rejetting

[luc8421]

I know i could find a lot of posts about this topic, but my question is for my specific bike, I have a 1985 gs700es, with yoshimirua 4n1 exhaust and cone filters. but I believe I have the stock 122.5 jets, and I was wondering if I should go larger or smaller because of these modifications. Thanks for your help.

[Jethro]

You'll most likely need larger jets.

[luc8421]

I actually am looking at one of the jets right now, I thought they were 122.5, but 134 is stamped on the side, is this the size of the jet? and if it is, isn't that a little big? final question: how do I measure the jet to figure out for sure, is it height, or diameter of the hole. Thanks again

[Jethro]

It's the diameter of the hole that dictates the jet size and amount of fuel. There are also pilot jets and needles that can be adjusted or changed. The number you saw is the jet size and may be the right size depending on:

1. how does it drive
2. what do the plugs say
3. do the plugs foul
3. does it pop
4. fuel economy
5. does it run hot
6. how does it start
7. idle
etc.

Does the bike run poorly or what? More info pleeeeze

[luc8421]

once started, the bike runs fine, with a little popping through out the upper range (>4500rpm). However it doesn't start easily, there doesn't seem to be enough vacum caused by the cone filters to suck fuel through the petcock, plugs seem fine. Are the jets good then, and what should I do with the pilot screws?

[Jeff Tate]

If it was me, I'd spring for a K&N stage 3 jet kit and have all the parts and directions at once. It can be a headache even then. Doing it from scratch is for the truly adventerous. OR.....pull the pod filters and install a stock airbox. The pod filters are the the biggest reason for installing a stage 3 kit.

[luc8421]

well after reading the instruction .pdf file for the stage three dynojet kit, I believe I already have the kit installed, by the previous owner. the slide life hole is already inlarged, and I have the 134 main jets. The only thing I noticed when I was looking at the carbs, was that the e-clip wasn't at the 3rd groove, what kind of difference would this make? I'm going to take them back off and do this step, hopefully it'll solve my starting problem.
One of the instructions was to drill through the plugs, I'm assuming these are the rubber plugs right above the pilot screws, and if so, what difference will it make if I drill these out? Thanks again

[KEITH KRAUSE]

Sounds to me like you have a jet kit already. A 134 main is a size Dynojet uses, not Mikuni. You would also get an adjustable jet needle. The "base settings" are not always correct. You have to test and take plug reads.
From what you've said so far, I would raise the needles 1 position and test. Raising the needle (by lowering the e-clip position) will richen the mixture. Be sure the carbs are synched well with a vacuum tool or you'll get uneven plug reads and poorer performance.

[Anonymous]

I'm sure the plugs the instructions tell you to drill through are the aluminum ones covering the idle adjustment screws. I don't think they want you to drill a hole in the rubber plugs for the pilot jets. 8O

[scotty]

I may have missed it but what color are your plugs--the hard starting could be lots of things.

[Mr. Jiggles]

once started, the bike runs fine, with a little popping through out the upper range (>4500rpm). However it doesn't start easily, there doesn't seem to be enough vacum caused by the cone filters to suck fuel through the petcock, plugs seem fine. Are the jets good then, and what should I do with the pilot screws?

Check the vacuum hose leading to the petcock - it might be leaking. Having pods shouldn't effect the vacuum. If you have a leak that might be causing it to starve for fuel as well as letting cylinder #2 run lean.

Ditto on Scotty's question. What do your plugs look like.

Also, I second Keith's suggestion - do a carb synch. Alot of people make the mistake of not re-synch'ing after re-jetting. The previous owner might not have been thorough.

Good luck.

Jeff

[luc8421]

I'll do what I can to sync the carbs.

I can't tell you what the plugs look like for two reasons, one, I replaced them soon after I bought the bike (about 20 miles ago), and two, I just moved into a new pad, and have been storing the bike at my parents, so I've only been able to see it every few weekends.
When I did replace the plugs, they looked fine, light brown with no carbon build up or oilyness.

I replaced all the fuel and vacuum lines just a few weeks ago with the correct diameter opening and wall width. all I know is that when I cover the carb intake hole with my palm and thumb the starter, gas spews out, so I put the cone filters on and it seemed to start better, getting a little more vacuum to get the gas in the carbs.
UDCO, what are you refering to about the aluminum plugs over the idle adjustment screws? I'm not sure which ones those are.

On an extreme side note, does a place like les schwabb replace motorcycle tires, and is it worth it to do it myself because of the labor they'd charge?

Thanks for all your guy's help, with the starting problem fixed and new tires, my gs will be road ready, and you're all bringing that day closer, can't wait.

[scotty]

"When I did replace the plugs, they looked fine, light brown with no carbon build up or oilyness. "

Had you driven the bike recently before you replaced the plugs that were burning correctly??

[luc8421]

Yes, I had driven the bike before I replaced the plugs, I'm not sure it was enough to leave hints on the plugs on what I should do, but then again it wasn't the most reliable bike before I started working on it, so I didn't really want to drive it much.

[Anonymous]

Check out this thread:

http://www.thegsresources.com/_forum/viewtopic.php?t=27653

It answers your question about the aluminum screw plugs.