89 FZR400 Need Help Carb Question

[1.3V8KILLER]

I have a 89 Yamaha FZR400 I am running individual air filters and a full V&H Pipe. I am currently jetting the carbs. I belive that I have the main jet that I need figured out. I am having the best luck with a 110 jet(had an 88 in there and the bike would not go over 8k/rpm). I have the needle clip set on the second spot from the top. I have the mixture screws set 2 turns out from the bottom. Bike is a little hard to start(have to crank it for a long time), Partial throtle(1/4-1/2) bike rides pretty good, WOT idle to 3.5k pretty good(a little boggy), 4k-8k really boggy, 8k-14k RUNS LIKE A BAT OUTA HELL. When I take it up to redline and shift really quick The bike bogs and loses alot of power till its back above 8k. When I start to get up into higher gears the midrange and (after-Shift) bog is increased(likely due to gear ratio) I am new to the carb tuning game and was wondering if anyone had some tips. Thanks in advance.

[XJ600s]

Got any pics? I want an old FZR400 or a 600 and think they are beautiful bikes!

For help on the jets, check out www.fzrarchives.com/ipb
Its a national FZR forum. Those guys know tons of stuff, and I'm sure if you did a quick search you might be able to get some answers.

Good luck!

[MattTLS]

Unless needed adjustments are very obvious, it's usually best to work on one circuit (pilots, needle position, mains, etc.) at a time as some crossover is to be expected. From your description, I'd next try to move the clip on the jet needle to the third position and test. Also, if you haven't already, check if leaning out the main jets one or two sizes at a time still gives strong running at high rpm. It could be that the engine is getting too much fuel. As a matter of fact, I'd do this before altering the jet needle position if not already done.

[BigE]

Fizzers are very susceptible to bogging when the needle jets are worn. These are 'spensive lil' buggers but they effin' work (with a capital F!), see http://www.factorypro.com/services/n...20rebuild.html

I had a 600 (actually a few of 'em) and those new jets make a huge difference.

[rybo]

So I've owned a few of these bikes over the years. The first two I ran with the factory carbs and the last one had some really sexy flatslides on it.

One part of your setup that's hurting you is the individual pod filters. The factory airbox is a MUCH better option on the 400. The individual pods help with the top end (where you seem to be doing fine) and makes it SUCK down low. If you still have the factory airbox I would STRONGLY encourage you to put it back on and use a factory air filter. I think you'll find the midrange much improved.

All of the Fizzer 4's I owned were cold blooded. If the valves are at all out of adjustment it makes this condition MUCH worse. The Fizzer 4 is extremely sensitive to having the valves in adjustment.

If it's a street bike keep the factory carbs, but if you think you want to make a track bike out of it (it's a GREAT track bike!) start looking for a set of flatslides for it, they really made the motor come alive.

The other advice given here is all very good. Work one part at a time (main, pilot, air screw) and the factory pro needles are the bomb.

Best of luck to you

Scott

[FZRguy]

I agree with the above. The pods are gonna be trouble on CV carbs, and I’ve installed the Factory Pro jet tubes on my FZR. Also, I think you’re too rich on the main jet. I’m running 107.5 jets in my 600 with no low-end bogs (stock box with K&N). A too rich issue gets worse as the motor gets hot…too lean gets better as the motor warms up.

[FZRguy]

XJ I might be selling my 600 next spring...she's pretty clean!

[XJ600s]

Thats a nice looking FZR!!!! But being that nice, means I probably can't afford her, but let me know if you decide to sell and I'd be interested in it. Have you thought of a ballpark price range? I'd be interested in what you think its worth, and feel free to PM me...might even be able to gather funds together by the spring.

I think the FZR's are pure sportbikes. I think they are classier than the numerous (and modern) R6's and GSXR's and Ninjas out there. Anybody can ride a new sportbike. Few can ride older bikes and keep up with the new bikes. But its not that only, I think they look better too!

[rybo]

John,

Your fizzer is stunning. I know someone who would be VERY interested if you decide to sell it.

s

[XJ600s]

Hey...I've got my dirty little fingers on that FZR600 first! No fair trying to take it out from under me...muhahahahah!

Watch, there'll be so much interest in his bike, he'll end up not selling it, or raise the price through the roof...

[FZRguy]

She’s been my buddy for a long time and I don’t think I could watch someone else ride her away. A new Street Triple would go far in easing my separation anxiety, but the little Fizzer that could has been the perfect bike from track days to multi-day trips. And she’s only got 2k on new over-bore pistons and new valves, so technically she’s a 609. I’ll probably just wait til I can buy a new bike without selling her. A man can’t have too many motorcycles!

[FZRguy]

This is a repost, but here ya go V8killer...

Below is a great article by Marc Salvisberg of Factory Pro on how to tune CV carbs.

