Are bigger carbs better?

[FJRider]

The GPZ isn't exactly a wonderful handling bike anyway...

Often in the rebuild of older bikes ... standard (or similar) suspension is fitted. A sensible upgrade with modern equipment wont give a speed increase ... but you wont need to go as slow as you did ...

Often the chase for better handling is more productive in terms of point A to point B times ... than the search for more power.

[bogan]

Often in the rebuild of older bikes ... standard (or similar) suspension is fitted. A sensible upgrade with modern equipment wont give a speed increase ... but you wont need to go as slow as you did ...

Often the chase for better handling is more productive in terms of point A to point B times ... than the search for more power.

And it's the suspension that has been rather static over the years. They need to compress the development time right down, and start rolling out bikes with proper bits on em.

Or just take your money, and bounce back a decade or two, spend a little on the bike, a little on the suspenders, then spring well ahead of the 'newer' crap!

We may be getting a bit off-line with regard to the original question now...

[nzspokes]

I think a major point missed here is the are people like myself that enjoy pulling these things apart to see how they tick. The enjoyment comes from the work as well as the use.

[ktm84mxc]

Yes sir re trying to up grade a older bike is a plan of self grow and applied knowledge gained through trial and error.
First of try shedding some weight from the GPZ eg exhaust, lighter wheels, pilllon pegs[ if not needed], tail tidy etc . Fairing lowers can also go if you want the rat look.
Second get into the air box open it up fit a K&N style filter, pods are great but have been known to cause stuck slides in the rain. FCR style carbs, Head mods, REprofiled cams, High comp pistons etc depends on your budget.
A well ridden 400 can stay with most bikes in the twisties only loosing on the longer straights.
A Bandit 1200 is the classic UJM a bike to fit every ones needs to a point.

[DEATH_INC.]

If the bike was a 'keeper' apart from the power? Maybe that would be an option. But at the end of the day you spend $X000 on tuning bits for a bike that wont be worth the extra $X000 at the end of the exercise, has had its reliability and longevity possibly compromised by the level of tune, only to still be out performed by a bigger bike that would have likely only cost the $X000 to begin with.

WTF has money got to do with it????? Who give a flying f**k if it costs way more than it's worth? Heaps of people buy new bikes even though you lose a bundle on em.....think about that for a bit....
If you don't get the idea of modding something, then you probably never will. It's not really about the money, or even the performance, it's like Burt said in the movie "it's in the doing of it"

[GrayWolf]

WTF has money got to do with it????? Who give a flying f**k if it costs way more than it's worth? Heaps of people buy new bikes even though you lose a bundle on em.....think about that for a bit....
If you don't get the idea of modding something, then you probably never will. It's not really about the money, or even the performance, it's like Burt said in the movie "it's in the doing of it"

The point IS the bike ISN'T a keeper, so a waste of time and money to work on more power.... if he doesn't think the bike is ideal in all aspects apart from the power.. why WASTE the dosh on it? Think about that for a bit??

[bogan]

The point IS the bike ISN'T a keeper, so a waste of time and money to work on more power.... if he doesn't think the bike is ideal in all aspects apart from the power.. why WASTE the dosh on it? Think about that for a bit??

Its about making the most of what you have. Spend 1k to improve your ride for the next year, or put up with it and save 8k for a newer bike, then spend 1k improving that. Why wait, when the cheapest option for a better bike now, will usually be to modify you current one. Who knows, maybe you'll be like me and end up with a 5k bike worth more than any of the newer bikes that come with 4x the price tag.
And then there is still the 'doing it' argument you don't seem to get.

[DEATH_INC.]

The point IS the bike ISN'T a keeper, so a waste of time and money to work on more power.... if he doesn't think the bike is ideal in all aspects apart from the power.. why WASTE the dosh on it? Think about that for a bit??

It's only money. Who cares?

[GrayWolf]

Its about making the most of what you have. Spend 1k to improve your ride for the next year, or put up with it and save 8k for a newer bike, then spend 1k improving that. Why wait, when the cheapest option for a better bike now, will usually be to modify you current one. Who knows, maybe you'll be like me and end up with a 5k bike worth more than any of the newer bikes that come with 4x the price tag.
And then there is still the 'doing it' argument you don't seem to get.

