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Author Topic: rougher at higher rpms  (Read 1592 times)

webnash

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rougher at higher rpms
« on: August 02, 2008, 05:41:57 PM »
I'm up to about 350 miles on my 2 week old avl classic. I've done some basic service on it (head bolts, changes fluids, chains and clutch adjustment....) It's running generally great as far as I can tell, since I've never had a single before. Starts easy on 1 kick, idles perfectly, gearbox is either getting smoother or I'm getting to know how much space between various gears. As I'm starting to open up the throttle a bit, for periods of a couple of minutes or less, it often seems to get a bit rough - not quite misfiring - but not as smooth as lower rpms. I'm wondering if this is just a "single " thing, a break-in thing, or if something is a bit off. If I had a non-electronic ignition, I would think that the timing isn't advancing enough.

I'm also wondering if it's jetted a bit rich on the top end. I've emptied the fuel bowl and doesn't seem to have any water in it. I was planning to change the plug today. The valves seem to be adjusted pretty well - at least with the spin method. Any other thoughts?

Oh yeah, one more thing... 20-30% of the time it is NOT rough at high rpms, it is just as smooth as lower - which has me wondering if it's just a "run-in" issue.

thanks, Mike

REpozer

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Re: rougher at higher rpms
« Reply #1 on: August 02, 2008, 06:24:05 PM »
Not sure of rough vs misfire. There should be some vibration as you open the throttle more as per break-in On my machine the front blinkers shake at approx 35-45.mph.
 You could check to make sure the carburetor to jug rubber boot clamp is on correctly and tight, may be sucking air(vacuum leak) .
2008 AVL Classic Bullet in British Racing Green
REA # 84 ( the first time)

luoma

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Re: rougher at higher rpms
« Reply #2 on: August 02, 2008, 11:25:16 PM »
It's a long-stroke single with a heavy crank/flywheel. At mid-range rpm's it self balances pretty well, but as it gets into the higher revs, it naturally creates a lot of vibration. Sometimes, if engine, chassis, road, wind, etc, are all in rythem, it seams very smeeth at higher rpm, but most times not. Enjoy your mid-range torque and shift when appropriate. You'll enjoy it more than if you try to ride ot like a re burner.

I rev mine up quite often, but only for acceleration.

Thumper

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Re: rougher at higher rpms
« Reply #3 on: August 03, 2008, 09:13:13 PM »
If it's stock then I doubt very much that it's running rich.

What road speeds do you feel it most and what gear(s) are you in at the time?

Doesn't sound right to me.

Putting in the new plug is a good idea.

Is the choke mechanism out of the equation?

Matt

webnash

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Re: rougher at higher rpms
« Reply #4 on: August 04, 2008, 11:25:59 AM »
I did a little more research on the issue yesterday, and also rode my brother's 2004 classic with about 3000 miles on it for comparison. It accelerates OK up to about 45-50mph, then if I keep running it at 45-50 or thereabout it seems to surge a bit - seems to gain and lose power. It definitely runs smoother accelerating or decellerating than to keep it at a constant speed. My brother's bike seemed substantially smoother at those same speeds. It's mostly 4th gear that I notice it going 40-45 or 5th gear going 50-55. I changed the plug and re-checked the valves. ???

Joe28

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Re: rougher at higher rpms
« Reply #5 on: August 04, 2008, 11:43:07 AM »
Hmmm, is it missing, surging, (that's a lean mixture), or vibration?
Sometimes it's hard to tell.
I'd check my engine mount bolts. if they are all tight, loosen them and let the motor,"settle" in the frame and re tighten.
Check ALL the bolts, the rear tire, exhaust, etc to find Something.
If it was the timing, you'd think it'd "ping", be gutless, hard to start.
Here's food for thought, could it be tire balance?
Might just be a "tight" motor protesting being asked to run at that RPM.
Does it do it at THAT RPM, no matter what gear?
RE check you trans lube, (could it be low?).
What did the plug look like? ???
Keep us posted.
Joe
So many bikes, so few $$ ;)

