The "Bum" GB400tt build.

mokie

Acting foolishly since '88
Right, well up until last week I was an aircraft engineer but seeing as how I told my boss where he can shove his shitbox job I have become a man of leisure, which is not all it's cracked up to be. At any rate, I am heading overseas in about 3 months and I got paid out enough to live on until I go and have some coin left over. Since I am too lazy to get another job if I don't need one I decided to spend the time and leftover notes on the '88 GB400tt I have had sitting round up to f-all for the last few months. I love these wee singles they handle great and man, that tank!

Hopefully I can keep her within budget and not end up having to leave her unfinished or dip into the funds I have saved for the trip. I will have to cut back on beer consumption. At any rate I started the disassembly today and have some pics If you lot are interested.

This is her as I bought her. A few bumps and bruises here and there but mostly sweet as.
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Most of the ally is covered in philiform corrosion like this
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The GB400 is a single with a dry sump. Basically the same engine as an XL600.
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Tank and seat off. Those stupid passenger peg rearsets and chain guard will be the first to go.
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I was going to use the original exhaust, I kinda liked it but didn't realise it had this thing. This is the first bike I have ever worked on so I assume its a catalytic converter, we don't have those things on airplanes so I am kinda clueless.
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Got the easy shit off, the airbox can't come out until the engine and oil tank come out. Don't have time for that today so it's gonna have to wait till next week when I have some time to get onto it properly. Stuck the tank back on to see how she looked with and without the side covers. Not sure if I'll keep em or not yet.
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The plan is (in no particular order):
-Get the engine out and clean up the corrosion/polish
-De tag and powder coat the frame
-Make a new seat/fairing
-Get rid of the airbox and stick a filter strait to the carby
-If I get rid of the side covers move the battery or eliminate it with a big ol capacitor if I can, I'm not sure yet.
-Raise the back a bit with some new shocks
-Possibly a new more aesthetically pleasing oil tank if I decide the original is just too ugly/intrusive.
-New rear sets
-Get all the paint off the tank and see how much bog is on there and a paint scheme to be decided
-All the usual tidy up bits: hide all the wiring, trim the front guard right down, fit really low profile indicators & brake light etc to get her lookin real sleek and tidy.
 
Re: Since I am a bum now; GB400tt Cafe.

Tell me what you think! I'm jumping into it pretty much blind so any big or small bits of advice or creative insight you guys have will help me heaps.
 
Re: Since I am a bum now; GB400tt Cafe.

Nice. I take it you dont live in the US? If you do, you might be the only person who has a GB400. I dont know if I would really do much of anything to it. I might have been one of the few, rare persons to ever have owned two GB500's at the same time. Since the GB is rare anyhow, in the States, even to have one. Honda did a good job at designing that bike, and the preformance of it was steller. Not sure if the seat you have is stock, but the 500 seat was more cafe, a single seat. It really changed the lines. The 500 also did not have the passenger pegs. These bikes really have a value on them, so be careful what you do. selling it on ebay, STOCK, would bring more cash. A lot of folks remove the smog snorkle and block the ports, unless you have laws that test emissions. good luck, cant wait to see what you do.
 
Re: Since I am a bum now; GB400tt Cafe.

mokie said:
I will have to cut back on beer consumption.

I would like to be the first to say that this is a foolish area to cut costs in. It can do serious damage by shocking your system, and it will inevitably lead to frustration and aggravation when building a motorcycle. Plus you'll have no friends to come by and help you as you won't have any method of payment on hand. Please reconsider this before you get too far into this build.

Great starting point and it's always refreshing to see something other than a CB 350/400/425/450/475/500/550/557/etc. on here.
 
Re: Since I am a bum now; GB400tt Cafe.

Mowillie said:
Nice. I take it you dont live in the US? If you do, you might be the only person who has a GB400.

These bikes really have a value on them, so be careful what you do. selling it on ebay, STOCK, would bring more cash.

Nope, I live in New Zealand and they sold tons of them over here. This one has been in two minor crashes so is not in great nick and not all original so it's worthless as a collectors item (here at least). They are great bikes and the 500 was sold here as well. Both had the option of the cafe seat and single pegs.

How long have you had your 500s? They look like real mintas, you obviously take good care of them.
 
Re: Since I am a bum now; GB400tt Cafe.

SquadraCorse said:
I would like to be the first to say that this is a foolish area to cut costs in. It can do serious damage by shocking your system, and it will inevitably lead to frustration and aggravation when building a motorcycle. Plus you'll have no friends to come by and help you as you won't have any method of payment on hand. Please reconsider this before you get too far into this build.

Wow, I didn't even think of that. You are absolutely correct on all points and I will certainly cease this foolish plan immediately. This is exactly why I need the advice of seasoned builders, so I can avoid such rookie mistakes.

SquadraCorse said:
Great starting point and it's always refreshing to see something other than a CB 350/400/425/450/475/500/550/557/etc. on here.

