Ok here it goes, I hope you are ready for a waffle!!! This will be a long one.......

So I am currently traveling work/holiday blah blah, but it means I have not ridden my bike in 6 months (having withdrawals and losing my mind) so it has got me thinking about the next stages of evolution for my little beastie which is a 1991 gsxr 400 gk76a rm (black and red).

So I will fill you up to date of the love loss victory and determination of Suzi (my bike) and I will post photos when I get home (month or so). But I thought it's about time I did a big post on here as I'm not going anywhere/never plan on selling my bike and need help with the end section of this post which will be where too next.

So it all started one sunny New Zealand day about December 2014, I had just given my cb500 bobber conversion to a friend who had just had a baby and needed another vehicle, I had ridden some friends sports bikes and was looking into getting one myself. As I was a student funds where low and a 675 Daytona was a pipe dream. Than I spotted Suzi, she was up for sale for $3000 so I emailed the person (lovely lady in the Air Force) I did not hear from her so I emailed here every week for a month till she finally got back to me, (she knew I was serious) so I went and had a look...........

Suzi had not been ridden in three years.
She had no keys.
And was no longer in the road system in New Zealand........
Hmmmm I looked at the bike, was still full of the correct amount of oil which was still a good golden color, the tires where good condition metzlers, the plastics where perfect, there was only one previous owner and the lady had all of the service history since it came from the factory, including all oil changes.... Everything.

So I rolled the dice and parted with 1600 for Suzi! I though was a good risk. And I was finally the owner of a gsxr400!!!!
Ok first thing I need to get some keys made... So I took the tank off and took it to the local lock guy to cut a key.... To try save the call out cost. He cut me a key that worked on the tank and the helmet lock but not the ignition...... Fu#k should have just done a call out. So he drove over and cut me a key for the ignition in all of about 10 min!!!
So before he had even left.
I had drained the old fuel ( which the lady put stabilizer in). Put a new battery and new plugs (which looked good). And tried to start.
No dice!!!!!
On closer look there was no spark on cylinders 1&4 so I ripped into the bike to pull out the coil, with it out I discovered it had arched out between the coil and was toast. The next day I had found one at a wreckers and had it in by the lunch with good spark. With a little bit of effort and some start you bastard she roared into life!!!!
The smile on my face could have been seen from the moon!!! After I went for a ride my smile could have been seen from the sun!!!! Once I noticed my battery was bulged and that the rec reg was toast my tears could have filled an ocean!!
Curse my amateur-ness another new battery because I didn't check the voltage across the battery!!! Won't do that again!!!!!
So ordered a shendengan which a million dollars and 3 weeks later had in my hot little hands. Made up a mount and wired it in!
Started up and after checking everything went for a ride!

Soooo good everything felt good!!!!
Came back replaced the oil, oil filter and coolant for fresh! Ok time to book it in for a certification to get it new plates and back in the system! So glad it's running so good!!!
Everything is peachy, get it in the system get it insured ride off into the sunset ah bobs me uncle!!!
........
The reality walk outside and it's gone............
My bike has been stolen!!!!!!!
Fuc# it's not insured!!!
My dreams up in smoke!!
Who the arghghghghghghghgh
Sadly travel to the police station to report it stolen.
Oh man need to travel overseas for work in three weeks and my bikes gone, spent every cent I have on it....
Words cannot describe the gut wrenching feeling of a stolen bike!
So I come to the realization it's gone.
Three weeks pass and I'm on the way to the airport, still sad about my lost love!
And my phone rings......
Hello this is the police can you identify your bike....... Well I can over the phone.... I have to catch a plane in 3 1/2 hours....
Ok..
Well it has these 4 stickers, this rec reg,
This that and if you pull apart the starter motor there is a piece of green garden hose stoping it arching out....
Ok we have found your bike here is a number to pick it up. She is a bit rough!

Well I sort out my uncle and dad to pick it up so I can pick it up from them when I get home.

