Something's taken a shit and it sounds expensive

**Akzle** · 10th January 2013, 19:59

yup. one of those.

bike started out not liking 5k RPM. i thought it was sick, parked it up last month, got into it today: syncd carbs and set valve clearances.

don't have 3/4" (which gook MF's idea was that?, the civilised world uses 13/16 or 5/8, since the fucken 60s assholes) wrench so haven't pulled or replaced plugs (now higher on my to-do list) and because i can't get them out yet, i cant tell you what they look like, or do a compression test.

so i took it for a skid to the corner shop (40kms) to make sure it go'd good. it dunnt. now it lacks power up to 4-5k, kindof feel like blown head gasket.

main Q: will shitty ignition cause this symptom? (do i need to start mentally preparing for a blown head gasket or rings?)

secondary Q: how fussy should i have been in doing valves. all of them spec'd, but might be difference of upto a thou, thou and a half, between any cylinders, should i have done em all to same numbers? intake is 4-6 thou, ex 7-9 thou.

tertiary Q: any one want a GSX750 for five bucks and a bag of chips?
(and a running bike)

**scumdog** · 10th January 2013, 20:16

OK, now that you're off my ignore list...

Did this happen suddenly or has the rev-range slowly getting lower and lower fpr longer than you have mentioned??

And if your valves are set within factory specs you should be OK there - whe did you last check them?

Anything is possible but how is your fuel flow? - it would be what I would first check.

Then a comp. check.

But your symptoms are not specific enough to get you pointed in the right direction.

**jellywrestler** · 10th January 2013, 20:18

Originally Posted by scumdog

Then a comp. check.

one needs to be able to take the plugs out for this...

**scumdog** · 10th January 2013, 20:20

Originally Posted by jellywrestler

one needs to be able to take the plugs out for this...

Time he got the gorse out of his pocket and bought a plug socket, hell, how has he been doing it up 'til now??

**Katman** · 10th January 2013, 20:26

Take the tops of the carbs and check the diaphragms for splits.

**Akzle** · 11th January 2013, 08:17

Originally Posted by scumdog

Did this happen suddenly or has the rev-range slowly getting lower and lower fpr longer than you have mentioned??

And if your valves are set within factory specs you should be OK there - whe did you last check them?

Anything is possible but how is your fuel flow? - it would be what I would first check.

Then a comp. check.

1 - <200km
2- yesterday,

3- fuel tap is fuckered, which is something i forgot to mentions, runs on res but not prime or ON
last time i checked (when it first started to hit at 5k - last month) there was fuel a plenty in the bowls. should probably check now. it never stalls or cuts out and will idle for days, so i dont think that is the problemo
just doesn't want to give me moar HPees.

Originally Posted by Katman

Take the tops of the carbs and check the diaphragms for splits.

i should have when i had em off yesterday. do they go suddenly? does a vacuum leak cause shit like this?

as an aside, it was worse when the engine was warm, ie it was doing the 5k thing on the way to the shops, and started lacking big time about 10km from home, the last 4 was painful, over revving and clutch slipping (intentional) etc.

**98tls** · 11th January 2013, 09:29

What about a bad coil,gets worse when hot.

**Akzle** · 11th January 2013, 16:31

Originally Posted by 98tls

What about a bad coil,gets worse when hot.

haven't tested. (how would i? resistance?) plus - there's two coils (four cyls) how likely is having two shit at once?

will wait for payday and new-plugs it (plus buy a f*king 3/4" wrench ><)

**scumdog** · 11th January 2013, 16:51

Still sounds like a lack of fuel situation to me Mr A.

I await the outcome - possibly with surprise!

**98tls** · 11th January 2013, 18:39

Originally Posted by Akzle

haven't tested. (how would i? resistance?) plus - there's two coils (four cyls) how likely is having two shit at once?

will wait for payday and new-plugs it (plus buy a f*king 3/4" wrench ><)

Would only need 1 to be bad,if its as T reckons a fuel problem then you should be able to tell by looking at the plugs you take out ie rich or lean,plug leads are worth inspection to.

**kiwi cowboy** · 11th January 2013, 20:18

Originally Posted by Akzle

haven't tested. (how would i? resistance?) plus - there's two coils (four cyls) how likely is having two shit at once?

will wait for payday and new-plugs it (plus buy a f*king 3/4" wrench ><)

You could also check your air filter.
If its realy gumed up it may be struggling for air at revs. (just a thought).

**ktm84mxc** · 11th January 2013, 20:48

I'd be checking for rust in the tank blocking the fuel tap/filter , another cause can be the idle adjusters on the CV carbs.

**ducatilover** · 11th January 2013, 20:52

I'm assuming you cleaned the carbs and there are no air leaks?
Katman's suggestion is good (as expected, he fondles bike apparently)
Is the carb bowl vent clear and routed correctly?
Are the intake rubbers seated correctly
Is the airbox sealed well?
What kind of chips do you want bro?

**Laava** · 11th January 2013, 21:24

Coils on my gixxer were fucked. They tested good on a coil testing machine but when you test for continuity between both plug ends ( per coil) it had nada. This is when the windings have actually started to burn out but arcing between burnt ends inside the coil.
So do the continuity test, it is easy and quick.