any motorcycle people on here? or know about valves?

[sirfunkeybut]

long story short i have a 91 fzr 600 that wont start, ive went through every wire and plugs are all good along with sensors. I checked the valves and assuming im checking them right all the intake valves are out of spec. Using a feeler gauge that says .004 and .008 it wont go in, the book says the clearance should be in between those numbers, so since it doesn't fit they are out right? and if they are indeed out, how are they fixed? i know i need new shims, but how do i tell what ones to get?

[FC]

You should look elsewhere, have you done a compression test? If you still have good compression the valves aren't an issue here. Start at the beginning.

If the motor turns over, does it have spark? That bike should have a pretty hot ignition system, I would expect it to be able to throw a big fat blue spark at least half an inch.

If you have spark, do you have fuel? Is the fuel any good? If the fuel has been sitting in the bike for a year or more you should change it.

If you have good fuel do you have proper pressure and flow? *Assuming it's an injected bike here.

The last thing on the list to check is compression in a no-start condition.

[TheSkyBuster]

This sounds like fun, tell us more please!
how long have you had it?  when was the last time the bike ran?   intake valve clearances are tighter than spec?  how about the exaust valves?  is this the EXUP valve bike?

[sirfunkeybut]

the bike is a 91 fzr 600, it was my buddy's bike and it started having problems starting when cold last year. He had to roll start it this year to get it to start and it started spitting out oil within minutes. he parked it and told me if i can get it running i can have it. Ive talked to a few people and they said that with carburated bikes they can get a float stuck and drain gas in with the oil and cause it to spit out there was two floats messed up that i fixed. I've went through everything on this bike and everything's good and still no start. I have plenty of spark and fuel(it backfires like crazy) So the last thing to check was the valves. The bike has 20,000 on it and they've never been checked or replaced. When i checked them, all of the exhaust valves check within spec but the intake side only has one valve on the #2 cylinder in spec. the other 7 are so i tight i cant get my feeler gauge in(.004-.006) specs say it should be between .004 and .008.

[FC]

Do a compression test, if you have good compression (check the spec) then the valves aren't what is causing it not to start. By good compression I mean above rebuild spec, if they are low then you should do a wet test to confirm whether or not it's rings or valves causing the problem but a bike that hasn't been run in a while and has had gas running down the cylinders WILL have lower compression then it normally would.

Have you been through the carbs and cleaned them very thoroughly AND changed the oil? The oil change is because you are right! When carbs leak fuel down it will fill the crankcase, if it's a possibility I would just change the oil to be safe and not risk damaging the engine by running with contaminated oil.

It takes very little dirt, water or fuel varnish in bike carbs to make the bike difficult if not impossible to start. If you aren't very familiar with bike carbs you might want to see if you can find someone locally who is to help you with them, I've gotten a lot of bikes to start by cleaning their carbs after their owners had already done so.

[sirfunkeybut]

yeah i did a full cleaning of the carbs, ill have to wait till tomorrow for the compression test. Ill report back after that. 

[MikeWalking]

yeah i did a full cleaning of the carbs, ill have to wait till tomorrow for the compression test. Ill report back after that. 

Did that include the jets??  I'd like to know if it came from California,  they required the EXUP valve.   A valve stuck closed where the headers meet could be a real pain..so could a crossed plug wire or two...

http://www.cartestsoftware.com/fz1/exupmaintenance.html

[sirfunkeybut]

yup did the jets. its not a cali bike. I hope to get this running this week, ive been working on the cursed thing for a while now and am getting pretty fed up with it! oh, well at least im learning something

[sirfunkeybut]

well my compression tester doesnt fit    have to wait till payday for money to get a different tip and test it.

[Bofire]

  sounds to me like maybe the cam has gone flat, maybe just the intake lobes.
seen it before.
Carl

[sirfunkeybut]

well i found a used complete head aside from the two shafts for 50 with free shipping. its also has a warranty so im just gonna swap heads and hopefully be done with it. i read on a forum that when your valves become so tight like that and you dont have any clearance that its likely that the valves have tulliped.

[Camp David]

I love these threads  Please keep us informed.

[FC]

i read on a forum that when your valves become so tight like that and you dont have any clearance that its likely that the valves have tulliped.

If that is the case you should be able to look down the spark plug hole and see evidence of damage to the valves. If you just swap out the head without figuring out if there is anything actually wrong with it you are seriously shooting yourself in the foot.

No start failures are very rarely mechanical in origin without some type of catastrophic sign like a hole in the case where a rod shot out or an engine not turning at all. Cams don't just suddenly go flat or any other such weirdness.

A tip: if it is backfiring out the exhaust it's very likely a carburetor problem, if it is backfiring out the intake it's very likely an ignition problem.

My guess at this point is that it is backfiring out the exhaust and that the carbs need a better going through and fresh gas.

[MikeWalking]

 

I have to agree. I've done every thing but replace valves and gears on my last 7 bikes.  You mentioned your buddy had cold weather starting problems last year.  I think that was the start of build up in the jets and floats.  They jets may look clean and shiny but  have seriously reduced flow due to build up still present.

I sent all this to an old friend, a factory trained Kawasaki mechanic and former sponsored racer (RR, Drag, Enduro). He strongly advised leaving the valves alone.   I bet it was parked long enough for a thick coat of varnish to build up and still be present even if it looks clean.  Jets are not expensive, replace them and see what happens.

20,000 without serious maintenance?   

[FC]

Usually the deal is that you have a huge pile of crap behind the jets and people just clean the outside and don't actually remove them for cleaning and clean out the passages while they are out. You also need to remove the idle mixture plugs if they haven't been already, remove the mixture screws and clean those passages too. Just tighten the screws GENTLY fist and count how many turns it takes to bottom them out and then reset the screws at that level when you are done.