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100 mph hard to achieve

5K views 36 replies 26 participants last post by  bikendad 
#1 ·
ok just asking , I have a new xc ,stage 1 af ,flash, and I modified stock muffler, gutted with a 2.25 pipe out, bike runs good but when I try to push 100 it seems to not have the power to get there , not that I need to be doing that speed but but my vtx1300 will go to 120 with no problem, again I am not looking to run these speeds often ,just like to know I can, do I need a fuel controller?am I loseing top end due to lack of backpressure ? im going to put A bolt and weld a washer on it in the exhaust pipe to see if that gives me the back pressure i need if that is the case ,just asking if any body has any ideas on this ,oh ya and I unplugged the o2 sensors also
 
#4 ·

I've had mine to 115 with drilled stock baffles, O2 sensors unplugged, and the strip removed from the air filter. There was a little left in it, but things were starting to vibrate (fairing, bags, and other plastic bits) so I let off. I will agree that once you hit 95-100 accelleration takes a while, but I didn't expect this bike to be as fast as my VTX 1800 anyway (yet
)
 
#5 ·

Interesting. Twisted the XCT up to a GPS buck o' seven once. Wanted to see when/where any instability started. Seemed to have pull left, plenty of throttle. We all know that can go away quickly, just saying.
Didn't find out much. For all the bike cared it could have been 50 but that was all I wanted. Mine is stock.

Happy hunting.
 
#6 ·

Lostintexas said:
Interesting. Twisted the XCT up to a GPS buck o' seven once. Wanted to see when/where any instability started. Seemed to have pull left, plenty of throttle. We all know that can go away quickly, just saying.
Didn't find out much. For all the bike cared it could have been 50 but that was all I wanted. Mine is stock.

Happy hunting.
Wonder if the extra wind management pieces on the tour help keep things stable at that speed? I'm betting my KW shield doesn't help a bit.
 
#7 ·

DarksideX said:
I've had mine to 115 with drilled stock baffles, O2 sensors unplugged, and the strip removed from the air filter. There was a little left in it, but things were starting to vibrate (fairing, bags, and other plastic bits) so I let off. I will agree that once you hit 95-100 accelleration takes a while, but I didn't expect this bike to be as fast as my VTX 1800 anyway (yet
)
Ya 90 is no prob but when you start to push 100 it seems to struggle ,trying to figure out if it needs fuel or if the back pressure is the prob, it just seems like it just wants to sit there, then again the speedo might not be right either,
 
#9 ·

I was running 100" Vegas, with Victory Leaf blowers, factory (K&N) up rated air filter and the stage 1 re-map.
It had no problem hitting 110 mph and then took its time up to 120 mph.
I now still have the same pipes and have progressed to the S&S free flow filter, with S&S re-map.
120 mph no problem, it gets there quicker and still wants to go faster!
 
#10 ·

DarksideX said:
Wonder if the extra wind management pieces on the tour help keep things stable at that speed? I'm betting my KW shield doesn't help a bit.
I have a KW Flair on the front. Usually all the extra pieces create funky wind patterns, dunno. Trunk has never been off either, some seem to think they create problems but I haven't seen it. There is a lot of dfference in 10 MPH at that speed. Bucko' eight might have been another story. Dunno. Faster than it will probably ever see again though.

Cheers
 
#11 ·

jdt3 said:
Ya 90 is no prob but when you start to push 100 it seems to struggle ,trying to figure out if it needs fuel or if the back pressure is the prob, it just seems like it just wants to sit there, then again the speedo might not be right either,
One thing I noticed, and this could just be perception, is that the throttle has a point where it 'sticks' about 1/8 turn short of WOT. Nothing that is going to stick it open, but it seems to become harder to turn after that point. It could just be the awfully long twist these bikes seem to have, I was paying more attention to the road for some reason
 
#12 ·

Your Honda speedometer is around10% optimistic... 120 is about 108 in reality. I promise you it takes a lot more HP than your 1300 VTX makes to go a true 120 mph thru the wind.

Weight meets wind resistance meetsHP. A stock (or close enough) Vic 106" makes what, 80 and a couple of HP? Weighs what, 850?How fast do you expect it to go?

What gear are you trying this in? It should break100 mph in 4th gear.
 
#13 ·

Half_Crazy said:
Your Honda speedometer is around10% optimistic... 120 is about 108 in reality. I promise you it takes a lot more HP than your 1300 VTX makes to go a true 120 mph thru the wind.

Weight meets wind resistance meetsHP. A stock (or close enough) Vic 106" makes what, 80 and a couple of HP? Weighs what, 850?How fast do you expect it to go?

What gear are you trying this in? It should break100 mph in 4th gear.
tried it in 5 th ,I dont expect to go as fast as a sport bike or any thing just figured it should climb past 100 instead of just sit there ,I know its a bagger and a cruiser and 70 to 80 is plenty fast ,not looking to race just asking the question if the back pressure is a prob or the fuel
 
#14 ·

I have a '09 100/5 vegas 8ball... 100mph no problem, only change from stock is the 2:1 RPW Thor exhaust.
 
#15 ·

I've hit 100 (indicated...probably mid 90s actual) on my bone stock '12 Vision with no problems (didn't know I was going that fast until I looked down). Of course, it's the Bronze Mist which everyone knows is the fastest.
 
#16 ·

I'm no expert here, but I've got my pipes gutted with nothing else done to it (no stage 1 or air filter), and I can get up to 100 with no problems what soever....I would look somewhere else. Besides the whole backpressure thing is pretty much a myth.
 
#17 ·

My guess is that you're bogging it because you should be able to hit 100 in 4th without touching redline. 6th gear doesn't have much umph so if you're in 6th too early it isn't going to do as well as giving it some revs through lower gears.
 
#19 ·

I have had mine up there a couple times. 2012 xct stock. Hit 105 with no hesitation. I too had the buzzing or rattles above that so I backed off at 110. I just had to see if I could do it. Now that I have the stage one I have never tried again. Now I am curious to see if there is a change at the top side. but I doubt I will ever do it again. Like I said I just wanted to see if I could do it.
 
#21 ·

ammo_umb said:
My guess is that you're bogging it because you should be able to hit 100 in 4th without touching redline. 6th gear doesn't have much umph so if you're in 6th too early it isn't going to do as well as giving it some revs through lower gears.
I will give that a try , im use to my vtx with a 5 speed ,just learning all the differences of where the power band is and so on and so forth ,thanks
 
#22 ·

I guess I wiil not say how far over 100 my Judge has been. Wouldn't be prudent.
 
#23 ·

Don't you just hate it when someone says something and you think to yourself "I'll have to check that out". Curiosity is not always a good thing ;)
 
#24 ·
Pretty tough to diagnose like this but typically lack of back pressure will effect low end more than top end, although I have seen some dyno graphs with modded exhaust that made real nice peak #'s but the top end did drop off pretty quick. Only way to really know for sure is to try a different set up. A PC-V or Lloyd's reprogrammed ecu will give you a higher redline which should make fourth gear get you well past 100. Once you start talking triple digit speeds the hp neccessary to overcome wind resistance becomes a huge factor. If you're in a taller gear like fifth or sixth, at 3000 rpm your motor is only making 50-60hp. That's enough to roll on and go from 60-80 nicely, but if you're trying to get from 80-100 that's a lot harder job. At 4500 rpm your much closer to 80 hp. So for a top speed type run you want to redline that thing before shifting. If you redline in fourth gear then shift into fifth you're much higher in your rpm range, making more power, than if you shift at 4000 rpm's. Driver technique does matter.
 
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