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Curious about squeaking a few extra HP from the bike

6K views 33 replies 20 participants last post by  stephenmarklay 
#1 ·
So I have been perusing this section of the forum, and read about many of the possibilities... There seem to be many. First let me tell you my situation and expectations, hopefully this will help with the suggestions.

I live at high altitude, in a very windy place. The highway speed limit is 75 mph. I often find myself, having downshifted with the throttle wide open and the bike not going anywhere possibly even losing speed. I recently replaced the plugs which were somewhat dark leads me to believe the bike is running rich. Not 100% sure if it is affecting the performance though.

That being said, I am hoping to get a few more HP a 5k rpm and up. I am not trying or wanting to turn the bike into a sport bike. Just get some more juice for the highway. I am envious of all of you living at sea level, the motor is incredible down there. Its just up here the wee struggles, sometimes even to go 65mph depending on the elevation and the wind.

Thanks!!!
 
#2 ·
I've ridden the Wee from 200 feet below sea level to 10,000+ feet, two up, and there was always ample power. I'd rather throw money at the suspension than try to get more HP.

If it's truly not fast enough for you, your best option would be to sell it and buy a Vee. You're not going to extract enough extra power to make it worth your while.
 
#3 ·
Its not that the bike is not fast enough. It is just I don't like having max throttle in 5th gear and slowing down below the speed limit. Please help me get the power the wee should have then.
 
#7 ·
I would go through everything on the bike and make sure there are no vacuum leaks, check air filter, throttle plate position, fuel filter, carb//injectors. you could also change the gearing but you lose torque in the process.

Sent from my DROID RAZR using Motorcycle.com Free App
 
#8 ·
Have you considered a complete tune up? sometimes small stuff like air filter and plugs can make a big difference.
I found that mine has loose adhesive on the grips and they rotate around as I ride. Especially with the Oxfods keeping my hands warm. When I feel like I'm loosing headway I roll the throttle off against the resistance and when I rotate the grip for acceleration the I have more power. I've been to lazy to pop them off and re-glue them. There are threads about good adhesives here I haven't made use of yet.
I noticed some folks seem to have some wired wrapped around their grips. That might help loose grips not gripping.
 
#10 ·
Ted,
Were your previous bikes used at the same elevations?
Did they suffer similar issues?



If not, you MAY be suffering from a fuel flow issue likely caused by a fuel filter that is getting plugged.



Do a search on the forum for fuel flow test using the Google search and see if that makes any sense.

Another thought: Is your air filter clean?
 
#13 ·
Last bike was 100 lbs heavier but 20hp more. Had no problems at altitude. I already replaced the plugs and even though they only had 7k miles on them the new ones made a big improvement. I am gonna do the air filter next, the plugs indicated rich mixture so the filter might be clogged with dust. Just a guess, I am thinking about trying to washable filter due to the dust here.... Is the fuel filter easy to replace? Last time I changed that on my subaru it made a huge improvement!
 
#11 ·
The simplest (and maybe best) answer is to get a Vee. The 650 is not very amenable to easy HP gains. You can do the SV cam swap (second gen SV cams in place of the Strom ones) get Power Commander, a full exhaust and do a good dyno tune, and get about 10hp. Roughly $1000.
 
#15 ·
What altitude do you live at ?

All of this seems normal except that you said you were at WOT and barely able to maintain speed. That sounds odd. WOT on these things (although not like a VEE), is not standing still either ... Mine at WOT moves my fat ass along pretty well.

When you say "High Altitude", from many of our perspectives you could be talking about 2000 above MSL as we are flatlanders ... So, are we talking 2000MSL or 11,000 MSL ?

Huge difference there ...
 
#18 ·
I live at 7200 Ft, that is location of my house. With regards to my experience on the highway, I was on I80 between Laramie-Cheyenne it is close to 8500ft on the stretch of highway I was really struggling.

I had downshifted from 6th to 5th gear (guess I could have dropped to forth but I did not at the time), and with the throttle all the way open I could not keep 70 MPH indicated, there was gusting wind of unknown speed. I got off the highway to the side roads until the large decent into town you have to use the highway no other way in or out of town in this direction due to mtns (it is about 10 miles downhill more than 1000 feet elevation drop).

have not ridden this passage interstate since replacing the plugs, but have noticed the bike is more perky just riding to work and back about 5 miles. I used the standard cr8s, but think I might need to go hotter due to the cool temps here, and older plugs indicating a rich condition.

Someone mentioned the windshield position, it is in the middle I believe I have not adjusted it since purchasing the bike 3 weeks ago.


I didn't remember the exact calculation from my flight training days so I looked it up. It is approximately 3% per 1000 feet loss .. So, lets say 8000 feet is about 25% less output than at sea level.

So, the wee is about 67 HP at sea level ? And thats at 8200 RPM. I think that is right ... 67 -25% is about 50 Horsepower. On a 450lb bike with 2 people, in the wind, on hills.

Im not going to ask your weight but assuming 2 people, that is at least 300 pounds in people ...

So, I'm not so sure that what you are seeing it really that out of line ... Maybe you have a vacuum leak or something like others have mentioned (fuel filter etc.), but maybe not.
 
#19 ·
I didn't remember the exact calculation from my flight training days so I looked it up. It is approximately 3% per 1000 feet loss .. So, lets say 8000 feet is about 25% less output than at sea level.

