Bimota SB6

[Gammaboy]

So, been struggling to find time here and there to work on it between getting dragged off on holidays and working on plastering and painting the front room (Fucking horsehair plaster, people who wallpaper over horsehair, and then paint over the wall paper!)... anyway, been hunting down bits and slowly rebuilding the carbs...

So, went back to the guys I bought it off and made a template off the seat of another SB6 they had - the seats are basically unobtanium, so the plan is mould my own base for the main seat, and carve a buck for the bum stop, mould it in carbon and enlarge the storage space while I'm at it.

So, to get to the carbs, it's off with the seat unit...

and out with the carbs.... a few pics of the sights along the way - including the main reason FCRs are a bear to fit  - you have to cut big holes in that crossmember for the float chambers.

Note the clearance pocket in the upper shock mount:

Oh, looky here - the oil filler. lol.

Guess Marconi really wanted to wrap the beams tight around the motor...

The original vacuum only fuel tap is another piece of unobtanium, and has been replaced with this piece of shit. Dunno how it fed the 1100, but it's got two, tiny 3mm holes inside it as part of the "turn to stop flow" arrangement... Bolt spacing is same as SRAD/SV650, but that's a whole nother story. Fuel level sensor is also missing,  but the OEM ones never worked very well - have a plan for a replacement though.

Onto the carbs - stripping in progress.

So, the 90's "Slingshot" GSXRs had Mikuni BS-SS series carbs - BS40SS for full fat 1100s (US got 36 i think? DR650 also got BS40SS fwiw), BS38SS for the 7fiddy. They all have these fragile fucking brass tubes down one side of the carb - 3 curved to clear the linkage, 1 straight on the outboard pot. Of course, i stupidly managed to fuck the outboard one while trying to get the airbox on to keep the water out on the trip home. Then, while removing the throttle butterflies and shafts, I fucked another one. Oh, and one of the carb caps is cracks and fucked.... and to the rescue comes the 750 carbs I had left over from the 750WP I briefly had... except the caps are different - the 750 caps have the internal stopper ~2mm deeper, so I guess I'll be ordering an OEM 1100 one to make sure all slides open fully. So I stripped the 750 carbs, discovering they had a Dynojet kit in them  (Dynojet bits are for sale if anyone wants them), and have started butchering them.... Have since got all of the casting off that brass tube, going to liberate a spare curved one, and the straight one too.

Using a Litek kit to replace bodgery like this:

Also took the one piece fairing off - I'll do it a better way next time!

Hoover hose is the factory cold air feed to the airbox - not sure I'll bother refitting it.

Some of the tight packaging (Headlights not fitted - from a Cagiva Elefant of all things, as is the tail light - later used by the1st gen Ducati Monster) - 2 small batteries under the gauges, overflow bottle wedged between the batteries, gauges and the headlights... and an adjustable steering damper, that you can't actually adjust without pulling the fairing off...

There's all sorts of fun to dig through with loose fasteners, disconnected wiring.... this may take a while!

Edited May 7, 2019 by Gammaboy

[Dezza]

Amazing - what the hell is going on with that fuel tap? Another cooled framed Suzkook that has had at least one half-wit as a previous owner. We should form a club

[Gammaboy]

I'm told that the fuel tap is common on Huskys from the Cagiva ownership period - I'm assuming for stuff like 125cc dirt squirters, because it wouldn't flow fuckall to feed anything more serious.

It's alarming how unloved some of these Jap delivered Bimotas have wound up.

Edited May 7, 2019 by Gammaboy

[Gammaboy]

Had some time to chip away at some smaller jobs on saturday - connecting up the ignition switch was one of them... fuck, what a ballache!

Abandon hope, all ye who enter:

Needed to move a coil to get enough space to connect the ignition switch connecter up in the steering head - well, fuck, that turned into a major effort - the spacers for the coils are loose, so you have to hold them in place while slotting the bolt in - and then not drop anything while getting the nut on the bottom. Had to pull the coil back out more than once to pick up a spacer or nut dropped and hiding inside the headstock areas...