So happy to have it back!!!!
(The guy who stole it got 6 months)
(Guess he had other charges)

So I get back to nz and the first thing I do is pick up my bike..........
Ok the pros
I got it back
The cons
Lever snapped
Missing indicator covers
They took to the plastics with a paint scrapper/spray paint
Snapped off wing mirror
Cracked plastics
Smashed ignition
Broken headlight (one of the worst)
Thrashed brakes
And they had blown the gearbox bearings!!!!!!
But funny thing is I think the crim got caught on the bike broken!!!!
The funny thing about it is the odometer reading was 666 when the bike was returned to me!!!

So I take lots of photos and start ordering parts
Could be worse but still pretty bad with no insurance
Order a new gearbox out of the U.K. As be good to have a spare in case
And start writing up a list from the parts manual.
Pretty good parts from Japan only took 7-12 days
And in less than three weeks I had rebuilt the gearbox and hoping I did it right!!!
Oh for others info the wing mirrors are the same as the rgv150!!!
But when your this far out of pocket you might as well do it right so changed the seals and oil in the front forks.
And put her back together with new liquids.
She was running again, but not as pretty anymore!!!
But hey I could put here back in the system!!! Even though the headlight mounts where still broken.
So I took her to get a brake deceleration........
Both fronts and rear are undersized!!!!!!
Will it ever end!!!!!!!
But this was just another little hurdle.
New ebc's up front and a metal gear (auz company) for the rear) new ebc pads and new fluids all around and she got the declaration.
Now how to register with no plate no engine numbers no stem numbers and no vin plate...........
Oh and the bike never being registered in my name....
Hmmm
I had a hand written receipt
A police report
And determination on my side
As it turns out I went to a justice of the peace and made a oath that it was mine and it all turned out ok.
It even flew threw the system and got a new plate and all.
I was one very happy very poor dirty looking sweaty son of a gun!!!
There was also lots of little things like me breaking the thermostat and silly things like that.
But the first long weekend I had off I went for a 1800km ride and it was the best.
But I noticed things right away after getting home.....
The rear shock needed an upgrade so did the front forks!!!

So with this much time and money in it I thought HEY why don't I just keep throwing money at my bike why not?!?!
So I got a ohlins race shock off a gsxr600 for the rear.
Hmmm front forks.... 636 ninja front end?! Hmmmm
Na why don't I be irrational again and pull them apart, re chrome them then get them titanium coated and replace all the bushings and everything?!?!? So I did that,
And damn they look slick but still not as nice as I would like so I'm getting some cartridges that should fit in them with a bit of machining, which should give me full adjustability with the same bike geometry.
I get the impression that if people are still reading this novel (sorry) they are
Wondering why I just didn't buy a new one?!?!
As a engineering student I find it really interesting and I don't mind if it takes me longer and costs me more money if I can learn from it, and properly grasp what's going on.
And I also feel that when you put that much energy into a bike and really get used to it you can really feel and notice the little things when riding it.

So that's roughly where Suzi is at right now......
I have brought a new full set of fairings for $1.50 yes one doller fifty for me to build up a Suzuka front cone.
And I'm looking at welding up a aluminum sub frame to build a different tail so I can do a tail tidy.

So now becomes question time from Nobbsie boy...
Has anyone used the Suzuka light kits from tyga?!

But more importantly I'm looking at engine stuff now.
I would like to rebuild a stock-ish engine for the road and hopefully build a second engine up to race in post classic or at least for the track.
The first engine after reading on this forum I would like to keep stock crank and bore (maybe do the 3mm? Over bore to the 442cc) and do some work on the head, hopefully matched with some fcr33s and autorimessa pipies.
The second will be a time and money project that will take awhile eg stroked crank maybe bigger overbore ( is it true 6mm is the max?!?!) has anyone had there own custom cams done?!

