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Main jet size for Tiger 885 motor

Started by xtruss, March 27, 2010, 12:08:33 PM

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xtruss

Hello one and all, i hope you can help me out, after much googling i can still not find the correct needle position and jet size for a Tiger 885 i am helping a friend with.  The bike has always suffered from poor running and a local garage has rebuilt the carbs twice, but now its suffering from really bad MPG once over 70MPH, ie 20 mpg.  I've got a set of carbs from a daytona to fit,  both bikes are fitted with 125 main jets, is that correct for the tiger ?  Also both have diffrent needle hights with the daytona midway and the tiger needle 4th from top. Does anyone know what the main jet size and needle settings are please. Thanks.

Mustang

I assume you have mikunis and not Keihin carbs ..............

The mikunis for tigers are
105 main jets  
#40 pilot jets
and the needles should be in the middle clip with the pilot screw set at 1 1/2 turns to 2 turns out from seated

(mikunis are also noted for having the o rings leaking on the float assemblys which will cause rich running )

at 70 mph and above on a tiger with mikunis you are going to get average 30-35 mpg depending on how heavy your throttle hand is !

if you have keihins they came lean from the factory , like seriously lean

factory settings were
98 main jets
#40 pilot jets
non adjustable needles and the pilot screws were basically almost closed

what works well with keihins is
105 main jets
shim the needles up with some washers that are .030-.050 of an inch thick  
and set the pilot screws to around 2 turns out
big improvement

on either setup it assuming that only one snorkel is open on the airbox , there should be a blanking cap on the right hand snorkel.

if not it will be sucking too much air will need some serious increase in mains  and fuel mileage will suffer

the mikunis were gas hogs thats why triumph went to keihins on their carb'd bikes

keihins with the modified jetting will return average 35-40 mpg at 70 mph
at 50 mph they will give 55 mpg ................big difference , it's just the nature of the beast

cascadetiger

I just got by 98 Steamer back from the 24,000 mile service.  The valves needed adjustment and the carbs were synched.I also installed 3 nology coils over the winter.  

It runs better but the throttle response is not exactly crisp.  Hard throttle brings a hesition before the power kicks in, especially at higher RPMs.  Is this behavior "normal" for a keihin carbed Steamer?  I also found out that the air cleaner element is a K&N.  Would this be enough to mess up the air/fuel balance?

I have been ruminating on changing the jets in the carb to see if this would help.

Mustang

Quote from: "cascadetiger"I just got by 98 Steamer back from the 24,000 mile service.  The valves needed adjustment and the carbs were synched.I also installed 3 nology coils over the winter.  

It runs better but the throttle response is not exactly crisp.  Hard throttle brings a hesition before the power kicks in, especially at higher RPMs.  Is this behavior "normal" for a keihin carbed Steamer?  I also found out that the air cleaner element is a K&N.  Would this be enough to mess up the air/fuel balance?

I have been ruminating on changing the jets in the carb to see if this would help.

yes indeedy
the hesitation is there because the mains are not big enough does it actually pick up speed if you roll the throttle back some from full on .....if yes your mains are too small

105's work very well in a keihin carbed tiger
stock is 98
shimming the needles up helps the mid range big time
and go to 2 1/4 turns on the pilot screws .....you will be impressed ! :D

cascadetiger

Hah!  You hit the nail on the head.  This is exactly what happens when I back off the gas.

cascadetiger

One more question, where would a person buy jets for this carb?

Mustang

you can get main jets from any good triumph dealer

or if you want to know what works really well is to hand spin a #59 drill bit thru your existing mains and presto chango you have 105 main jets

the marking sizes of main jets are just simply the hole diameter in mm
ie. a jet marked 100 is  1 mm hole
a jet marked 105 is 1.05 mm
stock jets are 98  , they are .98 mm hole size

ramseybella

Mustang,
I was reading on your 105mm main jet conversion for the Keihins, will this help over 7000 feet above sea level or just staying at stock setting.
Thinking Lean will be better at higher altitude will be doing a carb job next few weeks.
How do you shim the needles up and what do these washers look like?