Pulled out a mullered helicoil on the seat unit mounts - they're a 3 diameter helicoil from factory, so wound 2 1.5D coils in to replicate. Luckily they'd only damaged the first turn of the insert, cleaned up perfectly when the tap went through.

 Removed the hoover hose and the rubber heat trap that kills the alternators on these while I was there. Had a bit of a shitty moment though, as I sprung the lower seat unit mount areas out to get it off the frame - heard a quite loud "Keeerack!". Inspection showed this:

It appears when SB6s went from Mk1 to Mk2, the "reinforced seat unit" was a mess of chopped strand plastered inside the seat area after the beautifully laid up glass (most of it) and carbon (cosmetic for the exposed carbon in the "Raspberry Ripple" paint jobs) cloth was already cured.... anyway, looks like I'll be grinding that out and replacing it with some divinycell foam core and some carbon uni and cloth. There's the start of a similar delamination on the other side too. Not looking forward to the mess/itchyness of this job.

Here's a pic showing the transition from the main layup to the reinforcing - have a suspicion the M in paint pen was  to indicate that the job had been done.

Aiming to get the carbs finished this week (just need to install the brass tubes and finish screwing it all back together), and get as many of the coolant hoses sorted as I can.

Speaking of which... the lower clamps on the little connector hoses between the cylinders are completely inaccessable. Have to remove the lower steel tubes to do it. Sigh. (You can also see the rubber mat I removed here)

[Captain Chaos]

On 5/7/2019 at 8:51 AM, Gammaboy said:

 

 

this pic sums up Bimota ownership perfectly

[SiBag]

On ‎5‎/‎7‎/‎2019 at 6:51 AM, Gammaboy said:

Also took the one piece fairing off - I'll do it a better way next time!

 

 

The one piece fairing is a lot easier to get on and off with an "Abba" stand, I haven't invested in one yet, nut its on the shopping list.

Worrying about the delamination on the seat unit. Ill have to check mine as its a MK-II (well a bitsa made out of what they found in the parts bins)

[Gammaboy]

9 hours ago, SiBag said:

made out of what they found in the parts bins

That describes pretty much all Bimotas though doesn't it?

 

[Gammaboy]

Got a few minutes to do some coolant hose work - mainly the hoses between the inlet stubs. The steel stubs aren't so great, and are discontinued by suzuki...

I've slotted them back in with fresh hose and o-rings, plan is to machine up replacements out of alloy and have them welded up - will slot the alloy ones in at some point down the road.

Looks like I have to drop the rad to get the rest of the coolant pipes out of the thing - there's a y branched chromed steel hard line that goes from the thermostat (under the headstock bracing) up to the rad filler neck, and across to the radiator. It's been pretty easy to work on otherwise...  well, apart from everything being stuffed into the headstock!

 

[Blubber]

if i selected the correct model (GSXR1100W model P /R ) and year ( 1995 ) CMSNL stocks them .

At €35 each i thinks it's cheaper too make something .

[Captain Chaos]

14 hours ago, Gammaboy said:

at some point down the road.

don't take this too literally. You never know with Italian vehicles.

 

[Dezza]

4 hours ago, Captain Chaos said:

don't take this too literally. You never know with Italian vehicles.

 

At least it's not on fire, like what happened with my last Italian vehicle.

[Gammaboy]

Got a chance to finish the carbs last night. Apart from the o-rings for the balancing tubes being the wrong size and having to scour the floors and benches for the old ones (found 5 out of 8 - some came from the 750 carbs I chopped up), it's all good. Of course I forgot to take a photo of the completed carbs (They just looks like some carbs). Bench balanced by shining a torch down the progression holes and looking for the edge of the throttle blade. Also fitted the stepped carb washers from @jonny1bump- I measured the needle protrusion with verniers before fitment, and again after and was surprised so see it was bang on the same - I'd assumed, looking at the washers, that they'd sit a little thicker than stock, but they're bang on - I didn't realise the stupid step in the slides was quite that tall!

