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Increase in jet size on Mains ?

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I am thinking of going up from 107.5 mains to 110 or 112.5 . Mikuni CV BS34SS carbs, stock bike, except for 4 into 1 exhaust. Will I need to change pilot jets too? Thanks
 
I was incorrectly assuming an 1100E 16V

110 seems too little for a CA bike that is running lean to start with and teh 4:1 is only making it worse. Pods would require a jet it.

go 112.5 and see how it runs. Bike is totally stock except for 4:1 pipes correct?
Click to expand...
 
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posplayr said:
110 seems too little for a CA bike that is running lean to start with and teh 4:1 is only making it worse. Pods would require a jet it.

go 112.5 and see how it runs. Bike is totally stock except for 4:1 pipes correct?
Click to expand...
Yes stock. except exhaust. stumbles a little on exceleration. Pulls to red line but just seems a little off. I have the washers (3) on the needles helped a lot. I can't think of any other adjustment to make.
 
mike10 said:
I am thinking of going up from 107.5 mains to 110 or 112.5 . Mikuni CV BS34SS carbs, stock bike, except for 4 into 1 exhaust. Will I need to change pilot jets too? Thanks
Click to expand...

I ran 120 main jets and 42.5 pilots and shimmed the needles on my 1000ST. Airbox witha drop-in K&N filter. I also cut the breather holes; made a large oval out of the two circular holes. It ran great. I was in AZ at the time 1200ft elevation.
 
How did you shim the needles? Did you replace the spacer on top of the clip or place the washers under the clip?
 
rudeman said:
I ran 120 main jets and 42.5 pilots and shimmed the needles on my 1000ST. Airbox witha drop-in K&N filter. I also cut the breather holes; made a large oval out of the two circular holes. It ran great. I was in AZ at the time 1200ft elevation.
Click to expand...

Whoops I did not realize we were talking about a 8V 1000E; I was assuming an 1100E. Yours is probably a very good benchmark for the OP.
 
The needles need to be higher relative to the slide. Shims need to go on the needles beneath the C-clip.

I used the process described by Joe Minton (I think) at the time; move the plastic spacer from above the C-clip to beneath it.
 
Just for reference, the stock jets in 82 for an 1100SZ were 110 mains and 45 pilots and were still a bit lean. Don't have the 1980 E specs. Calif. sure got screwed on the jetting though.;) I'd up the mains to 120, leave your pilots and raised needles and see how she goes. The 4-1 exhaust will be more a top end thing then in the pilot range.
 
JTGS850GL said:
Just for reference, the stock jets in 82 for an 1100SZ were 110 mains and 45 pilots and were still a bit lean. Don't have the 1980 E specs. Calif. sure got screwed on the jetting though.;) I'd up the mains to 120, leave your pilots and raised needles and see how she goes. The 4-1 exhaust will be more a top end thing then in the pilot range.
Click to expand...

Pretty sure he's running a 1000ET...107.5 main, 40 pilots
 
rudeman said:
The needles need to be higher relative to the slide. Shims need to go on the needles beneath the C-clip.

I used the process described by Joe Minton (I think) at the time; move the plastic spacer from above the C-clip to beneath it.
Click to expand...
I don't have the plastic spacer on the needles. my needles are not adjustable.
 
Sorry for the typo, the jet sizes I was quoting is for a 1982 1000SZ not an 1100 so are still relevant. No huge difference between a 1000E and a 1000S engine wise.
 
I need to cancel this thread for now. I'm goin to re-clean these carbs and recheck everything. The idle is crazy up and down. I thought I had it dialed in but something is wrong. These carbs never gave me trouble like this before. Thanks
 
mike10 said:
I don't have the plastic spacer on the needles. my needles are not adjustable.
Click to expand...

Yes they are.

mike10 said:
I need to cancel this thread for now. I'm goin to re-clean these carbs and recheck everything. The idle is crazy up and down. I thought I had it dialed in but something is wrong. These carbs never gave me trouble like this before. Thanks
Click to expand...

What did you change right before the craziness started?
 
JTGS850GL said:
Sorry for the typo, the jet sizes I was quoting is for a 1982 1000SZ not an 1100 so are still relevant. No huge difference between a 1000E and a 1000S engine wise.
Click to expand...

An 82 1000SZ is a 16-valve engine while 1980 1000E or S are 8-valve engines, There is a significant difference between 16 and 8-valve engines.
 
rudeman said:
An 82 1000SZ is a 16-valve engine while 1980 1000E or S are 8-valve engines, There is a significant difference between 16 and 8-valve engines.
Click to expand...

Yep, sorry for not thinking this one out. Doing too many things at one time and my brain wasn't fully involved. Thanks for catching my screwup. With that said, a 1981 1000G is an 8 valve engine and, factory stock, came with 115 mains and 40 pilots. Now using 120 mains, 40 pilots and needles with 3 washers. Only change is 4-1 exhaust and K/N filter in stock airbox. Don't think that there's much difference between a 1000 shaft drive v/s chain drive of the same year.
 
Ok, I have recleaned my carbs. No dip this time. I dipped them about 3 weeks ago 4 hours in the Berrymans. and installed 112.5 main jets. Original issue, stumble into mid range A little boggy full throttle. a little back firing/ popping on hard decelleration. All because I put the Delkevic 4 into 1 exhaust on a compleatly stock GS1000E 1980 CV BS34SS carbs 107.5 mains. 3 washers on top of the clip on the non adjustable needles. replacing the plactic spacer. All O rings are new. Before I put them back on do I need to change pilot jets too. the pilots are 40s, thanks
 
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mike10 said:
Ok, I have recleaned my carbs. No dip this time. I dipped them about 3 weeks ago 4 hours in the Berrymans. and installed 112.5 main jets. Original issue, stumble into mid range A little boggy full throttle. a little back firing/ popping on hard decelleration. All because I put the Delkevic 4 into 1 exhaust on a compleatly stock GS1000E 1980 CV BS34SS carbs 107.5 mains. 3 washers on top of the clip on the non adjustable needles. replacing the plactic spacer. All O rings are new. Before I put them back on do I need to change pilot jets too. the pilots are 40s, thanks
Click to expand...
Ansewer to my own question. 40 pilots will be fine because I have the stock airbox on.
 
By placing the washers on top of the clip you are not changing the needle height. You want them to extend into the fuel feed tube less than they are at stock setting. In other words the distance from the bottom of the slide to the lower end (tip) of the needle needs to be shorter. I ran 42.5 pilots and a stock air box. It ran significantly better than with the 40 pilots. Have you tried 42.5 pilots yet?

If that pipe is worth its salt you will need to compensate for increased airflow.

I ran 120 main jets and it ran perfectly. Like I mentioned earlier in this post, with those main jets and 42.5 pilots and RAISED needles the my 1000ST had great snap off idle; no bog when rolling open the throttle; and pulled hard all the way through redline.

1980 GS1000 has 107.5 main and 40 pilots.
 
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