tuning the head

Want the specs for a valve adjustment? Can you provide tips for bleeding brakes? Please use this section.
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adg
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Joined: Thu Mar 13, 2003 7:48 pm

tuning the head

Post by adg »

ok, so if Im going to take the engine apart, what things can I do to improve the torque and power?<br><br>1) clean up the intake and exhaust ports with a dremmel<br>2) fit new valve oil seals<br>3) lap the valves into the head with some paste<br>4) Swap the cams for EXUP or FZR750 items which have more lift?<br>5) Get adjustable cam sprockets and tweak the engine's torque curve?<br>6) I thought of skimming the head a little but that doesnt seem to be a good idea according to ChuckD.<br>7) ignition advancer?? anyone tried one of these? - Id kindof hope it would help at the top end a bit?<br><br>I know the carbs are probably restrictive but I dont want to spend forever sorting out bigger carbs... and besides then I'd end up getting a new exhaust system to match which I dont want to (and cant afford!<!--EZCODE EMOTICON START :eek --><img src=http://www.ezboard.com/images/emoticons/eek.gif ALT=":eek"><!--EZCODE EMOTICON END--> ) yet.<br><br>Big bore kits get good reviews but Im trying to do the rebuild on a budget so that can probably wait if possible.<br><br>Any thoughts?<br><br>ade<br> <p></p><i></i>

ChuckD
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Location: Missoula, MT

Tuning specs

Post by ChuckD »

These bikes are't like other designs, Yamaha builds them right the first time and only improves upon their idea. Many manufacturers let their customers do the R&D and then change the design year after year. The FZR 1000 has perfect jetting stock (122.5 & 125), make sure that you restore the jetting to stock or else it will run like @#%$! The only real improvement to the carbs is new needles from factory racing, yes you have to buy the whole kit for the needles and springs. Run a stock header w/ a quality slip-on, K&N oem filter, and that's the best it's going to get from the fuel/air system. The way to get big HP gains is through cam degreeing and from there you go into head porting and polishing, Big bore kits, aftermarket conn rods and crank work. If that's not enough, while your in there through in a 6 speed tranny from a YZF 750 because most likely if you have a pre 94 model FZR 1000, 2nd gear is prone to go south when more power, or high miles are present. Then you have to address the weak clutch basket and get a billet one. Well that about covers it. W/ one or all of these mods you get substantial increases in TQ and real rear wheel HP and an engine that will fit in any FZR and YZF EXUP from 89-97 (adaptor plates necessary on some models). For the same price as a new bike, you could create an uber engine that will allow you travel across the continent and not have a sore back, not to mention the look on a 954 owners face when you absolutely blow them away. The 5 valve head is a incredible design, make sure to stay on top of valve adj, yes they are very spendy, but you own a motorcycle that operates on a F-16 budget, and you can produce anywhere from 130 to 175 HP. <p></p><i></i>

adg
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Joined: Thu Mar 13, 2003 7:48 pm

tuning the head

Post by adg »

cheers, so what kind of gain can be got by dialling in the cams and basic cleaning up of the ports?<br><br>You mentioned the jetting, my bike was running a bit rich, probably because it had a dirty stock air filter but its pulling really cleanly from low revs. <br><br>Is the DynoJet kit any good? (theyre a lot easier to get hold of over here)<br><br>The engine is an early 87 Jap one which has a fairly healthy 116bhp at the wheel. Its just got me thinking about how I could boost that figure to something like 125+ by just some tweaking. <br><br>The 3rd gear has gone (which is why Im looking to get inside the engine) but Im told that the YZF 750 transmission is different and wont fit. Besides, I like the 5 speeds, it means Im not wondering if I should be in a different gear..<!--EZCODE EMOTICON START :lol --><img src=http://www.ezboard.com/images/emoticons/laugh.gif ALT=":lol"><!--EZCODE EMOTICON END--> <br><br>Another option is to get hold of an EXUP engine but I dont know if its a straight swap? and if so could I run with my standard exhaust system?<br><br>Are some EXUp engines better than others?<br><br> <p></p><i></i>

LC130LOAD1
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Joined: Tue May 20, 2003 7:06 pm

info

Post by LC130LOAD1 »

