Valk performance sucks!!! (long)

[old grouch]

OK, maybe not QUITE that bad, but not very good.  I have posted about this before, without much success, but I am getting frustrated.  I bought this '99 I/S about two years ago.  It had approx 50K on it and now has 80K.  Since I have owned it, I have never been able to get above 100 mph, except twice going down a steep grade while passing where I needed to go fast.

  The engine starts easily, no choke needed above 40* F, idle is smooth except for a slight "loping" of maybe +/- 50 RPM.  No "stumbling" or missing at any RPM or speed.  No popping on decelration.  Overall MPG is around 30.  Acceleration is very strong up through 3rd gear, right up to redline, and into 4th .  Max RPM in 4th is about 5000.  Max RPM in 5th is about 4200.  When running Wide Open Throttle, if the throttle is backed off a slight amount, there is a small but noticeable increase in power.

    I want to restate that this has been the situation for as long as I have owned the bike.

 I Triked the I/S about 20K miles ago.  The final drive is 2.73:1, with 215-65R 15 tires.  I can spin both back tires from a standing start.  (once, just to see if it would)  At WOT, in 5th gear, on a level road, the fastest speed ever attained is 99.4 mph, GPS indicated.  That was achieved about a week ago, after about three miles at WOT. 

    That said, the bike is stock except for being de-smogged, having the piggies cut & drilled, (outer baffles only) a Pingle and a DanMark electric fuel valve.  Air cleaner is new.  I have removed the carbs and gone through them.  The floats are normal.  The jets are stock and clean.  I can find no damage to the diaphragms that lift the needles, nor the needles themselves. 
   
The plugs appear as shown in the pictures below.  Pictures were taken after using the kill switch and coasting to a stop.  Not pictured are the plugs at idle.  They appear identical to the other situations.  These were replaced during the Trike install, and appear identical to the ones removed. (yes, I kept the originals)  The brown streak evident on #4 in the WOT picture is found on all the plugs in all situations, but in various places around the insulator. (maybe nearest the exhaust valve???)

To my not so professional eye, it appears that the mixture is lean.  I plan to shim the needles about .008 today and see if the mixture fattens up, which would indicate the need for larger main jets?  I don't know if that would improve the top end??  Beyond that, I am at a loss.  Anyone able to contribute any sage advice?  Stan

70MPH


WOT

[old grouch]

Forgot to say carbs have been recently synched, and pilot screws are at 2 1/4 turns out.  Stan

[BigMac (SoCal)]

Almost seems like a timing issue. Have you checked you timing belts to make sure that they are in the right position. Maybe someone put new ones in and didn't aline the cam marks properly. Just a thought.

Dave   

[old grouch]

Dave
I just changed the belts.  To the best of my knowledge, I got the alignment correct, but I will open her up and check again.  Thanks for the input.  Stan

[old2soon]

I ain't for sure-could be talkin out my a$$ here-but you are what 4000 feet above sea level there in the springs? Could the altitude be part of the problem?? I used to live in lamar-and the altitude affected all my naturally aspirated engines and we were at like 3100 feet. Just sayin. RIDE SAFE.

[Challenger]

old2soon maybe on to something, A buddy of mine lived in Greeley for a while, Said when he put the front tank spacer in to lift it up for his carb stacks, he picked up 5 MPH on top end. I assume because of more air available at WOT.

[old grouch]

old2soon--actually 6200 feet, but who's counting?  I had considered that, but Misfit who lives here as well doesn't have any problem running up to 100+mph, nor do several others around here, including Valks from low altitudes I have ridden with here.  Also, unless I am wrong, the plugs are showing a lean condition.  Am I reading the plugs wrong?

Challenger--I have heard that before as well, but again, the lean condition indicated by the plugs argues against more airflow.  I did replace the K&N filter with a stock one, which supposedly has a lower airflow, which should produce a richer mixture, and had no discernable change in the appearance of the plugs.  Thanks, Stan

[old2soon]

Is there a trigger wheel in yours other than stock?? If there is isn't it supposed to be a 4 degree wheel for the I/S and six degrees for the others?? Just scratchin and guessing here-ilive down in the flat lands (99 I/S stock near as i can tell) and have no problems what so ever doubling+ the 65 mph speed limit at will. Also get about 30 mpg-if i play nice with it. Course i hardly ever play nice. The one thing that stands out from your post is the fact you've had this situation/problem/glitch since you've had the valk. Really wish i could be more help here. I'm still learning about these fine machines we have chosen to ride. RIDE SAFE.

