Graham_gib
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| posted on 14/2/17 at 08:53 PM |
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R1 running poor after pipercross help
Hi all
My mk was running fine with the air box on no issues whatsoever but I decided to remove the air box and fit a pipercross sausage filter so I bored the
baseplate holes to fit the small standard rubber crossovers from the carb to the plate and fitted it , now it starts ok but runs really bad
won't rev above 8k and sounds like it's overfueling I'm assuming now it would end re-jetted I've worked my way up and down
with the jet needle grooves found that fitting the circlip closest notch to the tip of the needle makes it slightly better I was wandering if anyone
has had this issue and what jets they used to overcome it ? It's a 5jj r1
Cheers
Graham
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StevieB
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| posted on 14/2/17 at 09:37 PM |
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If you haven't done jets and needles, then that's likely the answer. Bike engines are really sensitive to exhaust design/length and carb
set up.
For the 5JJ you'll want new needles, main jet and IIRC block one of the pilots. I got my kit from TTS when I built my Indy R1 (waaaaaaay back!)
which they don't seem to list on their site anymore, but still might be able to help if you give them a call.
[Edited on 14/2/17 by StevieB]
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CosKev3
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| posted on 14/2/17 at 09:42 PM |
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Be careful if it is running rich,you can soon knacker the bores/or engine if the oil gets too much fuel in it.
I ran 145 main jet in mine,but that had a worked head on it so was running quite a lot more power than a standard one.
You need a bigger main jet,then the needles need to be set correctly. As you've got it now with the circlip nearest the point that's the
richest setting,circip in the furthest away slot is the weakest.
On mine the air correctors were sealed off,and one of the holes on the sliders too.
Mine ran perfect tbf 
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kingster996
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| posted on 14/2/17 at 10:36 PM |
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"Was running fine until I removed the air box" says it all I'm afraid.
Been tinkering with bike engines, especially carb'd Japanese 4 cylinder ones, since 1979 and they nearly always run better with an airbox
(especially later engines).
If you must remove it, then the carbs will need rejetting, needles moved or replaced, pilot jets changed or drilled etc. Even then, you may never get
it running as well as it did with an airbox without either a lot of luck or a jet/needle kit from someone who has spent a wedge developing one
specifically for the setup you have.
Well, that's my experience anyway
I used to be indecisive, but now I'm not so sure
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Graham_gib
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| posted on 14/2/17 at 11:09 PM |
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I'm going to fit the standard box back on for now but I wanted the noise and aesthetics of the piperx I didn't antisipate the change would
be so dramatic I just wandered if anyone had come across this problem and had an easy fix/info on jet sizes etc
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r1_pete
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| posted on 14/2/17 at 11:21 PM |
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As Kingster says it difficult to match the performance of the stock airbox.
On the bike the intakes face forwards, and are usually incoperated into the fairing so the arbox is slightly pressurised whrn the bike is moving.
The engine is then set up to run on this slightly pressurised and relatively still air.
The trumpets also play a part, there is a harmonic effect, which when the trumpets are removed is lost and the fuelling is all over the place.
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gaz_gaz
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| posted on 15/2/17 at 09:38 AM |
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I had a very similar issue when I swapped to a sausage filter from an airbox.
Do you still have the rubber trumpets installed?
I found that mine would run fine with the rubber trumpets and filter as long as the bonnet was off.
We removed the trumpets and the car ran perfectly with the bonnet back on.
PDQ in Taplow ran the car on the dyno a few times and removing the rubber trumpets had zero effect on performance.
Cars long gone but the trumpets are still in my garage.
When I had the carbs setup with the sausage filter not much had changed from when the carbs had been setup for the car in the first place.
[Edited on 15/2/17 by gaz_gaz]
[Edited on 15/2/17 by gaz_gaz]
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FASTdan
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| posted on 15/2/17 at 09:42 AM |
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Did you put holes in the plate to still allow airflow to the air correctors etc? The two large slots under the carb mouths....
NEW danST WEBSITE NOW LIVE! Bike carbs, throttle bodies and more......
http://www.danstengineering.co.uk/
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Graham_gib
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| posted on 15/2/17 at 09:54 AM |
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Thanks for all the replies
I'm trying to load an image of it with no joy
Yes the trumpets are still installed I cut a hole to suit the standard rubber crossovers from the carb so where the standard air box would attach to
these I've got the plate so the two large slots are fully exposed
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kingster996
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| posted on 15/2/17 at 10:13 AM |
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When you say "small rubber crossovers" - what do you mean?
