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SB6R Fueling Issues? Not wanting to REV in gear.
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Jaguar



Joined: 15 Sep 2017
Posts: 268
Location: Albany NY

PostPosted: Mon Oct 14, 2019 2:51 am    Post subject: Reply with quote

Ran it a bit more and re checked the compression
150-150-170-150

Running in all four for sure.
Opened up the ignition and it looks to be installed correctly and in good shape.
Fair bit of oil on it.

Took the coils out and the body is perfect and the leads seem fine.

Could it be the ECU?
How does one troubleshoot that?
There is an “extension” between the harness and the ECU.
It has a small resistor or something on it.
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Mon Oct 14, 2019 10:31 am    Post subject: SB6R Reply with quote

This is most likely to be a fuelling issue. That fuel pump wrecks the fuelling and owners then start adjusting everything else in the carbs trying to address the problems caused by the pump and end up in a hell of a mess.

I would try to get the carbs back to their original setting:

Mixture screws 2 turns out, with new O rings (the originals have now had it and are letting air past)
Pilot jet: 40
Pilot Air Jet: 1.20
Main jet: 150 (assuming you still have original air filter and pipe)
Float Height: 14.7mm
Needle: 6ZD13 with clip on the second indent from top - must be showing no wear - replace if it is
Needle Jet: 699P-2, if the needle shows wear the needle jet needs replacing as well
Slide should have 2 holes - if one is closed up, drill it out again.

No point looking for other problems until all of the afore-going is right.

Good luck!
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Mon Oct 14, 2019 10:37 am    Post subject: SB6R Reply with quote

PS whilst valve lash may be out of speck, it's unlikely to be impeding the engine to that extent. I would try to get it running half way decently and that will give you the encouragement to do the valve clearances - once you've got the rocker box cover off it's no different to any other in-line 4, but there's a lot got to happen before that rocker box cover comes off - cooling plumbing off, down pipes off and engine pivotted forward on its rear mounts.
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Jaguar



Joined: 15 Sep 2017
Posts: 268
Location: Albany NY

PostPosted: Mon Oct 14, 2019 12:24 pm    Post subject: Reply with quote

All the o rings are new.
Bike has the corse exhaust.
Original airbox with new uni foam filter.

Currently 145 mains, 40 idle

Needles look great, bike has 2500 miles.
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Mon Oct 14, 2019 5:37 pm    Post subject: SB6R Reply with quote

You've probably identified much of the problem right there. With Moto Corse end cans you will need 155 mains in there.
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Jaguar



Joined: 15 Sep 2017
Posts: 268
Location: Albany NY

PostPosted: Mon Oct 14, 2019 6:00 pm    Post subject: Re: SB6R Reply with quote

Jonny B Bad wrote:
You've probably identified much of the problem right there. With Moto Corse end cans you will need 155 mains in there.


Really?
I was just working on the assumption that the bike had been running correctly in the past. Maybe that was the wrong thinking.

I checked the float height this morning.
They were about 10-12mm.
Set them to 15 and went for a ride.

It was choppy around 5k rpm, still will not rev out.
But now the choke seems to effect things.
Before the choke had no impact on how it was running.
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Mon Oct 14, 2019 7:35 pm    Post subject: SB6R Reply with quote

Originally it would have come with 150 mains - somebody has been in there trying to negate excessive richness, caused by the fuel pump, by putting 145s in. With Corse cans on and 145 mains, that bike has never run properly.
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Mon Oct 14, 2019 7:39 pm    Post subject: SB6R Reply with quote

PS the choke is now effecting things because you have leaned it off further by increasing the float height - the poor thing is desperate for gas! Get some 155s in there quick before the Cycle welfare people come round and take you away for cruelty Laughing
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Evilchicken0



Joined: 12 May 2010
Posts: 2996
Location: London

PostPosted: Mon Oct 14, 2019 11:20 pm    Post subject: Reply with quote

The guns are cheap
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Jaguar



Joined: 15 Sep 2017
Posts: 268
Location: Albany NY

PostPosted: Mon Oct 14, 2019 11:21 pm    Post subject: Reply with quote

**Not at all being argumentative**

I have literally read nothing positive about the pulse style fuel pump that came on these things.
Mine appears clean, and also seems to be working.

