Gap between seat & Gas tank

[THEMADTYPH00N]

Looking through some pictures of members have posted of there R's I noticed something. Some of them have a large gap between the seat pan & the gas tank while others sit flush. Why is this? I know there is a difference in the way the seats mount between 86-87's & 88-89's. But is there a difference in the shape of the seats? Or the shape of the tank? Maybe mixing and matching parts between the years causes this? Or is the seat pan just old and warped? My R has always had this gap and if possible I'd like to get rid of it.

Here's a picture of what I'm talking about

http://img.photobucket.com/albums/v610/THEMADTYPH00N/photo.jpg

[Honda 250r 001]

im guessing its from having your seat cover really tight.

[8686]

From the factory there are two rubber bumpers that mount to the bottom of the rear fenders under the seat, about halfway back. They take up the gap between the fenders and the subframe. Over the years they often don't find their way on to new sets of fenders/seats. If they are missing the seat may have a tendency to curve up a little in the front cuz when weight is on the seat it is bending down in the middle. I'm not saying that's definitely what happened, I'm just throwing something out there.

[voodoochassis]

alot of people put seat covers on differently..supposed to start from rear and go forward but a lot of people get wrinkles in them and do not like it..so they start from the front and pull it too hard pulling seat pan back..
Originally posted by Honda 250r 001
im guessing its from having your seat cover really tight.

[snacob14]

the gas tank can also slide forward and backward to cover that gap.

[Pro1200]

yea I have this same problem..but i just ordered a new seatcover and foam..so well see what happens

[leatherface]

anotherpotential reason is the thick rubber bushings at the very back of the seat. the thickness of that bushing(the one the posts sit in) is different on 86-87 and 88-89. just about a 1/4" difference but spread that distance out over 3' and it adds up. using the taller bushings will lower the front of your seat and close that gap:)

[Ruf Racing]

Originally posted by leatherface
anotherpotential reason is the thick rubber bushings at the very back of the seat. the thickness of that bushing(the one the posts sit in) is different on 86-87 and 88-89. just about a 1/4" difference but spread that distance out over 3' and it adds up. using the taller bushings will lower the front of your seat and close that gap:)

Which years has the thicker bushing? Thanks.

[leatherface]

i believe the 88-89

[Ruf Racing]

Originally posted by leatherface
i believe the 88-89

Thanks.

[FMF250r]

the 86-87 seat pan on an 88-89 will give you a gap like that.

[troybilt]

Originally posted by FMF250r
the 86-87 seat pan on an 88-89 will give you a gap like that.

Mines an 89 with 86 pan and seat and no gap, see pic in FW carbon hood thread. The gap bw. the tank and seat comes from worn out seat pans, or tank pushed too far forward.

[Pumashine]

Originally posted by troybilt
The gap bw. the tank and seat comes from worn out seat pans, or tank pushed too far forward.

How can the tank be pushed forward or backward? The mounts toward the rear of the gas tank are in a fixed place. I know the front mount has an obround shape for adjustment but do not see how it can be used. I keep new rubber grommets on my bike to keep it sturdy. But they tend to wear out quite quickly. I see this as a big problem. I also have acquired frames with a flat spot wore on the mount for the rubber gromets. So yes alot of guys loose these groments and end up forming the seat to an unatural position without them there.

The second point is the rubber bushings in the rear. In time they become worn. The seat latch is loose for this reason. A quick fix is the OMF seat latch for $45. Another quick fix is the OEM 3 wheeler rubbers. They are a 1/4" taller and take the difference in worn out seatlatches. Another fix is a nylon or plastic washer put over the mounts protruding out of the seat to take out any discrepacy.

My only real point is the OEM rubber gromets that the seat slide onto are to soft. In time they self desruct. A solution if anyone is interested is a harderd grommet that won't break down in time. I know of one company that never mass produced this product but does have the molds to make them is UPP. If anyone is interested in getting a set of these polyurethane grommets that will last forever let me know and I will get ahold of Brandon and Bill and get them to make a run of these grommets needed by the 250r society.

[troybilt]

Puma I didn't read you whole post, but I elongate the holes on the mounting brackets and then there is quite a bit of adjustment. Especially with an aftermarket tank. The downspout with the IMS hits the frame unless you move the tank back about 1/2"...

[Pumashine]

Originally posted by troybilt
Puma I didn't read you whole post, but I elongate the holes on the mounting brackets and then there is quite a bit of adjustment. Especially with an aftermarket tank. The downspout with the IMS hits the frame unless you move the tank back about 1/2"...

Yeah I got you on that one. I made a 1/2" spacer for the Clarke and IMS tanks that goes between the front mounting bracket and the tank. Thought it was easier than elongating the holes but does the same thing. Why can't the aftermarket companies reproduce the stock tank. They all know plastic shrinks when it is formed. Are they just lazy or stupid? Its been how many years? and they can't get it right.

So you put the adjustment in. Like I stated they are not adjustable. I perfer not to alter the stock measurements of the R. Once altered there is no room for discussion on where the problem really lies. The rest of my post addressed a fix for the rubber grommets that wear out year after year.

[Higgy87TRX425]

I was just reading that thread about the gap between the seat and the tank. I was noticing that on my R yesterday when I was working on it. So I purposely in spected it to see if everything was there and looked to see if the rubber was worn out and I noticed that the rubber where my seat latches in the 2 pins that go through the rubber gromets is a little worn. The rubber in the subframe is loose so the metal pins that hold the seat in place wiggle around a little, but the rubber on the seat pan is good. I was thinking yesterday that the seat cover must be a little tight, or at least thats what it looked like yesterday. It was bugging me yesterday because I had just installed a carbon fiber tank cover and so I really noticed it. I think pumashine is on the right track though, some of those polyurethane grommets would be great. I'd commit to buying some. So let me know if you guys wanna get a parts run going, I'm in!!

[Pumashine]

I was thinking yesterday that the seat cover must be a little tight, or at least thats what it looked like yesterday.
We all put the seat cover on a little tight to get that bubble out of the middle. Even if you heat it up and stretch it out it seems not to go away. In time when the seat cover shrinks it then pulls the front part of the seat up even more. I think it is live and learn in this situation. But the grommets always wear loose. When riding your weight pushes the seat down and the front of it up. In time it will form to that position. When you get off the bike you see it like a sore thumb. I hope to meet with the UPP guys labor day weekend for the unofficial coosbay racing at boxcar.

[troybilt]

I haven't had any trouble with the rubber grommets yet, mine are original and look like new, but I will say my 89 is rare low hour bike... I don't get as much "seat time" on it either... I'll be needing something for my Laeger that's for sure.

The other "adjustment" that I do is with the 86 front seat mounts you can bend them up slightly to take up some space as well.

You're right though, factory there is no "adjustment". ...but I prefer a custom fit with no gaps.

I also prefer the 86 seat to the 89's, I like the lower height foam, and the metal mounting brackets are better than the 89 integrated plastic molded ones....