[old grouch]

It did have a 4* wheel when I got it.  Replaced with the stock one with no changes noted.  I appreciate your thoughts.  At this point I will try just about anything!!!  Stan

[Ricky-D]

Your plugs look fine! And:

At higher altitudes your bike will want to run rich which is evidenced by you comment about what happens at WOT.

When running Wide Open Throttle, if the throttle is backed off a slight amount, there is a small but noticeable increase in power.

This is clear evidence of too much fuel and a smaller main jet would be indicated.

As far as the plugs,,, here is a good link for plug reading guidance!

http://www.dragstuff.com/techarticles/how-to-read-plugs.html

You can try to use some "Kentucky Windage" to solve your problems but denial of the obvious will be counterproductive and not help at all.

I think that comment about trigger wheels would cause you to investigate what may be in your motor. The best trigger wheel for top end is the stock Honda Valkyrie trigger wheel.

Another point would be what gasoline you are burning. I don't think ethanol enriched varieties are as productive as are the lower grades of gasoline.

You don't mention the air filter.

***

[olddog1946]

I am not sure that you have any problem with your bike...the rear end gear ratio from the OEM setup is something like a 4.10:1, and you have a 2.73 gear set now...you may just not have the power to run that set up...if it accelerates fine in 4th but dogs out in 5th...you've got the wrong rear gears..

[Garland]

I think he said it ran just as poorly before the conversion.

You might try swapping another bikes ICU, see if it makes a difference. I don't think it is the timing-I have had mine a tooth off and it ran much worse than your bike does. I had a loose coil wire once that also caused it to run pretty bad-again much worse than you are experiencing.

[old grouch]

Ricky
Thanks for the input.  I agree that higher altitude will cause the engine to run rich.  I am trying not to "deny the obvious" but may be a little short on knowledge in this area.  I had thought the plugs were indicating a lean condition.  After looking at the link you provided, seems I may have been wrong.  I have had the bike, in both its 2 & 3 wheel form at or near sea level and over 12,000 feet.  While I have not done the plug checks anywhere but where I live, I have tried to exceed 100 mph at lower altitudes without success.  The bike did have a 4* trigger wheel, which I replaced with a stock one.  I could not see any difference in performance (top end) or plug condition between the two.  I also replaced the K&N filter, w/o prefilter, with a stock filter.  Again, I did not note any change in performance or plug condition.  In place of "Kentucky Windage", what would you suggest my next step should be?  Stan

[Kaiser]

Was the desmog done when you bought the bike, or did you do it?

If you bought it that way, it might be that the bottom of the airbox wasn't plugged.  Did you happen to notice when you put in the new filter if the bottom hole (resulting from the desmog) was plugged?

You've ruled out gear-ratios and anything in the final drive by stating the same problem existed prior to triking - that really only leaves fuel and air.  And - you said the carbs look good - so that only leaves air.

It just sounds like you aren't getting enough air, and I wonder if that hole is still open if that has anything to do with it.

[Jeff K]

From my experience...

If you let off the throttle and it picks up power it is a sign of being lean not rich.

It is a common symptom on a blown bike running out of fuel on the top end. In that situation it's because the cab bowl can't fill fast enough to feed the jets.

Have you checked the fuel screen? The fuel vent?

Sounds like lack of high end fuel to me.

[Ricky-D]

OldDog1946 makes a very cogent point and must not be dismissed out of hand!

I have no clue about the rear end you have but if you could borrow some smaller wheels that would fit you would get a definite indication if it is in fact too high gearing.  

Also, what would be good is to have the relationship posted between speed and rpm in top gear.

I would if it were my bike, perform a compression test on all the cylinders just to ascertain the condition of the motor.

Have you tried any other things attempting to get better performance?

I think wind resistance may factor in with the larger swept area of the trike set-up.

***

[Ricky-D]

I stand corrected.

I went and checked my tuning manual and Jeff is correct.

