jet question

[Monkhouse]

I got a 78 gs1000 with Vance and Hines pipe and pod filters. A rep told my friend(who put the pipe on several years ago) that it needed a dynojet 138 main jet. I was wondering if i can just use the dynojet jet with the stock mikuni carb, or do i need to get the complete carb rebuild kit? Something i read on here said you needed to get the rebuild kit, but I think that was for the CV carb. I am having trouble finding the correct size mikuni jet for this (I think i've found 135, and 140 sizes). It's my understanding that DJ jets numbers are interchangeable to the mikuni ones. also, where is the best place to buy jets/carb kits? Thanks for the help.


Monkhouse

 

[Dave8338]

Z1` is where to go for the Dyna Jet kits. I think that if you are looking for the most complete carb kits/ jets that are likely to be sized very close to your set up, I would just get the complete Stage 3 kits and keep your existing jets for another project.

 

[Guest]

It's my understanding that DJ jets numbers are interchangeable to the mikuni ones. Monkhouse

No, not true...

http://www.thegsresources.com/_forum/showthread.php?t=162372&highlight=jet+conversion+chart

 

[Monkhouse]

I had read somewhere that although the size was different there were other factors that contributed to fuel mixture, and so the dj jets were standardized to the mikuni ones or something. So I have to replace the internal carb (needles etc) parts with the DJ ones to get this to work properly, or can I merely replace the jets?

 

[Steve]

Also, if you have read anything about "rebuild kits" on this forum, you should have noticed that we all listened to Nancy Reagan.
We just say "NO".

Too many times, the brass pieces in the kits are of inferior quality and will mess you up much more than they helped. About the only useable item in there is the bowl gasket, and we have heard of problems with those, too. Besides, $25 or so for a rebuild kit (that does not include everything you need, including the parts that you need the most) is a lot to pay for a $4 bowl gasket.

Your best bet, if you need to "rebuild" your carbs is to order an o-ring kit from forum member Robert Barr. You can contact his site at cycleorings.com. While you are there, consider getting the intake o-rings (if your bike uses them) and the stainless bolts that hold the intake tubes (if your bike uses them). The total for ALL of those is about the same as one "rebuild kit" and will do the job far better. Then get a can of Berryman's Carb Cleaner Dip, disassemble the carbs, dip each carb for the appropriate time to clean it (varies between 2 and 24 hours, depending on how bad they are), reassemble with the new o-rings, set your pilot jets, sync the carbs and enjoy your ride.

As you have also noticed by now, yes, the Dynojet jets will fit in the carbs, but the numbers to not match exactly. Hikermikem gave a link to the conversion, but basically, the DJ jets' numbers are larger than the Mikuni numbers. The DJ 138 is about the same size as a Mikuni 130.

.

 

[sparki]

difference in numbers being flow rate vs physical hole size

 

[Big T]

A 130 jet might be a bit large for your set up, but being rich too start doesn't hurt

The VM carbs don't really need a DJ kit, you can buy any jets/needle/slide combo you want

Most people end up in the 120/125 range, with the needle raised one notch

You can get jets at

www.jetsrus.com

at better prices

 

[78GS1KNH]

the only place i've found that had the correct jets and needles was Jerry's cycles. They dont have the air mixture screws but yours should be fine. here's a link:
http://www.jerryscycles.com/catalog/i191.html

 

[Monkhouse]

A 130 jet might be a bit large for your set up, but being rich too start doesn't hurt

The VM carbs don't really need a DJ kit, you can buy any jets/needle/slide combo you want

Most people end up in the 120/125 range, with the needle raised one notch

You can get jets at

www.jetsrus.com

at better prices

I think my original needles and slides are in good working order. How would i know if they weren't? So I can just buy new main jets? I think I've got a 132 in there now and that's running rich.