You have an 87 FZR1000 motor, right?<br>If it is stock then you can drop in a set of FZ750 cams. They have more lift and about the same duration as the FZR1000 motor cams do. Anything YZF will not work in your engine. You ars stuck having to use FZ750 or (if you can find them) FZR750RR parts.<br><br>I don't know what country you are in, for USA models one of the hot tips for the 87 and 88 bikes was to use the stock Canadian spec intake "velocity stacks".<br><br>For you to get 125 rwhp out of an 87 engine you would need to go with a big bore kit, cams, carbs and a pipe.<br><br>As I said before the YZF750 transmission won't fit in your FZR1000 engine. Placing a 6 speed 750 transmission in a 1000 motor is cool, but you are going to run into more relability problems since the gears on the 750 are thinner than the gears are on the 1000.<br>If you do swap the transmission don't forget to swap out the 5 speed oil spray bar for the 6 speed oil spray bar. I know of at least two guys who destroyed their 6 speed transmissions by not changing out that spray bar.<br><br>You won't be able to run an EXUP system on your 87 engine as the brain box is not set up to use it. The brain box for the 98 bikes won't work, and besides, your engine is not set up to run an EXUP system.<br><br>Dialing in your cams alone won't produce more power, what it will do is change where the engines powerband is located. Stock the 87 FZR1000's have a big hole in the powerband from about 3500-5000 rpms. The 88 motors had different cam timing, it was set up to have the power come on in the lower RPM ranges. It fell on its face in the higher RPMS though.<br><br>That is what the EXUP valve is for, to create backpressure in the exhaust so that the the hole (or flat spot) in the powerband is minimized.<br><br>I had an 89 FZR1000 with a full system, I had a flat spot from about 3500 to 4700 RPMs. My solution to the flat spot? Never alllow the RPMS to drop into that range.<br><br>Depending on how you ride you could dial in the cams for more midrange, more bottom end or more top end, although your cams are set up for more mid and top end power.<br>Your bike really dosen't need to have any porting done to it at this stage unless you are going to do some more engine work. A good valve job and matching of the intake ports to the intake boots would go a long way.<br>If you drop in the FZ750 cams you will have a lot more top end power at the expense of bottom end power.<br><br>I rode a friends 87 FZR1000 that had the FZ750 cams in it, the FZ750 transmission, it had a 5 angle valve job (the hot setup at the time), the FZ750 carbs and it had a full Supertrapp pipe. It was never ran on the dyno, I would say that it made about 120 rwhp.<br>The bike was very fast, the downside was that since it used the 750 transmission, carbs and cams it ran like a FZ750, meaning that all of the power was up on the top end, and since the FZ750 transmission is pretty close to being a race geared transmission (very tall first gear, very short 2-5 gears and 6th being more of an overdrive) you had to always keep the engine soinning in order to make power.<br><br>He raced this bike at Willow back in 1988, it was faster (at the time) through turn 8 and 9 than the full on FUSA bikes. <p></p><i></i>

adg
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Joined: Thu Mar 13, 2003 7:48 pm

thanks

Post by adg »

thanks for all the tips, Im watching out for a late model EXUP or a Thunderace engine if I can get one, but filing that Im going to stick with this motor and start pulling it apart. <p></p><i></i>

flyingcircus68
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Joined: Sun Apr 07, 2002 8:10 am

Re: thanks

Post by flyingcircus68 »

LC130LOAD1 - <br><br>first question: what the heck does your handle signify? <br><br>Main topic: FZ750 CAMS.<br>I have had a set of these cams laying around for years. Its been a good ten years since I did a rough comparison of the base circles and peak dimensions of the lobes. If my memory serves me correct, the dimensions were basically the same. The main difference I noticed was that the timing sprockets were at different angular positions, which made sense. The fzr 1000 has larger valves, so the location of the valve gear would have to move outward to accomodate them. I don't believe that you could just take a set of fz 750 cams and throw them into an fzr 1000 without modifying the sprocket positions. I suspect, although I have not checked, that it might be a simple case of swapping the sprockets for a set from an fzr 1000.<br><br>You mention that your friend swapped the cams and intake set up from an fz 750 and increased his top end. This is counter intuitive. The bike came with mikuni BDS34 carbs. I would think that swapping a set of 37mm for a set of 34mm carbs would limit top end. You mention the canadian spec. stacks were the ticket. What was the difference? Were they longer for more bottem end grunt? <p></p><i></i>

LC130LOAD1
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Joined: Tue May 20, 2003 7:06 pm

info

Post by LC130LOAD1 »

Good catch on the carb size - I called my friend up and asked him about his old FZR1000.<br><br>He did use the FZR1000 carbs on his bike. <br><br>We had another friend who put an 88 FZR1000 motor in his 1986 FZ750, he kept the FZ750 carbs.<br><br>The 1985 FZ750 and the 1987 FZR1000 used the same exhaust cam with different cam sprockets.<br>The intake cams were different between the two but they used the same cam sprocket.<br><br>He put a 1985 FZ750 intake cam and a 1987 exhaust cam sprocket in his 1987 FZR1000.<br>He didn't have any valve clearance problems.<br><br>He did buy the Canadian intake boots, they were longer, but they didn't work with his engine. <br><br>He also did a transmission swap using the 6 speed from an 85 FZ750 motor and put it in the 87 FZR1000 engine. He didn't swap over the 6 speed oil spray bar so he cooked 6th gear on his engine.<br><br>He also used the 1985 FZ750 brain box with his bike. He had to modify the wiring harness to get it to work.<br><br>Our friend with the 86/88 bike tried to use the FZR1000 brain box with his bike and ended up frying the brainbox.<br><br>Part of the problem trying to remember this stuff is aside from it being over 15 years ago he was also dealing with California and non-California parts.<br><br>He remembers that the McDonald brothers from Texas gave him a lot of advice. <p></p><i></i>

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