But for now the most important for me is the fcrs and the autorimessa pipes
With the fcrs is it true I should be looking for the downdraft 33s? And what is the difference between the standards and the d model?! Is it throttle position sensor?!
Also has anyone with autorimessa pipes measured them up to get more made by someone else?! Or does anyone know someone who knows someone who has some kicking around?!
Does anyone have a part number for the cbr 600f3 thermo to do the factory pro mod?
Thanks so much for reading my giant waffling novel
And any help would be much appriciated!
I'll also keep you posted on my progress!
Cheers Nobbsie



Sent from my iPhone

yup, that's a long story. Good job I had a large cup of tea.
FCR's are nearly impossible to find, not worth it for the street, but deffo worth having for track use, easy tuning and the accelerator pump. The CV carbs wont really hold you back, as they are quite big for the cc displacement of your bike.
Exhaust systems are always a compromise, you either build them for the track or street use. I had a custom built header system for an old ex works bike I had, from a local guy here in the UK who does historic F1 zorsts, and it worked out pretty well. I gave him the street version, he copied it, made it out of the next tubing size bigger, and stuck it on a 2" outlet. The power gain was good. That system had a 'stepped' header design, which prevented gases re-entering the comb chamber.
One thing to remember about the Suzi engine is, that it is not very durable. They seem reliable in std fair, but I would be conservative and sensible in tuning ideas. The metal used in the cases isn't the best (stripped threads/cracks appearing in crankcases-ie from high stress areas) especially after 30 years.
Your Suzuki has semi downdraft design, so you could fabricate a ram air box, and cut away some of the rad for a high pressure intake. Works on the zxr's.
Another idea to try is high velocity intake ports. I am sure this would work on the Suzuki, as, as soon as I ported one out it lost power. The idea is to make the port smaller which increases gas speed, and 'supercharges' the cylinder.

Nick.

I agree with Nick that they don't like being opened out, no gains from opening the ports up.

The port shape is not great and the inner two are different from the outside two.

Seem to suffer from lack of air getting in.
A guy I know in the usa was racing a bandit and was really suffering against the other bikes, he fitted the fcr's and was instantly staying with other riders that had cleared off before so the extra he got from the fcr's definitely made a difference.

Not sure you would get any benefit from them on a road bike though as you spend most of the time on mod throttle.

Thanks so much for the input! I was just reading about that! The molding of ports to better suit the engine it is a interesting read for a novice like me:
http://www.racedevelopments.co.uk/asset ... 1/head.pdf
I really have my heart set on the fcrs as I know one day the bike will end up on the track, and on the road would be handy to try keep up with my friends. Does anyone know which ones?! The down drafts right?!
I would really like to track down some autorimessa pipes or measurements too.
The stock design with bigger pipe is always a option though.
Does anyone know a good place to look for more information on ram air and port profiling?
What's the best way to measure ports and shape? Some moulding putty?!
So with high pressure intakes build them up to create more speed through the port, combined with the intake valves opening slightly earlier to use the overlap to really get it sucking through?!
Sorry for all the questions it is still new to me
Cheers
Nobbsie

Nobbsie,
You will need semi- downdraft fcr's with the correct pitching and ideally around 33mm. Like I said before you can get large (35mm) cv's with tps, which when set-up will only be a gnat's cock behind the fcr's. I have a friend with 32mm cv's on his ram air zxr400 (72rwhp) and it is faster than an FCR GSXR400 will ever be!! It pulls really well through the revs, and will do 140mph.
There is an art to riding cv's fast on the track, you have to open them up really early, so it feels like you are in danger of highsiding, but you have to do that as the power delivery is soft. Once you master that you will not lose ground.
There is a downside of fcr's is that the power is immediate! As My poor 4 back vertebrae found out at Cadwell Park when I highsided my fcr33 shodded 400 at Cadwell Park. Broke my ankle as well.. But fcr's look cool don't they!! You can buy them new for about £1500GBP off ebay which will fit with minimal effort. http://www.ebay.co.uk/itm/JB-POWER-FCR- ... SwOgdYm~9i

As for porting, only intake port modding is a viable cost effective way to tune the head. As Chris says you can find improvements here. Don't go making the zorst too big without balancing the whole intake/carb/port size scenario up. You will end up with a really weak motor that only works in a small rev range. The exhaust has to have high gas speed also. The gsxr400 already has quite long duration cams as std, so port modding would be ok on it's own. http://cfmmotorsports.com/services/4-st ... ad-porting

My advise would be is to first check you are getting at least 170 psi compression out of each cylinder, stick a new cam chain on her, find some 4 into 1 headers with balance pipes, invest in a Kent cam regrind (they have a profile for the gsxr400 on record). Doing that will get you maybe up to 10hp from what you have now.

