reverting jets back to stock?

[serrow]

I bought my bike with the mixture plugs out, and with the previous owner saying he had upgraded his exhaust. He put back the stocks for the sale, but with HORRIBLE gas mileage i'm wondering if he upgraded the jets and that might be causing me such horrible gas mileage.


what do you think? can the wrong jets be that bad? should i revert back to stock? if so, where's the cheapest way to get all the parts?

 

[one2dmax]

he may have put in a jet kit which almost always gets put in with it set too rich. You'll need to pull the carbs to see what he mains are but you can look at one of the needles to see if it is one without removing the carbs.

Sean Morley

 

[maleko89]

Yep, I would check all the jetting. More than likely need to put stock main jets which are Mikuni 152.5. Also see if you have stage 1 needles. If so it'll help if you go back to stock needles. I have included a picture showing what the different needles look like. Stock needles aren't adjustable and have a fixed "e" clip.

Best place to get replacement parts is through Sean Morley at [email protected]. If he doesn't have something, try U. Motors. Contact information there is in the Vendors section of this forum.

Mark
#1098

 

[maleko89]

he may have put in a jet kit which almost always gets put in with it set too rich. You'll need to pull the carbs to see what he mains are but you can look at one of the needles to see if it is one without removing the carbs.

Sean Morley

Dammit, that Morley beat me.

Mark
#1098

 

[4gasem]

I guess my question would first be. What's horrible MPG?:ummm:

 

[113s&s]

with stock jetting and 2000 miles...i can rub my finger in the exhaust and come out clean no soot..that with air fuel open 2 1/4 in cooler weather average for 3 gallons of gas when fuel lights comes on is between 90 100 miles..thats with a heavy hand

 

[Rusty McNeil]

Most stock maxes get around 30-32 riding the crap out of them around town and 35-38 highway taking it easy.

Most max owners would probably tell you that thier low fuel light comes on around 90-110 miles which is 3.18 gallons on my bike.

I ride the living **** out of mine and stoplight to stoplight with some highway thrown in I get around 28-30 most of the time.

Rusty

 

[one2dmax]

my best economy is when I am running high speeds. Riding it hard mixed in with town and country driving I usually get no less then 38mpg. Two up with luggage/gear I still got 44mpg with the wind and 41 against it.

Sean Morley

 

[serrow]

i hit reserve at about 60 miles. no, i didnt say 60 mpg. you heard me correctly.

also noticed that my slides have a hole through them at the bottom. Is this normal, or is that what they tell you to do for stage 7 mods. the hole did not look like the factory put it there as some of the plastic was chipped around it.

also had 2 diaphragms needing replacement, so is there any way to just plug the holes in the other 2? jbweld perhaps?

also noticed i was missing the oring under the carb cover. wouldnt be a bad idea to find a stock replacement set of carbs but darn ebay isnt quick to list these. i could always resell my current set.

 

[4gasem]

my best economy is when I am running high speeds. Riding it hard mixed in with town and country driving I usually get no less then 38mpg. Two up with luggage/gear I still got 44mpg with the wind and 41 against it.

Sean Morley

I've seen 39 but mines running rich up top... :whistlin:

 

[one2dmax]

Sounds like you may have a stage 1 or stage seven. Compare your needles to the ones in the picture Mark posted. Drilling the slides won't hurt you fuel mileage and there is already a hole there. It's only enlarged a small amount with the kit. Stage seven usually eliminates the V-boost and has indiviual filters. Stage ones generally get **** mileage and poorer performance (when installed per instructions).

I've got a few sets of carbs but if yours weren't all that bad I would just get a few replacement parts (I keep most on hand).

Sean Morley

 

[Rusty McNeil]

When I bought mine it was missing one of the small o-rings under the diaphragm cover and ran like crap.

I used a small diameter rubber hose and made an o-ring out of it.

 

[maxcruiser]

I thought I would throw this link in that I found on ebay. It's a stock rebuild kit for all 4 carbs.

Edited: I removed the link because it seems that there is problems with the Keyster kits. Sorry about putting it on the the first place, just trying to help.

Mike

 

[serrow]

damn take that link off. that is my auction. I messaged him asking him when he was gonna have more vmax kits up.

I'm waiting for him to send me a paypal request to buy only 2 of the kits.

 

[m-cman]

I have been told that that particular kit does not work well. It is the Keyster brand and many of the components do not fit properly. The float valve in particular along with o-rings seem to be the main problems. I emailed previous winners of that kit and only one had actually installed it yet and was disappointed. Also my parts source guy (Mike at U-Motors) said they had tried them at their shop and went back to Yamaha parts. Just what I have heard....

 

[serrow]

Thanks! u motors seems the way to go. the mixture plug there costs $9 but in town costs me $20. Shipping sucks, but I guess I'll just put together a bigger order. Gotta love a company that is so service oriented.

 

[serrow]

in the pic of the needles? what's the FP stand for?

 

[maleko89]

Those are from the Factory Pro kit. That kit sucks and the needles are way too aggressive. IMHO.

Mark
#1098

 

[shawn kloker]

Thanks! u motors seems the way to go. the mixture plug there costs $9 but in town costs me $20. Shipping sucks, but I guess I'll just put together a bigger order. Gotta love a company that is so service oriented.

The good thing about U/Motors is that you pay no taxes.That usually more than covers the shipping unless its a small order.They can get my parts to me faster than the local stealership and its usually half of what they want.Full retail blows!

 

[serrow]

Hi, reviving this thread. Will have the carbs off this week to check all the jets. could someone please tell me what size all of the stock jets should be?

i know that 152.5 is fine for the main. what about PAJ1 & 2