LWB /5 seat pan same as a /7

woodly1069 · 01-16-2013, 11:33 AM

May have a line on a replacement seat pan from an R80/7 for my old R75/5 LWB but I seem to remember that the later models were slightly shorter or that they didn't meet the tank the same way as the earlier seats. Please educate me, maybe, hopefully, I am wrong...

blaine.hale · 01-16-2013, 01:54 PM

The /7 seat will be an inch or two too short.
You'll want a /6 series seat pan or the LWB /5 seat pan for things to fit against the tank as they should.

/6 = shorter tank, longer seat
/7 = longer tank, shorter seat

I know this because I was stuck with a /7 seat on my 74 r90 for 3 years and had a lovely 2 inch gap between the seat and tank.

disston · 01-16-2013, 01:55 PM

Pay attention. There will be a test later.

LWB /5 and /6 seats are the same. I think the only difference in the seats is the direction of the stripes on the cover and the trim, emblem package. Only 1974 gets that badge on the back that has the engine size /6. Only 1970 or also maybe '71 gets the two part hand holds.

R90S seats are not /6 seats and they do not fit LWB /5s. R90S seats will work on a /7 and vice versa.

What determines which seat fits your bike is which gas tank you have. The R90S has the larger tank used with the /7s. The /5 and the /6 have the same external dimensions. The /5 tank does not have the larger space for the front brakes master cylinder so the /5 tank will usually not work on a /6. A /6 tank will work on a /5.

In 1977 with the beginning of the /7 the gas tank is larger, it holds more gas. This larger gas tank is longer. The longer gas tank means that the seat is shorter. If you use a /7 seat on a /6 or LWB /5 there will be an ugly gap between the seat and the tank. Every time you show up at any affair with other Airheads there the aficionados will be sure to point this out to you ad nauseum.

It is even worse if you put a /6 seat on a /7. The seat will put a dent in the tank and will be scrunched up where it meets the tank.

Reproduction seat from Capitol Cycle. They have a plastic pan so they don't rust. I added the hand hold and the 1974 only emblem. It's a 1975 bike so be sure to point this improper use of a BMW emblem out to me. If you can catch me.

woodly1069 · 01-16-2013, 01:59 PM

thanks guys! thought I remembered that!

01-16-2013, 11:33 AM	#1
woodly1069 ^OP Beastly Adventurer Joined: Jun 2008 Location: Louisville, KY...really too far from the hills! Oddometer: 1,099	LWB /5 seat pan same as a /7 May have a line on a replacement seat pan from an R80/7 for my old R75/5 LWB but I seem to remember that the later models were slightly shorter or that they didn't meet the tank the same way as the earlier seats. Please educate me, maybe, hopefully, I am wrong... __________________ If you can't fix it with a hammer, you've got an electrical problem!

01-16-2013, 01:54 PM	#2
blaine.hale Beastly Adventurer Joined: Feb 2009 Location: Atlanta, Ga Oddometer: 2,295	The /7 seat will be an inch or two too short. You'll want a /6 series seat pan or the LWB /5 seat pan for things to fit against the tank as they should. /6 = shorter tank, longer seat /7 = longer tank, shorter seat I know this because I was stuck with a /7 seat on my 74 r90 for 3 years and had a lovely 2 inch gap between the seat and tank. __________________ 1974 BMW R90 /6 1968 Bultaco Matador MK3 1973 BMW R75 /5 Toaster LWB 1969 Bultaco Bandido MK2 2013 Husqvarna Terra TR650

01-16-2013, 01:55 PM	#3
disston ShadeTreeExpert Joined: Mar 2011 Location: Silver Spring, Md Oddometer: 5,020	Pay attention. There will be a test later. LWB /5 and /6 seats are the same. I think the only difference in the seats is the direction of the stripes on the cover and the trim, emblem package. Only 1974 gets that badge on the back that has the engine size /6. Only 1970 or also maybe '71 gets the two part hand holds. R90S seats are not /6 seats and they do not fit LWB /5s. R90S seats will work on a /7 and vice versa. What determines which seat fits your bike is which gas tank you have. The R90S has the larger tank used with the /7s. The /5 and the /6 have the same external dimensions. The /5 tank does not have the larger space for the front brakes master cylinder so the /5 tank will usually not work on a /6. A /6 tank will work on a /5. In 1977 with the beginning of the /7 the gas tank is larger, it holds more gas. This larger gas tank is longer. The longer gas tank means that the seat is shorter. If you use a /7 seat on a /6 or LWB /5 there will be an ugly gap between the seat and the tank. Every time you show up at any affair with other Airheads there the aficionados will be sure to point this out to you ad nauseum. It is even worse if you put a /6 seat on a /7. The seat will put a dent in the tank and will be scrunched up where it meets the tank. Reproduction seat from Capitol Cycle. They have a plastic pan so they don't rust. I added the hand hold and the 1974 only emblem. It's a 1975 bike so be sure to point this improper use of a BMW emblem out to me. If you can catch me. __________________ Never memorize something you can look up. ---Albert Einstein

01-16-2013, 01:59 PM	#4
woodly1069 ^OP Beastly Adventurer Joined: Jun 2008 Location: Louisville, KY...really too far from the hills! Oddometer: 1,099	thanks guys! thought I remembered that! __________________ If you can't fix it with a hammer, you've got an electrical problem!

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