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Db2 rear sprocket

 
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Jimip86



Joined: 15 Jul 2015
Posts: 49
Location: Derbyshire

PostPosted: Fri Apr 12, 2019 5:43 pm    Post subject: Db2 rear sprocket Reply with quote

Finally getting round to giving my Db2 hf a refresh.
Question is how many teeth should the rear sprocket have ?
Mine currently has a 36 tooth rear.
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Fri Apr 12, 2019 6:56 pm    Post subject: Reply with quote

It can have what you want....BUT....Dont go too big as the chain run can conflict with the tubular spurs on the swingarm where it passes through on the top run....Mine is a 36 rear and its fine....cant recall the front...But....The engine is far from standard......It has ALL the acceleration I could ever want...lifting its front in 1st 2nd and 3rd if thats you bag...its not mine...I'm pretty sure the owners manual actually states the teeth size front and rear as standard.....

I've just turned down a 36tooth genuine NOS rear sprocket for DB2/3/4..as they all fit regardless of whether its Oscom, Marchesini or antera rims....Which is with a USA seller thats bringing me parts over to the UK in his hold baggage...then we are secretly meeting up and swapping bags of cash for Bimota goodies at a location I cant disclose....for fear of Snipers..I already have a spare 36....so let me know if your interested as Theres still time.....Main thing...what wheels are yours?..If its Oscom then you need to pull the cush drive assembly off and check for sheared studs....Bimota changed the sizes twice as they were known to shear the heads off...too much torque from the Duc unit for Italian steel.....Also....check the cush drive rubbers and collats...as I presume they've never been changed.....theres 6 of them....must be 26 years old now???..>Again...speak up...I have a full set of collats and rubbers...and new studs.....Theres 2 bearings in the cush drive also...and evidently 2 in the wheel also
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Fri Apr 12, 2019 6:57 pm    Post subject: Reply with quote

double

Last edited by 2bims on Sat May 11, 2019 6:55 pm; edited 2 times in total
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brian



Joined: 22 Aug 2011
Posts: 3769
Location: Australia

PostPosted: Fri Apr 12, 2019 10:45 pm    Post subject: Reply with quote

2bims wrote:
It can have what you want....BUT....Dont go too big as the chain run can conflict with the tubular spurs on the swingarm where it passes through on the top run....Mine is a 36 rear and its fine


How big are you talking here 2bims? The DB2 Junior has a much larger rear sprocket as standard. I can't recall how many teeth.... maybe 55?? I'm pretty sure the swingarm / frame etc is the same on the DB2 and Junior.
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'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

PostPosted: Fri Apr 12, 2019 11:20 pm    Post subject: Reply with quote

Maybe a smaller front sprocket also??..maybe a lesser gauge chain?...the db1 junior has a completely different front sprocket to the 900cc version...
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Fri Apr 12, 2019 11:25 pm    Post subject: Reply with quote

May be different shims arrangement and spacers. The junior has a narrower rear rim also...maybe sprocket alignment is different??...bottom end on the 400 is completely different to the 900....the 750 is a sleeved down 900...the 600 is different to all...some thought the 409 is a slimmed sleeved down 600...but its not....
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brian



Joined: 22 Aug 2011
Posts: 3769
Location: Australia

PostPosted: Fri Apr 12, 2019 11:47 pm    Post subject: Reply with quote

I still haven't had a chance to look at my DB2 Junior yet. It will be like having another new bike when I finally get around to it Very Happy
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'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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Jimip86



Joined: 15 Jul 2015
Posts: 49
Location: Derbyshire

PostPosted: Sat Apr 13, 2019 10:10 am    Post subject: Rear sprocket Reply with quote

Thanks for the reply’s.

2 bims , would be interested in the sprocket. Will go and take a good look at the Cush drive etc and check it’s condition.
I’ve been considering dropping the engine at some point and going down the 944 conversion route and flat slides , just wondering is it really worth the cost ?
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Sat Apr 13, 2019 2:53 pm    Post subject: Re: Rear sprocket Reply with quote

Jimip86 wrote:
Thanks for the reply’s.

2 bims , would be interested in the sprocket. Will go and take a good look at the Cush drive etc and check it’s condition.
I’ve been considering dropping the engine at some point and going down the 944 conversion route and flat slides , just wondering is it really worth the cost ?


I'll ask my mate what cost for the sprocket....rear....as it wouldn't weigh much for him to carry it in his luggage as it is alloy.

"Worth" and "Cost"....Both terms that are very relative to how you ride and how wealthy you are.....And I would find it very easy to convince you one way or the other....Theres 2 things that are certain...re worth and cost....Firstly...Yes...it transforms an already good torquey engine.....and secondly re cost...Its money spent that you will never ever see again...For any subsequent new owners its a "nice to have"....that would make the bike more attractive to buy and sell easier....but If you got 1o or even 20% of the cost of your outlay back I would be very surprised.....Its not some 25 year old BHP King of the road that would be buying your bike...more likely some 50-60 year old....Theres 3 levels of tune...and I have a handy article somewhere giving you all the details...

