TOPIC:

Been a long time since I have been on the forum, I like the new look!

I have a couple grueling problems with my lightly modded 1000 motor. Id like to see if anyone has seen this before.

1.) My number 1 sparkplug has a seepage of oil which increases when at WOT. Makes a nice coating on the outside of the cylinder head. I have not been able to plug this and I fear that the only solution is to pull the head, drill it out and timesert it. Anyone know of an easier solution for this problem?

2.) This one is most troublesome. and requires knowledge of my setup.

so..

KZ1000 A2A motor
1075CC pistons 10.25:1 CR
Pistons are above flush a few thou
Stock thickness gasket.

Cylinder head is a Z1
planed but not sure how much
was originally built for a turbo bike. so mild intake and wide exhaust port job. TI hardware.

When I originally has this problem it ended up being the keepers were being sucked through the retainer, Fixed that.

I have VM33 carbs with 137.5 mains and yes it idles fine.

After about 20 minutes of riding I notice more heat, I get a flappy exhaust note at around 4K but it smooths out past there. I also get a distinct sharp-metal-to-metal-blow sound. almost like I was pulling another valve. But every time I pull the cover my clearences check out okay. This would sound like fuel starvation. I have a dual port pingle pet with 5/16 line going to carbs 1+2, 3+4 respectively. My gascap vent is clean and I dont seem to be having flow issues.

The one thing I havent done is a compression check. Should I be using higher octane gas for this motor?

The valve slap and leaky plug is killing my riding time! Its our first 90 degree day here in Portland, OR. If anyone has any suggestions please let me know. Thanks

-John

What octain fuel are you running?With the metal to metal sound I would check the ignition timing for starters.Sounds to me you might be possibly having pre-detionation happening.Possibly the advance unit is stuck after sitting for a while.

I am running 87. I have tried 92 with the same result. I spoke with another engineer here at work who was big into cars and he suggested the same thing. Should I just run higher octane gas? Or retard the timing more? or a bit of both? Could this be an explanation for the leaky plug as well?

What kind of ignition do you have? If you have an OEM igniter type, I would swap it for a Dyna S and retard the advance a couple of degrees. I would set the ignition up as normal using their directions then turn the plate counter clockwise JUST A TAD. You need to be running 93 octane for 10:1 compression especially if the head is shaved which is hard to understand on a turbo bike build. I wouldn't mess with race gas or octane booster as it is too hard to keep it on the bike or mix when you fill up. Try retarding the ignition. If you can get ahold of a Dyna2000, they have premapped curves that have two retarding curves that work well with bikes with a bit higher compression to squelch the predetonation you seem to be having. I wish I could hear the bike myself as I generally just make poor assumptions based on other folks explanation of noises THEY hear.

I have a standard points-type ignition with accel coils. I plan to pick up a dyna S. I wonder if a 2000 would be more suitable. Maybe I will just buy an S right away and install it. I wonder if they have a dealer locator.

I am also wondering about the tunable circuits on the VM33 carbs, I probably should have bought 29s but what the hell. I am sure WG knows something about these carbs.

Post edited by: A2-Cow-A-Socki, at: 2006/05/15 16:20

You say you are getting oil blowby around #1 plug. I wouls suggest checking compression for broken or worn rings and or valve seals.
Harry

How do the keepers get sucked through the retainer? What causes it, is my question.

There is a guy with a 615 kit in his gpz550 that had the problem of a keeper coming loose, and holding his valve opens he believes, as clearance was zero'd and the keeper had popped up, lifting the shim.

Anyway, I was trying to help, but not really sure how it happens. I mean I have some educated leads to educated guesses.. but I'll spare you.

Not to hi-jack the thread.. but I may be seeing something like this down the road. 615 kit, 10.25:1, and I had the head and block resurfaced.. only because they had around .004" warp and the clymer says .002" is the max. Howevery I realize most people must not even check that (and it must not seem to matter, what with no coolant passages, both block and head being aluminum, and the oil passages being o-ring'd)

Anyway, as far as the problem at hand, I wouldn't have any other suggestion that hasn't already been made, if that.

POST HYJACKER! JK

The reason the keepers sank was a combination of a couple things. One on my part (or the machinists at Star).

Reason 1.) Magic.

Reason 2.) They are 900 Style valve and keepers which are about half the depth of the 1000 keepers and rigid in the profile instead of rounded.

Reason 3.) Maybe the differentiated cte's of the valve and retainer material had something to do with it growing and then being beat back in by the cam lobe, but I would have heard more about this if it was an issue.

As far as internal blowby I really hope I havent popped a ring. I have had this setup less than 200 miles. I will do a compression check on it and be back with the result. I know this head used to have a top end oiler on it at one point in time. Ill have to examine it closer. Better just tear into it after the compression test and ignition change. (doh)

And your head warp? Just put some spit on the gasket and crank that sucker down, machining to make it flat? getouttahere!

Thanks for all the help guys. I really appreciate it.

Post edited by: A2-Cow-A-Socki, at: 2006/05/16 00:23

Hm. Well I'm assuming the guy with the keeper popping loose problem was using the stock 550 valvetrain components.

At one place in my clymer manual, it tells you how to check the valve clearances, and that if the smallest shim won't increase the clearance enough, the seat must need work. Repair the seat, and shave a bit off the valve stem, and you should be good to go.

In another part (the engine section) it tells you how to check the max valve stem length (with the valve instaleld inteh head, from the bottom of the lifter bore). It says that if the length is too long, it has to do with seat/valve wear and to replace the valve. It says whatever you do, do NOT grind the valve stem, as this can cause the lifter to contact the retainer and drop teh valve into the engine.

Well, I know my valves were touched a bit on the heads. I was told thats part of the valve job, mainly just to keep the surface of the stem true if it is worn. I don't think the intakes were touched, but one of my exhaust valves actaully came out with .001" more clearance after the valve work, using the same shim.

The manuals concerns about cutting down a valve head are in regards to the spatial clearence and the contact area for the keepers. However you can shorten this significantly if you also cut down the keepers and retainer. Its not like you are cutting from the bottom side or shaving down a SOT shim. I havent noticed increased wear when the valve is above the recommended height.