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struggle start without giving some throttle

3K views 15 replies 4 participants last post by  Kjell 
#1 ·
hi guys.

i have been having a nagging issue with this 99 R1 since i have had it, the damn thing will never start unless i give it some throttle. Even if its warm and i just walked away and come back to it.

i did a carb sync 2 weeks ago and purr's better now. i also found the pilot jets were only 1/4 from closed so i re-set those to stock, but this issue still remains. fuel pump is working fine when i turn the key.

all i can tell the bike has had done to it is a stubby carbon silencer. EXUP is still attached though.
 
#3 ·
Since you said you found your pilot jets 1/4 from closed, I don't believe you know what your pilot jets are. Pilot jets are not adjustable and are inside the float bowl. I can almost guarantee your's are clogged need to be cleaned as they control idle fuel. Here's a procedure on how to clean them:

Pull the tank, remove your choke cable, drain your float bowls, loosen the screws on the carb boots, remove entire carb bank and flip it upside down. Pull float bowls, remove your pilot and main jets and clean them with carb cleaner. I'd also squirt a bit of carb cleaner into the fuel inlet ports and also clean the little rubber stoppers. No reason to pull the throttle cables and make sure you put an old rag over the intake ports so you don't lose any screws in unwanted places. After cleaning your pilot jets, it's a good idea to blow compressed air through them to make sure they're open.

Mark
 
#5 ·
Sorry i meant idle mixture screws no idea why i said pilot jets. The pilots have been cleaned along side the mains too. Float height are 6mm average accross all carbs.

I have had blocked pilots before so i know what you mean but this is not it i dont think. im not twisting the throttle enough to pass onto another jet.

Im talking like 2/10 of a turn on the throttle. Idles fine when its running.

I have noticed if i walk away then back to the bike after a few mins the fuel pump will have to build up pressure again but im not sure if thats normal.
 
#7 · (Edited)
hi, i cleaned them myself with a strand of copper wire and the air blower on my compressor. runs fine top end, runs fine in general it's just starting it up. i will admit it runs "cleaner" after 3k rpm. i put this down to the power curve of the engine

is it worth noting i only get around 25-8mpg on average and as i am currently all weather riding, we have been having lots of ice here so it doesn't see more than 6k rpm or i get a lot of back end swings. i tend to ride around the 4k mark unless i am on the motorway (your highway)

i run out of fuel the other week while on reserve after after only 8 miles, caught me off guard that day.
 
#8 · (Edited)
guys i may have come across something interesting. i have just checked the TPS and found that when i unplug it, and plug it back in it flickers like nuts from anything from 3-5k randomly and quite fast. if i apply some pressure to the connector on the TPS, it stays dead on 5k on the tach.

i am going to check the resistance of the TPS now

EDIT:

Checked readings

closed reading (blue and blue/black wires
5.9k
closed to open readings yellow and blue/black
0.8k to 4.9k

within spec
 
#12 ·
cable tied the tps to keep it reading steady and seems to have improved the torque during riding. Exup stripped and greased, all working fine. starting issue still the same but i left the carbs till this weekend as i have ordered new carb gaskets. Going to check to see if the needles have gone oval as i ready this can make them drink fuel. if so, ivan jet kit time.
 
#13 ·
carbs have been stripped and cleaned again, soaked the jets in carb cleaner, threaded some copper wire through and blew them out too. new gaskets fitted also, still starting like a sack of spuds. runs crap cold!

decided to check the plugs, they are fine. decided to do a compression test, engine was slightly warm but not much and i am only getting 150psi across all cylinders.

That's got me worried now so i am going to drop a bit of oil down there i should be able to tell if it's valves or rings doing that right?

i know vales are due for a service (24550 miles)
 
#14 ·
i have bumped this because it's really doing my head in.

starting the bike after i have turned it off for a few minutes is a right nightmare, i have to rev it and then i look like a tosser when people are walking past! it's worse to start when it's warm thats for sure

i really don't know if it's fueling or electrical. when turning my lights on, my clocks go dim and the back-light pulses with the indicator flash if i put my indicators on.

so far i have tested the battery, sitting at 12.8v bike off, idle is 14v and 5k is 13.9v with the lights off.

with the lights on it idles at 13.1v and 5k is 13.9v

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 15.6kohm
1/4 15.50kohm

manual says (12-18k)
if i rev the bike the pulsing is still there even though the rpm is like 4k.

i have upped my idle from 1k to 1500 just to see what it does and it's just the same. same hard starting, same thottle blip lag. seriously considering selling up and getting another!
 
#15 ·
I have the same problem with mine, or similar at least.. My bike tends to bog down when i releas the clutch. I have to rev it up to 4-6k in order for it to pull at all. It runs fine in the midle and top end. But from idle to about 3k it is really at bitch. Some times when it start to bog down it will go in to som sort of limp mode where it hardly runs and the second i touch the gas it dies. I have to find the sweet spot with the throttle and wait for the revs to build. Takes a few seconds before it revs up..

The bike was sort of like this when i bought it, but after cleaning the carbs, new plugs it's worse than ever.
The pilot valves was set at 3,5 turns witch made the plugs really white. I have tried to set it back to the original setting or 2,5 turns, the mixture is better but still stumbles of the line..
This shit is getting really frustrating!
 
#16 ·
Just to let you know, I ****ing solved it! At least with my bike.. Turned out the float level in the carbs where about 5mm to high on all of them. Did a adjustment and now it pulls like never before! I can start easy from idle, some thing that was impossible to do before. Then it was a struggle to make it pull below 4k. Usually I ended up with reving it like crazy and taking off like a rocket (or an total asshole).. I highly recomend that you check your carbs to!
 
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