Hmm let me see..... Suzuki AP50 with an AS100 hop up (moped rules in the UK) RD250 hop up to 350, RD250-RD400, hop up with extra fin removed and 250cc stamped on barrells, re stamped engine cases (I was trained as a toolmaker ) RD 350LC Stevens tuned, uprated brakes, Micron pipes, Ace bars etc, etc.
Nope your right, I dont have an effing clue what your talking about....
What I DO know is, having moved up to larger capacity machines, the 'need' to modify for performance reduced. Maybe in direct relation to the fact the bikes were not cheapo S/hand ones but generally only a few years old or new. Regardless of tuning and improving the GPz400 is an 'old bike' and a more modern 600 would offer a substantial improvement on performance and frame technology for about the same price as the sale of the 400 plus the 1-2k he could spend on the 400 improving it.
As I have said so many ruddy times the 'need for speed' from this years XYZRD1500vkr superturbocrotchrocket, or; tuning an older bike to perform as well or better for speed 99% of the time is NOT ability driven. Its simply EGO driven, "I have and ride the 'shizzz' so my nuts are bigger than yours". Reality is, a good rider will outrun an average rider on a bike with substantially more power due to ABILITY. A sprot 600cc will perform in hard riding, beyond the ability of 95% of riders on the road.

Disclaimer: I will also admit that the 'average' brain out no thought of life or limb 'crotch jockey' can often outrun most other riders due to complete and utter disregard for roadcraft, safety of self and/or others... there's plenty of those out there too.

[bogan]

Again, modding for the fun of it, and the sense of achievement gained from improving something is a good enough reason. I would have thought with your list of modded bikes you would understand that...
Maybe the GPZ is old enough to be a lost cause for some, but seems like it isn't for others.

[GrayWolf]

Again, modding for the fun of it, and the sense of achievement gained from improving something is a good enough reason. I would have thought with your list of modded bikes you would understand that...
Maybe the GPZ is old enough to be a lost cause for some, but seems like it isn't for others.

The difference is to my mind, uprating modern bikes is an extremely expensive affair for a minimal to moderate return. The old bikes I played with, were mostly easy and simple head, barrel and piston swaps. The RD400 conversion, the motor was a straight bolt in with no plates or offsetting required. Brakes across the ranges were fairly standardised... Even a simple forks or wheel change/swap these days is a bloody minefield. The bikes themselves were in a much lower state of tune than even the GPz400 we're referring to, so the tuning was more 'effective' for the cost involved.

Reading the OP's post, he isnt considering doing it as an exercise of love, its a stop gap, which for the cost of performing the upgrades? PLus the bike could be higher miliage which brings on some other 'issues' possibly with the upgrade. I will still stand by saying sell the 400 and put the 1-2k he'll spend, on a mid 90's onwards 600cc.

[schrodingers cat]

Bogan,
you presume the OP is geared to learn from the experience.
Tee throwaway 'I learned my Dad with my 12A' (and other comments) suggests he isn't.

Others appear to be able to see an alternative view. Think about that for a bit

[bogan]

Bogan,
you presume the OP is geared to learn from the experience.
Tee throwaway 'I learned my Dad with my 12A' (and other comments) suggests he isn't.

Others appear to be able to see an alternative view. Think about that for a bit

I would think that the other threads hes posted up, and previous work he has done, suggests he does learn from the experience, and enjoys the experience. And since its his bike, his view is the only one that matters. Think about that for a bit

Anyway, when did we stop discussing the best way to supercharge it? I reckon the clutch side cover could be modified so the supercharger runs off the crankshaft primary drive gear. Thus mounting the supercharger in front of the engine. Of course this would mean moving the headers, I think a scrambler pipe setup for each side would be brilliant.

[nzspokes]

Bogan,
you presume the OP is geared to learn from the experience.
Tee throwaway 'I learned my Dad with my 12A' (and other comments) suggests he isn't.

Others appear to be able to see an alternative view. Think about that for a bit

Well champ, I just got home from a morning blasting around on an 82 XR200. I got that bike for $400 with a stuffed motor. Why would I do that when Ive never pulled a motor cycle engine apart? Because I wanted to learn how to. So I got a manual and got amazing advice on this site. The bikes still old and ugly but is huge fun on Trail rides.

My Dad told me getting an old RX7 S1 was a waste of time and get something more modern. I learned how to rebuild the motor and bridged it. I raced that car in club events.

The CBX250 I started riding on was in rough shape when I got it. And at one stage it refused to run. But with advice from this site I got it running and rode it from auck to the cape and other adventures for 13000k. And by the end it gave modern 250s a good nudge.

There are many other projects ive had and had fun with.

All of that is from learning. So please tell me what is wrong with that?

[ducatilover]

I would think that the other threads hes posted up, and previous work he has done, suggests he does learn from the experience, and enjoys the experience. And since its his bike, his view is the only one that matters. Think about that for a bit

Anyway, when did we stop discussing the best way to supercharge it? I reckon the clutch side cover could be modified so the supercharger runs off the crankshaft primary drive gear. Thus mounting the supercharger in front of the engine. Of course this would mean moving the headers, I think a scrambler pipe setup for each side would be brilliant.

Nah, put the blower pulley out the stator side, would be easy enough to make a shaft that bolts on to the flywheel/crank bolt with a pulley on the end


Thought I'd add, I spent another whole day playing with both my bikes, which are apparently too old and shit to bother with. I challenge any to who think so to present a better bike they've built