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Hi guys.I finaly got my motor out and am checking it over.I just checked the cams and heres the #'s.Int opens at20 btdc. closes at 60.= 110 LC. Ex opens at 58* BBDC. closes @ 17* BTDC= 110.5 LC.These were taken @ .050". lift= .420" These are RC400 cams.The specs I got are int. 45* and 85* ex 85* and 45* duration310.I dont know what lift these #'s are at.So I'm new to this and could use your advice on wheather I should change any thing here?.Not sure why my #s are dif on in and ex .But I can tell you that I degreed them 23 years ago and didnt understand very well what I was doing(the bike sat in my barn for 23 years now I'm learning again and loving it)This will be a street bike ,see sig below.I ran it this summer and the motor came on strong at 6 to 7000rpm.But I felt it lacked torque,also blows a little oil(looks like a ring job is next)compresion was around 145psi.
Also just want to clarify if its accepable to use a feeler guage under the lobe to acheave 0 clearance for the testing(dial indicator is on bucket)?

Doing lobe center method doesn't require 0-lash on kaw cams. Having lash will just show less duation but lobe center will be the same.

When you say "The specs I got are 45 and 85" duration 310" I assume you mean the cam card specs? Or the measurements you've taken? Anyway, 20 and 60 is short duration nowhere near 310. If the numbers were taken using .004 to .008 lash the opening number will be late. For example: op. will be 30 with no lash, 20 with some lash. On the closing side example, closing will be late with no lash 80. With some lash 60. My guess is that the actual opening is around 35 and closing is close to 75. 45 and 85 is long duration and with that you would not see compression at 145 due to the late closing, unless you have a piston kit with higher compression. After checking with zero lash you can compare op. and cl. to the stock 30 and 70 and that will tell you what you will expect for torque. 110 lobe center on cams with numbers like 35 and 75 will run 6 to 7,ooo rpm or so. After you have checked your ignition timing and advancer, and checked your cam card, you can reduce the intake lobe center number by advancing 3 to 5 degrees for more torque at low and mid ranges. The improvement is dramatic. Take additional compression readings to ensure there are no stuck piston rings. Keep in mind that at least three deg. of advance is necessary bfore a dyno even knows the diff. At 2deg. we can feel the "bump". You may want to retard the ex. a couple deg. to increase torque also. Both the adjustments decrease piston to valve clearance so use a piece of solder bent to fit into the piston pocket to check for clearance there. With a little playing around you'll have that up and running good. Pay most attention to the lobe centers. Double check by putting the engine at highest point of lift center of cam lift and check the degree wheel, the lobe center should be right on or very close to your calculations made.

Post edited by: nads.com, at: 2007/01/18 14:29

Post edited by: nads.com, at: 2007/01/18 14:40

I just read your post in dragbike forum. I'm running 111deg. lobe center on the ex. This gave me around 85thou. clearance piston to valve. I've over revved my motor so bad missing shifts because of a second gear problem i be about deaf because of the noise. I've never touched a valve. I'm sure it's becuase of the extra clearance. I run 109 on the intake and the motor has plenty of power from idle on up and comes on the cam real strong up top. I've seen heads with bent ex. valves due to clearance minimums, some of those heads were mine. It may be a good idea to install ape springs for 60.00 and feel that fresh tight feeling again and the power that comes with it.

Post edited by: nads.com, at: 2007/01/18 15:09

nads. Thanks for a great responce. 20 + 60 = 180 = 260 duration.Ape.jay said that 310duration was just an advertized duration and most cams duration is read at .050" so if you take 310 - 50 = 260.So these 30 year old cams must be similar to new ones advertized at 260 I guess.These are old cams like the rest of my motor but there is very little milage on the motor.Only a few thousand.
You mentioned I should check my egnition timing and advancer.Can you explain why that would be important.I set up the points and verified the timing with a lite so the were ok.I just bought a new Dyna 2000.
You said you run 111 ex. 109 intake. Is there such a thing as proven # that kz's run best at.

