[dakman74]

I know carburetors are covered again and again here...but here's my problem. I am trying to step down to a 112 Jet for a little more fine-tuning since I'm at approx. 7000 above sea level, and even after a thorough tuning/cleaning/etc. it's still running rich on the main circuit.



I know the part number for the 112 jet. I tried to order a YAMAHA jet from stadium yamaha (who everyone recommends) and I could paste the e-mail here but basically the answer is...they don't have one, and yamaha doesn't have any in stock either and doesn't have a projected time when they WILL be in stock. I called the few places that "claimed" to have them in stock (yamaha marine powersports places, mostly) and they all said the same thing...not really in stock, but can put in an order and "see what happens."



So I went to my local shop and surprise surprise...same answer BUT they SWEAR that the round jets that they use in their kits are compatible and comparable size. Since it's about a 45 min drive to the shop from my house, I bought a couple (112 and 110) "mikuni-style" jets from the kit they use to see if 1) they physically fit without hassle (thread pitch the same) and 2) are indeed comparable to the short/small hex stock TK/Mikuni/whatever they are jets.



I have read that the mikuni jets for the NEWER TK carbs run bigger than the stock "size" but haven't read/heard a clear comparison on the OLDER TK carb stock jet vs. mikuni replacement.



I'll keep you posted but if anyone else has any experience with this, I'd like to hear about it.



Thanks!



EDIT: Oh yeah I've seen it written that the old-style carbs are Mikuni but mine says TK on the side and yes it is a round-slide carb. I suppose it's a Mikuni-style carb built by TK?

 

[qwerty]

I know carburetors are covered again and again here...but here's my problem. I am trying to step down to a 112 Jet for a little more fine-tuning since I'm at approx. 7000 above sea level, and even after a thorough tuning/cleaning/etc. it's still running rich on the main circuit.



I know the part number for the 112 jet. I tried to order a YAMAHA jet from stadium yamaha (who everyone recommends) and I could paste the e-mail here but basically the answer is...they don't have one, and yamaha doesn't have any in stock either and doesn't have a projected time when they WILL be in stock. I called the few places that "claimed" to have them in stock (yamaha marine powersports places, mostly) and they all said the same thing...not really in stock, but can put in an order and "see what happens."



So I went to my local shop and surprise surprise...same answer BUT they SWEAR that the round jets that they use in their kits are compatible and comparable size. Since it's about a 45 min drive to the shop from my house, I bought a couple (112 and 110) "mikuni-style" jets from the kit they use to see if 1) they physically fit without hassle (thread pitch the same) and 2) are indeed comparable to the short/small hex stock TK/Mikuni/whatever they are jets.



I have read that the mikuni jets for the NEWER TK carbs run bigger than the stock "size" but haven't read/heard a clear comparison on the OLDER TK carb stock jet vs. mikuni replacement.



I'll keep you posted but if anyone else has any experience with this, I'd like to hear about it.



Thanks!

It is possible another Yamaha product uses the same series of jets, but the part number will be entirely different since often identical parts will have different numbers for different products.

 

[dakman74]

It is possible another Yamaha product uses the same series of jets, but the part number will be entirely different since often identical parts will have different numbers for different products.

Thanks, I know the list of part numbers that someone posted on here actually applied to the XT350 IIRC, but those matched the TW200 part numbers I found also. We'll see if the "parts guy" at the shop really knew what he was talking about.



All I can do is apply trial and error at this point and keep everyone posted.

 

[lizrdbrth]

http://www.motorcyclecarbs.com/TK_LARGE_MAIN_JET_112_P9981C825.cfm



Here's sort of a crossreference. If accurate there are a few options you could research at the dealer. Parts guys don't like to think ouside the box much these days, and if it ain't in the puter for your model of bike it don't exist. Looks like a Kawi dealer might be another potential source as well.



I've got a similar problem, in a way. I live at around 4,000 ft. but within an hour's ride I can be either at 10,000 ft. or at sea level, depending which fork in the road I take.



It's a real pain, so I have to run a bit rich at home in order not to run lean below 1,000 ft.



