Low speed pulsing problem

[mrc]

I have a 2007 Royal Star Venture and have a pulse what feels like the front tire. At 50Km (30 miles)/hr on new pavement and going straight the bike front end pulses up and down not a wobble side to side. The dealership has checked the driveshaft, the bearings in the steering and I have replaced the two tires. It has improved somewhat but I can still feel it. Has anyone had this problem and can you suggest what I need to check next?

[eazyduzzit]

Have you jacked it up and spun the front wheel to see if you can see anything?

[BradT]

Welcome to the site. I see that you meet Hal at the show (please don't judge us all by him ). I would have thought steering bearing or a tire, but next I would look at the air pressure, or possible drag on the rotors.

 

Brad

[friesman]

get the front tire off the ground on a lift or similar and then spin the wheel to see if a rotor is warped and possibly dragging on the pad. Perhaps it only does it when hot so check it when brakes both are hot and then cold.

 

Brian

[M61A1MECH]

My 07 does the very same thing. I did not notice it until after a set of Metzler tires were installed. I have checked the tires for the dreaded chuncking, did not find any thing on the tires. I jacked up the bike so both wheels were off the ground. I spun both wheels while monitoring the distance between the floor and the tire, expecting to find something out of round, nothing showed up. Tire pressure was checked and it was fine.

I am at a loss also, starting to wonder if an out of balance tire would show up at such a slow speed.

[mrc]

Brad and Eazyduzzit

Thanks, I did meet Hal at the Toronto Bike show, good guy and a great ambassador and he hooked me up with this site. So far I have had all that checked by a 5 star dealer. How can I check the drag on the rotors? Do I lift the front end and spin the tire because I can’t feel any thing when I do that. It feels smooth.The tires are new less then 100 miles on them with proper air pressure. The shop seam to think it may be the drive shaft at first but they said everything was fine.

[Eck]

My suggestions are:

Jack the front wheel off the ground.

Place a small 2x4 block in front of your tire and as close as you can to the front of the tire but not touching the tire, just very very close to the tire.

Then by hand, you slowly (very slowly) turn the tire and carefully watch to see if the tire touches the 2x4. Make sure the 2x4 is as close to the tire as you can get it with out it touching before you start.

If the tire does rub or touch the 2x4 you could have a bent, (or out of round), rim.

Another test:

Again with the front wheel off the floor.

Squeeze the front brake lever. Pump it up good and squeeze it about 4 or five times.

Now again slowly turn your front wheel and dilligently listen & feel if the rotor is "dragging" on the front brake pads..itmay touch just a tiny bit, but Im saying you are checking for a "drag" where it becomes harder to turn the tire...

If it does become harder to turn, you could have a warped rotor, or your front caliper may be sticking and not releasing properly.

Another test:

Check the oil level in the front forks.

I would never ever think that the dealer may have forgotten to install fork oil now ... but hey, you never know and you could be running on air pressure only...

you cant tell with out checking..

I would also check the air pressure in each fork and I personally run 3 to 5 lbs in each fork..

Caution Note: Do not use an air compressor to put air into the front fork fittings..I suggest using a small hand pump where you can control the amount you are putting in so you dont blow out the fork seals..

You can also do the tire check, the brake caliper check and air pressure check to your rear tire to make sure it is ok too..

[Marcarl]

SO these solutions may be right off the wall, but sometimes the wall is kind of handie. Check to make sure the tire is mounted properly, it should be even by the ridge all the way around and even side to side.

After checking for brake drag, back off the pads a little with a screw driver, lift the front wheel and give it a spin. Do this a number of times and each time mark the top spot. I should not come to rest in the same spot twice. That would indicate that it is not balanced right. Also check to see how much weight is on the wheel to balance it, more than 25gr would not be good either and if you have that much it should be placed evenly on both sides of the ridge.

Also check to make sure that the tire is turning in the direction it's designed to. There is an arrow on the side wall that tells you which way it should be turning when you're going forwards.

keep us posted

Carl

[Eck]

Very very good point Marcarl...!!!!!!!! ...

thanks for reminding me of this one...

(tire should be even by the ridge all the way around and even side to side)

[mrc]

It is winter wonder land in Barrie Ontario but I will try the different things you brought up, once the temp raises a bit. Fork oil, brake disk and rim are the next things I will try. Come on spring, every white flake is one too many. I will let you know once I find the fix.

 

Mark

Edited January 9, 2009 by mrc