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brian
Joined: 22 Aug 2011 Posts: 3769 Location: Australia
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Posted: Wed Apr 04, 2012 8:59 am Post subject: |
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2bims wrote: |
brian wrote: |
Can be a bit of a trap though as they can sometimes get neglected for that very reason. |
Mind you thats a good thing on the odd time I put it on the paddock stands you can hear them groaning under the weight as she weighs 50% more than the DB4/2. It always throws me when I pull it out of the garage as I feel like Samson after a short back and sides haircut |
I'm hearing you. My VTX weighs almost as much as BOTH of the bimotas put together. Even though one is fatter than the other. _________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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2bims
Joined: 03 Apr 2010 Posts: 7289
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Posted: Wed Apr 04, 2012 9:26 am Post subject: |
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Jeeso yeh its a mere 10 kilos shy of the combined weight of my Db2 and Db4, does it have a reverse gear? |
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2bims
Joined: 03 Apr 2010 Posts: 7289
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Posted: Wed Apr 04, 2012 9:31 am Post subject: |
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Just as a quickie Brian, I got a reply from "Bob" of bimotaSpirit in the US, saying he had original copies of the DB4 owners handbook. I think you got the same link also, but what price did he quote you for the handbook? He's told me he has some but didn't give a price. Perhaps he would give a better price for 2? I'm waiting to hear a price and confirmation that it is for the carbed version and not the ie injected one.
Maybe theres a chance of a deal |
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brian
Joined: 22 Aug 2011 Posts: 3769 Location: Australia
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Posted: Wed Apr 04, 2012 1:56 pm Post subject: |
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2bims wrote: |
Jeeso yeh its a mere 10 kilos shy of the combined weight of my Db2 and Db4, does it have a reverse gear? |
Haa, i knew you'd have to check it out. No reverse gear, just have to pick a parking spot carefully . It's nice on a long trip and low enough to be easily managed even with my short arse legs. _________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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2bims
Joined: 03 Apr 2010 Posts: 7289
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Posted: Wed Apr 04, 2012 1:59 pm Post subject: |
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Hi Brian, you still up?? Isn't it late there, I think you have an email or 2 re Db4 parts, handbooks etc, cheers |
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brian
Joined: 22 Aug 2011 Posts: 3769 Location: Australia
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Posted: Wed Apr 04, 2012 2:01 pm Post subject: |
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2bims wrote: |
Just as a quickie Brian, I got a reply from "Bob" of bimotaSpirit in the US, saying he had original copies of the DB4 owners handbook. I think you got the same link also, but what price did he quote you for the handbook? He's told me he has some but didn't give a price. Perhaps he would give a better price for 2? I'm waiting to hear a price and confirmation that it is for the carbed version and not the ie injected one.
Maybe theres a chance of a deal |
Thanks Steve... email sent _________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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deebee4
Joined: 08 Jan 2011 Posts: 266 Location: Netherlands
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Posted: Mon Apr 09, 2012 9:23 pm Post subject: |
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brian wrote: |
2bims wrote: |
Just as a quickie Brian, I got a reply from "Bob" of bimotaSpirit in the US, saying he had original copies of the DB4 owners handbook. I think you got the same link also, but what price did he quote you for the handbook? He's told me he has some but didn't give a price. Perhaps he would give a better price for 2? I'm waiting to hear a price and confirmation that it is for the carbed version and not the ie injected one.
Maybe theres a chance of a deal |
Thanks Steve... email sent |
As I have the db4 owners manual, the official db4 workshop manual, parts list and also the Paioli RSU43 service manual (that I have already scanned) I'll scan the db4
stuff. When someone would like to give me a link where I can post them where they're free available, that would make a lot of db4 owners happy, right? _________________ Track riding on a Bimota: FUN! |
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brian
Joined: 22 Aug 2011 Posts: 3769 Location: Australia
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Posted: Sat Apr 14, 2012 11:33 am Post subject: |
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Ok, i'm running out of ideas here. The db4 is still not running properly if at all. It just splutters and backfires.
I've never had much to do with carbs and never had much luck getting them to run right but i've stripped these, cleaned them, checked everything twice and found enough info on the net to set them up enough that it should at least run.
The only thing i haven't done yet is replace the plugs which i will do next week when i can buy some. I still think it's got to be something that i've done because it was running better before pulled the carbs to clean them. It would run reasonably well when riding but just wouldn't idle very well.
Things i've now done -
Stripped and cleaned the carbs. The carbs look fine.
Set the float height at 14mm.
Set the pilot screws at 2 3/4 turns out.
Replaced the air filter.
Checked and cleaned all of the electrical connectors.
Cleaned battery terminals and starter connection.
Bypassed the fuel vacuum switch as it wasn't closing anyway and i thought it may not be letting enough fuel through.
Checked fuel tap - good flow through filter.
Any ideas are welcom, thanks.
_________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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oily
Joined: 05 Apr 2008 Posts: 4788 Location: worcestershire
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Posted: Sat Apr 14, 2012 11:54 am Post subject: |
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Have you got enough cylinders?
