Mah baby has a cold

[MrSavvy]

I can clear the air on one point, the rust is from a pair of vice grips I have. They were exposed to water at some point, and have rusted a bit in places. I sanded most of the rust off and greased them up. They're just too good to toss.


Edit: Epoxy is set. Wish me luck tomorrow.
Lowes nor Home Depot had the 6mm bolts I needed. I'll have to check Fastenal tomorrow.
Edit edit: Fastenal is closed on the weekends.

[MrSavvy]

Originally Posted by alex.s

also.... you don't use zinc plated steel inside an oil bathed engine.

I got all 3 out!!
http://oi60.tinypic.com/2rpea6f.jpg

Now I just have to find 6mm brass hardware in the right length..
Quick question, on that topic; Do the bolts need to be half-thread and half-smooth, like these OEM bolts? Or can they be 100% threaded?

[JohnnyBravo]

Glad you got your bolts out!

[alex.s]

i don't think it matters if its halfthread/half smooth since it has alignment dowels and all that

the new fasteners dont have to be brass. just be extra careful to torque it to the right amount if they aren't brass

[alex.s]

also usually you can just throw the glued bolt/socket on the ground and it busts apart and you can reuse the sockets

[jkv45]

I don't think those are brass bolts. They look like standard plated steel to me.

If it were mine, I would get the correct OEM shouldered bolts from Kawasaki.

Do you have good quality sockets? If they are only torqued to 14 ft/lb I wouldn't expect to round them off on the way out.

[MrSavvy]

I was using a craftsman 1/4" drive socket, no extension. I didn't have an 8mm 3/8" socket. I would assume they were torqued correctly, I've never taken the VC off. But man, they were fused in there real tight.

[ninjunk]

Originally Posted by alex.s

how to tell its not steel: put grinder to it. no sparks means its not steel.

the thread size is 6mm. the head size is 8mm.

why do they do this? because its an aluminum head that has weak threads. they dont want to risk damaging the head so they use brass fasteners which will strip before damaging the head of the engine.

also. what the hell are you talking about with an sae washer and a 10.9 bolt. have you ever stripped the threads out of aluminum? its a bad idea to have fasteners stronger than your threads.

There is not a single brass bolt inside a kawasaki ninja of any year.

Nevermind the grinder, just stick a magnet to it. It will stick because its alloy steel. It is shiny silver colored because it has zinc plating, if it didn't have zinc plating it would be black oxide finished (the color of the dark black bolts inside the engine) if it were brass it would be, uh, brass colored. Like yellowish.

Every single bolt inside the engine is much stronger than the aluminum its screwed into. The loading on the threads is distributed over a large area and the load on the shank of the bolt is concentrated over a small surface area. Torqued fasteners are very highly loaded. Look at the head studs, they usually have yield strength in excess of 130,000 psi.

The washer is to distribute the load over a larger area and allow the head of the bolt to spin, thereby not impacting the torque measurement. The stock bolts have flanged heads, which you can find but you have to be careful to have exactly the correct flanged head or the torque value will change. Lots of flanged head bolts have serrations which isn't bueno for this application.

When a bolt head applies force to a surface, it can warp or dish the adjacent surface, so a washer is required to spread out the force... at least, thats the short version. OEM's use bolts with flanged heads to save a few cents and make it easier to assemble.



Blah blah blah, don't believe me if you don't want to... Long story short that is a pretty important bolt so you should probably buy the OEM one or try to find someone with a junk motor to pull them for you. For the love of god don't use a brass bolt.



At the risk of dragging this out further, to the OP: check your CDI box, find someone that will let you swap one.

Use a DMM to check the coil resistance on your High tension coil and your stator coil and your exciter coil.

Not sure if you've done that yet or not, but it would be the first thing i'd check with an rpm 'cutting out' type situation.

Another easy test is to hook up a timing strobe and watch the timing mark, free rev the engine up to where it starts to die and see if it starts jumping around or flickering.

[alex.s]

if its not brass, then its some other alloy that has no iron in it. no sparks from a grinder. soft as ****. yellow all the way through.

[MrSavvy]

Originally Posted by alex.s

if its not brass, then its some other alloy that has no iron in it. no sparks from a grinder. soft as ****. yellow all the way through.

Hmmm, what model/s did you work with?

The bolts are magnetic, and not just the coating.
I cut one of the bolts up and it's silver all the way through. And it threw off sparks the whole way.

Not trying to prove anybody wrong or right here, just showing results/facts.

I'll resume work on my bike by Tuesday at the latest. I think it's going to storm tomorrow, which means I can't work on her.
I'll probably go with OEM bolts to be safe.

