Vibrations
01-15-2008 | 10:48 PM
#1
Thread Starter
Senior Member
Superstock
Joined: Apr 2005
Posts: 281
From: Denver, CO
Vibrations
Ever since I took my SHawk to Colorado Powersports and had the following work done:
Valve Check
New Plugs (NGK Iridium)
K&N
New chain
New brake fluid
Carb sync & clean
..the engine vibrates such that I feel it buzz through the handlebars. Furthermore, the bike is hesitant at WOT at 3k rpms by a delay of about 1 or 2 seconds. Bike idles a bit rougher than usual and is noticeably louder.
In the General Forum, people suggested something wasn't tightened correctly perhaps. Colorado Powersports may have adjusted the carbs by eyeballing the screws 2.5 turns out without using a pressure gauge. When I cornered them on this, they said they actually -did- use a pressure gauge. I can't be sure.
Suggestions?
Bike vibration could be anything, but I suspect it's either:
1. The carb sync was done hastily
2. The K&N is loose
3. The sparkplug gaps are not to specification (Honda Superhawk OEM plugs are NGK Platinum)
Suggestions?
Valve Check
New Plugs (NGK Iridium)
K&N
New chain
New brake fluid
Carb sync & clean
..the engine vibrates such that I feel it buzz through the handlebars. Furthermore, the bike is hesitant at WOT at 3k rpms by a delay of about 1 or 2 seconds. Bike idles a bit rougher than usual and is noticeably louder.
In the General Forum, people suggested something wasn't tightened correctly perhaps. Colorado Powersports may have adjusted the carbs by eyeballing the screws 2.5 turns out without using a pressure gauge. When I cornered them on this, they said they actually -did- use a pressure gauge. I can't be sure.
Suggestions?
Bike vibration could be anything, but I suspect it's either:
1. The carb sync was done hastily
2. The K&N is loose
3. The sparkplug gaps are not to specification (Honda Superhawk OEM plugs are NGK Platinum)
Suggestions?
Last edited by mikecronis; 01-15-2008 at 10:57 PM.
01-16-2008 | 08:33 AM
#2
Senior Member
MotoGP
Joined: Aug 2007
Posts: 2,547
From: Way Out West
My VTR vibrates way more when the carbs are out of sync. That is the first thing I'd check. My local dealer assured me my TPS was in spec (500). When I dug out my multi meter and checked it myself, it was actually just under 900.
Like the saying goes, when you want something done right, do it yourself. If you search this site and the web you can find several ways to build a sync guage for five or ten dollars.
Like the saying goes, when you want something done right, do it yourself. If you search this site and the web you can find several ways to build a sync guage for five or ten dollars.
01-16-2008 | 08:41 AM
#3
Moderator
MotoGP
Joined: Dec 2004
Posts: 2,553
From: South Texas
+1 on the carb sync and TPS.
If it doesn't vibrate at a stand still, it could be the chain but the hesitation issue surely means it's engine induced. Another thought, throw the old filter back in to see if it's a fuel mixture issue.
If it doesn't vibrate at a stand still, it could be the chain but the hesitation issue surely means it's engine induced. Another thought, throw the old filter back in to see if it's a fuel mixture issue.
01-16-2008 | 09:14 AM
#4
Senior Member
MotoGP
Joined: Aug 2007
Posts: 2,547
From: Way Out West
My VTR seems to benefit more from really careful carb sync than other bikes I've owned.
The Honda manual spec for carb sync is equal to something like 10 or 12 column inches of water, which I think is pretty sloppy. I can dial it down to 1/10 or 1/20 of that and it makes a big difference even if it was "in spec" before I started. Maybe the dealer is bullshitting you, or maybe it is just barely "in spec". Either way, on the VTR, it is one of those things worth doing yourself.
The Honda manual spec for carb sync is equal to something like 10 or 12 column inches of water, which I think is pretty sloppy. I can dial it down to 1/10 or 1/20 of that and it makes a big difference even if it was "in spec" before I started. Maybe the dealer is bullshitting you, or maybe it is just barely "in spec". Either way, on the VTR, it is one of those things worth doing yourself.
