for no improvement. Cleaned out #4 carb and vroooom!

[DiverRay]

Looking at the pics again, I realize THERE IS NO TACH!! All you can do is rev it up, dump the clutch and twist the throttle until it starts to NOT pull, then shift. This engine does BEST between 7 and 9K, although it WILL pull from 1500 on up.

[81xsproject]

yeah, that shouldn't even be a contest. You should blow him away.

[tw1980]

Like the others said.Your friend should be looking at your tail light getting smaller.Are you sure your bike isn't running on 3 cylinders?

[foreda]

Pull

Definitley sounds like you're bike is not running to its potential. Have you ever sync'd the carbs?