CV Carb Tuning
High RPM engines

Have a website? Want to provide tuning information?
Please do not plagiarize this page - it took years to develop and write and is not based on any other previous work by anybody else. If you want to link to this page on your site, please ask - we are perfectly willing to allow links as long as proper credit is provided. Thanks - Marc

Follow steps in order....First dial in:

 1. Top end (full throttle / 7.5k to redline -
Best Main Jet must be selected before starting step 2 (needle height)!
 Select Best Main Jet
 To get the best, most even top end power (full throttle/after 7500 rpm), select the main jet that produces the highest top speed / pulls hardest at high rpm.
 If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large. Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges.
 If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small.
 In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use!
 Do not pay too much attention to the low-end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low-end / cruise later - after step 2.

 2. Midrange (full throttle /5k-7k)
Step 1 (Best Main Jet) must be selected before starting step 2!
 Select best needle clip position
 To get the best power at full throttle / 5k-7k rpm, adjust the needle height, after you have already selected the best main jet.
 If the engine pulls better or is smoother at full throttle/5k-7k in a full throttle roll-on starting at <3k when cool but soft and/or rough when at full operating temperature, it is too rich in the midrange and the needle should be lowered.
 If the engine pulls better when fully warmed up but still not great between 5k-7k, try raising the needle to richen 5k-7k.
 If the engine pulls equally well between 5k-7k when cooler as compared to fully warmed up, the needle height is probably properly set.
 Do not pay too much attention to the low-end richness when you are changing needle clip positions - you still need to be using the clip position that produces the best full throttle / 5k-7k power in conjunction with the main jets (Step 1) that produce the best power at high rpm. You will deal with the low-end / cruise next.

 3. Low end (full throttle / 2k-3k)
Step 1 (Best Main Jet) and Step 2 (needle height) must be selected before starting step 3!
 Float height (AKA fuel level & how to..)
 To get best low-end power, set float height (fuel level) so that the engine will accept full throttle, without missing or stumbling, in 2nd gear from 2.5k to 3k rpm at minimum.
 Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.
 If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 2k-3k rpm leaner.
 If the engine is "dry" and flat between 2k to 3k rpm, raise the fuel level.
 Example: change float height from 15mm to 14mm to richen up that area.
 REMEMBER, since the main jet WILL affect low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before final float setting.
 Warning: If the engine is left with the fuel level too high,, the engine may foul plugs on the street and will be "soft" and boggy at part throttle operation. Adjust Floats to raise/ lower the Fuel Level.
 Base settings are usually given if a particular application has a history of fuel level criticalness. The Fuel level height in the float bowl affects full throttle/low rpm and, also, richness or leanness at cruise/low rpm.
 Reference: a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. Check out and RESET all: Suzuki (all), Yamaha (all) and Kawasaki (if low speed problems occur). Needless to say, FUEL LEVEL IS EXTREMELY IMPORTANT!!!
 If there are low-end richness problems, even after lowering the fuel level much more than 1.5mm from our initial settings, check for needle wear and needle jet (part of the emulsion tube). See Worn Needle and Worn Needle Jet diagram. It is VERY common for the brass needle jets (in the top of the "emulsion tube") in 36mm, 38mm and 40mm Mikuni CV carbs to wear out in as little as 5,000 miles. Check them for "oblong" wear - the needle jet orifice starts out round! Factory Pro produces stock replacement needle jets / emulsion tubes for 36mm and 38mm Mikuni carbs. Click here

 4. Idle and low rpm cruise
 Fuel Screw setting (AKA mixture screws)
 There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs have no caps, but use a special "D" shaped driver, usually supplied in the carb recal kit. We do have them available separately, too. 800 869-0497 to order -
 Set for smoothest idle and 2nd gear, 4k rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear 4000 rpm steady state cruise , and 1/8 throttle high rpm operation. (pj tuning information)
 Pilot fuel mixture screw settings, float level (but, you've "fixed" the fuel level in Step 3 - which you have already done!) AND pilot jet size are the primary sources of mixture delivery during 4000 rpm steady state cruise operation.
 If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.

 Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem.

 NOTE: A rich problem gets worse as the engine heats up.
 If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.

 NOTE: A lean problem gets better as the engine heats up.
 If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!

 Carb Kit Design is a combination of science, art, intuition and and at times, a fair dose of wizardry. There is no dyno that "tells" one how to assemble or modify the carb to deliver proper power and response.
 Perfect Carb Kit TUNING requires patience and perseverance and "reasonable" feel to feel the changes - of which - most motorcycle riders have a good ability to do.
When a dyno "operator" says he/she has to ride the bike after dyno tuning to do the final tune for cruise smoothness - that's what they are doing. Avoid any dyno operator who says that they don't have to do that!!!
The only dyno that I know of that will duplicate and visually display the engine smoothness is the EC997 dyno (yes, I know, we make it) - that's one reason why, if you can, you'd like to use one for tuning - a smoother engine IS getting the best mixture. Other dynos claim to "tune to an "A/F Ratio" - probably the biggest marketing scheme in the dyno industry at this time - and they never can equal the quality of tune as designed -
These tuning kits have been thoroughly tested to ensure easy, trouble-free, optimized performance.

