More power for GB400 needed

**Brutus** · 18th April 2007, 20:43

any ideas on changing the piston to bigger size.
I have been told that the bottom end is the same as an XR 600.
anyone know what i need to do to make this happen?
what are the best carbs to use ?
I am in gissy and heard a few years back there was a GB owners club of sorts
operated by a bloke out of Napier?
Any leads?

**tri boy** · 18th April 2007, 20:57

Think carefully about chasing a bit more hp from such bikes. Sometimes the end result can cost twice as much as trading up to a bigger/more powerful beast.
I know it's tempting, and with a bit of help from people in the industry great things can be created. However cost of parts, machining, and possibly less than spectacular results hp wise could make this an unwise choice. But if you have heaps of dosh go for it.

**avgas** · 18th April 2007, 20:57

Spankme has a thread here somewhere on how to bolt the 600cc kit on. But there are about a million ways to get more stonk out of the good ol' gb. Google (with translation) about a million japanese sites on it.
The quickest fix i ever did on the gb4 was to preload the front forks with about $1.40 of the old 20 cent coins in each fork, and swap the back shocks for Koni's.
Didnt increase the HP at all - but the 0-100 time felt like it halved.
Also iridium plug is your friend. And it will only cost you $25 for that mod.
I also ran 5w50 (Visco5000) in it - as it offers the best of both world for the gb. Motul couldnt quite do the same unfortunately (i hate bp and love motul

)
But search the threads as there are a few hundred on the ol gb's here.
ps: what year is yours? single or dual seat?

**limbimtimwim** · 18th April 2007, 21:02

GB500?

10chars

**deeknow** · 19th April 2007, 20:32

Originally Posted by Brutus

any ideas on changing the piston to bigger size.

There are a few threads with lots of links to sites on GBs already. Coincidentally I was just reading up on the same thing myself tonite, e.g.

http://www.kiwibiker.co.nz/forums/showthread.php?t=4661

They're great little machines arent they, I took an old workmates one out for a strop a couple of years back and loved it, do you reckon it'd put up with being a commuter?

**Bonez** · 19th April 2007, 21:00

Take your GB400 add REALLY tight twisty roads. Fun. They tour no problem. And with a 300k plus fuel range the country is your oyster. I've posted plenty on KB about my Gbs sojourns.

tri boys comment is a very valid one btw.

**MGST** · 19th April 2007, 21:54

You might be able to get a manual from davidsilverspares.co.uk I got a photocopy of the original Honda manual for my GB250 Clubman from him, cost $62 NZD all up on my doorstep. He has got heaps of genuine and pattern parts for just about every old Honda under the sun! Good luck . Choice bike!!

**mark247** · 22nd April 2007, 19:37

Originally Posted by MGST

You might be able to get a manual from davidsilverspares.co.uk I got a photocopy of the original Honda manual for my GB250 Clubman from him, cost $62 NZD all up on my doorstep. He has got heaps of genuine and pattern parts for just about every old Honda under the sun! Good luck . Choice bike!!

I have a pdf version of the manual. If anyone wants it just send me a PM.

GB's are awesome bikes! I have a guy looking at buying mine at the moment, if i get the right price i think ill just buy another one :P

**Brutus** · 22nd April 2007, 21:22

Did the Waioeka gorge again yesterday, GB loves it.

**Brutus** · 22nd April 2007, 21:31

They are great commuters. i didn't own a tin top for a few years and just rode the GB everyday for everything. Just got to get the cam chain renewed every 30000km,.

Thanks team for all the replys. Much appreciated.

**avgas** · 24th April 2007, 17:02

Originally Posted by Brutus

They are great commuters. i didn't own a tin top for a few years and just rode the GB everyday for everything. Just got to get the cam chain renewed every 30000km,.

Thanks team for all the replys. Much appreciated.

Commuters? mine sat at 140 all night between auckland and tauranga. everyweekend.
Not to mention leaving the occasional ducati monster at the lights round town.
I found the dual seat more comfy than the single - anyone else had that?

**Sanx** · 24th April 2007, 19:52

NOS. You know it makes sense

**mark247** · 24th April 2007, 21:01

Originally Posted by Sanx

NOS. You know it makes sense

Easy as well, but do you really wanna melt your pistons?

**Buddha#81:Me** · 24th April 2007, 22:18

I brought a mildly damaged one when they first came out and hamered a solid piece of round bar through the baffles in the muffler and I'm not sure if I gained any power but it sounded farken cool.

That was a way cool bike until my then girlfriend bined it into a cage.