[ninjunk]

I just had my EX-250F valve cover off today and the bolt was similar to this one from fastenal.

mine had 10mm heads and were flanged. they were black oxide and not plated.

http://www.fastenal.com/web/products...endingMachine=

take that with a grain of salt as it is for the 'pre gen'

[Motofool]

Originally Posted by MrSavvy

.............
I'll probably go with OEM bolts to be safe.

If not available, check the JIS marks on the heads of the bolts and find the ISO Metric equivalent:
http://forums.ninja250.org/viewtopic.php?p=853294

Buy six-side sockets and a torque wrench.
Here is how to use it:
https://www.ninjette.org/forums/showthread.php?t=111031

[MrSavvy]

Thanks, I already have two torque wrenches, a 1/4" drive and a 3/8".
Also, I picked up my 4 new cam chain guard bolts that had to be epoxied out. hah
Also a new o-ring for that 90 degree coolant elbow coming off the top of the engine by the VC.

I didn't think to order a new gasket for the cam chain tensioner, though. Hopefully the one in the now won't leak.

Sad news;
I somehow botched my calculations.
I used the matrix from this thread...
https://www.ninjette.org/forums/showthread.php?t=73240
in conjunction with the one from this DIY guide to double check myself.

Basically, I used this equation "a+b-c=d"
[a] Present Shim Thickness
[b] Measured Valve Clearance
[c] Specified Valve Clearance
[d] Replace Shim Thickness

Example of my process:
Farthest left column I selected my clearance for valve #1, then I selected my current shim thickness from the top row. I followed the column/row, noted where they meet.
So; .203mm gap, 2.89mm shim (rounded to 2.90), goal of 0.25mm (specified clearance mean) gave me a shim of 2.85mm to buy. Which is .05mm thinner than originally.
Or (in mm) 2.89+0.203-0.25=2.843 or 2.85.


I want to increase my gap, not decrease it. I figured there was something I was misunderstanding, so I bought the shims I needed.
Sure enough, all my gaps are slimmer than before.

Clearly something isn't clicking with me.
What did I flip or get wrong to get a smaller shim rather than larger?

Edit: my paper of calculations and measurements.



Edit 2: I think I figured out my own calculation. I'll use exhaust for example. Specified lash .22-.29
I take my maximum allowed lash, subtract the no-go current lash, and this gives me how much I need to increase in shim size. I use the "no-go" current lash measurement instead of the "go" measurement, because I know my lash is under that number. So I'm safe if I round down.

Example for valve #1, exhaust.
A+B=X then X+Y=Z
A: Max allowed lash.
B: Current no-go lash.
X: Increase new shim by this amount.
Y: Current shim size.
Z: New shim size.

so...

0.29-0.22=0.07, 0.07+2.89=2.96mm, rounded down to be safe is 2.95mm.
Since I used my no-go measurement, I know my new lash will be less than the max allowed of 0.29mm. It will range between .26 and .28 (since I rounded down 0.01 from 2.96mm to 2.95mm). Since my current lash is between .203mm and .229mm.


Did that make any sense? Is it flawed? I'm trying to power through this and figure out the math so I can start work on the 250 bright and early tomorrow.
I'm a bit tired from work. lol

[MrSavvy]

If my calculations are correct with my formula I created...

Exhaust/current shim:
1) .203mm / 2.89
2) .203mm / 2.94
3) .178mm / 2.91
4) .152mm / 2.93
Intake/current shim:
5) .178mm / 2.94
6) .178mm / 2.87
7) .205mm / 2.87
8) .152mm / 2.82

Shims to buy:
1) 2.95
2) 3.00
3) 3.00
4) 3.05
5) 2.95
6) 2.90
7) Fine
8) 2.85

Tagging so you guys see sooner. Haha sorry, I'm impatient to ride my 250 again.
No obligation to comment, but if you have any thoughts please chime in. Thanks so much!

Originally Posted by Motofool

If not available, check the JIS marks on the heads of the bolts and find the ISO Metric equivalent:
http://forums.ninja250.org/viewtopic.php?p=853294

Buy six-side sockets and a torque wrench.
Here is how to use it:
https://www.ninjette.org/forums/showthread.php?t=111031

Originally Posted by ninjunk

I just had my EX-250F valve cover off today and the bolt was similar to this one from fastenal.

mine had 10mm heads and were flanged. they were black oxide and not plated.

http://www.fastenal.com/web/products...endingMachine=

take that with a grain of salt as it is for the 'pre gen'

Originally Posted by alex.s

if its not brass, then its some other alloy that has no iron in it. no sparks from a grinder. soft as ****. yellow all the way through.

