Annoying R1 99 starting problem and fuel use

[MartZ0r]

hi guys. i have a 99 Yamaha YZF R1 that i have had for a while and having some starting issues

Basically unless i slightly turn the throttle and i mean like 1/10th of a throttle, just touching it, the bike wont start. with or without choke

soon as i apply some tension on the throttle it will start on the choke but idles high on full choke so i back it down.

once i have ridden the bike and got it up to temp, if i shut it off and go back to it a minute later it will not start unless i apply the tension to the throttle again, this time a little worse.

also if i blip the throttle there is a little of instant lag before it responds. rolling throttle it's ok. i think this is less noticeable in the warmer days though

Carbs have been stripped Twice and cleaned. Balanced twice and they are within 1/2cm HG, they are spot on. floats heights are spot on also

Bike specs

25k miles
Stock jetting and mixture screw set to stock.
Slipon without baffle
Stock headers
EXUP attached and working
Stock airfilter
no lean symptoms on plugs

[Jaco]

Checked the state of the carb inlet rubbers?

All I can think of with my limited knowledge, I'm afraid

[lihp]

Test coils and do a compression test.
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covent.gardens: lihp is my most favourite member ever

[MartZ0r]

Hi guys. Inlet rubbersare good. Compression test has not been done so i will get one and test coils to the book specs.

Any other suggestions while im there?

[MartZ0r]

wanted to add to this, i let engine cool for 2 mins, dropped from 100c to 80c and tried starting it and wouldnt start without throttle, applying choke made things a LOT worse

Also, i have read up on stator issues with these bikes. i have noticed my clock backlight pulses with my indicators when i turn my indicators on, but cant say as iv noticed any sluggish cranking speed and this wouldn't explain why it's worse when it's warm. plus it's been like this for 8 months!

[MartZ0r]

resting battery voltage is 12.7., bit on the low side dont you think?

will check tomorrow over all the electrics as i dont want to wake next door with my stubby can!

[MartZ0r]

Here are the readings so far. Will check coils when I get home.

Lights off

1krpm 14.32
5k 14.32

Lights on

1k 13.1
5k 13.9

all seems fine I think

[CaNsA]

Has anyone though to increase the idle speed a touch?

[MartZ0r]

I thought about it but when it's warm it idles at 1200-1300 as it is

[CaNsA]

Have you tried increasing the idle speed?

[Aceslock]

I have similar issues with my 2000 Thundercat, similar age and mileage......

It wont start unless i give it a bit of throttle, and revs keep increasing when the choke is on so i have to lower it gradually for the first couple of minutes, then it idles ok (although it does 'pulse' a little) not sure if this is normal though as i have only had the bike a month or so....

The only thing i have checked on mine is the plugs and battery tho which are fine. I am a bit of a noob when it comes to bike engines, so if you find out what it is hopefully i can carry the info over to my bike and fix it!!!
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Previous Bike: Skyjet SJ27
Sold: Yamaha YZF 600 R Thundercat. Sold: ZX636R
Current bike: R1 14B (Beast)

[MartZ0r]

Turned up idle lights are less dim but still struggles to start after shutting it off.

Also got the throttle blip lag still.

Idle is now 1500

[MartZ0r]

Just checked it again left it 5 mins temp reading 86c refuses to start without my touching that throttle then starts lumpy for a second then it's fine

[MCN.]

Crank seal on way out?

[MartZ0r]

primary coil test
3/2 2.3ohm
1/4 2.1ohm

manual says (1.83-2.57 ohm)

cap test

cap 4 8.9k
cap 3 9.87k
cap 2 10.4k
cap 1 9.6k

manual says (10k)

secondary coil
3/2 15.6
1/4 15.50

manual says (12-18k)

also warmed coils up with a hair dryer and they both increased by the same amount and stayed within spec

[MartZ0r]

Weather is hot today and bike started without throttle and choke and wasn't rough. Indicating a jetting issue on the pilot circuit ?

Could oval needlejets effect the idle circuit?

[MartZ0r]

Weather is hot today and bike started without throttle and choke and wasn't rough. Indicating a jetting issue on the pilot circuit ?

Could oval needlejets effect the idle circuit?