Cam options

tmdoth

tmdoth

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I know this topic is a bit of a rehash, but some opinions are definitely welcome. This was posted by zlrx:
The bike pulls harder on every rpm because the lift is 1 mm bigger
even in the low rpm
You can buy them used on every corner of the street and they are cheap
Also use gpz1000 carbs and your bike pulls like hell
about a 15 hp more
Timing marks are the same
cheers ZLRX

I made a point of searching past threads before asking any questions but this seems to be an area of little info. I am finally getting the head back together (just got started on the valve swap), and next up are the rockers. The only problem is that the cams are pressure damaged on a couple of the lobes. There is no point putting in new rockers only to have them damaged again by faulty cams. I have the number of a fellow in another province that might..."might" be able to regrind them for me. But really I would also like to shop around and see what else might be a good match. Preferably new, or at least fairly new. Higher quality /durability if possible, but I will not in any way sacrifice the low end torque that I love about these bikes. My worries about the zrx or gpz cams is that with a different lift I might start affect some of the other components in the engine top end (banging on the rocker screws too much etc.). Anyone?
cheers, Richard
 
I know more about auto engines than bike engines,but here is my thoughts.I think you need to be more concerened about the cams duration,than the lift.The duration and lobe seperation determen the operating range of the engine.So with that said.More lift will give you more power.The duration determens at what rpm you will get that power.I don't know what the specs are on the stock zl cams,but once you know that then you can compare the difference.You would wan't more lift,but keeping the duration close to the stock cams.With more lift,you might also have to check the piston to valve clearance.(not sure how much room there is to play with.)This is all based on single cam automotive type engins,but I think the same rules apply.
Keep in mind also the gearing on the zl is different than the zx,and ninja motors.But that is another story.Good luck.
 
If you want exactly the same operating peramiters, have the cam reground with a bit more lift. This will increase power accoss the board with almost no effects on rpm/power curves.
 
I was curious how regrinding the cams works? Will it not take some of the overall height and circumference off of the lobes?
 
The way the regrind will take more off the low side of the lobe so that the lift amounts to the same as factory on the high side. If the cam is seriously worn it will need to be welded,reground , then hardend to achive the factory specs in some cases.
 
Ok that makes sense.. They aren't very worn really, more a case of some pitting on them that will transfer damage to the rockers when they get replaced. I still haven't heard back from the cam regrinder I was put in touch with. Does anyone know of anyone else who does it? I would at least like to get a quote or two since they are still available from Mama K and the regrind needs to be the price odf a new set (about $500) for the pair. The next step is to find someone who can help me get them over the border along with the other parts I need to order since my uncle has just moved and is so swamped with work that to kepp asking him for help would be cruel (I have shipped so many parts to him that I swear I could build a whole new bike). I feel like that GI that shipped a jeep home to his mom piece by piece in the mail. The import duties that they slap on makes the parts nearly double in price.
 
ditto on PF idea...I have thought about this at length...Usually all that is required is to reset the clearances. Ramp speed can be an issue with some cams but only if its near the max accel point which i doubt. Then you can just reset the spring pressures
 
tmdoth said:
They aren't very worn really, more a case of some pitting on them that will transfer damage to the rockers when they get replaced..
Click to expand...

fyi - from concours.org -

A quick comment about your cams and pitting and scoring. This was posted on the COG listserv. I'm sorry, but no name was with the post. But thank-you to the anonymous individual who contributed this bit of info.
"Several years ago a fellow member had an interesting conversation with Frank at Crane Cams in Daytona Beach. He called them because he had noticed some pitting in some of his cam lobes. He had heard that they weld up and regrind damaged cams. Frank told the fella that the pitting which looks like "pin-holes" (which is what his looked like) is absolutely normal in cast iron cams, (and the same thing on cam followers) is just not a problem. He says the initial surface of the cam is only considered a "break-in" surface, and that the porous nature of cast iron makes the kind of pitting that was being seen inevitable. He said unless the cams and followers are actually gouged, and the cams scored around the circumference of the lobe, to forget about it. He said that real damage would be noticeable in terms of noise and performance degradation, and it is quite common for the "uneducated" to become unduly alarmed at the appearance of cast iron cams with some miles on
them."
 