So, the wee is about 67 HP at sea level ? And thats at 8200 RPM. I think that is right ... 67 -25% is about 50 Horsepower. On a 450lb bike with 2 people, in the wind, on hills.

Im not going to ask your weight but assuming 2 people, that is at least 300 pounds in people ...

So, I'm not so sure that what you are seeing it really that out of line ... Maybe you have a vacuum leak or something like others have mentioned (fuel filter etc.), but maybe not.
Thanks for the info. So per previous suggestions I think slight improvement will be made by replacing the filter, it is very dusty and dirty. Not surprising considering where I live and how windy it is. I think you are right, between the power loss, a headwind and 175 lbs of me. The little twin just can't do it. This is really unfortunate. I had managed on a calmer day to get out of town, and ride the bike 1100 miles in a few days. Although all but 100 or 200 miles of these were at sea level, where the motor handled beautifully. Lots of mixed feelings about the wee-strom at this point.
 
#21 ·
#27 ·
did this, sprockets are 15-47. Have not done a fuel flow test yet. Could it be kind of clogged from so low miles in 7 years?
 
#25 ·
That would only be true for a properly running engine that is fouling plugs. If plug fouling is a problem with stock heat range plugs on a V-Strom, there is something wrong with the engine that is causing it.
 
#24 ·
If I can ride at 85mph all day long on a geared up KLR650 with 36hp at sea level with hills and wind, I'm sure 50HP would be more than enough for you to keep up at 70 without issue.

Time to change the air filter and do some diagnostics. Something isn't right at all.
 
#29 ·
A 4-stroke fuel injected engine should NEVER foul a spark plug. The dark coloring of the plug you described indicates a rich mixture as you correctly ascertained. A rich mixture is either too much fuel or too little air. My first thought was a dirty air filter as suggested by someone else. One rather inexpensive fix would be to go to a K&N filter to maximize air flow. The lack of power as you've described should not be happening. Sure, the elevation is robbing some power but it should not be happening to the extent you've described. I recently took a trip thru the Ozarks, two-up with luggage and my Wee had enough power to accelerate in 6th gear up a rather steep incline at about 4500 feet. I realize that this elevation was well below yours, but my concerns about a lack of power were laid to rest. One thing comes to mind as I write this. When you first start the bike now, does it emit any smoke....like a puff of blue or black smoke...and then clear up quickly? Blue smoke indicates oil burning in the combustion chamber...black smoke indicates a too-rich mixture. I would do this, get a friend/wqife to follow you and after warming up your engine thoroughly, run it full throttle from 2nd thru 4 gears and have the person look for smoking if so, what color. I'm talking about running the engine up to about 10k rpms up a slight incline to load the engine. Hope this helps as I'm sure you are frustrated.
 
#31 · (Edited)
No smoke, I ride her pretty hard. No oil loss either. However she smells pretty rich upon start up, my bike has plenty of power at 4000' feet. But riding two up on an incline I am frequently in 5th at 65-80mph in order to have enough power.

Edit: I think I previously mentioned it. I put brand new plugs in and started running 85 octane, the bike seems to be running much better. At sea level the wee feels so good, so I really just think it is the crazy altitude here.
 
#30 ·
At 8000 feet you've lost 25% of the power, assuming you are still at a "standard temperature," which lately you have not been. It's been pretty hot everywhere. Hot air (which is less dense) robs you even more. Was at 8000' in Utah a few weeks ago and performance from my car was just plain terrible.

All things considered, these conditions could have been costing you as much as a third of the available power, even if there is absolutely nothing wrong with the bike. It's part of the reason we worry a lot about "density altitude" (combination of altitude and temperature) in aviation. Hot and high is dangerous for a whole host of reasons, only some of them related to engine performance. Wing performance is even more degraded.

Honestly, I've noticed significant slowdowns driving on I-80 in a fairly normal car. To "keep up" at the limit on that stretch of road really requires lots of excess power. I don't think you're easily going to get it from this bike no matter what you do.
 
#32 ·
I'd agree. I know that stretch of I-80 pretty well. Most normal vehicles will not maintain 75mph on that road without a downshift or two and it can get pretty miserable. Motorcycles of course typically have lots more power up top than your typical Honda Accord or my CRV, but the Wee is not wildly overpowered as motorcycles go, and it sounds like you've got yours pretty heavily loaded.

Last time I moved cross country in a heavily loaded car (Accord circa 2000), I was struggling to keep it at 65 on some of the uphills. It could do it, but was two gears down and running at a very uncomfortable RPM. Eventually just reconciled myself to the fact that I was going to be slow on that stretch of road, as I have several times before. It's part of the reason you see so many larger vehicles when you get to the mountains. There's nothing like an oversized engine to keep you moving when things get high and hot.
 
#33 ·
I must agree that the Wee is not a particularly powerful bike although there are some who may think that it is. I have found on long reasonably steep grades that the Wee is sluggish even though it is in good state of tune and I don't have to contend with high altitude. I did however change the countershaft sprocket from std. of 15 to 16 teeth which will tend to behave like an overdrive gear.
Is your front sprocket OEM 15?

Saturn 5 .... bikes still give me a high!
 
#34 ·
My experience is very limited. However I rode my bike through a few passes with elevations in the 6500 range last week. Never once did I drop to 5th and never once did I get below about 75 indicated. I was not WOT or even near that actually. I don't know the grade of your pass but these must be in the 5-7 range I am guessing. Honestly there was not a lot on the road that was going as quickly. I was cold :)
 
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