Thumper

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Re: rougher at higher rpms
« Reply #6 on: August 04, 2008, 12:43:16 PM »
I did a little more research on the issue yesterday, and also rode my brother's 2004 classic with about 3000 miles on it for comparison. It accelerates OK up to about 45-50mph, then if I keep running it at 45-50 or thereabout it seems to surge a bit - seems to gain and lose power. It definitely runs smoother accelerating or decellerating than to keep it at a constant speed. My brother's bike seemed substantially smoother at those same speeds. It's mostly 4th gear that I notice it going 40-45 or 5th gear going 50-55. I changed the plug and re-checked the valves. ???

Those are the speed ranges I'd expect for 4th and 5th. You're on the needle at those speeds so I'd begin my search there. Maybe the needle clip is loose or off. Maybe the diaphragm has a tear or is not seated/sealed completely. You can follow the last section 'VI Carb Information' to examine the needle clip and diaphragm:

http://members.verizon.net/allofusmorrows/RE_maintenance.htm

Another possibility is that there is blockage in the carb that doesn't affect the lower ranges where fuel consumption is less - and only manifests itself as the need for additional fuel increases. So you might consider pulling the carb and disassembling and checking all the passages. Likewise the petcock - which would give an indication if gunk is in the system.

Matt

erk187

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Re: rougher at higher rpms
« Reply #7 on: August 05, 2008, 02:43:58 PM »
How about this one... His petcock, when turned on, dribbles fuel out, when turned off, dribbles fuel out a bit slower. My guess is that it is fuel-starved due to a screwed up petcock.

Thumper

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Re: rougher at higher rpms
« Reply #8 on: August 05, 2008, 02:53:13 PM »
How about this one... His petcock, when turned on, dribbles fuel out, when turned off, dribbles fuel out a bit slower. My guess is that it is fuel-starved due to a screwed up petcock.

Yep, could be that. Now that you mention it, it could be an incorrect float level - where it allows fuel at lower RPMs but not enough for sustained higher RPMs.

Matt

Joe28

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Re: rougher at higher rpms
« Reply #9 on: August 05, 2008, 03:31:16 PM »
Ya'd think if it was a fuel starve problem, it'd be a loss of power, fall on it face, kind of like if you turned the ign switch off deal.
But that is a good place to start, stranger things have been know to happen! :-\


Reminds me of a guy I used to race with/against. ;)
No matter WHAT the problem was, you crashed and broke your leg, "You crashed cuz your jetting was off", to, threw a rock into your cases and cracked them causing the gear oil to leak out and seize the motor, "it seized cuz the jets were too lean"! ;D
Joe
So many bikes, so few $$ ::)

The Garbone

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Re: rougher at higher rpms
« Reply #10 on: August 05, 2008, 05:20:54 PM »
I did my 300 mile tune up last week myself.  My bike ran very rough for the break in period I kept it under 45mph.  Too the point it would cause my hands and seat to get numb.   

I put in Mobil 1 Synthetic 20W50 the difference was instantly noticeable,  the bike has smoothed out quite a bit and is now a joy at any speed,  I believe the new lube did the trick.  This might not be your problem but it is worth mentioning,  I initially balked at paying $8 a quart for the Mobil 1 but figured what the hell,  and am glad I did.
Gary
57' RE Crusader 250
67' Ford Mustang
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95 RE Ace Clubman 535
01 HD 1200 Custom
07 RE 5spd HaCK