Ok... that is really interesting to hear. I should try to take a few pictures and let you guys see what I see and let me know if you consider it wear or normal pitting. If it is just normal pitting and they are ok to reinstall, then i will be saving myself about 1500 dollars in new parts.
 
I have some old high performance cams layin around that have had some serious miles put on them before they came out, and absolutely none of them have pitting on them.
I wont accept the answer given by anyone from crane as I have had more crane cams break in half and wear excessively over the years than any other make.
 
Last edited:
Time for me to open up I guess!
I thought about it for a year and finally purchased a set of ZX1000R cams on evil. I figured for the price I paid, the worst that could happen is I pull them back out and relist on evil!
The ZX1000R has quite a bit faster 1/4mile time than the ZL 11.08 in the test I am looking at at 122MPH. I figured that with the lower gear ratio on the ZL, I wouldn't lose too much at the bottom end so I went ahead and installed them. Very easy upgrade! I did lose a little bottom and but really only notice it around 2-3000RPM in mid gears. In 1st I don't notice any loss at all! What is impressive is when I get over 5000RPM! The beast comes out! Hopefully, I will make it to the strip before winter to get some numbers but with my work schedule its gonna be tough!
The next time Mark and I ride, we will play, switch bikes and do some roll on's to get a good comparison with the stock cams! I still need to tune my carbs and degree the cams to get the full potential. The carbs, Mark and I can do but the degreeing will depend on Gremlin and I getting together! (he is the one with the brains)!
Another plus is what it sounds like at idle!

Bottom line, I would definitly recommend this simple upgrade if you want to get a lil more and don't want to spend a lot of time or money!
 
The ones I bought were out of a 1986 ZX1000R. I have not done the research but the ZX900 may have used the same cams. I have a friend that has one, I rode it a few times and it is actually pretty gutless at the bottom end due to the higher gearing but once it hit 5gs it came alive! I made the decision to do it because of our low gearing and after all, the way I ride I don't spend a lot of time idling around!!:)

Do this mod, you won't be sorry!
 
All stock, so far!
Have Supertrapps to go on and may go pods too.
 
so just dropped in the cams and she hauls arse, huh?
 
wuputt said:
The ones I bought were out of a 1986 ZX1000R. I have not done the research but the ZX900 may have used the same cams. I have a friend that has one, I rode it a few times and it is actually pretty gutless at the bottom end due to the higher gearing but once it hit 5gs it came alive! I made the decision to do it because of our low gearing and after all, the way I ride I don't spend a lot of time idling around!!:)

Do this mod, you won't be sorry!
Click to expand...

Did you drop them into the zl1000 or the 900?
Did you have any way of inspecting them before they were purchased?
 
Bought em on evil for $80, trusted the guy and was not let down. I put them in the ZL1000 but am seriously thinking of doing the same on one of the ZL900's!
 
They will work on the 900?
This may sound dumb, but they are the same engine right?
Just a few differences like the carbs and the bore?
 
im sorry up front as this will be a little long-winded. i also installed the zx1000r cams in my zl1k. if i remember correctly the duration was the same but lift was different. on the zl the intake/exhaust was dif. and the ninja was the same lift on both cams. lift was app. .020 more on the ninja. as for the dur. i would have to dig up my notes to verify maybe this weekend. there is plenty of room/clearance for the cams and work on head etc., as i also have decked the block .005 and had head shaved another .020 and still had plenty of room after checking with solder for piston clearance. i dont remember how much of f my head but it was enough to not sweat/think/worry about crashing. the years i know will work are 86 & 87. dont know about the zrx cams. i do believe that you need to stick with 900 or 1000 respectively as they are differences in lift/duration etc and physical size etc. as for the pitting issue it is NOT normal for a cam to pit and that is a sign of FAILURE! it was an issue back in the day for kaw. cams to pit and take out followers. if it is pitted it means the metal has fatigued and lost its hardness. it will get worse and noisey and break and get expensive! i did this same cam swap in my bro.inlaws 86 900 because his cams had pitted to the point of rocker failure/noise. and yes you will lose some bottom end but will gain some upper end. again sorry for the long post as i could go on forever about this as i have been into my engine a few times [gotta go faster!] and yes i beat this bike like a dead horse and so far no major issues [hits head with hammer] going on ten years now.
 
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