[alex.s]

most mechanic dealers stock them... many will let you trade shims too.

[MrSavvy]

I put the bike back together today. I installed the original shims in their original places (for the most part). I measured the lash after reinstalling and the exhaust are still out of spec and intake still within spec.

The second set of shims was even further off than the first set. I was close the first purchase of shims.
In all, I fully disassembled and reassembled the top end/VC/set timing about 5 times.

My problem with this repair boils down to poor equipment. The micrometer I borrowed from a friend is a sh**** harbor freight brand, and turns out is very inaccurate.
And I need to purchase a full Hotcam shim set. I made two trips to the dealer for shims alone, three total this repair. The local Kawa dealer is a good one hour round trip from my house.

I've never gotten frustrated and quit a repair before, but I've already been without my bike for over a week and it's my only transportation. I'm just hoping she'll fire up, be in correct timing, and run for me until I can hopefully buy a car a couple months down the road.
I'm transferring jobs next week and will have the $ to buy a good caliper and a shim set.

Edit: I'll continue to diagnose my loss of power issue that I originally started this thread for, if it's not resolved. But the valves are on hold.

[MrSavvy]

Originally Posted by jkv45

Did you change the float levels when you had the carbs apart?

I have to ask, for personal clarification and understanding... How would one adjust the float level? Is that actually "a thing"?

Originally Posted by Motofool

The way you have been chasing the problem is not the best.

Re-read your posts and list all the things that you have checked or manipulated, without having a final conclusion on any.

I perfectly understand that you have limited experience with these things.
Nevertheless, a step by step testing process is the only way to narrow the actual problem.

You need to test each thing/system until you eliminate any doubt about its proper functioning.
Otherwise, you may introduce new problems that did not exist in the first place, making the proper diagnostic more complicated.

http://faq.ninja250.org/wiki/Troubleshooting

http://faq.ninja250.org/wiki/Intake

http://faq.ninja250.org/wiki/Exhaust

http://www.theyeagergroup.com/2008_n..._clearance.htm

http://faq.ninja250.org/wiki/Engine

I still believe that those spark plugs show excessive fuel in the mix and that your intake and/or exhaust passages are sporadically restricting the flow of gasses/air.

Out of adjustment valves and carbs do not produce sporadic behavior in an engine.
Possible causes could be:
1) Something blocking the intake (rag under the seat, loose part).
2) Something blocking the exhaust (loose baffle, loose noise reducing material).
3) Loose electrical connection at any point of the ignition circuit (more frequent it is the connections to the coils).

Things that can worsen the problem:
1) Valves that do not fully close after the shafts have dilated (low compression = low torque and missing explosions).
2) Excessive level of fuel in each bowl.
3) Dirty air filter.
4) Choke that does not fully close.

Regarding the adjustment of valves:
- Keep journals and bearings of cam shafts matched. Mark each part before disassembling and return it to the same exact orientation and position. When in doubt, take pictures.
- There are two top end centers for one cycle or full rotation of each camshaft. That is why these are 4-stroke engines. The TDC that you need for each cylinder is the one that has all four valves closed. Do not rotate the engine backwards.
- Service your cam tensioner.

Please don't feel bad; we all have been learning and at the point where you are now.
You will resolve the current mystery and your machine will perform again.

I read through the links you posted again.

Battery.
I checked battery voltage. Even though the battery has sat for a week+, the voltage is at 12.8v while off (I checked after it had idled for a few minutes).
While cranking the bike, voltage is at 11.2v.

So we know 100% the battery is perfect.

Spark plugs.
I currently have CR8E's installed, because I don't like reinstalling old plugs (NGK crush washer 'n such).
I used one of the CR8E Iridium's I had installed up until the valve adjustment fail to test the following; I took a CR8EIX and tested both coil packs, using point 4 under the "spark" section here. Both plugs fired brightly, and as far as the naked eye can tell, rhythmically.

Choke and throttle.
I inspected the choke and confirmed there's no snagging or sticking of the cable or choke slide on the carbs.
The throttle cables and the carb components work perfectly. The throttle has no resistance in opening with a twist of the grip, and the throttle snaps shut when released.

Air intake.
Under the seat is spotless, no air restriction to snorkel. Inside the air box is clean. The filter is clean, well oiled but not too much, and in decent condition.
The seals on the two little "tubes" going from the airbox to each carb are wearing out around the seam. Meaning there could be some extra air coming in after the filter. I am unsure if that would cause issues.