Crap photo of the step in the slide - difficult to photograph - was shining a torch down it to try to get it to show up.

Stepped needle washers vs stock - you can clearly see why they cock off to one side and wear the emulsion tube oval.

Wife was happy to have her friand tray back. (I think she's used it maybe once?)

[Dezza]

What's a friand tray? Anyway, does that frame spar prevent the fitting of e.g. RS carbs to this engine when it's in this particular frame? I ask as MikuniOZ sell Rs's for a lot less than they cost here and it looks like they are just up the road from where you are

[SiBag]

7 hours ago, Dezza said:

What's a friand tray? Anyway, does that frame spar prevent the fitting of e.g. RS carbs to this engine when it's in this particular frame? I ask as MikuniOZ sell Rs's for a lot less than they cost here and it looks like they are just up the road from where you are

I know of some one who fitted fcr39's to their SB6. Not sure what he did for filters.

[jonny1bump]

15 hours ago, Gammaboy said:

Got a chance to finish the carbs last night. Apart from the o-rings for the balancing tubes being the wrong size and having to scour the floors and benches for the old ones (found 5 out of 8 - some came from the 750 carbs I chopped up), it's all good. Of course I forgot to take a photo of the completed carbs (They just looks like some carbs). Bench balanced by shining a torch down the progression holes and looking for the edge of the throttle blade. Also fitted the stepped carb washers from @jonny1bump- I measured the needle protrusion with verniers before fitment, and again after and was surprised so see it was bang on the same - I'd assumed, looking at the washers, that they'd sit a little thicker than stock, but they're bang on - I didn't realise the stupid step in the slides was quite that tall!

Crap photo of the step in the slide - difficult to photograph - was shining a torch down it to try to get it to show up.

Stepped needle washers vs stock - you can clearly see why they cock off to one side and wear the emulsion tube oval.

Wife was happy to have her friand tray back. (I think she's used it maybe once?)

I'm pleased your happy and worked out as they should. Looking at pic advantage you have the plastics not warn to start with, so very astute move.

The difficulty is replacing all worn stuff base setting lost really unless you renew tubes and needles.

 

Edited May 24, 2019 by jonny1bump

[Gammaboy]

On 5/24/2019 at 5:47 PM, Dezza said:

What's a friand tray? Anyway, does that frame spar prevent the fitting of e.g. RS carbs to this engine when it's in this particular frame? I ask as MikuniOZ sell Rs's for a lot less than they cost here and it looks like they are just up the road from where you are

It's like a muffin tray but the pockets are oval (works better for sitting needles and stuff in as it turns out!).

Spacing RSs for the WC1100 is one part of the problem, the other part is the clearance with the crossmember (And a lesser problem is the factory airbox supports the back of the fuel tank). To fit FCRs you need to pocket out the cross member for float bowl clearance, and grind the right hand side of the upper shock mount... I've also seen pics of an install of a set of TMRs on a SB7  - the shallower float bowls on the TMRs meant that for the SB7 the carb rubbers needed a wedge spacer under them to kick the the carbs up a little for clearance - depending on the difference in height between the 750 ports and the 1100 ports (What's the bet they're at exactly the same height from the deck - higher ports on the 750 head making up for the shorter barrels - wouldn't surprise me in the least), the TMRs *might* clear on an 1100... anyway, would need some mods to the airbox and rubbers, scratch built airbox or pods and a tank support to make it work.

On 5/25/2019 at 4:05 AM, jonny1bump said:

I'm pleased your happy and worked out as they should. Looking at pic advantage you have the plastics not warn to start with, so very astute move.

The difficulty is replacing all worn stuff base setting lost really unless you renew tubes and needles. 

  

The Carbs have only done 8,000ish KM - figured it was a good idea to try to keep them happy with the stepped washers. The washers that came out of my parts carbs have about a 1/2mm step worn in them!

Given the issues with fitting non CV carbs to these things, what I'd really like to find is a Yoshimura MJN setup for the CV carbs - they were available in the mid 90's apparently, but are super rare.