01-16-2008 | 10:12 AM
#6
Sexual Daredevil
SuperSport
Joined: Sep 2005
Posts: 597
From: Mother Earth- orbiting around Charlotte, NC. But now over the border in S.C.
I worked as a tech for several dealers over the years. If the dealer cares about your business they will have the tech who did the work previously, perform a "comeback" check and re-do the sync. If you call the Service Manager to discuss the problem your having, ask to be there when it is on the bench and see for yourself what the sync looks like once it is hooked up and running. If they are a dealer that has standards and want to retain customer service they will allow you to view the settings of the cab sync. If not, cut your losses and seek another dealership for future services or learn how to do it yourself: http://www.powerchutes.com/manometer.asp
01-16-2008 | 11:07 PM
#8
Thread Starter
Senior Member
Superstock
Joined: Apr 2005
Posts: 281
From: Denver, CO
Took it back to CP. They were happy to look at it. Thing is though, and why I'm hesitant, and told them so, is it's such a subtle thing. A lot of bikes vibrate. Kawasaki is violently notorious for it that your hands feel like you've stuck them in an electric socket for a week once your ride more than an hour. I doubt they can detect anything wrong with the bike. I generally can't find any motorcycle mechanic that's even relatively mediocre in the Denver area. They're all about maybe one notch better than me at best, or just about even. I mean, I can do basic maintenance and can guess what's wrong generally, but the labor is such a pita I usually just take it to a shop and pray they don't fubar it, because in my 5 years experience here, all my bikes, once fubared, never come back alive, and I end up selling them out of frustration. I had a Ninja 500 that this happened to, and my wife's Ninja 250 is toast and it's a 2007. It'll never run again properly, though 3 local motorcycle businesses and $800 later and they say it's fine, though my own Ninja 250 runs 2000 times better and doesn't stall in a turn, which is nice. There's just no decent mechanics anymore. It's luck at best.
01-17-2008 | 06:11 AM
#9
Senior Member
SuperSport
Joined: Aug 2007
Posts: 599
From: Eagle, ID.
Mike:
At least have them re-check the carb sync to be sure that is right. You can have it checked at idle and at 4K rpm, either or. That way you eliminate the carbs, plus since it is your bike, you are going to notice any subtle changes in the way it runs, handles, etc.
As far as your SH getting fubared, this site is a wealth of information both in posts and individuals knowledgeable with this particular model of Honda.
As a side note, I went ahead and spent $35 to purchase the 2-cylinder carb sync tool off Ebay and I have used it several times and has paid for itself many times over. My local Honda dealership charged me $60 to do this once.
Good Luck whatever you do.
At least have them re-check the carb sync to be sure that is right. You can have it checked at idle and at 4K rpm, either or. That way you eliminate the carbs, plus since it is your bike, you are going to notice any subtle changes in the way it runs, handles, etc.
As far as your SH getting fubared, this site is a wealth of information both in posts and individuals knowledgeable with this particular model of Honda.
As a side note, I went ahead and spent $35 to purchase the 2-cylinder carb sync tool off Ebay and I have used it several times and has paid for itself many times over. My local Honda dealership charged me $60 to do this once.
Good Luck whatever you do.
01-17-2008 | 07:00 AM
#11
Post Whore Junior
MotoGP
Joined: Nov 2006
Posts: 4,825
From: Triad, NC
Ever since I took my SHawk to Colorado Powersports and had the following work done:
Valve Check
New Plugs (NGK Iridium)
K&N
New chain
New brake fluid
Carb sync & clean
..the engine vibrates such that I feel it buzz through the handlebars. Furthermore, the bike is hesitant at WOT at 3k rpms by a delay of about 1 or 2 seconds. Bike idles a bit rougher than usual and is noticeably louder.
In the General Forum, people suggested something wasn't tightened correctly perhaps. Colorado Powersports may have adjusted the carbs by eyeballing the screws 2.5 turns out without using a pressure gauge. When I cornered them on this, they said they actually -did- use a pressure gauge. I can't be sure.