Yeah, when I was reading up on bikes and deciding what to get one of the biggest factors for me was one that wasn't just another CB, even though I really like the way the 550 looks and then I found out these are as rare as pleasant smelling Australians over in the States I couldn't resist. I have only ever seen one other made into a cafe racer and reckoned I could do a heaps better job so here we are. This is the one.
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Re: Since I am a bum now; GB400tt Cafe.

Since you are a bum now, you are in jolly good company here :)
 
Re: Since I am a bum now; GB400tt Cafe.

Where in NZ are you? My Father is from Hamilton. I try and get down there every couple of years to see the family.
 
Re: Since I am a bum now; GB400tt Cafe.

"I will have to cut back on beer consumption."

SquadraCorse said:
I would like to be the first to say that this is a foolish area to cut costs in. It can do serious damage by shocking your system, and it will inevitably lead to frustration and aggravation when building a motorcycle. Plus you'll have no friends to come by and help you as you won't have any method of payment on hand. Please reconsider this before you get too far into this build.

Probably the best advice I have ever read on here.
Should be a sticky.
 
Re: Since I am a bum now; GB400tt Cafe.

Yeah bum, or I prefer to list my occupation as "gentleman of/at leisure". I live in Blenheim in the South Island.
 
Re: Since I am a bum now; GB400tt Cafe.

Pulled out the engine today. Tomorrow the airbox, oil tank and maybe the swing arm and rear wheel. Didn't have as much trouble with the engine as I thought I would, everything unbolted easily without shearing, cracking or snapping so its already ten times better quality than most aircraft I ever worked on. Had a buddy come round to help me lift it out.


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Re: Since I am a bum now; GB400tt Cafe.

Got side tracked today and cut down the front mud guard instead. Turned out pretty much how I wanted.

Before
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I cut it out freehand with a pneumatic die grinder with a cutting disk using the Mk I eyecrometer to keep it even and then filed it to take off the rough edge. I will sand it down nice once the paint comes off.
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Then I got stuck into getting the light and indicators, the front brake, gauges and clipons and most of the wiring off the front of the bike. Gotta read up in manual about how the front wheel and forks come off properly so I don't fudge it tomorrow.
 
Re: Since I am a bum now; GB400tt Cafe.

Entertaining read so far, pal. Should be interesting to see this thing come together.
 
Re: Since I am a bum now; GB400tt Cafe.

Good Start! I REALLY Like the GB's, I have wanted one for the last 10 years, but I am unwilling to drop the kind of cash people want for them here in Texas - no matter the condition! I am dreaming of the day I find one in a barn ( it could be in ANY condition, as long as the price was right) !!!
 
Re: Since I am a bum now; GB400tt Cafe.

Got the thing entirely disassembled. Now I just have to make a few decisions and figure some stuff out before I start de-tagging the frame. To keep the side covers or not, what to do with that ugly oil tank, blah blah blah. Gotta actually do some planning now, not my strong point.

Holy spaghetti Batman!
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So naked...
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Here I'm wondering whether or not to strip the old upholstery off the seat, cut down the moulding and use it as the base for the new seat, glassing strait on to it. It would mean I could use the helmet lock/seat hinge thing and the seat would be mounted really securely but I don't know if I like the look of the bulky lock on the side of the bike, it doesn't follow the super clean look I want.
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Re: Since I am a bum now; GB400tt Cafe.

vtwin650 said:
Good Start! I REALLY Like the GB's, I have wanted one for the last 10 years, but I am unwilling to drop the kind of cash people want for them here in Texas - no matter the condition! I am dreaming of the day I find one in a barn ( it could be in ANY condition, as long as the price was right) !!!

I'll even put it on the boat for ya! Our dollar is only around 70 of your cents. Cheap as chips mate!
http://www.trademe.co.nz/motors/motorbikes/motorbikes/classic-vintage/auction-428662772.htm

There are several more on the same site for two or three thousand NZD just search "gb500" or "gb500tt"
 
Re: Since I am a bum now; GB400tt Cafe.

sxecafe said:
Entertaining read so far, pal. Should be interesting to see this thing come together.

Haha thanks, I'll try to make sure it meets expectations.
 
Re: Since I am a bum now; GB400tt Cafe.

Glad I read the whole thread, at first I thought, "Poor sap, doesn't even know what cc his GB is" turns out I am the unknowing twit on what was offered outside the States. Now you got my attention! I always wanted a GB500 since I saw one on the local showroom floor back when they were new. Interested in what was offered in other displacements.
Hope you get her all buttoned up before you head out on your adventure, keep us updated.

even though I really like the way the 550 looks and then I found out these are as rare as pleasant smelling Australians over in the States I couldn't resist.
Not that I would know first hand, but I imagine that is some funny stuff right there!
 
Re: Since I am a bum now; GB400tt Cafe.

nice to see another kiwi on the forum, and nice to see a gb. Has it got rego? if you can keep the rego on hold while u work on it that will save a lot of headaches later. 400 donk is reliable & can be hotted up easy or swapped for 500 or 600 xr motor easily. Have you looked for stock single seats, there are a few around and that would be the easiest answer there. I would strongly suggest leaving detabbing and painting the frame till last, when you are certain that you have added and removed everything you want to. Enjoy your liberty and your project.
 
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