You could then maybe think about getting a mould to fit the fcr's for a high volume ram air box. I would estimate that the zxr400 ram air box would be around 5 litres, so I would copy that one as it works a treat.

For reliability, you should have the engine totally stripped down, and check the oil delivery passages and nozzles are clean. A couple of mine were nearly totally blocked after 40k km, and could have ruined the small ends and gearbox, if I had continued to use it. It will probably need doing after 25 odd years. Replacing the shell bearings also will be a wise investment. I know this last bit is totally boring!!

Thanks again for the info!!! Has anyone done a ram air conversion for the gsxr400?'
That really does look like a fun project!!! And I imagine it would really help.
So the middle intakes are smaller?! Is this because they get the majority of the air coming straight from the filter?!
Or is this another reason?!
Yea a engine rebuild is on the cards. I did all new bearings in the bottom end when she was stolen and threw one.
But as soon as I get home will do a compression test and se how she is.
I guess in the mean time I'll keep saving and looking for parts.
Any suggestions on cdi's?!

Just looking through the whole website I see with a ram air I will need the sp carbs with pressure balancing float bowls!!
Do fcrs have inlets for the ram air?!
Is there any littiture on the fcrs??!

I think my zxr400 had the carbs vented to the airbox with ram air, I had to run massive 190 main jets to keep the fuelling at the top. It's easy to achieve, just use a 15mm rubber grommet and run the vent hose into the airbox bottom.
You will be restricted to airbox volume due to the amount of space once the tank is fitted. You can use the tank as the airbox top with just a rubber seal, you will have to have a play. I don't think anyone has ram air'd a gsxr, everyone ran to the zxr400 camp.
The trumpets usually come with the fcr's. they are usually blue or red, and should be perfect as stock items. Just remember you need semi downdraft fcr's in around 32/33mm sizing. You do get a set-up manual with fcr carbs when you buy them new. I personally would stick with the 33mm or 35mm CV carb with TPS. That is a great spec carb.
Standard cdi should be fine. Rev increase and ignition advance may not make you any more power, it will just add heat and undue stress into the engine. Trust me 15000 rpm on a gsxr400 is enough.
My race zxr400 made 78 rwhp at around 13000 rpm.

Once I saw some article about a guy who made a ram air GSXR-400. It was from one czech motorcycle magazine circa 1996 to 1998. In the article he went through all the troubles he had with the conversion. Basically it was like solenoid here solenoid there so he prevented overflowing when the throttle was closed or overpressuring float bowl when airbox pressurized. IIRC he used standard carbs with a lot of bijoutery around.

Finally he stated that ram air worked only from like 100km/h up and allowed to raise top speed by like 5 or 6 km/h compared to stock engine.

There has been some big developments since the 90's. My zxr400 was tuned by Mr S Bass in the IOM, and it was a a monster. It had fcr's, made over 20hp more than the std bike with only top end mods. https://www.youtube.com/watch?v=jabw8EnGc6A It won the F400 championship with 6 rounds left.... (but it twas a zxr)
The airbox was huge, and just fitted under the tank. It had a crude air filter pushed into the intake snout. I can't remember where the carbs vented to, but it was only a pipe with a grommet, pretty sure it went into the airbox.
Go for the airbox, it will make make 70hp easy, once you have the design in the ball park. You just need a tidy job, and a good dyno man who knows how to make it all happen.
Anyway gsxr's are always cooler than kwak's, so just do it anyway

Thanks again for the info!!
I have started researching religiously!
Will keep you posted on my findings!!!
Does anyone know where I can find the length of the front fork internals ( not near my bike)
From under the cap to the bottom of the internal, and the length of the fork from the center of the axle to underneath the cap?!
Can't seem to find info on the net anywhere!!
Thanks all
Nobbsie