What sized jets?
 

I had my mechanic sync my carbs just before he closed up his business and he told me the bike is running lean at the top of the rev range. I would like to get a set of jets to suit but the jet option list does not list all my mods, which are;
K&N air filter,
Remus 4into1 carbon s/s exhaust,
Wiseco big bore kit 2mm o/size (just run in)
Hope this is enough info for some suggestions.

Hey:

If your refering to your 3rd gen linked brake model, in Europe and North America they are jetted a little rich from the factory. Stock is 122.5 in North America and does just fine@ sea level, with those mods minus the bore kit. About 128 or 130 mains is a good starting point with 2 washer spacing or 1 up from mid point on adj needles. A kit is not needed just the main jets, unless you want adj needles, Hope this helps.

Dub

Maybe I should just get this and give to my mechanic (He now does some work from home);
eBay Australia: Buy new & used fashion, electronics & home d

Hey:

"jarvid Maybe I should just get this and give to my mechanic
(He now does some work from home);
eBay Australia: Buy new & used fashion, electronics & home d "



Yep jarvid, that's what I use, A kit just like that from them.

Dub

That kit looks pretty complete. Here's what happened to me with my 79 Suzuki GS1000. In the early 80's, Motorcyclist magazine recommended to take the lid off the air box and add a K&N for better flow. I did that and it worked. Then they said to replace the 95 main jets with 115's. I did and the bike ran like crap. Mileage went from 45 down to 39. The magazines are based at sea level and I'm at a mile high. I tried 105's, but then went back to 95's.

Here's how I determined the main was too big. Wide open throttle, then close the throttle slightly. If the bike speeds up, the main jet is too big. What happens is the jet needle slides down into the main jet slightly making it smaller. Like making a 105 into a 95. If the bike speeds up with the throttle slightly closed, you know the main is too big. Of course this was done with old carbs where the slides were connected directly to the throttle. I don't know if this will work with our CV (Constant Velocity) carbs.

Thanks slowpoke, my mech used a co2 meter to tell him it leans out at high rpm, so I might just get the kit and let him decide which to try.

My bike was actually running rich, not lean at the top end as I took the bike to the mech today with my jet kit. We found the mains said 122 on them but had obviously been reemed out at some stage. We tried the 130's they were too lean then the 135's almost but still lean then went for the largest 140's and adjusted the needles as well(CO2 meter reading about 13-14 all the way). The bike seems smoother in acceleration but has lost the viscious get up and bogey at 5000 to 8000rpm(It used to pick the front wheel up pretty easily at those revs) but seems to pull harder from 8000 to 10000(front wheel just getting lift off at about 85000.

I noted the mech set my pilot jets at 2.5 turns out, in my book it says it should be 2 turns(2.5 is for California) I also had to turn up the throttle stop screw to get the bike to idle at 1000rpm, the bike seems less responsive around 3000rpm to before the rejetting and mucking around, my question is would the half a turn difference on the pilot screw be causing this?

Hey:

Jarvid, they could make a difference, also the needle jets, have a big affect on this.
Did you space them at all. The slow/pilot jets also may need to go bigger. What is your elevation?

Dub

It has got adjustable needles, I believe he removed th spacer/washers and set the circlip on the highest setting when the 135 mains went in as it was still running a bit lean, he then put in the 140's and said that must be right and did not put the co2 meter on again and did not play with the needles either, I might have to take it to the Honda dealer, I wasn't too impressed with his $220 bill seeing how he is now working out of home and I was TAing for him and Honda said they would charge me 2 hrs labour for the same job!

Hey:

Jarvid, get a set of 145, 150, 155, and 160 jets (CBR1100xx kit), move the needles slot down after going up in jet size, also see if you can find 45 pilots or at least the next size up (42), save your money from the dealer and just make one change at a time, (That is if you have time) now that your in the ball park, and do it yourself. You know what you are looking for at this point rather starting with another person from scratch. This is just test and tune from here and you have to ride it to find out if it is where you want it anyway, good luck. Pilot Jetting - for up to 1/4 throttle position, Needle Shimming - 1/4 > 3/4 throttle position, Main Jetting - 3/4 > full throttle, Air/Fuel Mixture Screw is idle off idle response. Pull over and an instant Plug check at full throttle top gear is best way to check plug for lean/rich conditions.

Dub

Raising the clip on the needle lets the needle sit deeper in the jet leaning out the mixture lowering it raises the needle out of the needle jet enrichening the mixture.

Thanks for the info guys, The 140 mains I have in would seem to be correct, I talked to the mech today abut the pilot screw adjustment and he said he will fix for me next week and may raise the needles as well and will test ride himself(we ran out of time the other day) he believes were are pretty close to having it just right as Dub suggested. I will give him one more go as he has done so much work already. Would the carbs need another sync after all this playing around? It was synced about 800klm ago.

Hey:

Jarvid, it never can hurt, except maybe your wallet, but should be done after all the fiddling is complete and after a valve adjustment just to insure everything is spot on. After pilot and needle adj are done you should look at a power increase everywhere in all of the rev range. Since you have not done cams which is what moves the powerband up, and give a huge boost in hp you should be very happy with how it goes.

Dub

I don't think I want to ask about doing the cams, do I?

Hey:

It depends on what you want out of your bike, daily driver you are good as you are and then some, play bike, Web Cams or Orient Express is awaiting your call and money. But plan on more tuning and a moved up powerband. It is not for everyone I went with a 25hp then 50hp N2O shot but you need real good fuel (Race gas) with good forged piston ceramic coated with Crower or Falicon rods/crank kit and such if you want the motor to last more than a couple good runs, and a real strong grip. Good Luck on your choices.

Dub