Thanks for your help..

if you have keihins they came lean from the factory , like seriously lean

factory settings were
98 main jets
#40 pilot jets
non adjustable needles and the pilot screws were basically almost closed

what works well with keihins is
105 main jets
shim the needles up with some washers that are .030-.050 of an inch thick
and set the pilot screws to around 2 turns out
big improvement

cascadetiger

I put the larger jets in over the weekend.  The air box removal and install is a real bugger, otherwise it was uneventful.  

The bike runs really good.  Warm up is faster and throttle response is much improved.  No more hestitation when throttle is applied, it actually lofted the front wheel off the ground when I did a launch in 1st gear, it has never done that before!

Mustang

Quote from: "ramseybella"Mustang,
I was reading on your 105mm main jet conversion for the Keihins, will this help over 7000 feet above sea level or just staying at stock setting.
Thinking Lean will be better at higher altitude will be doing a carb job next few weeks.
How do you shim the needles up and what do these washers look like?

Thanks for your help..


I doubt 105's are going to hurt at higher elevations it will just run a little richer
my bike with 105's ran exceptionally well anywhere I went in the rockies last summer , did beartooth pass with out a hiccup .

the washers to shim the needles in a keihin are just flat washers 8mm diameter with a 3mm diameter hole in them bought at a hardware store . in inch size that is 5/16 ths x 3/16 ths  use three that are the same thickness , 1 for each needle

Mustang

Quote from: "cascadetiger"I put the larger jets in over the weekend.  The air box removal and install is a real bugger, otherwise it was uneventful.  

The bike runs really good.  Warm up is faster and throttle response is much improved.  No more hestitation when throttle is applied, it actually lofted the front wheel off the ground when I did a launch in 1st gear, it has never done that before!

 :thumbsup  Works really well doesn't it !

ramseybella

So is it a big deal cleaning my keihin carbs, does not look that big of a deal?

Cracked the air box open if I was not so cheap (Conservatively Conservative) I would have bought a new one what a pain in the A.

Also Mustang my Cam clearance on my exhaust is around .008 one is .0065 my local Mechanic who I bought my shims told me to leave them alone and just do the intake shims that are way tight.
Think that is a good plan?
 :roll:


I just bought a set of these from harbor freight $12.99 each.
Mounted them on a board.

http://www.harborfreight.com/cpi/ctaf/d ... mber=93547 (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93547)

Mustang

the exhausts are fine do the tight intakes


those vacuum gauges may or may not work

the needles might flutter violently and be unreadable
or they may work fine if they flutter badly  you will need to reduce the sie of the hose with a restrictor which is a pc of hose that has nothing more than a pin hole for a diameter

ramseybella

Quote from: "Mustang"the exhausts are fine do the tight intakes


those vacuum gauges may or may not work

the needles might flutter violently and be unreadable
or they may work fine if they flutter badly  you will need to reduce the sie of the hose with a restrictor which is a pc of hose that has nothing more than a pin hole for a diameter

I remember reading on that about the flutter, will see what I need to do thanks for all your help..

nightrunner

Just another data point here.  I rejetted my 98 with 102 mains and 40 pilots.  The screws are at about 1.5 turns and I used a CO analyzer to set them for 2% CO in the exhaust.  Runs great, easy cold starts (unless its been sitting all winter), and mileage in the mid 40's.

Jets are not specific to the brand of bike.  Keihin and Mikuni are used by all major brands.  Any bike shop will have a big box of jets.  Just bring in the old one so you get the right style of jet.

On the airbox, its a steamer rite of passage to remove one.  Coat all 6 rubber boots with wheel bearing grease or Vaseline.  It will give you a better seal and removal/install is a snap.  BTW I have the Hepco and Becker crash bars and I just slide the carbs out and secure them to the crash bar to work on them.  No fuss with removing the throttle cable that way.
Scott

Seeking adventure and peril