Why so much hate for them?









-----------------------------------------------------------

I thought that I read that stock jet size was something like 125 or so?
Just figured that the 145s in my bike were already upsized.

Will have to order a few sets of brass and tune the thing.
Why would Bimota make it so hard to even get to the carbs?
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sb8rs



Joined: 05 Aug 2011
Posts: 150
Location: London

PostPosted: Tue Oct 15, 2019 9:11 am    Post subject: Reply with quote

Jaguar,
I have come into this thread very late, but have read all the comments carefully.
The advice you have been given, by many people, will serve you well; you have to trust as they do know what they are saying.
I have had 2 SB6r's and have just bought my third.
I have followed this advice and can assure you it works.
I have removed the mechanical pump as it was immensely difficult, no impossible to set up correctly with it installed. It always "hunted" at low revs with it in place. Good for a lawnmower, but not a motorcycle I am afraid.
I have put an after market air filter in.
I have "cored" the original exhausts.
I have followed JBB's advice to the letter.
And they all run perfectly.
As Nike say, just do it! What is there to lose, other than your sanity........
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Anders



Joined: 05 May 2009
Posts: 121
Location: Norway

PostPosted: Tue Oct 15, 2019 9:32 am    Post subject: Reply with quote

Jaguar wrote:
**Not at all being argumentative**

Why would Bimota make it so hard to even get to the carbs?


For the same reason I have to remove the exhaust to change the oil filter. And remove the front sprocket to remove the exhaust. And remove the engine from the frame to do the valves. Etc.

Mass centralization, low weight, short wheelbase and generally a great handling bike. That's why Very Happy
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bb1, Mille S2, Guzzi / Watsonian, Morini Corsaro 125, EC200, RD350YPVS etc
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Tue Oct 15, 2019 9:40 am    Post subject: SB6R Reply with quote

I'm surmising that since the pump runs off engine vacuum, which is not constant, the thing may be increasing pressure in the float bowls when it is not needed. Perhaps Bimota ran it flat out at the track and decided it was a bit lean, which the pump addressed, because it would be operating at a near constant vacuum. There were various things they did to carburation as they developed the bike. For instance, the carb breathers (under the diaphragm and the float bowls) were vented to the air intake on some 6Rs. On others, they didn't bother with venting the under-diaphragm breathers into the air intake. Have a look at your's next time you've got the air box off - the 2 carb breathers that each have a filter on them should be plugged into the underside of the air intake. If not, they should be, as this is a ram-air system.

You are absolutely right that the GSXR1100, which was the motor donor ran much smaller mains, in the 120s, but the 6R breathes much better, because of the ram air, different filter and exhaust, which required 150s. The Corse system flows better than the standard Bimota system and therefore needs a bit more - hence the 155s.

If you think these carbs are difficult to get at, you should cross the YB series off your wish list - brilliant bikes as they are, they make the 6R look very easy, at least in the carb department - of course lowering the motor on the 6R to change chain and sprockets spoils the party a bit Laughing
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Jaguar



Joined: 15 Sep 2017
Posts: 268
Location: Albany NY

PostPosted: Tue Oct 15, 2019 11:38 am    Post subject: Reply with quote

Couple of jets are in the mail.
Ordered a pingel filter that will help clean up the line routing now that the pump is not being used.

Fingers crossed this all works.

Wonder how those 145s ended up in the bike.

Thanks for all the help.
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Tue Oct 15, 2019 3:42 pm    Post subject: SB6R Reply with quote

A Pingel 1 in/2 out is a good addition.

Let us know how you get on.
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