 Please note: If you have installed the kit and gone through the optional screw settings, clip positions and main jets, and still have a persistent flat spot/problem, we ask you to call us. Unique engine / exhaust / filter / altitude / temperature combinations may require individualized setups. We are here to help. The information gained to your solution will be installed in our computerized reference database. PLEASE CALL!
 We ask that upon completion of installation and tuning, that you call us with specifications of your installation, (pipe brand, filters, advancer, altitude, humidity, temperature and final carb settings) to be entered in our TUNING DATABASE. The database allows us to include the "most used" jet sizes and setup specifications in every kit.
 Use (415) 491-5920, (800) 869-0497 or fax (415) 492-8803.

Thanks!

Marc W. Salvisberg

[slayermd]

Damn FZRguy, you make me miss my FZR. Luckily I do have one in my garage as my track day bike!

I wish I had some advise for you on carb work. Im not too familiar with the 400 but Im sure they share the same problems with the 600 and Im usually asking the questions about carbs. Best of luck to getting your 400 to run, I have yet to see one on the street.

[FZRguy]

I’ve seen one 400 on the street and it was beat…sure would like to have a clean one.

[1.3V8KILLER]

Thank you so much for the help all.

I’ve seen one 400 on the street and it was beat…sure would like to have a clean one.

mine is not nearly as clean as your 600 but she was free and she only has 17k.

[FZRguy]

You can’t beat free! An FZR400 in street trim is fairly rare as they were imported into the U.S for only a couple of years (1988-90). They make for a great track bike but not so great street bike (buzzy motor and not real comfy erogs). I forgot about another 400 that someone on this forum was selling a few years back. I went and looked at it and rode it around the block. It needed lots of work and I think he wanted $3k for it. Anyone here ever see a FZR250? I’ve never seen one anywhere.

[rybo]

Anyone here ever see a FZR250? I’ve never seen one anywhere.

I saw one in Canada when I lived in Northern Idaho. It was pretty cool, redlined at like 18K RPM.\

The FZR 400 is a great bike. I agree with John that it's not so good as a street bike due to the character of the engine, but it's a wicked fun trackbike. The 400 frame is FAR superior to the 600 model (sorry John) both in geometry and material. The 400 frame (and the 1990 version swing arm) are aluminum vs. steel on the 600.

The good news is that if you want to make it a 600 the FZR 600 motor is almost a direct bolt up into the frame, and if you want an even more modern motor the YZF 600 (not R6) motor fits with only minor modifications. My last race bike was a 400 frame and motor with flatslides, an 0w01 front end, HUGE brakes and TZ250 magnesium wheels on it. It was a VERY fun bike to ride and race. It was a tough decision to part with it, but if I had kept it I probably would have grafted the YZF600 motor into it.

Free is good! Now, I'm hopeful that you get the airbox for it. at 17K miles you really should adjust the valves too, along with other little basics, like changing spark plugs. I think if you do these things you'll notice a much improved bike.

[lovinCO]

400/600 FTW! This thread makes me miss my old bike.

[FZRguy]

I’ve thought about the 400/600 conversion…it would be cool. V8, dibs on the frame/swingarm if you ever decide to part her out.

[BigE]

4/6 conversions are sweet! A buddy of mine had one with the YZF engine, gixxer forks w/ Duc front wheel, TZR swinger and rear wheel, just all sorts of trick parts he got from a buddy in japan. Actually he had it on CL a lil while back because he was moving. That bike was better to ride on the street than an R6 because of the torque curve.

[ChrisCBX]

A lot of good info on this thread on tuning CV carbs. I hope your FZ carb issue is resolved soon.

Be grateful that you aren't trying to tune carbs on a CBX. 6 carbs each and if they have stock air box, the engine needs removed to get at the carbs.

[slayermd]

I’ve thought about the 400/600 conversion…it would be cool. V8, dibs on the frame/swingarm if you ever decide to part her out.

I just got done doing that swap. It was fun to do. I would never do it for a street FZR, I dont see any benifits on doing it but for race/track use its a no brainer.

[lovinCO]

4/6 conversions are sweet! A buddy of mine had one with the YZF engine...

The first year I ran my 4/6 I had the FZR motor, then swapped to a YZF engine for the next couple years. Had someone machine the 400 cases so the YZF crank would drop in, don't remember all the details but it wasn't that hard to do and kept it legal. It was a fast little bike for it's time.