Running rich ?

[sharky]

Correct me if I'm wrong, but if I give full throttle and it stutters, then I back off slightly and it clears/accelerates then the mains is too rich Yes ??

[xjrjack01]

Yep, what size jets you running?

[alfiestorm]

The needles turned up ok ?

[Large]

Won't it do that if it's lean as well?

[sharky]

Yes mate(Alfie) they have....see other thread ;)
Xjrjack....I have about 130's (used jet drills) in there...running K&N pods and a dynojet kit. Gonna put some 125's in and see.
Just wanted to make sure my brain wasn't making stuff up again [:p]

[xjrjack01]

I've got 112.5's in my 1300, Runs sweet til about 7500 - 8000 rpm then runs out of puff. What mods have you done to the engine?

[sharky]

Xjrjack....No mods, stock FJ11 motor at the moment.
Large......Not sure, so I've gone back down a jet size.
Another test run tomoro.

[xjrjack01]

Don't forget dynojet sizes aren't the same as minkuni sizes

[alfiestorm]

It must have been the beer that made me forget

[sharky]

At last...making progress...:)..
Discovered that 2 of the floats were slightly bent so that they would just touch on the carby body and thus stick open....thats why I couldn't set the buggers right :(!!!
So with that sorted and a 130 mains is yippee kay yay upto 225kph :D(which is as good as these things get...135mph in real money ;)).
Gently rolling on the throttle no problem, snap it open and it splutters,back off slightly and she clears...did a plug chop....black and sooty.
Gonna try some 125's (cheers Ed) and if thats too weak go for the middle spot..127.5 (Anyone got any spare ??)

[shift1313]

what kind of carbs? the studder might also be caused by slow rising pistons. Some bikes need the air passage hole drilled out slightly in the piston. What happens is you will get a pressure buildup in the top and the piston wont come up fast enough. Usually causes studders when you crack the throttle open. The description you gave could be lean or right. There might also be an air correction jet in your carb depending on the model that needs to be larger.

how did you get your plug reading? did you shut the bike off while on full throttle? if not then it wont be an accurate reading.

[sharky]

Yes mate, full throttle with it spluttering for about 15 secs. Hit kill switch, clutch in and came to a quick stop.
The slides were drilled out with the bit that came with the jet kit.

[shift1313]

well it sounds like your on the right track. let us know what happens

[sharky]

Shift, I am looking at some bits on ebay usa for the 38mm CV's.
If I got 'em posted to you could you put them all in one parcel & ship them on to me ? One of the sellers wants a 'handling fee'....for a jet kit !!
I can cover your costs (and a beer) with paypal if you could ?

[sharky]

127.5's needed
Fitted the 125's.....full throttle...surging badly....so its gotta be 127.5's (130 too rich)

[latheboy]

Sharky why dont you just put it on a dyno and be done with it? It'll save you alot of fuckin around and save you engine from going Kaboom if you get wrong ..

[sharky]

I will at some point mate, but theres no point going to a dyno until I have got it as close as. Once I have the main jet size right I will look at dyno's 'cos then its easy adjustments ie needle height and pilot jets. Also nearest dyno for me (worth using) is down Keysborough...I'm in Seymour...

[Deano]

sounds odd mate that the differnece between pleasure and pair is only 1 jet size.

i have fucked around with different jet sizes on several occasions and weather i was using 145,147.5 or 150s i couldn't tell the difference at full throttle. the only thing that may change slightly is the tuning of the pilot as it would occasionally cough and splutter on light load light throttle taking off from the light. once over 2500rpm cleared up and ran beutiful

good luck

[sharky]

quote:I have fucked around with different jet sizes on several occasions and weather i was using 145,147.5 or 150s i couldn't tell the difference at full throttle

But I'm running a finely tuned machine rather than some old oil boiler ;)

130 on full throttle splutters and is black'n'sooty. 125 surges on full bore. 127.5 SHOULD be right on the money.