* all actions described in this post are fictional *

webnash

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Re: rougher at higher rpms
« Reply #11 on: August 06, 2008, 12:16:58 AM »
My brother rode my avl today and came back saying that it was running great and I just needed to run it at faster rpms - wind it up a bit more in 3rd and 4th. Since I have a hard time leaving well enough alone, I pulled the carb apart and moved the needle clip two knotches, to the richest setting. I just rode it for an hour and it's running noticably smoother. I also wound it up more in 3rd and 4th, per my brother's advice and it ate up road nicely - passed two asian bikes and a harley on a twisty road near my house.
I've owned a few triumphs, a bsa, a motoguzzi, a couple of ducati's - and then a 20 year period with family responsibilities and no bikes. I would say that the RE is hands down the most fun I've had on a bike. Not only is it a blast to ride, looks great, and corners like a dream; it is the first bike that I've had constant success with maintaining and tweaking myself. I'm remembering that every time that I got out a wrench with the triumphs - I needed a mechanic to fix what I broke. The Italian bikes never needed anything that I could begin to think about working on. The RE has responded to research and wrenching in a consistantly positive way and I'm actually developing the confidence to think that I can maintain it on my own, without hauling it hours to a dealer and being without a bike for weeks.
RE's look like  a huge success, not only to the riders and owners, but what a great thing that the hosts of this forum have created in having a market of excited people to buy all of the great aftermarket stuff that's available, and help them keep their bikes running. My hat's off to them for keeping this awesome thing going!!

Thumper

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Re: rougher at higher rpms
« Reply #12 on: August 06, 2008, 11:31:40 AM »
Glad it's running the way you want it to! Don't worry about scraping that left foot peg, replacement rubber is cheap!

Joe28

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Re: rougher at higher rpms
« Reply #13 on: August 07, 2008, 11:32:50 AM »
Cool that you figured it out! ;D
(although 2 positions on the needle is extreme, but not un-heard of. I'd set my air screw,(no more than 2 1/2 out), and do a chop test on the spark plug, (idle to 1/8 throttle, pilot jet, 18-3/4 needle, 3/4 full main jet, but I'd wait until you got maybe 1500 miles before changing anything). You want the spark plug a nice tan).
It's always a rush when you find and fix a problem, both you and the bike become more confident!
I think you made the right choice in bikes!
Next spend the $$ and get the shop manual and do what I do.
I have it in the "Throne room" ;) and when I sitting there, I look though it.
I also cruise this site on a regular basis, looking for problems other Bulleteers have found, (and fixed), so if'n it ever happens to my fine ride, I'll know EXACTLY what to do!
Keep up on the maintenance on your scoot and you'll both be happy!
Joe
So many bikes, so few $$ :)

ridgerunner

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Re: rougher at higher rpms
« Reply #14 on: August 09, 2008, 01:29:37 AM »
I did my 300 mile tune up last week myself.  My bike ran very rough for the break in period I kept it under 45mph.  Too the point it would cause my hands and seat to get numb.   

I put in Mobil 1 Synthetic 20W50 the difference was instantly noticeable,  the bike has smoothed out quite a bit and is now a joy at any speed,  I believe the new lube did the trick.  This might not be your problem but it is worth mentioning,  I initially balked at paying $8 a quart for the Mobil 1 but figured what the hell,  and am glad I did.

Just a little advice...My clutch fried at 661 miles. The mechanic thought there was something wrong with the oil as the heat damage was very noticable. The clutch was replaced under warranty (thanks again Kevin) and I was back on the road. After 340 miles I changed the fluid and it was nasty. Lots of metal slivers and chunks of clutch material. The next fluid change revealed the same. I switched to synthetic 20W50 as recommended by Vince and the results were immediate and startling. The bike shifted smoother than ever, easy to find neutral when stopping, and just overall felt better. I was changing the 10W40 every 300-400 miles and shocked by the trash in the oil. I just went over 1000 miles on the 20W50 and there was hardly any wear material in the oil. So, I have to say that Vince nailed that one. I'm finally riding the bike without babying it and worrying about being left on the side of the road. Riding has become the pleasure it used to be. 
08 Bullet ES (AVL)
The Enfield saves on gas, riding the Enfield saves on Prozac. ;)