op. and cl.#'s taken at .050 lift using your cams represents 260deg. duration. If measured at .040 lift it would be closer to 265 or higher. Taken at .030 the duration number is higher yet. By this example you can see that your cams appear to have more duration as compared to the a.p.e. 410's. The benifit desighned into your cams is focused toward increasing torque. Stock cams are around 280deg. at .000 lash. They make peak torque at around 8500rpm. If you want more torque, advancing the intake cam 2to3 deg. will open the intake earlier, like say 25deg. btdc. This will allow the valve to open sooner, starting cylinder fill earlier, and be open farther when the piston is part way down, allowing more volume of charge to be pulled into the cylinder. The lobe center will be closer to 109, 108 ,107 ,106, depending on how many degrees exactly, that you advance the cam. The closing of the intake valve will occur sooner also, closing at around 55deg. abdc. This will trap the charge, and start compression early. Your cranking pressure will bump to 160 or even 180. This is good for lots of low end and midrange power. You will lose some up top. Now the motor will peak earlier, as you will have built in a new redline, or peak output rpm, which is lower. Making a small advancement will keep the broadness to the band. You may or may not want monster torque that peaks at 6,000 or so. So take advantage of the comp. increase and run with it. Meaning advance only a couple deg. No matter what the tools say a little is alot and you'd get tired of doing the adjustments more than you should have to. I know of no specific magic for lobe centers except the cam card,s specs and making small adjustments to tailer the band to your liking. For instance, since the cams I used had more dur. than stock, i thought I could get away with advancing them 1deg. without losing top end, and maybe supporting low and midrange. Using only 1deg. of advance, I was also able to keep the valve a safe distance from the piston allowing for over-revv. On the exhaust side you start with less clrnce and at 111 it was getting closer than I was willing to gamble with and figured I'd get early blown down anyway so I went with it. I believe my cams are close in duration to yours as the card says 280deg. at .020. This would be near 260 at .050. The motor works like a rocket with the best of all worlds-(for me). I play with the ignition timing to change the power band dramatically. Changes in ig. timing are like changes in cams, in a way that effects when the power comes on. Make sure your advancer is moving freely to answer that question. I noticed you have your deg. wheel on the wrong side of the motor, does it work that way? I put mine on that side before but i turned it 180 and read it from the other side. To see how close to the stock cams yours are, zero the lash and take readings from the point the valve opens to the very point it closed, and compare the open and close numbers to stock. Any later closing of the intake than stock, will shift the band higher than it was with the stock cams. Remember that exhaust is the opposite. For example 111deg. is 1deg. advanced. When measuring your cams with zero lash, if the intake opens sooner than stock and closes later, you know the durations of your cams are greater than the stock ones. If this is the case and you want more torque than you have, (once you fix the leaking down of clinders), the motor will respond nicely to some advance of the intake. You'll know something once you find the compression to be "higher", after advancing a couple deg. Once your done with it, you have the lash to play with. If you want to fine tune the band further, less lash will give you more on top, and more will give you more on the bottom. This is mainly do to the intake closing later or earlier. Once your done, check valve to piston clearance with a piece of solder. Bring the piston up half way and put the solder into the valve releif on the piston. turn the motor over and squish the solder then measure it with a caliper. Your not going to be close to trouble unless you make some radical changes. The exhaust is the most sensitive side but keep in mind you have oversized intake valves and that will narrow the clearance there. The op. and cl. numbers obtained with the lash zero'd will lead the way to estimating the "new" power band, by simply referencing them to the stock numbers, since you already know the stock rpm band. Keep the same amount of tension on the timing chain when making before and after measurements of op. cl. numbers, lobe center calc's or whatever. You'll be surprised and comfortable with the accurracy of the maneuvers you make. That includes the effects of lash on the op and cl numbers. I would run around .005 lash to utilize the ramps of the cam. This will keep down any bouncing and banging that beat the valve train.

Post edited by: nads.com, at: 2007/01/19 04:30

Post edited by: nads.com, at: 2007/01/19 06:16

Post edited by: nads.com, at: 2007/01/19 14:07

Post edited by: nads.com, at: 2007/01/19 14:10

Yes that was a lot to say ,but I'm glad you did.Thanks.It will be interesting to see if my rings are siezed.I did a leak down test today and avraged 15% loss at rings(if you remember ,the bike sat for 22 years).I also found a piece of what looks like a clutch basket spring in the sump.I'm sure I will see a huge improvement in the spring.Can't waite.

Post edited by: mark1122, at: 2007/01/19 04:22

You're going to need an air gun to take that nut off that holds the clutch onto the shaft. That's one tight son of a gun!

While your in there spray off your clutch plates with carb cleaner and wipe them down with a rag.

If your rings are tight, pour some Yamaha Ring Free down each plug hole and let it sit overnight. That stuff can unseize piston rings that have been sitting. As far as cleaning the clutch plates...a good idea but coat them with motor oil before reinstalling.

Rings were free.Clearance is .0015 to.002". Ring gap is .016" can still see hash marks .Whats up with the blow by? Rings dont have much spring tention to loose do they?I'll have to rering and hone i guess.

degreeing the cams are the #1 reason well built engines go slower! ha!
let's all agree to measure at .050 I set my lobe centers for power at the upper end of the rev range == 112-114 intake and 113-115 exaust now at these numbers measurements need to be taken at valve to valve clearance during overlap .060 minimum.. same with piston crown to valve also .060-.065 on high lift cams.

different numbers work with different head porting and different cam profiles

to design a powerful balanced engine all details need to be considered.
but like I said degreeing off of stock numbers will probably make your engine slower
my $.02

Post edited by: trippivot, at: 2007/01/25 11:21