Here is the applicative paragraph from Mikuni:

ROLL-OFF:

The Roll-Off technique is the quickest and is almost as accurate as the Roll-On method. First, one gets the engine warm on the way to a safe roadway. If there is room, use fourth gear as this allows more time to assess the result.

Now, get the engine rpm high enough that it is on the cam and in its power band. This may need to be as high as 4000 rpm with some cam choices. Apply full throttle. Let the engine accelerate for a couple of seconds until it has settled in and is pulling hard. Quickly roll the throttle off to about the 7/8ths position. When you do this, the mixture richens slightly for a second or so.
If the engine gains power as you roll the throttle off, then the main jet is too small and you need to fit a larger one.
If the engine staggers slightly or has a hard hesitation, then the main jet is too large and you need to fit a smaller one.

Ref:  http://www.mikuni.com/fs-tuning_guide.html 

I apologize for the misleading post.

***

[Kaiser]

If the bowls don't fill fast enough, in theory couldn't he "crawl" to top speed instead of hammering down on it and get a different result (higher top MPH)?

[Mr Steve]

Wouldn't happen to have a slightly pinched or slightly collapsed tank vent hose, would you?

[Daniel Meyer]

Also put a voltmeter on it...say at the ignition fuse...where you can see it running hard...and go run hard. The valk ignition uses an amazing amount of power at high sustained rpm...could be your experiencing a voltage drop...when mine did it, the issue was a bad connection to ground...but I got a more pronounced stumbling.

Worth a check anyway.

Oh, and triple check the tank vent and tank screen...

[Spirited-6]

  The engine starts easily, no choke needed above 40* F, idle is smooth except for a slight "loping" of maybe +/- 50 RPM.  No "stumbling" or missing at any RPM or speed.  No popping on decelration.  Overall MPG is around 30.  Acceleration is very strong up through 3rd gear, right up to redline, and into 4th .  Max RPM in 4th is about 5000.  Max RPM in 5th is about 4200.  When running Wide Open Throttle, if the throttle is backed off a slight amount, there is a small but noticeable increase in power.

Old Grouch, I`m somewhat of a smart a$$ so I gotta ask; how often do you need to run 100+ MPH and WHY. Sounds like your Trike is great at all other speeds, except for MPG. Riders that let the hide meet the road at that speed require to be cleaned off the road with a "puddy knife" The best way to enjoy our great USA and our Valkyries is at a speed where you can see the USA.  How ever, good luck in finding your problem. 

[Jeff K]

If the bowls don't fill fast enough, in theory couldn't he "crawl" to top speed instead of hammering down on it and get a different result (higher top MPH)?

Sometimes that will work. But at that is why why you let the throttle off a bit it comes back, because the bowls have a chance to refill.
Feed problem or jet issue.

[Hoser]

Perhaps a higher flow petcock like the pingel would help, but anytime your pushing wind, especially a trike, its gonna be tough to accelerate a whole lot over 100mph.  Remember, all those mph figures you see at stationary dyno runs are completely invalid at real conditions.  Kinda like riding into a 40 mph wind, turning around and having 40 mph tailwind.  Much faster, much better milage, and much more enjoyable.  Lots of tail and headwinds out here on the plains.  Hoser

[old grouch]

Thanks for all the input.  I AM listening & will try all the suggestions unless I have already done so.  I will try to answer the questions.

I don't often want to go 100+ mph.  I prefer to cruise along and enjoy the scenery.  Except when my wife tells me to watch the road (Independence Pass etc) and she will take pictures for me to look at!  The problem is that at 70, in 5th gear, there is very little left for such things as passing.  In order to get from 70 to say 85 or 90, in a timely manner, if for instance I have misjudged the speed of an oncoming vehicle, and need to complete the pass faster than I had thought, a downshift to 4th is required, and even then it ain't real quick.

Tank vent and screen are clean.  No kinking or pinching in vent hose or fuel line.  I am sure of that.

According to the shop manual (thanks, Dag) the final drive on the Valk is 2.833:1.  My final drive is 2.73:1.  The diameter of the tires is 26" +/-  If memory serves the diameter of the stock rear tire is something like 25.9", so the final drive while somewhat different, should not cause the problem, plus this was also present BEFORE the conversion.

De-smog was done by PO and yes the hole is plugged.