The point of this being that if much of your riding is at lower elevations you may need to compromise on the rich side. I have to run a 116 up here or I can really smell the engine paint when I'm down in the lower desert.

 

[dakman74]

http://www.motorcyclecarbs.com/TK_LARGE_MAIN_JET_112_P9981C825.cfm



Here's sort of a crossreference. If accurate there are a few options you could research at the dealer. Parts guys don't like to think ouside the box much these days, and if it ain't in the puter for your model of bike it don't exist. Looks like a Kawi dealer might be another potential source as well.



I've got a similar problem, in a way. I live at around 4,000 ft. but within an hour's ride I can be either at 10,000 ft. or at sea level, depending which fork in the road I take.



It's a real pain, so I have to run a bit rich at home in order not to run lean below 1,000 ft.



The point of this being that if much of your riding is at lower elevations you may need to compromise on the rich side. I have to run a 116 up here or I can really smell the engine paint when I'm down in the lower desert.

Thanks for the link! That looks pretty much JUST like the round mikuni-style jets that I got from the parts dept. After looking it up, the jets they have are these: http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=172399975 Oh, and the jet I got was actually a 112.5. Weird huh?





I installed the "112" tonight and went for a test ride. First impression after letting it get nice and warmed up is that it's definitely running "leaner" but I still need to do some adjustment on the idle circuit now to perhaps lean it out a bit at idle/partial throttle. Before swapping the main jet I was content with about 3.5 turns out on the pilot. Half a turn either way and it was either stumbling or popping pretty bad. Now it's slightly stumbling when chopping the throttle and then rolling back on until I get about 1/4 throttle. So hopefully I can take it back in a little at a time and find the sweet spot again.



Qwerty...I have to say huge thanks for the great pilot-adjustment-tool idea. I have been carrying my "bit wrapped in duct tape" around for a few weeks and making tweaks. It'll come in handy again as I re-adjust!



Oh yeah...if anything I go from 7000' to higher, and not much lower. Planning on picking up a 116 jet also just in case. I'll probably just trade in the 110 since I can't forsee installing it. Yeah my local parts dept is pretty flexible! I have also drilled 4 1" holes in the airbox cover and I have some plastic plugs that I can pop in and out as needed for rough adjustment. Another great idea from this forum, btw. I don't know if the 112 is a compromise on the rich side still, but I can tell you that for me the 114 was running WAY rich. Rideability was pretty iffy after it warmed up and the air temp got into 70+. I might have to swap back to the 114 when the temps drop in the fall...we'll see.



Thanks again guys and gals!



EDIT: UPDATE--adjusted to 3 turns out and rode to work this AM at 55F and still just a little-tiny stumble. Gonna try 2.75 turns and see if that's the new "sweet spot."

 

[demarko69]

running a yamaha #116 jet all week 6700 to 7500 feet elevation, ran very good but lost a 1.43 hp

 

[lizrdbrth]

That's good. I hear they blow up at 1.44.

 

[dakman74]

running a yamaha #116 jet all week 6700 to 7500 feet elevation, ran very good but lost a 1.43 hp

That's cool...I would suspect that after a few weeks you'll start seeing the effects of a fouled plug. That's what I was running into at ~7000' and the stock 114.

 

[demarko69]

thanks.

1 plug and 1 qt of oil machine, I change both often, well before they are needed, cheap and easy. and if I do foul a plug on a ride - its ok I carry 2 spares

 

[dakman74]

thanks.

1 plug and 1 qt of oil machine, I change both often, well before they are needed, cheap and easy. and if I do foul a plug on a ride - its ok I carry 2 spares

Live above 7000', change plug every two weeks...then tell me if you'd rejet! ;-) Not to mention...excess fuel washing oil off the cylinder wall. Not conducive to long engine life!

 

[dakman74]

Bike was still running rich with the RD 112.5 jet (back to about the same as the stock 114, I suspect), so installed the 110, and seems to be running much better! I would guess that the RD's are running a half or full step richer than a comparable Yamaha jet, similar to the mikuni jets. And now it likes 3 1/4 turns on the pilot.