Ongoing Fueling issues

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Beef
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Ongoing Fueling issues

Post by Beef »

Afternoon!
It would appear my fuel issue isn’t sorted!
I can ride up to 1/2 throttle any rpm and she runs sweet, 1/2 - 3/4 and she hunts real bad WOT she will big down for a bit then clear & fire off as if nothing was wrong.
I know it’s carb setup, do you think the main jets are too big?
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freeridenick
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Re: Ongoing Fueling issues

Post by freeridenick »

What's your current setup and what modifications?
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Beef
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Re: Ongoing Fueling issues

Post by Beef »

I don’t honestly know right now but gimme a bit. I took the baffles out for the last session and it was better than with them!
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fabiostar
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Re: Ongoing Fueling issues

Post by fabiostar »

it does kinda sound like an engine thats going rich as you go onto the mains, as nick said see whats in your carbs to start with.
the older i get,the faster i was :lol:
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Beef
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Re: Ongoing Fueling issues

Post by Beef »

OK, just looked through my old posts with this issue....

I have 45 pilots and 180 main front & 182 main rear.

It doesn't need very much choke to get her started which leads me to think she is running rich.

Last session before I called it quits, I rode slowly not going over 3rd -1/2 throttle and no issues at all, ran well and ran very smooth. just a shame it looked like I was going backwards (more than normal) :lol:

I then opened her up and from running fine to WOT she's absolutely fine & pulls all the way to redline, it only happens after prolonged over run with closed throttle and then opening.
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freeridenick
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Re: Ongoing Fueling issues

Post by freeridenick »

I think those mains are too big and it's rich coming onto the needle. Try going up one from std front and rear. Or dropping the needle if it's after market.
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Beef
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Re: Ongoing Fueling issues

Post by Beef »

TBH I didn't even look at the needles when I had the carbs apart at Christmas, I just assumed they were stock!
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Beef
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Re: Ongoing Fueling issues

Post by Beef »

OK, I have booked some dyno time with Dynotech in Bramley, They are happy to run the bike and then let me change bits to suit their advice.

I am thinking that I will change the mains as advised by freeridenick prior to going.
I will also look at the needles to see what are fitted & see if they are totally standard or aftermarket, and again, turn to standard.

Looking at the velocity stack thread, I thought about changing the long one to a short so that they are the same, I know people have used both long and felt it's better on road, so my thinking was go for the shorts for track use!! I did look at the ones from Oz... but I have way too many other priorities to justify the spend!! Well, I say that....but the more I look, the more my mind can justify them :lol:

Also, as my bike must be an earlier model with the 45 pilots, should I change them to the later larger ones, would there be any advantage to doing this or would setting up on the dyno properly with the 45's be just as good?

Thanks guys
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Beef
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Re: Ongoing Fueling issues

Post by Beef »

Also,
I know the emulsion tubes are different front to rear, should they be matched to jets or, as long as the front is in the front and rear in rear, will they be fine for whatever jets I use?
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freeridenick
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Re: Ongoing Fueling issues

Post by freeridenick »

Beef wrote: Mon Jul 15, 2019 12:10 pm Also,
I know the emulsion tubes are different front to rear, should they be matched to jets or, as long as the front is in the front and rear in rear, will they be fine for whatever jets I use?
Jets aren't front or rear specific by fit. The emulsion tubes aren't either, just the holes are in a different place. You can fit them the wrong way round without damaging the threads of anything, iirc.
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freeridenick
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Re: Ongoing Fueling issues

Post by freeridenick »

Beef wrote: Mon Jul 15, 2019 10:15 am
Also, as my bike must be an earlier model with the 45 pilots, should I change them to the later larger ones, would there be any advantage to doing this or would setting up on the dyno properly with the 45's be just as good?

Thanks guys
Sort the mains out first, then the needle before the piolts. Have a read of the setup page, brilliant write-up. viewtopic.php?f=31&t=14214
tony.mon
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Re: Ongoing Fueling issues

Post by tony.mon »

Use the emulsion tube (pilot jets) that are appropriate, same with the main jets.
They don't come as a matched pair!

Dont mistake "later" for "better".
It's not falling off, it's an upgrade opportunity.
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Beef
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Re: Ongoing Fueling issues

Post by Beef »

tony.mon wrote: Wed Jul 17, 2019 8:00 am Use the emulsion tube (pilot jets) that are appropriate, same with the main jets.
They don't come as a matched pair!

Dont mistake "later" for "better".
Got it :thumbup:

Has anyone used two short velocity stacks, has any trialling been done with 2?
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Re: Ongoing Fueling issues

Post by tony.mon »

Many years back Benny Hedges used to swear by two short stacks, but then he'd swear at anything!
He liked his bike to be more like an il4, lighter flywheel, and all.
I could Hever understand why you'd buy a torque vee twin then try to make it feel like a revvy il4, why not just buy an il4.
The few times people have dyno'd this mod it helps top end slightly at the expense of some torque lower down but nothing dramatic.
Losing the grunt out of corners would be a bigger disadvantage than gaining a bhp or two top end; you still aren't going to catch il4's on the straights but you'll find it harder to gain an advantage exiting corners.
It's not falling off, it's an upgrade opportunity.
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Beef
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Re: Ongoing Fueling issues

Post by Beef »

That’s clear - I’ll go with the long ones :thumbup:
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