If I missed answering any body's question, throw rocks.  I respond well to violence 

Since the consensus seems to be that the engine is lean, has anyone ever found that the floats were so low as to not allow the bowls to fill?  I don't have a float guage anymore, so when I had the carbs apart, I had to estimate the float height, but all appeared to about the same.  Stan

[Lonerbtw]

 I have a 98 standard that I triked. Sounds like you have a Mustang 7.5 rear end. Same rear end ,same tires and I can easily run over 110 realy quickly and with more to turn. Just saying gears are not your problem.

[X Ring]

Stan, didn't you say this has been going on BEFORE you triked your I/S?  If so, triking it only added to the problem.

Marty

[Brad]

  The engine starts easily, no choke needed above 40* F, idle is smooth except for a slight "loping" of maybe +/- 50 RPM. 

The "loping" or searching a little at idle seems strange to me.  All of the Valks that I have been around idle at a constant speed with no loping.  Is this normal for a Valk

[bigdog99]

i heard once that the gas tank cap "venting" if you will, causes the tank to vacuum lock. is it possible the gas cant get out of the tank fast enough even though the vent tube is open.
use the spare key and open the gas cap, try to get to 100 plus then.
i never had the problem but knew a friend that did, carried his spare key every trip

[John U.]

I think you said you have a Dan-Marc installed. Is it possible that the fuel line was cut a bit too long and has created a narrow spot to restrict max flow? Just a thought; based on your description of the problem, I agree with the lean/restricted flow diagnosis,
Have you checked vacume hoses and caps and the clamps on the rubber connecting boots to the carbs.
It's possible though rare that pinholes can develop in the diaphragms above the jet needles which can mess up their movement.
It's also possible for vacume leaks to develop in the vacume hose to the petcock or in the petcock diaphragm which could prevent the petcock from opening fully.
Good luck with it, I'm out of ideas.
Keep us posted.

[old grouch]

Marty-  Long time no see.  Guess you are right about that! 

Brad-  I agree, the loping is not the norm.  I just don't know if it is related.

bigdog-  I don't think that is the problem, but I will give your suggestion a try.  Can't hurt.

John U-  Misfit suggested that my fuel line might be too long.  I trimmed it & it will just barely reach now, so that doesn't seem to be the answer.  Yes I checked all the possible sources of vacuum leaks.  All the clamps are tight and the caps are new.  I checked the diaphragms for pinholes and didn't find any.  That doesn't mean they aren't there, just that I didn't find them.   The petcock is a manual pingle, so there goes that idea.  I'm out of original ideas my ownself, but the VRCC folks are doing their usual great job of helping out, so I have great faith that eventually, a solution will be found.  I will try anything suggested here that I haven't already tried.  And maybe I will try some a second time.  Thanks again for all the input!  You guys are great.  Stan

[Ricky-D]

Regardless of what the reality is:

I think that the combination of slightly higher gearing and the additional weight of the trike addition definitely plays a part in the lower than expected top speed of you bike!

Understanding that you can get a higher speed/rpm in 4th gear than in 5th gear; probably,  the most preferred option would be to change the gearing in the rear end.

Attempting to compare one bike to another is folly and can not by any imagination be a real yardstick.

Motor condition is the real suspect as is the state of tune!

***

[GREENDRAGON]

Stan, I bet if you repaint it GREEN / Silver it will be much faster.

[Chiefy]

Regardless of what the reality is:

I think that the combination of slightly higher gearing and the additional weight of the trike addition definitely plays a part in the lower than expected top speed of you bike!

Understanding that you can get a higher speed/rpm in 4th gear than in 5th gear; probably,  the most preferred option would be to change the gearing in the rear end.

Attempting to compare one bike to another is folly and can not by any imagination be a real yardstick.

Motor condition is the real suspect as is the state of tune!

***

Old Grouch, before you start changing the rear end gears, I'd ask the Valk trike owners on this link if they've had the same experience: www.triketalk.com.

[X Ring]

Regardless of what the reality is:

I think that the combination of slightly higher gearing and the additional weight of the trike addition definitely plays a part in the lower than expected top speed of you bike!

Understanding that you can get a higher speed/rpm in 4th gear than in 5th gear; probably,  the most preferred option would be to change the gearing in the rear end.

