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92mm jetting

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Hey guys I tried searching but not much information around for 92 mm bore.

Just got the bike not to long ago with the 92 mm and 13.5 cr. I got it for a steal because it wouldn't run for the PO. It was never jetted after plus sizing. It does run now at stock compression but is lean

I've put the compression back down to 11.3 and would like your advise for a starting point for the needle and main jet. I've got 25 and 27.5 pilot jets on the way to straighten out the idle mixture.

Bike has bsr36 (I know an fcr would give best performance but I've got a new baby and would probably become a single man if I dropped that coin)

3x3

Fmf powercore 4 with stock head pipe

Current carb settings

22.5 pj

DJ needle clip 3 from top

62.5 air jet

160 main

I live around 800 ft elevation and almost all riding will be close to the same

Thanks guys

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Take the airbox door off and see if your bike likes it with the configuration you have now

Edited by mickeydee
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Good point Mickeydee....If it's currently lean, it will run much worse will door removed....

and if it's better it will confirm richness.... :)

Edited by Craigo 485sm

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I'm glad you brought that up, the air box door was off when I test rode. Maybe putting it back on will help.

I had popping on decel and it felt like it ran out of fuel doing approximately 80 at wot.

I rode this exact bike before it was bored out and ran like a dream with this carb setup. So I figured bigger displacement probably needed more fuel

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I'm glad you brought that up, the air box door was off when I test rode. Maybe putting it back on will help.

I had popping on decel and it felt like it ran out of fuel doing approximately 80 at wot.

I rode this exact bike before it was bored out and ran like a dream with this carb setup. So I figured bigger displacement probably needed more fuel

 

A larger piston sucks the required fuel from a smaller jet..

So is it better or worse running without the air box door.????

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I've only ridden it with the door off. I didn't even think if it making a difference. I'll ride with it installed after work and report back.

If I need top adjust the needle, are you counting clips from the top down or bottom up?

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He bought it used from a dealer and it was already installed. I'm assuming stage 1 bc it only had the exhaust and 3x3

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He bought it used from a dealer and it was already installed. I'm assuming stage 1 bc it only had the exhaust and 3x3

 

Stage 1 is intended for stock airbox opening....but some guy use it with 3x3 mod...It can be made to work, but it's good to know what stage Jet kit we are dealing with from the Get Go...

Edited by Craigo 485sm

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Well I moved the needle to clip 2 as advised in an earlier posting and ride with the side cover installed. Might have been slightly better, but I think doing those 2 together were probably canceling each other out somewhat.

It was getting dark so I didn't get to push it, I'm going to move back to clip 3 for the next ride and see if the popping on deceleration gets any better.

I think it's supposed to be off and on showers tomorrow so maybe no riding tomorrow.

New pilot and main jets will hopefully arrive tomorrow or Monday. I'm ready to get it right so I can leave the 18 mpg jeep at home.

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From here on out I'm only going to change one thing at a time so I can figure out what's helping.

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Well I moved the needle to clip 2 as advised in an earlier posting and ride with the side cover installed. Might have been slightly better, but I think doing those 2 together were probably canceling each other out somewhat.

It was getting dark so I didn't get to push it, I'm going to move back to clip 3 for the next ride and see if the popping on deceleration gets any better.

I think it's supposed to be off and on showers tomorrow so maybe no riding tomorrow.

New pilot and main jets will hopefully arrive tomorrow or Monday. I'm ready to get it right so I can leave the 18 mpg jeep at home.

 

Here is the deal.....

If you have Dynojet stage 1 jet kit you would run clip #4 and if it's stage 2 you would use clip #2....

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Ok I'll move to clip 4 and ride on the next dry day, Thanks for all the help guys

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The bike must have a stage 1 needle, I rode it earlier and had much better midrange power with the needle on clip 4. It still had popping on deceleration. Hopefully that will get better once I get the pilot jets on that I ordered.

I'm going to move up in main jet also, I'm geared +3 on the rear but it felt like I ran out of gas at 80 mph @ wot

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Nothing to report yet, we've been under tornado watchesthe past 2 evenings.

I did drain the oil and noticed a considerable amount of coolant in it. I went in to do the water pump fix and had noticed some black gasket maker around the side case... little did I know at the time that there wasn't actually a gasket in there. I remedied that situation along with changing the shifter seal the P.O. tried to replace.

Tomorrow is jetting and stator cover gasket

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