_________________ SB6 mk1 (project mega light, big bore)
Sb6 mk2 ( Big Bore)
Sb6 mk2 ( Restored)
Sb6R fighter
Sb6 or Sb7 WANTED |
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2bims
Joined: 03 Apr 2010 Posts: 7289
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Posted: Sat Apr 14, 2012 12:13 pm Post subject: |
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If the needles and jets are worn it would not idle so well, but have you tried adjusting the idle screw situated midway between the carbs? Can't be reached with the bodywork on though, but tank the seat/tank cover off and lift the tank and down inbetween the carbs it should be accessible. Large Philips head screw with a big spring clip behind it. Try it full turn in from what it is, and a full turn out from what it is, Other than that, theres the coils and pick-ups on the left side of the crank. Try out the header pipes to make sure they are tight. Mine were when I bought the DB4, but a shake down run, sure shook a few things loose |
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2bims
Joined: 03 Apr 2010 Posts: 7289
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Posted: Sat Apr 14, 2012 1:01 pm Post subject: |
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Even if you haven't any spare spark plugs I'd pull them out and have a look at the colour of them anyhow, and check the gap, should be 0.6mm. The firing end cap should be a brown, tan or grey color. If its not and its something different let me know what, i.e. dry, black sooty, or Wet Oily deposits or blistered white insulator/glazed electrodes |
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brian
Joined: 22 Aug 2011 Posts: 3769 Location: Australia
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Posted: Sun Apr 15, 2012 6:06 am Post subject: |
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Plugs are dry and black. I cleaned and gapped them, put them back in and still runs the same. Carbs back out. checked carb to manifold rubbers, no signs of cracks or perrishing, good condition. Checked headers, ok. Double checked fuel delivery, looks ok. Seems to be fuel to me. Starts and runs for a few seconds then misses and backfires. Why does it backfire... no idea.
This is doing my head in! I'm missing something here. _________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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deebee4
Joined: 08 Jan 2011 Posts: 266 Location: Netherlands
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Posted: Sun Apr 15, 2012 8:21 am Post subject: |
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brian wrote: |
Plugs are dry and black. I cleaned and gapped them, put them back in and still runs the same. Carbs back out. checked carb to manifold rubbers, no signs of cracks or perrishing, good condition. Checked headers, ok. Double checked fuel delivery, looks ok. Seems to be fuel to me. Starts and runs for a few seconds then misses and backfires. Why does it backfire... no idea.
This is doing my head in! I'm missing something here. |
Hi, when my db4 still had the Mikuni CV carbs it had all sorts of running problems too. Backfiring is more a sign of too lean mixture. It fires right up on the chocke I suppose? But as soon as the float bowl is empty it starves, so I'll advise to check fuel delivery first. If you still have the vacuum pump fitted check if that's pumping well. It's just a simple scooter like vacuum operated membrane pump. So check vacuum line for leaks by sucking and blowing "mouthwise". An air leak will be appearant and that means ditching it, preferably for a low pressure electric fuel pump.
Anyway, try to be analytic: start at the fuel feed, then the floats and needles (are these stuck?) and check all jets for obstruction.
Float height adjustment needs a tool to keep the foat holder in the position as if the float bowl is fitted. I made one myself by cutting away an old float bowl so far that only the edge that holds the float assembly is left over. Ony now you can adjust and synchronise float height correctly. Check membranes for cracks and slides for excessive wear.
Then set both butterfly valves indentically, and the air and fuel screws in a base position. When you fit the carbs on the rubber manifolds do it gently without damaging the rubber. Tighten hose clamps but do not over tighten.
Here's some links that I found useful:
http://www.ducatisuite.com/jetkit.html
http://www.mikuni.com/fs-tuning_guide.html
http://en.allexperts.com/q/Motorcycle-Repair-837/Idle-problem-92-Yamaha.htm (the Yammie TDM850 had the same carbs & problems)
http://www.ukmonster.co.uk/monster/showthread.php?t=36859
First try to keep the bike running by itself, maybe adjust the idle screw up. Then check for air leaks around the manifolds by spraying WD40 around the places where the carbs go in and where they go over the manifolds. No change in revs? Then you're OK. If it does respond to the WD40 then you have an air leak. First solve that before continuing further carb tuning.
Well, you have enough stuff to work on for now. Get back on us when you found something.
Cheers! _________________ Track riding on a Bimota: FUN! |
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2bims
Joined: 03 Apr 2010 Posts: 7289
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Posted: Sun Apr 15, 2012 10:27 am Post subject: |
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brian wrote: |
Plugs are dry and black. . |
Hhmm, Haynes Manual says if plugs are dry and black with sooty deposits, then it leads to misfure/weak spark, caused by an over-rich fuel/air mixture, faulty choke operation or blocked air filter, evidently you have sorted the air filter if too much fuel going in then perhaps worn needles etc? Whats the mileage on the DB4? Need the link again for the 80GBP brand new 38mm Mikunis?? |
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brian
Joined: 22 Aug 2011 Posts: 3769 Location: Australia
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Posted: Sun Apr 15, 2012 10:54 am Post subject: |
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Went back to it this afternoon. Stripped carbs again, re-assembled and set float levels to 14mm. Set pilot screws to 3 1/4 turns out this time. Put the carbs back in the bike, still running rough and backfiring. Running better in mid range but wouldn't idle well. Changed pilot screws to 3 turns out. Ran better when hot, still some backfiring. I had been runnig with the tank hung up and a long fuel hose direct to carbs. Put the tank back on with original fuel hose asnd filter which i had earlier confirmed that i was getting fuel through. Tok bike for a test ride. Died in the driveway, back to the shed. Fitted new fuel hose with no filter. Bike ran again. Took for a test ride up abd down the road, still coughing and backfiring.
On the 3rd run up the road it suddenly cleared and pulled like a train. No more backfiring or missing at all. Pulls good, runs good, idles good.
I think the fuel hose was 'a' problem but not 'the' problem. Still not sure has happened but is now running perfect.
I'll put all the fairing back on next week and take it for a descent ride when i can. Happy again.
DeeBee, no pump at all on mine, just a tap and vacuum valve on bottom of the tank then straight to the carbs. I've bypassed the vacuum valve as it doesn't seal anyway. Thanks for the links too.
2bims, my next trick was going to be to buy the NOS carbs from italy! I still might buy them anyway, for 100 euros they're pretty cheap i recon. I'll still put new plugs in next week and give it an oil change. _________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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