[Gammaboy]

So, I managed to get a solid slab of Saturday to work on this thing, which was great, but fuck it was kicking my arse for a chunk of it. I'd pulled all the coolant pipes out of it with the aim of replacing all the old fucked rubber... of course, there was gems like this, straight hose used to connect a bend... turns out the GSXR piece for the top of the rad was the perfect shape to use here.

Original hose was a bit crimped and fucked...

All the stuff on the side of the bike was a breeze, and 2 out of the 3 chromed bits polished back up nicely.

Could tell just by looking at it, that this one would be much harder work... and in fact the chrome was fucked, so it got a coat of black killrust.

Anyway, getting all the hoses/pipes/thermostat reinstalled and located right in and under the headstock was a bitch. Install with hose clamps loose, move shit around as best i could, fit radiator neck (the only bit bolted to the frame), refit radiator, check thermostat clearance, remove rad, tweak thermostat so the bypass hose sat right, refit rad, do up the hose clamps I could reach... Because I only had the one top hose, I used the straight piece intended for where I used the top hose - may wind up replacing with a top elbow, but seems to be ok. (Incidentally, because of part supecession, the length of hose used between the carbs is about 3 times the length used, so you only need to order one - the piece used across the front of the block is similarly over twice the necessary length). Also looks like this thing had a new rad fitted before being pulled off the road, which is nice.

Sat down and cut and oiled the new air filter - comically small for a 150hp bike, really. Installed the airbox to the carbs first to get everything lined up, then in with the filter:

While we're on this photo, note the location of the idle adjuster bracket, this will become important later...

Also knocked up and oiled a new filter for the carb vent filter thing, and drilled the housing for a zip tie to make up for the latchy bit being fucked. And bang, on with the carbs and airbox...

Should be able to just drop the tank on and it'll all sit bang on supported on the little rubber bits on the bottom, right?

Nope. Spent 15 minutes tryting to figure out what the fuck was going on - decided the venty filter thing attached to the cam cover was the culprit... pulled it off, nope, what the fuck. Why isn't the back of the airbox sitting down where it should either? Knew the float bowls are swapped between #2 & #3, and ground down a bit on #4 for clearance against the upper shock mount, but when I looked, there was 1/2-3/4" clearance - why would they bother? Something was definiteley stopping the carbs sitting down in the rubbers properly... and there it was. The idle adjuster. Whoever had been into the thing before me, had assembled the adjuster to the bowl the "Suzuki way" not the "Bimota way", so it fouled on that fucking crossmember! Carbs back out, flipped the bracket over, and bang, down they sit. See below - this is the "Bimota way". The "Suzuki way" has the adjuster hard in the corner of the crossmember.

Cool. But what about that fucking venty thing holding the tank up? Tried tweaking the bracket a little - nope, no chance. Udid the screw that held it to the bracket (which is a low head cap screw like Bimota uses *everywhere* on this thing - this should have been my flashing big red warning light!), and just tucked it under the mounting bracket - bam - tank fits. At this point, I'd messaged another SB6 owner who currently has all the bodywork off his, and he sent me a picture of his venty thing. Of course it's bolted to the wrong fucking side of the bracket. Bimota, you cunts. Seriously?

Anyway, his is about 100 frames newer than mine, and the crankcase breather runs quite differently (as does his plug leads - no two bikes the same huh?), which I'll probably copy when I redo my breather hose - which is about 1" too short to sit in the right spot for the tank to finally sit down completely.

Anyway, everything where it should be (apart from the breather hose)...

And the bottom of the tank, Carbied SRAD fuel tap sat in place (need to either convert it to dual outlet, use a t-piece or machine up a new top half without the dogleg and to put the outlets in the right spot)... Can see why it's so tight for clearance. And yes, the overflow tube needs replacing.