First and cheapest is Keihin FCR39 Flatslides (Or mikunis)and cone filters...just throw the old airbox away....comes with a push pull throttle assembly...and no messing with the tank needed to route the cables through to the bank of carbs.....This is the cheapest and best increase of power per £ spent.....and very easy to manage by yourself....Budget £800 for the carbs unless you can find 2nd hand....adds up to 10bhp.....

2nd...the "drop the engine"...oh how he laughed....swingarm pivots off the back....shock fixes to rear assembly and frame....You have to totally strip the bike down....its wheels off...rear swinging arm off....calipers off...but dangling....Disconnect lots of wires...but...the wiring connecters only serve its male/feamle counterpart...as they are all different...so thats idiot proof....Chain off.....disconnect carb cables...take forks out and away....you can unplug the main assmbly of wired behind the haedlight and leave it on its subframe and just walk the thing away....So...frame is now apart and so is swinger....might as well clean it up...powder coat it refresh...new swingarm bearings in the engine block....if theyre not OK....And you WILL have fun figuring how to get the clamp bolt off the RHS of the swinging arm pivot shaft alongside the engine...as the clutch basket and crankcase assembly is in the way.....

Now you have your engine all on its own...Whilst youre ripping off the heads you may as well change out the Stainless steel cylinder head bolts that were subject to Ducati warranty claims because they should be black high tensile....your engine WILL have the old bolts if no-ones changed them...£40 each....the old ones WILL chear off if you give the engine more power...they will at some point shear off even if you dont...Did I say £40 each?...And theres 8 of them.....Budget another £2500-£3000 to change the heads...V2 pistons....944cc kit....Stage 2 cams....all new gaskets...Keihin FCR41 flat slides K&N cone filters....gas flow and polish the head...lighten and balance the crank and flywheel...upgrade to billet clutch basket and HD barnett Billet clutch plates and billet clutch pressure plate.....Dont forget More air and More Fuel in means wxhaust too small now...So upgrade and get a one off SS or titanium 50mm system made and new end cans.....Committed suicide yet?...as the engine is all apart get them acqua/soda blasted and repainted...no point in spoiling the ship for ha'penny of tar.......Upgrade your cush drive bolts to larger dia HT steel ones coz the old ones will snap their heads off...so turn out and remill and tap and thread the back wheel locating sockets...>Perhaps add a further oil rad or larger one...new hoses...add a temp gauge coz you want to know if you are cooking the oil and going to blow your engine.....essential....New Coil packs and HT leads....girt balst and powder coat your valve and crankcase covers....new belts, pulley and tensioners....Make it around £6000....My DB2 had £13,500 spent on it in 1996...and it was a one owner bike only 2 years old with less than 2K on the clock at the time....These changes will go from stock of 76bhp to 90-95bhp

3rd stage...dont bother...it only adds 5BHP but is a few more £000's and makes it a race bike not fit for the road....

And dont forget...either type of flat slides have no choke.....but...if only using on a fine dry day.....they do start OK...you just need to know how.....May as well add a hiCold Cranking new battery as they take more cranking more often due to high comp and bigger bore...Throw in new fuel lines whilst youre there.....and a new fuel pump and filter...some plugs...new belts....chuck some carbon fibre cam belt covers on...some billet or carbon vented sprocket and clutch covers....upgrade your brakes to either gold series master or radial brembos...calipers and discs are still fine though...refresh your forks...and 5 years later marvel at the results....they become addictive with flatslides....defo worth it...but then I didnt do the work or pay the bucks.....

I can dig out the article if you like....maybe 20 years old but its still relevant for today...and costs are about the same
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Jimip86



Joined: 15 Jul 2015
Posts: 49
Location: Derbyshire

PostPosted: Sat Apr 13, 2019 5:25 pm    Post subject: Thanks Reply with quote

2bims

Your knowledge is always appreciated !

Thinking maybe keep my eye out for some 39s on eBay.
To be fair the bike has plenty enough poke to embarrass much more powerful bikes.

Spending thousands is out of the question right now anyway.

Checked the Cush drive and bolts , all seem fine to me.
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Sat Apr 13, 2019 6:07 pm    Post subject: Reply with quote

I suspected that way be your chosen route...But to be fair....it gives you the most power and character and a reasonable bump in power for the least bucks by far.....and still transforms what is a nice little beastie in to a more characterful one...the flapping of the flatsides and Darth Vadar sucking of the K&N mesh cone filters is quite seductive and addictive....you will need the respective quick turn push pull throttle assembly also with the right crank on the cable...fortunately the Db2 has a separate kill switch/start button switchgear to the throttle twist grip so its an easy change......the DB4 throttle is integral to the switchgear.....

Dont bother with the foam air filters....I've heard too many horror stories of them catching a spark from the carbs and catching fire and torching your bike....K&N cone.mesh filters...are guaranteed for life ...just buy the cleaning and oiling bottle with them
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Wed Apr 17, 2019 7:04 pm    Post subject: Re: Thanks Reply with quote

Jimip86 wrote:
2bims

Your knowledge is always appreciated !

Thinking maybe keep my eye out for some 39s on eBay.
To be fair the bike has plenty enough poke to embarrass much more powerful bikes.

Spending thousands is out of the question right now anyway.

Checked the Cush drive and bolts , all seem fine to me.


You have a pm Jimi....
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