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1997 DB2 EF Antera Front Wheel Swap
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vort28



Joined: 22 Mar 2010
Posts: 2194
Location: Northwest , UK

PostPosted: Mon Jul 18, 2016 12:59 pm    Post subject: Reply with quote

I am sure I have heard of someone heating a tank to deform it to fit the flatsides but don't quote me, memory getting fuzzy now I'm mid 40's !!
I have a standard tank in the 'spares' collection and the FCR tank on the bike. I will take a picture next time I have the bodywork off the DB4.

It is an amazing transformation. Riding a standard DB4 and mine with FCR's you would'nt even think they were related never mind the same bike.
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brian



Joined: 22 Aug 2011
Posts: 3769
Location: Australia

PostPosted: Mon Jul 18, 2016 1:41 pm    Post subject: Reply with quote

Yeah a photo of the bottom of the Corse tank would be helpful thanks Stu. I'm guessing it's got a notch or recess to allow for the throttle mechanism on the FCR's
_________________
'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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vort28



Joined: 22 Mar 2010
Posts: 2194
Location: Northwest , UK

PostPosted: Mon Jul 18, 2016 2:19 pm    Post subject: Reply with quote

From memory it is just a small notch to allow clearance for the throttle bell crank, but I will get you a picture. May be a few months though until I get time. Shocked
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brian



Joined: 22 Aug 2011
Posts: 3769
Location: Australia

PostPosted: Mon Jul 18, 2016 4:52 pm    Post subject: Reply with quote

vort28 wrote:
From memory it is just a small notch to allow clearance for the throttle bell crank, but I will get you a picture. May be a few months though until I get time. Shocked


No hurry... it'll probably take me another 2 years to find a set of carbs anyway Very Happy
_________________
'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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Ray916MN



Joined: 29 Apr 2015
Posts: 71
Location: Orono, MN

PostPosted: Mon Jul 18, 2016 5:06 pm    Post subject: Reply with quote

brian wrote:
Looks fantastic mate. Are you happy with Dyno tune, did it take many runs to get it right?


My tuner (Lofgren) has done a DB2 FE with FCRs before as well as allot of 900 2 valve air cooled motors with FCRs before so I'm happy with the results. It was still not simple. For example, the DB2 uses a fuel pump which is too much for the "stock" FCR float valve to handle so the fuel pump gets eliminated. The tank doesn't sit high enough to provide consistent fuel pressure when near empty so the tank must be filled to some degree in order to tune properly. The vent tube can create enough vacuum when air is blown over them to influence jetting, so it needs to be tucked into the stock overflow pots. The low/mid on the FCRs benefits from having emulsion tubes from the 1993/94 ZX7R M1/2 which came from the factory with 39mm FCRs. These are no longer available and are very hard to source since Kawasaki was the only source for these. Finally, separate FCRs produce slightly better results than ganged FCRs. The separate FCRs require different intake manifolds and eliminate clearance problems using the regular DB2 tank, but are tougher to keep in sync due to the split throttle cable that must be used. I went with ganged FCRs. To address the clearance problem with the tank I got custom cables with different ends to reduce the amount of clearance I needed for the cables coming off the carbs. It took allot of runs to get right, but Lofgren is a friend and I make it a point to never be in a hurry when I give him something to tune.
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Bud977



Joined: 03 Mar 2013
Posts: 525
Location: Sydney

PostPosted: Mon Jul 18, 2016 10:27 pm    Post subject: Reply with quote

What sort of flatslides would you use? This place can supply most Mikunis at a good price.

http://www.nichecycle.com/ncs/mikuni/carburetors/tm48-1-mikuni-hsr48-flatslide-carburetor-by-mikuni.html
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Bud977



Joined: 03 Mar 2013
Posts: 525
Location: Sydney

PostPosted: Mon Jul 18, 2016 10:29 pm    Post subject: Reply with quote

That DB2 looks great Ray. The DB2 is one of my favourite Bimotas.
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brian



Joined: 22 Aug 2011
Posts: 3769
Location: Australia

PostPosted: Tue Jul 19, 2016 12:47 am    Post subject: Reply with quote

Bud977 wrote:
What sort of flatslides would you use? This place can supply most Mikunis at a good price.

http://www.nichecycle.com/ncs/mikuni/carburetors/tm48-1-mikuni-hsr48-flatslide-carburetor-by-mikuni.html


I'm told that the Mikuni TDMR40's will fit the db4 without any modification but to fit Keihin FCR's you either need the special Corse fuel tank or modify the stock tank
_________________
'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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Ray916MN



Joined: 29 Apr 2015
Posts: 71
Location: Orono, MN

PostPosted: Thu Jul 21, 2016 3:36 pm    Post subject: Reply with quote

Bud977 wrote:
What sort of flatslides would you use? This place can supply most Mikunis at a good price.

http://www.nichecycle.com/ncs/mikuni/carburetors/tm48-1-mikuni-hsr48-flatslide-carburetor-by-mikuni.html


The 900SS engine in the DB2 works best with either 39 or 41mm Keihin FCR carbs paired or un-paired. Selecting which configuration is best depends a bit on what you want out the carbs. 39mm is generally preferred for stock engines used for casual street riding. 41mm is generally preferred for modified engines and/or race use. Paired setups where the carbs use a common throttle bell crank are preferred for casual street riding, giving up a little performance for being less sensitive to maintenance. Paired setups have clearance problems with the regular DB2 tank. I addressed the clearance problem with a set of custom throttle cables with different carb ends. Un-paired setups where each carb has its own throttle bell crank, require different intake manifolds and produce a little bit better performance. The split throttle cable which is required to use these carbs can over time develop differential stretch which affects carburetor synchronization and therefore require more maintenance attention. Un-paired setups do not have clearance problems with the regular DB2 tank.

All 39mm and 41mm FCRs are not the same. These carbs are used in a number of different applications (eg. I have one of these on a dirtbike) and are configured differently with respect to features and jetting so it is necessary to only buy carbs which are configured for use with the 900SS motor.


Last edited by Ray916MN on Thu Jul 21, 2016 3:41 pm; edited 1 time in total
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Ray916MN



Joined: 29 Apr 2015
Posts: 71
Location: Orono, MN

PostPosted: Thu Jul 21, 2016 3:38 pm    Post subject: Reply with quote

Bud977 wrote:
That DB2 looks great Ray. The DB2 is one of my favourite Bimotas.


Thanks for the compliment. Had a 900SS/SP for a few years and sold it thinking eventually I'd get a DB1 or 2, so I'm happy.
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