Carbs.
While cleaning the carbs I did find some crystallized gas(?) on at least one of the jets, and a small speck of something inside another jet port.
The carbs are 100% clean now.
The o-rings between the metal washer/spring/mixture screw and the carb body were worn but in-tact and no visible damage aside from being decently compacted.

The float bowl rubber gaskets were compressed further than I feel comfortable with, and there was possibly metal-on-metal contact with the float bowl cover and carb body (meaning the float bowl gasket is too old). But that could just be in my head, too. Another item I'll be replacing in a month or so when I have/can afford a Hotcam shim set.

One of the diaphragms did have some warp-age going on, but nothing too bad. Both diaphragms acted identically when depressed in their housings. Neither had problems compacted and expanding.



Unfinished diagnostics and/or inconclusive results.

1. Check gas flow from fuel petcock under vacuum.
2. Compression test.
3. Exhaust hasn't been inspected or diagnosed (unsure how to proceed).
4. Electrical system undiagnosed (aside from checking physical connection on coil pack electrical connections, spark plugs firing, and battery voltage).

I used new 50/50 Kawasaki coolant, distilled water. I have 2qt of Kawa oil and oil filter ready to go tomorrow.
It was difficult to sync the carbs this time. I finally got them close. I had to adjust the carb butterfly valve sync screw too.

It could be in my head, but the bike runs a bit rough it seems.
After a short trip around the block, the backfire/afterfire appears to be gone on all levels. But it's too soon to tell anything.
I'll be forever nervous until I get the valves taken care of, regardless of whether or not I can find anything else wrong tomorrow.

[Motofool]

Originally Posted by MrSavvy

I have to ask, for personal clarification and understanding... How would one adjust the float level? Is that actually "a thing"?

Check this out:
http://forums.ninja250.org/posting.p...&t=85429&tro=1

I read through the links you posted again.

Battery.
..........

Spark plugs.
Check this out:
http://www.dansmc.com/spark_plugs/sp...s_catalog.html

Choke and throttle.
............

Air intake.
Under the seat is spotless, no air restriction to snorkel. Inside the air box is clean. The filter is clean, well oiled but not too much, and in decent condition.
The seals on the two little "tubes" going from the airbox to each carb are wearing out around the seam. Meaning there could be some extra air coming in after the filter. I am unsure if that would cause issues.

You can apply some grease over those seams in order to provisionally stop any air leak.
If air leaks are present, the idle would be unstable and hard to set.

Carbs.
...........
The o-rings between the metal washer/spring/mixture screw and the carb body were worn but in-tact and no visible damage aside from being decently compacted.

If worn, those could let air get in.
Same grease trick could help during the diagnostic.

The float bowl rubber gaskets were compressed further than I feel comfortable with, and there was possibly metal-on-metal contact with the float bowl cover and carb body (meaning the float bowl gasket is too old). But that could just be in my head, too. Another item I'll be replacing in a month or so when I have/can afford a Hotcam shim set.

This could cause fuel leaks as level of fuel in the bowls reach the matching surfaces.
No problem if fuel leak/dripping is not noticeable.
...........


Unfinished diagnostics and/or inconclusive results.

1. Check gas flow from fuel petcock under vacuum.
   A flow of at least 2 c.c. per second would be normal.
   
2. Compression test.
   Check this out:
   http://www.dansmc.com/compression_test.htm
   
   For a compression test:
   You need a tester and a 10 mm adapter that goes into the spark plug hole.
   You crank the engine until the pressure indicator reaches max reading.
   Proper reading should be between 140 and 220 psi for each cylinder.
   
   If you don't have the instrument, use some wood bar with some conical rubber end to put hand pressure against one plug hole at a time.
   At normal cranking speed, you should not be able to prevent some air from leaking out.
   
3. Exhaust hasn't been inspected or diagnosed (unsure how to proceed).
   I would disassemble if possible and check for loose baffles or fiber material.
   With engine firing, your hand should feel a good kick from the exhaust gases if placed half a foot from discharge.
   
4. Electrical system undiagnosed (aside from checking physical connection on coil pack electrical connections, spark plugs firing, and battery voltage).
   CDI could be bad, but installing a test replacement is the only way to know.

At this point, a leak test will tell you if all the valves are properly sealing:
http://www.dansmc.com/leakdown.htm

[MrSavvy]

Just a final update for closure of this thread; my bike hasn't had a single problem, at any RPM range, since reassembling the bike. It still needs the exhaust valve lash corrected, and the cam chain tensioner needs to be serviced, but the bogging down and power loss have been resolved. I assume it was the crystalized gas or dirt or whatever it was I found on the jets in one of the carbs.

Thanks for all the help.