Difficulty starting with airbox on

[t-j-b]

Hello all,

I've recently got my FZR up and just about running again, with some very useful advice from Mawler and yamaha_george (cant be viewed viewtopic.php?f=8&t=6237)!

Right, as is usually the case with anything, I've fixed a number of problems to find myself facing another! before i explain the problem here's a quick rundown of bits Ive changed on the bike:

Plugs,
Coils,
CDI,
Carb's (i broke one of the emulsion tube nuts replacement carb came off a running bike),
Manifold rubbers taken off, cleaned and tightened up (stop any vacuum leaks)
Oil
Battery

The bike runs pretty well without the air box on, its spitting a bit of fuel out the top of the carb's (possibly a bit rich?) but other than that it will start and rev quite freely.
The problem arises when I put the air box back on. I can hear it firing but not enough to get started. I've tried taking the element out and just about started like that.

I'm a bit of a novice with carbs. I tried messing around with the first set I had, screwing the A/F screw in and out, and felt like i was just making things worse.
Can anybody give me a quick rundown on what I should be checking, and what can/cant be adjusted to get the bike to start with the box on.

Sorry if I've been unclear at any point, hopefully someone's had a simialr issue and can point me in the right direction.

Thank you very much in advance

Tom

[thatkid]

Squirt oil in all 4 cylinders VIA the plug holes, the piston rings need oil to seal.

Run the bike @ standstill for an hour or so, It was stood for 2 years it will not run properly. At least 2 valves will have corrosion, until they bed in the engine breathing will change.

So messing with the carbs is futile. Adjusting the carbs will get you nowhere.

[tony]

very good comment by mawler,when a bike is used regular and the engine does enough miles to reach the correct temperature all moving parts are lubricated properly,as is the use of the correct oil,when the bike is just started or just doing a short journey and does not reach the correct temperatue it allows condensation or moisture to build in the head and can create corrosion through out the un lubricated parts of the engine ,this causes the likes of sticking valves etc,it also wears components at a greater rate , once this happens your engine is not ballanced therfore the performance will suffer and problems will occur, the well lubricated ballanced bike is a well balanced happy rider .

[t-j-b]

Thanks for the help guys,

This weekend I'll spend sometime giving it a good run in and will get back with how it goes!

[thatkid]

I've read your first post again.

1. Why did you replace the coils? and did you test them?

2. Carbs from a running bike are set up/adjusted for that engine. Not yours, they will need adjusting/balancing to your engine when the rings/valves bed in.

3. Have you opened the airbox, and checked for any obstructions? (rats nests e.t.c.)? is the element clean?

4. Was the battery new, did you charge the battery before you fitted it? (new batteries are only @ 80% charge when filled with acid)

5. Did the Manifold rubbers appear to be cracked?