If there were some small bore pipes interconnecting the inlets, these are usually for attaching Vacuum Gauges when balancing carbs. If they are not
interconnected or blanked off altogether, then they will let way too much air in and it will run like a bag of hammers.
If FastDan has provided this setup then listen to him - as he will be one of the people I quoted in my earlier post who will have spent a lot of time
testing and addressing the issues caused by the swap!
I used to be indecisive, but now I'm not so sure
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Graham_gib
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| posted on 15/2/17 at 10:38 AM |
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http://www.locostbuilders.co.uk/galpreviews/3IMG_0060.JPG
See if that works it will explain the last trumpet is off just to see
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FASTdan
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| posted on 15/2/17 at 11:28 AM |
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OK so the way you've done it should be ok as far as the air correctors etc.
I have no experience with these carbs on the actual bike engine - what surprises me is them being so 'very sensitive' to airbox changes,
given that you can slap these carbs on a car engine (with a pipercross filter), make a few tweaks and get great AFR's throughout the rpm range.
You'd expect what you've done to make 'some' difference, but to make it run really badly surprises me.
NEW danST WEBSITE NOW LIVE! Bike carbs, throttle bodies and more......
http://www.danstengineering.co.uk/
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Graham_gib
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| posted on 15/2/17 at 11:44 AM |
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Yes I'm a bit confused myself I'm going to try the air box back on just to make sure coincidentaly nothing else has happened
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gaz_gaz
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| posted on 15/2/17 at 12:02 PM |
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Mine mounted a little different.
It had some 4mm holes either side of each large hole and these where used to hold it down. It sealed from underneath so I could remove the
trumpets.
Have you tried running it with the filter off and just the baseplate to see how it goes.
A couple of minutes won't cause any harm.
[Edited on 15/2/17 by gaz_gaz]
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Graham_gib
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| posted on 15/2/17 at 03:26 PM |
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I've tried all combinations I can think to get it to run I put the air box back on and it runs perfect back to the drawing board
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Graham_gib
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| posted on 16/2/17 at 10:26 AM |
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Figured it out basically the main jet is not fit to cope the idle jet works 0-1200 rpm the needle works up to 8000 and the main jet takes over after
8000 so that's why it's not liking over 8k so I'll need to rejet it , never thought just a filter would cause such an impact but
there you go cheers for all your input
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jeffw
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| posted on 16/2/17 at 11:37 AM |
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Filters/Airbox makes a huge difference. Stick with what Yamaha spent lots of money developing unless you think you can match it with a generic
product.
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Graham_gib
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 posted on 16/2/17 at 11:51 AM |
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True I guess it's about preferance I just wanted the noise of the piperx filter if I was to stick with what Yamaha intended it would still be in
an r1 ha ha
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kingster996
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| posted on 16/2/17 at 01:33 PM |
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quote:
Originally posted by jeffw
Filters/Airbox makes a huge difference. Stick with what Yamaha spent lots of money developing unless you think you can match it with a generic
product.
I know from past personal experience that ditching the airbox that Yamhondukisaki designed will nearly always result in poor running followed by a lot
of effort to get right.
However, we also have to remember that the money and effort the manufacturers spend also has to ensure the engine complies with tough emissions and
noise laws that if (and it's a big IF) we remove and replace correctly can release some ponies.
Easier to use an airbox though!
Also - it amazes me how (relatively) easy it is to get a bog standard 2.0 Zetec to release an extra 40 or more bhp by removing the OEM induction and
exhaust and replacing with ITBs - and ZERO engine mods. I guess bike engines are really well tuned to start with!
[Edited on 16/2/17 by kingster996]
I used to be indecisive, but now I'm not so sure
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Graham_gib
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| posted on 25/2/17 at 08:44 PM |
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Might help someone, so I blocked the fixed air pilot on all 4 Carbs worked my way through the jets till a dj155 jet and the slide needle on second
from the top groove top being furthest away from the needle seemed to do the trick feel a noticeable difference with the pipercross fitted and love
the induction noise of it 
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CosKev3
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| posted on 25/2/17 at 09:46 PM |
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quote:
Originally posted by Graham_gib
Might help someone, so I blocked the fixed air pilot on all 4 Carbs worked my way through the jets till a dj155 jet and the slide needle on second
from the top groove top being furthest away from the needle seemed to do the trick feel a noticeable difference with the pipercross fitted and love
the induction noise of it
Basically what I suggested at the start of the thread.........
But I'm pretty sure if you get it on a RR and check the AFR a 155 main jet will be too big,mine had head work and produced nearly 170bhp on a
145 main jet
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Graham_gib
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| posted on 25/2/17 at 09:53 PM |
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your the boy 
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