Suggestions?
Bike vibration could be anything, but I suspect it's either:
1. The carb sync was done hastily
2. The K&N is loose
3. The sparkplug gaps are not to specification (Honda Superhawk OEM plugs are NGK Platinum)
Suggestions?
Valve Check
New Plugs (NGK Iridium)
K&N
New chain
New brake fluid
Carb sync & clean
..the engine vibrates such that I feel it buzz through the handlebars. Furthermore, the bike is hesitant at WOT at 3k rpms by a delay of about 1 or 2 seconds. Bike idles a bit rougher than usual and is noticeably louder.
In the General Forum, people suggested something wasn't tightened correctly perhaps. Colorado Powersports may have adjusted the carbs by eyeballing the screws 2.5 turns out without using a pressure gauge. When I cornered them on this, they said they actually -did- use a pressure gauge. I can't be sure.
Suggestions?
Bike vibration could be anything, but I suspect it's either:
1. The carb sync was done hastily
2. The K&N is loose
3. The sparkplug gaps are not to specification (Honda Superhawk OEM plugs are NGK Platinum)
Suggestions?
I know this sounds crazy, but it will happen.
01-17-2008 | 08:14 AM
#12
Moderator
MotoGP
Joined: Dec 2004
Posts: 2,553
From: South Texas
TIP: On carb synching, the HSM says to remove the tank and use a temporary tank during the sync. This is because you need to connect the petcocks' vacuum line, which comes from the rear cylinder vacuum port, to the sync gauge. This is a huge PITA for the DIY'er.
There is no need to do this! Cut the line a few inches back from the petcock, insert a plastic vacuum "T" and then feed the gauge with this extra connection. Plug the T when you are done, ready for next time. T and extra hose available at any auto parts store.
To make future sync's even more easy, order the rear cylinder vacuum port nipple. The front cylinder doesn't have this part, just a plug in the "V", and it is a real bastard to reach. Exchange the plug for the nipple along with a hose long enough to extend out of the "V" and plug it. Now it will be MUCH, MUCH easier to hook up the front cylinder the next time.
You will be able to do a sync in under 20 minutes compared to a couple of hours a shop would charge.
Another TIP: a $5 automotive carb adjuster tool (nut driver on a foot long slinky cable) from the auto parts store will reach the sync adjustment screw (nut) easily.
There is no need to do this! Cut the line a few inches back from the petcock, insert a plastic vacuum "T" and then feed the gauge with this extra connection. Plug the T when you are done, ready for next time. T and extra hose available at any auto parts store.
To make future sync's even more easy, order the rear cylinder vacuum port nipple. The front cylinder doesn't have this part, just a plug in the "V", and it is a real bastard to reach. Exchange the plug for the nipple along with a hose long enough to extend out of the "V" and plug it. Now it will be MUCH, MUCH easier to hook up the front cylinder the next time.
You will be able to do a sync in under 20 minutes compared to a couple of hours a shop would charge.
Another TIP: a $5 automotive carb adjuster tool (nut driver on a foot long slinky cable) from the auto parts store will reach the sync adjustment screw (nut) easily.
01-17-2008 | 10:26 AM
#13
Senior Member
SuperBike
Joined: Sep 2005
Posts: 1,572
From: Buffalo, NY
Thanks for the tips 'bling 
I need to check mine this spring...
I need to check mine this spring...TIP: On carb synching, the HSM says to remove the tank and use a temporary tank during the sync. This is because you need to connect the petcocks' vacuum line, which comes from the rear cylinder vacuum port, to the sync gauge. This is a huge PITA for the DIY'er.
There is no need to do this! Cut the line a few inches back from the petcock, insert a plastic vacuum "T" and then feed the gauge with this extra connection. Plug the T when you are done, ready for next time. T and extra hose available at any auto parts store.
To make future sync's even more easy, order the rear cylinder vacuum port nipple. The front cylinder doesn't have this part, just a plug in the "V", and it is a real bastard to reach. Exchange the plug for the nipple along with a hose long enough to extend out of the "V" and plug it. Now it will be MUCH, MUCH easier to hook up the front cylinder the next time.
