[Yamato-41]

Hi all, I recently bought a 2003 Blackbird which seems in overall good condition, however I noticed the seat height appears to be on the low side at about 780mm whereas according to factory spec it should be approx 810mm so 30mm too low. I am almost exactly 6ft tall so would be fine on the standard seat height. I have checked the position of the linkage plates on the lower mounting point under the shock and the arrow is facing forwards which I understand to be the standard setting, also the shock appears to be the factory original so I can't understand why it's 30mm lower.
I have read about shimming the top mount by 6mm but this would still be too little. Any advise would be greatly appreciated

yamato

 

[bikerian]

Have you got the original seat?
Has any padding been taken out from it?

 

[Yamato-41]

I did check this as I also thought it might be a lowered or modified seat but it looks factory.

 

[CarlCox]

How are you measuring the seat height? I'm 6'3 and the bird feels like one of the smallest bikes I've ever had. I am away until Sunday, I would think I can measure to the bottom of the tail light for you?

 

[bikerian]

Apparently I did read some were that honda actually did a slightly lower oem seat years ago, you can't buy them any more though.
So hmmm, yeah by what you put, your linkage triangles are correctly fitted the right way around.
I dont have the standard seat my self, and have added 3ish mm in washer and 3mm on my nitron rear shock so I can't give you my seat hight, I am sure another member should be along soon who can give you a more oem seat hight.

 

[Yamato-41]

How are you measuring the seat height? I'm 6'3 and the bird feels like one of the smallest bikes I've ever had. I am away until Sunday, I would think I can measure to the bottom of the tail light for you?

Off the center stand both wheels on the ground bike sitting level, I placed a spirit level across the riders seat and measured from the ground to the underside of the spirit level and got 780mm, I applied exactly the same method to my mates 2021 Honda cb650r which also has a factory seat height of 810mm and that's exactly what we measured on the cb650r (i.e 810mm) It would be great if you could measure your bike for comparison to the underside of the tail light, then It should be clear if I do indeed have a lowered seat or if there is something else going on.

 

[beestoys]

19 year old springs.

 

[CarlCox]

Using a straight measure, 80cm from bottom of the tail light touching the back tyre to the floor. Mine has a 21 year old shock and spring and a 6mm spacer.

 

[macka20]

Off the center stand both wheels on the ground bike sitting level, I placed a spirit level across the riders seat and measured from the ground to the underside of the spirit level and got 780mm, I applied exactly the same method to my mates 2021 Honda cb650r which also has a factory seat height of 810mm and that's exactly what we measured on the cb650r (i.e 810mm) It would be great if you could measure your bike for comparison to the underside of the tail light, then It should be clear if I do indeed have a lowered seat or if there is something else going on.

Once you have measured up the front and rear sag the ride height will sorted then. start worrying about the seat then

 

[Yamato-41]

Using a straight measure, 80cm from bottom of the tail light touching the back tyre to the floor. Mine has a 21 year old shock and spring and a 6mm spacer.

Hi and thanks for taking the time to check this, there is definitely something up with my bike as I am only seeing 74 cm measuring the same way, booked it in at Honda to have this checked, hopefully it's nothing too serious

Thanks again

 

[Aussie Dave]

G'day Yamato-41,

I devised a way to measure my 05 height to tail light. I had to allow for it being on the center stand, a 190/50 tyre instead of a 4mm taller 180/55, and the forks (with helibars) raised up an extra 6mm.

I used a piece of timber to approximate the tyre being on the ground and the nose at stock height, so it's not a perfect measurement but I got 810mm to the tail light bottom, so it looks like your Bird is low.

Check your tyre size & profile and if worn down to nil tread in the center, also check if the forks are in the stock position with stock clipons.

Also, if the shockie has been rebuilt at some stage it may be shorter than stock. They are supposedly not rebuildable but my local shockie service guy says all shocks can be rebuilt at the cost of being a little shorter....

Many little things can add up to a lower seat height.

You will like the extra cornering clearance for the Bird once you sort out the seat height issue

 

[CarlCox]

Hi and thanks for taking the time to check this, there is definitely something up with my bike as I am only seeing 74 cm measuring the same way, booked it in at Honda to have this checked, hopefully it's nothing too serious

Thanks again

no problem.

with my new Nitron shock it's 82cm

 

[CarlCox]

Did you get anywhere with this?

 

[Yamato-41]

Did you get anywhere with this?

Hi, not yet, but I did visit my Honda dealer (not on the Blackbird as I'm still waiting on my no.plate) they are incredibly
busy and closing for summer holidays next week so it will be after that before I can take it in. I was armed with several pictures of the lower linkage and shock, he looked up the micro fiche for the rear suspension and reckons everything looks factory he then membered he had an old Blackbird in the back of his workshop which we measured up, the linkage
seems to be exactly the same as my bike but his bike is a good 5cm higher measuring from the rear light to the floor compared to mine so the mystery continues, if I get the chance this week I'm going to strip down the linkage and shock
and take it over to him to have a look at, bouncing the rear of the bike to test the shock isn't knackered as he showed me was also good on my bike. I'll post the results once we find what's causing this mad difference in ride height

cheers

 

[Yamato-41]

Did you get anywhere with this?

Hi, I've just taken out the rear shock and triangles (shock length 315mm mounting hole to mounting hole) I also want to remove the "dog bone" is this bolt also the hinge point for the center stand ? do I need to support the bike somehow prior to removing it? would it be ok to support the bike with a trolly jack under the sump ?
thanks

 

[Yamato-41]

Hi, I've just taken out the rear shock and triangles (shock length 315mm mounting hole to mounting hole) I also want to remove the "dog bone" is this bolt also the hinge point for the center stand ? do I need to support the bike somehow prior to removing it? would it be ok to support the bike with a trolly jack under the sump ?
thanks

Ignore the above.... I figured it out, the dimension of the shock mounts are actually 320mm which is what I think others have said, my main suspect is now the dog bone linkage, mine is 110mm from center to center mounting points and overall length is 145mm, could someone confirm this is correct for the standard part.
many thanks

 

[CarlCox]

I will be under mine in about an hour. I will check.

 

[CarlCox]

I would say mine is about 11cm centre to centre. So yeah 110mm.

 

[Yamato-41]

I would say mine is about 11cm centre to centre. So yeah 110mm.

ok thanks for that

 

[Yamato-41]

Now I'm really confused, the shock is the correct item, the linkage all seems correct so I really can't see what else could be causing the bike to sit up to 45mm too low, I'll take the parts over to Honda this week and let them have a look.
thanks again for checking your bike