Spent some time cleaning it with a combination of carby cleaner and wax and grease remover. The wax and grease remover did an excellent job on bringing up the carbon guards and around the gauges, removing tape residue etc - it's actually in way better shape than I initially though... although I did discover that a bunch of the filth around the rear shock is the remains of the bump stop - which is completely gone. Sigh.

Tank sat on:

Next job is an oil change, sort out the fuel lines (and the fuel level switch), get the new batteries into it and kick it in the guts!

Then some fiberglass work, and some more cleaning.... by which point some of the parts i'm waiting on will hopefully have arrived.

 

Edited June 4, 2019 by Gammaboy

[Leblowski]

Awesome write up !

[bluedog59]

Bimota ownership is very similar to the Eric Morecambe/Andre Previn situation. You have all the right notes.......................

The tune is in there somewhere, you've just got to find it.

[SiBag]

Oh the joys of BIM ownership.

I must admit the SB6 without its clothes on if fugly.

Incidentally I have some weird K&N panel filter thats been cut about in my airbox, seem to fit OK and does the job.

I see you have the old stainless steel heat shield on the exhaust, there was a chap on the BIM forum doing some nice tasty carbon fibber versions for reasonable money. They do save a fair bit of weight.

[bluedog59]

Bike, I've had a couple and they can be equally frustrating and brilliant. I still have a late model YB and it is clear it is exactly the same chassis as their WSB racers. Adding all the extra bits to make it road legal have been done with the same focus, any servicing issues it causes are the owners problem.

[Gammaboy]

I spoke to P3 composites who did the heat shield, heel plates and frame protectors a little while ago - he doesn't do wet layup carbon anymore, and I don't think he has the moulds for the heat shield anymore either... anyway, I was planning on replacing or adding to the stainless heat shield with some of the better heat shield products that are available now.

Got part way through the oil change process last night, old oil drained (came out in pretty good shape), filter off, new filter on and drain plug back in, didn't do the fill though, need to source a bit of hose and funnel for filling through the cam cover breather. Might see if I can hunt down a SB6R filler neck at some point too.

Also started dummying up the little Lithium batteries - they're about 40mm shorter than the stock batteries, so looks like I'll be knocking up a platform for them to sit on so they're still clamped properly. Actually, come to think of it, I wonder if the overflow tank will fit under there? Spose I could fabricate an overflow tank to fit there if not.

[Gammaboy]

Well I finished filling it with oil - not really that bad a job - 6mm driver bit held in a 1/4" ring spanner to get the filler bung out from behind the frame rail, then a flexi rubber funnel thing to fill it (slowly).

So, about a week ago, I had a delivery of some bits that came from Denmark... Now, I know I said I was going to make my own seat, but I had the realisation that I really want to get this thing on the road sooner rather than later, so I grabbed one from the same guy I was getting the rear mudguard/brakelight mount/plate holder and rear sub-loom from. The photos he sent me of the carbon plate holder made it look pretty rough, with a chipped corner and the finish being a bit rough in general... but once I popped it out of the box and cleaned it up, and then hit it with some cut and polish, it came up pretty nicely. Seat was in pretty good shape too.

So, trimmed the bottom 1/2" or so off the plate holder and bolted it up. The I realised I needed to source the rubber isolators for mounting the tail light, so packed it up for the day....

The next night I realised I actually had a set of isolators attached to the *other* tail light that i had (it came from a DB3 with the short loom - had been intending to use it's connectors to make the tail light loom, but the complete one was cheaper than buying the 6 spools of wire and the terminals), so in went the isolators and on went the tail light...

Clearly, drilling the holes was an after lunch job... with a bottle of chianti forming a large part of the lunch...

Of course, I guess you should expect this shit on a "Hand Built" $35,000 motorcycle.. lol.

a few minutes with the dremel and a small sanding drum sorted it out. What this photo also exposed was the issue with the exhaust tips, which I've been struggling with for the last few days. Went back to the guys I bought it from, and borrowed the mufflers off their parts bike - nope, no significant difference. Suspect it's something in the front half of the system - appears to be pushing the front of the mufflers up hard against the bottom of the seat area,  resulting in the tips being hard against the bottom of the cutout...