Attempting to compare one bike to another is folly and can not by any imagination be a real yardstick.

Motor condition is the real suspect as is the state of tune!

***

Old Grouch, before you start changing the rear end gears, I'd ask the Valk trike owners on this link if they've had the same experience: www.triketalk.com.

Chiefy, this was going on before he triked it.

Marty

[Skinhead]

To me your plugs look a little on the light side (lean).  Sounds like your not getting enough fuel under high load.  This may be somewhat of a pain in the butt, but I would temporarily replace the Dan-Marc (you could still leave it wired, just along for the ride)with a straight piece of fuel line, to make sure that isn't your restriction.  Is there still a petcock on it or was that eliminated when the DM was installed?  if so, check that as well.

[valkyriemc]

  The engine starts easily, no choke needed above 40* F, idle is smooth except for a slight "loping" of maybe +/- 50 RPM.

The "loping" or searching a little at idle seems strange to me.  All of the Valks that I have been around idle at a constant speed with no loping.  Is this normal for a Valk

+1 -Nope lope is not kosher and may indicate timing.

[old grouch]

Thanks all.  I will answer your comments then add some new stuff at the end.

valkyrienc-- While the "loping" may be related, it may not, so I will deal with that after I get the top end issue sorted out.

skinhead-- I will add that to the list of things to try.  Intended to try a lot of things today, but "Life" got in the way.  Will try to get some done tomorrow.

Chiefy-- Have actually talked to a couple, not via the TrikeTalk board but by e-mail.  No joy.

Ricky-D-- I have spoken with a shop here that can run a full up Dyno on it.  Just want to try and eliminate some of the simpler stuff before I start spending big bucks.

Phil-- Come on down and bring your spray gun!!!

Now, I had a Honda motorcycle mechanic make some comments, suggestions & would like to know what you all think.  He said my problem was not a lack of fuel, but too much air.  Said I should check ALL places where the engine could get air besides where it is supposed to.  He suggested I restrict the intake of the airbox with duct tape.  Said it would either run better or worse.  If it ran better, excess air is the problem, if worse then it is a fuel issue.  Make sense?  I have assured myself that all the vacuum caps are intact, all the clamps between the air box and carbs are tight, gaskets are in the air box.  I did discover when reinstalling the air box/carbs that all six of the tubes between the box and the carbs were loose enough to turn easily.  That didn't register until after his commments.  I sealed them last night but haven't had a chance to see what if any difference it made.  Any other places where air could conceivably get in?  Thanks again for the input.  Hopefully I will get to try some more things tomorrow.  I will keep you posted.  Stan

[Chiefy]

Regardless of what the reality is:

I think that the combination of slightly higher gearing and the additional weight of the trike addition definitely plays a part in the lower than expected top speed of you bike!

Understanding that you can get a higher speed/rpm in 4th gear than in 5th gear; probably,  the most preferred option would be to change the gearing in the rear end.

Attempting to compare one bike to another is folly and can not by any imagination be a real yardstick.

Motor condition is the real suspect as is the state of tune!

***

Old Grouch, before you start changing the rear end gears, I'd ask the Valk trike owners on this link if they've had the same experience: www.triketalk.com.

Chiefy, this was going on before he triked it.

Marty

All the more reason to not start changing rear end gears.

Old Grouch, I think you said the PO de-smogged it?  How?  And could any of the plugged up ports be leaking?

To my basic wrench skills, what the Mechanic says sounds interesting enough to try.  What have you got to lose, except a little time?

[John U.]

The only other place, for air to enter (assuming you have tightened both the upper and lower clamps on the rubber connectors) is the O-rings between the chrome intake tubes and the heads.
Rust, or some nasty gas can clog a petcock screen pretty fast. Just sayin.
One more thought; stretched or badly worn timing belts might screw up the timing enough to make a difference.

[Russell Rice]

there is a "timing" mark on the tubes that match a timing mark on the air box, make sure that they are lined up right. I would also double and triple check the air tubes where they go on the carbs and make dang sure they are on all the way around, they do not need to be gorilla tight but the clamps that hold them on do need to be snug. I would also double check all vacuum lines for leaks, the stock lines get hard and are bad about having tiny holes in the bends, I would use silicon line with with silicon grease on the ends of the lines.