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Tiger 885cc idle and acceleration problems!!!

Started by ngm8x, March 15, 2010, 08:56:28 PM

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ngm8x

Hey all
I have a 1995 885cc tiger with mikuni carbs
All was well with her before the cold snow so i didnt ride her just started her up over the 2 months.

She would die on blipping the throttle. I drained the float bowls and found lots of water in there, so i took the carbs off cleaned them and drained all the old fuel. Problem solved i thought.

Put in fresh and  started it up. She ran better but idles funny and when accelerating quickly she stutters but seems ok once over 5000rpm.

At normal idle 1100rpm, she suddenly drops to 800rpm app and struggles for a bit then picks back up to normal for a bit, then drops and struggles again.

Could this be the float heights?
When cleaning the bowls i whizzed a bit of compressed air in there and can only think this might have bent /changed the float heights?

other than that i cant think what else it might be?

am guessing the floats aren't  supplying enough fuel at low revs but ok at   high revs when the flow of fuel into the bowl is more constant?

ideas?
will be taking the carbs off again i guess.

Mustang

PILOT JETS are clogged in one or more of the carbs is my guess .

pull the carbs out and bench clean them by removing everything and then give a good cleaning with gumout spray carb cleaner
when you reassemble the float assemblies use a drop of oil on the o rings so they will insert back into the bodies without any drama

ngm8x

which ones are the pilot jets?
there are quite a few in there.

the needle jet in the emulsion tube has a jet screwed into the bottom of it, which i think is the main jet yes?

the pilots are the small little ones to the side of the main and the 2 small ones facing out of the venturi tube?

i have a haynes manual but dont trust them!!

So you dont think its the float levels?

Mustang



#11 is the pilot jet  unscrew it and hold it up to the light you should be able to see a little tiny hole thru it soakit in carb clleaner and then give it a shot of compressed air

just went thru this on a set of mikunis on the wifes tigger dirty or clogged  pilots are the culprit for the symptoms you describe..............

make sure the orings on the float assembly are in good condition and lube them with some oil when you reassemble it helps them seat in the carb body without causing damage to them
if those orings are knackered it will piss fuel by them and that will cause a whole nuther headache for ya  :shock:

BR

yup, those little pilot jets seem to get clogged easily.. esp if bike has sat around. The actual hole in the jet is small!  I just did mine AGAIN.  Been sitting for a few months again but I had drained the bowls this time... didn't make any #%$#@%@ difference.  Fired it up and it's hitting on 2... a run around the block didn't clear it out.  Off they came again.  Cleaned all three and gently blew out the idle circuits.  What a difference once again on the idle and throttle response.  Quick carb synch and I'm back in biz again.  Here's a crappy cell ph pic of the happy occasion. Note: my '98 has the Kehin carbs so they look slightly different than the OP's Mikunis.




Brendan
'98 BRG Steamer

nightrunner

If she stills runs funny after cleaning the pilots, then I would replace the coils.  This is how it happened to me.  It ran fine when I put it to bed for the winter a few years ago.  Come spring I start it up and get all this funny behavior, won't idle but runs OK at high RPM, stumbles on roll-on, etc., etc.  I fought with the carbs for months until I read about the infamous Tiger coils.  Try the pilot cleaning first though.  Also might want to make sure you got all the water out of the tank.  Even on reserve, will every last drop drain out?  Or will there be some small amount of trapped liquid where the petcock sticks up in the tank even a tiny bit?
Scott

Seeking adventure and peril

ngm8x

thanks for the heads up on the coils scott.
i have pvl coils on her so think they should be ok as they are not the standard ones.

i removed the petrol tap to drain all the fuel and any water. the fuel that cam e out looked ok but am not going to use it.
there wasnt any build up around the filters in there so i think it must have been moisture in the carbs over a long period of time.

gonna take the carbs off one day this week when i get time.
taking the pilot screws out is tricky as the heads tend to chew up easily and getting the right size screw driver is hard as it needs to be so narrow!!!

thanks again

nightrunner

Another trick is to smear some bearing grease or vaseline around the 6 rubber carb boots.   It wont help the first time you remove them but after that its worth it.  With a steamer you will be taking the carbs off routinely.  They pop off very easily with greased boots and the grease helps form a tight seal.   The throttle cable is a pain to remove.  I just suspend the carb assembly on the side of the bike and work on it there so I don't have undo the throttle.  The choke cable comes off easy though.
Scott

Seeking adventure and peril

ngm8x

right .... i took the carbs off again and cleaned them thouroughly.
The pilot jet on the middle cylinder had a smaller hole in than the other 2 so i cleaned it out with a but if flexible wire and carb cleaner and she is now the same size as the others.


i reset the air mixture screws to 1.5 turns out as they were between 2 and 2.25.
 

Put all back together and started.
she seeemed to be idleing poor still with the hunting and it would cut out and die sometimes.

i opened the air screws to around 2 turns and she seems to be ok now so the stock measurement was a little too low for the bike.
will take it for a ride tomorrow and test fully,

One way i found to make more room to get the carbs off was to leave out  the bottom centre screw of the airbox that is impossible to get to while the airbox is still in place.

With this screw not there i could get to all the others, move the air box back but remove the side of the airbx with the carb rubbers on and once that side slid out there was lots of room for the carbs to move.

With that one bottom centre screw in you have to get the carbs out first before being able to get the airbox out and get to the filter.
makes air filter changes alot easier too.


the tricky bit to master is the acc cable from the throttle linkage, that always takes me a while to get back in.

Mustang

Quote from: "ngm8x"the tricky bit to master is the acc cable from the throttle linkage, that always takes me a while to get back in.
save yourself a lot of grief and leave the throttle cable connected to the carb linkage and unhook the end from the twist grip ......much easier

Sin_Tiger

Quote from: "Mustang"
Quote from: "ngm8x"the tricky bit to master is the acc cable from the throttle linkage, that always takes me a while to get back in.
save yourself a lot of grief and leave the throttle cable connected to the carb linkage and unhook the end from the twist grip ......much easier

Must remember that one  8)
I used to have long hair, took acid and went to hip joints. Now I long for hair, take antacid and need a new hip joint

ngm8x

took the tiger out yesterday and she was running nicely.
lots of popping on the over run due to the straight thru race cans but that was always there.

will be draining the carbs when not using the bike for any period of time but the sun is coming out so the bike will be too!!!