Tonight's job is modifying the SRAD fuel tap to be dual outlet with 90* barbs to let me run the fuel lines the right way. If I'd realised the SRAD tap was going to be such a fuckaround (The guy who's used one previously wasn't using the stock airbox, which makes a massive difference in that you can actually run the fuel line out of the tap without issue), I'd have just bought a new OEM one (twice the price of a SRAD unit though, although, when you take into account the time i've wasted fucking around with it, the fittings and 1/8 bspt tap etc, it runs pretty close). Tomorrow should hopefully see me borrowing/swapping the headers for the parts bike set - *hopefully* that will sort the exhaust fitment issues.

I also finally used my mini sheet metal brake to make the platform for the batteries, and also knocked up the jumper cables that connect the batteries in parallel - this appears to be the one place so far where running the plumbing/wiring a different way to stock is actually a good idea. Of course, I forgot to take photos - will sort that out.

Edited June 19, 2019 by Gammaboy

[Gammaboy]

Ok, once again, there are photos I forgot to take... but, got some progress happening.

A quick photo of the batteries sitting on the platform with the link cables.

And the platform sitting in place. I will strip and repaint the front subframe at some point.

The tab sticking out of the subframe is for hanging the CDI off - standard Suzuki 1100 unit. Not sure if I'm going to just fit an advancer, or go to a Ignitech.

So, I'm still fucking around with exhaust fitment - the headers from the other bike made a tiny difference, and I can't be fucked swapping them back, but I *think* I have a plan now.

SRAD tap conversion - well the SRAD tap has provision in the casting for the outlet barb to be in one of three positions - plan was to fit a 90* elbow to the existing position (drilling/tapping to suit), and drilling and tapping one of the positions on the opposite side for the other elbow. Did that, fitted it up, and the hose routing from the "front" elbow sucks completely. Wound in a blanking plug, and tried the other spot. Not great, there's ~2mm clearance against the seat unit, so I'll grind it down a bit, but not sure i'll stick with this plan. I'll include a pic of the modded tap in the next update. May just say fuckit and buy a new OEM one, which I didn't know was available when I grabbed the SRAD tap... anyway, between that and the exhaust malarkey, I had the shits a bit.

So last night, i had ~30 minutes to spare, so I thought I'd whip the clutch master off and see how fucked it was, given that the piston was stuck in the bore at full travel. Good news was, the fluid in the lines and reservoir, while not great, was not utterly manky.... which was promising. So I removed the sheet metal nut on the pivot (discovering it was fitted upside down!), dropped the lever and pushrod out and tried to have a look - but the boot that protects everything is locked in place with a pressfit ring and wouldn't let me see anything. Put a thin allen key up the end to try to dislodge the piston. Nope.

So, violence it will be.

Two taps of the soft faced hammer and it was free. Movement really freed up with cycling it in and out a couple of times, and blowing in the banjo bolt end confirmed the feed port was clear... one thing left to do. Screwed it all back together, bled the master up, and then bled the slave. Slave bleeder access on these is renowned for being fucked. The bleeder itself is hiding behind the frame rail, only visible from the top with a torch. Managed to get an 8mm ring spanner onto it, cracked it open and then snaked my bleeder hose onto it. Pump hold pump hold pump hold... and we're bleeding. a couple of reservoir refills and all the air is out, tied the lever down, fucked around getting the bleeder tight, released the lever and gave it a go. Clutch is remarkably light, and the sprocket cover flex indicates it's working perfectly. Knocked it into gear, pulled the clutch in, and tried to turn the back wheel... and bam, movement. Clutch hydraulics work and the clutch pack isn't stuck. I'll take that as a win!

[Gammaboy]

Aaaaand the "OEM" tap is not an option - turns out it's a substitute unit that some guys use, doesn't look nearly man enough for the 1100 (Hell, I think they use two of these particular substitute taps to feed an aircooled ducati motor in the DB1).

Guess i'm sticking with the SRAD tap.