Have you thought about running an EGO sensor on it Deano? You can get the meter kit from Jaycar for $25, dead simple to put together, plus an old Toyota sensor from the wreckers. You can monitor your air/fuel mixture in real time.

http://www.jaycar.com.au/productView.asp?ID=KC5374&CATID=25&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=347

Or I can provide you with the plans for a cheaper, simpler one that doesn't reqire air flow input, better for older carburettored bikes

[Deano]

i plan yo get myself a wide band o2 sensor once the turbo`bike starts making more progress. i will then be able to swap it between my other bikes and sort them out aswell

[xjrjack01]

Hey Sharky, git ya fuel probs sorted or what?

[sharky]

Got me 127.5's turning up tomoro (should have been friday...bloody express post !) Should do the job, If not I'll stick with the 130's for now. I am gonna do a dyno run after the AFR so that I will have a benchmark to compare to the 38mm CV's.

[xjrjack01]

Getting the right jet setup can be tricky without the right equipment (dyno, air fuel meter etc). I know where your coming from when you say you want to get it as close as possible before you put it on the dyno, I've been working on mine off & on for the past year trying to find the right carb settings, & I've only just now got it sorted so it will run clean from idle to redline. it's taken so long mostly because it's been trial and error without an air-fuel meter or running it on the dyno. Heres a thread that may be of interest to you as xxdrac's bike is also running individual filters.http://yamahaxjr1300.com/invision/index.php?showtopic=5312&hl=bhp&st=0

[sharky]

So there I am in the garage and wonder "What if I took off the s/trapp discs and end caps"....You know just to see what happens.......
And what do you know...[:I]....they were strangling the friggin engine.
Comes on power 500rpm lower and kicks you in the arse at 4k like they should.[}:)] :D







thud...thud...thud.........(me banging head against brick wall)

So Fimp...wanna buy some s/trapp discs and end caps ?????

[xjrjack01]

I,ve got some if you want them I'm not sure what size they are but I'l measure them & find out.

[xjrjack01]

By that I mean if you add more disks it will free up your engine.

[sharky]

Cheers Jack, that would be great. I did try putting washers in between the discs and trying that but it still wasn't right. I was running 10 discs each side and then tried 8 discs with washers.
My discs are the 4" ones. Be interested depending how many you've got.

[xjrjack01]

Just measured one of the discs it was 96mm outside diameter, I think I have about 10 of them.

[sharky]

Thats spot on mate.:D
Some of the 4" discs are about 99mm, mine are 96. Not a lot different until you fit them together.
How much you want for 'em ? Any xjr bits you're after ? ;)
Now I know that the main jet is right its just a case of getting the discs number to match.

[sharky]

Just found a s/trapp race site that gives the equivalent open area for x number of discs per muffler. 10 discs equalled only 3.6cm diameter hole. 15 will be 4.8 which is more like it.

[sharky]

So some more checking on the above site and I found I can use an open end cap and 10 discs to give the right(hopefully) whole size.
So to make 2 of these......
http://www.streetfighters.com.au/forum/upload/6721763839448.jpg


Take 2 of these.....


http://www.streetfighters.com.au/forum/upload/6721763835229.jpg


And half hour with the drill and dremel...
http://www.streetfighters.com.au/forum/upload/6721763835230.jpg


I'll still have the discs if you have 'em Jack...I will probably need to fine tune it and will need more discs for the next engine ;)

[xjrjack01]

quote:I'll still have the discs if you have 'em Jack...I will probably need to fine tune it and will need more discs for the next engine
No worries mate pm me your address and I'll post em' to ya.

[sharky]

Cheers mate, but you haven't got an email contact listed.

[sharky]

http://www.streetfighters.com.au/forum/upload/67217829834197.jpg

[xjrjack01]

quote: Cheers mate, but you haven't got an email contact listed.
OK I fixed that up so you should be able to email now.

[sharky]

Sorted mate. You have mail.

[xjrjack01]

Doesn't look like the email went through, try again & I'll post em out to you today.