You will be able to do a sync in under 20 minutes compared to a couple of hours a shop would charge.
Another TIP: a $5 automotive carb adjuster tool (nut driver on a foot long slinky cable) from the auto parts store will reach the sync adjustment screw (nut) easily.
There is no need to do this! Cut the line a few inches back from the petcock, insert a plastic vacuum "T" and then feed the gauge with this extra connection. Plug the T when you are done, ready for next time. T and extra hose available at any auto parts store.
To make future sync's even more easy, order the rear cylinder vacuum port nipple. The front cylinder doesn't have this part, just a plug in the "V", and it is a real bastard to reach. Exchange the plug for the nipple along with a hose long enough to extend out of the "V" and plug it. Now it will be MUCH, MUCH easier to hook up the front cylinder the next time.
You will be able to do a sync in under 20 minutes compared to a couple of hours a shop would charge.
Another TIP: a $5 automotive carb adjuster tool (nut driver on a foot long slinky cable) from the auto parts store will reach the sync adjustment screw (nut) easily.
01-17-2008 | 11:43 AM
#14
Thread Starter
Senior Member
Superstock
Joined: Apr 2005
Posts: 281
From: Denver, CO
Wow, very good info. Carbs were checked and spot-on. Bike was dyno'ed (neat) and I have 87Hp and 57lbs RWHP torque which is impressive at 6000 feet altitude and lean jets. They noticed a flat spot at 4k rpms, which is pretty normal for leaner jets and a K&N I'd say.
Still, they cannot find the culprit but are working towards a solution, which is nice.
Still, they cannot find the culprit but are working towards a solution, which is nice.
01-19-2008 | 09:56 AM
#15
Senior Member
Back Marker
Joined: Oct 2007
Posts: 226
From: East TX
"TIP: On carb synching, the HSM says to remove the tank and use a temporary tank during the sync. This is because you need to connect the petcocks' vacuum line, which comes from the rear cylinder vacuum port, to the sync gauge. This is a huge PITA for the DIY'er.
There is no need to do this! Cut the line a few inches back from the petcock, insert a plastic vacuum "T" and then feed the gauge with this extra connection. Plug the T when you are done, ready for next time. T and extra hose available at any auto parts store.
To make future sync's even more easy, order the rear cylinder vacuum port nipple. The front cylinder doesn't have this part, just a plug in the "V", and it is a real bastard to reach. Exchange the plug for the nipple along with a hose long enough to extend out of the "V" and plug it. Now it will be MUCH, MUCH easier to hook up the front cylinder the next time.
You will be able to do a sync in under 20 minutes compared to a couple of hours a shop would charge.
Another TIP: a $5 automotive carb adjuster tool (nut driver on a foot long slinky cable) from the auto parts store will reach the sync adjustment screw (nut) easily."
MRCycles.com has brass adapters just for this procedure. They come in 5mm or 6mm for $8(part # 15-8218 or 19). Anyone know whether the VTR takes 5 or 6mm?
There is no need to do this! Cut the line a few inches back from the petcock, insert a plastic vacuum "T" and then feed the gauge with this extra connection. Plug the T when you are done, ready for next time. T and extra hose available at any auto parts store.
To make future sync's even more easy, order the rear cylinder vacuum port nipple. The front cylinder doesn't have this part, just a plug in the "V", and it is a real bastard to reach. Exchange the plug for the nipple along with a hose long enough to extend out of the "V" and plug it. Now it will be MUCH, MUCH easier to hook up the front cylinder the next time.
You will be able to do a sync in under 20 minutes compared to a couple of hours a shop would charge.
Another TIP: a $5 automotive carb adjuster tool (nut driver on a foot long slinky cable) from the auto parts store will reach the sync adjustment screw (nut) easily."
MRCycles.com has brass adapters just for this procedure. They come in 5mm or 6mm for $8(part # 15-8218 or 19). Anyone know whether the VTR takes 5 or 6mm?
