Gamma's Eternal Project, VJ23 powered Mito.

[Gammaboy]

I figure this actually covers all of the bases in this forum - It's a water cooled, 2 stroke V-twin, stuffed into a bike that was a single. The engine is Suzuki, so hopefully there's sufficient OSS content?

So, back in 2001 I bought a Mito - 1995, 7 speed 125, TMX35 carb put a Jolly Moto pipe on it and rode the wheels off it on my Ls untill it shat a big end riding to work one day. Was trying to figure out what to do with it, briefly contemplated putting the engine out of my RG500 in it, contemplated a big single, and then one day saw an add for a VJ23 RGV motor for sale for $400 (at the time, it was about 150Quid), no pipes, no CDi, no starter, but complete with carbs etc. Now at the time I desired a VJ23, but then, as now, no-one complianced them for road use here. The one road going VJ23 in the country was a private import. Being an engineery type, I figured it shouldn't be too hard to sort, and in no time the VJ23 motor was in my shed. It was followed by a race kit loom and CDI, jet set, and a set of Vega Sports Race pipes that came via Stu Jones. I sorted some billet engine mounts and a billet ride height adjuster, slung it in, and then it sat for a while - My RG500 spat 2nd gear out the back of the cases, so sorting that became a priority.

Notice the yellow skipping rope for exhaust hangers, and the rags stuffed in the Gamma's cassete gearbox hole:

 

Shit everywhere:

Wheels were shiny once.

Got exhaust hangers welded to the mounting plate for the back of the cases (mito has no rear engine mounts, uses the swingarm pivot instead). I then moved 3500km and it sat in the shed at my new place for years, picked up a starter for it during this period. Wheels were still shiny at that point..

Eventually I dragged it to my work, and started working on it after hours - while also building the Katana, and a race car (too many fucking projects). While it was at work, I sorted the exhaust hangers (CNC'd by our CNC guy), wiring (merging the race kit loom and the Mito loom), throttle, clutch and choke cables and got it running on premix, and pod filters. Straightened the dog leg out of the Mito side stand in a press, then modified the mounting bracket to get it clear of the pipes and the shift linkage, meaning it could finally stand without a paddock stand.

Took it home, where it sat for a while while I restored my Alfa and figured out getting the oil pump to work without the bypass solenoids - basically frankensteined bits of the mito pump into the VJ23 pump and connected it to the throttle cable. Yeah, I need to replace some of the bolts that are going brown. Sorted out an oil tank that fits up in the headstock too - the original Mito one was no good due to the integrated coolant reservoir not working with VJ23 plumbing.

Got the thing up and running, registered and mod plated just before my first Daughter was born in 2013... still on pod filters. Rode it around the block a couple of times, and to the department of transport and back. Went pretty well, not that I put a lot of miles on it.

Decided to build a carbon airbox for it while I was off on paternity leave, using a RM450 filter in the airbox lid. Carbon airbox came uppretty nicely, not sure why I bought gold Dzus fastners - sleep deprivation maybe?

Due to a fuckup it actually stopped one of the carbs seating properly - combined with a mod that i added to the wiring (ignition key originally didn't kill power to the CDI, only the killswitch did. put a solid state relay in to do it), meant that it wouldn't start, and due to the relay dropping in and out with low voltage, I burned a capacitor in the CDI. Cue pushing the thing to the back of the shed for a while (again!). At some point I decided to figure out how to slot an upgraded single spring for a Mk1 Aprilia RS250 into the Marzocchi forks, at which point i discovered that morons had been at the forks at some point, and they were fucked. Cue further dejection. Eventually found a likely pair of forks to put into it - a pair of WPs off a Zane Laverda 650 Formula. The WP forks slotted straight into the Mito lower triples, but the uppers needed boring out to 54mm, which meant that the integrated clip on bars had to be abandoned. A set of clip ons were sourced, a mate bored the triples and bored the fork bottoms to take the Mito axle (25mm vs the Laverda's 17mm), and the forks wandered off down to Suspensionsmith in NSW to be chopped down 40mm in length (without losing any travel), resprung and revalved to suit. The brake caliper mounting points were chopped back to allow the brembo to line back up, and once they came back from rebuilding, it all slotted together nicely. Back early on in the process, I bought a Gurls blouse RS125 Ohlins - I alternated between planning to fit it to the RG and the Mito, so wound up with bottom fittings machined up to suit both. I put a R6 shock in the RG in the end, and resprung the Ohlins to suit the Mito + my weight - being that I'm 15kg heavier than when I started riding the Mito. Last week I put the shock back into the bike to set the preload and figure out the res hose routing prior to shipping it down to Suspensionsmith for revalve and rebuild. Over the weekend, I decided to revisit the fairing cut lines, and trimmed the front guard to work on the forks...

And so here we are:

Need to sort out mounting for the front guard - either plastic weld a new mounting point in between the existing one and the bottom of the guard, or fab up a stay from the caliper mounting arms to the back of the guard. About a year ago I bought a Zeeltronic CDI, and a handfull of Deutsch motorsport connectors to wire it in. Hate wiring - still haven't gotten around to it. Also still have to drop the motor to get the airbox out for modification - probably should have gone with an early plan that was to mount the airbox to the reedblocks and basically lay the carbon straight against the cases - would have avoided that problem. Also planning on plumbing in water injection into the pipes to broaden the band of useable power. Anyway - the goal is 130kg with a half tank, ~70ish crank hp (depending on whose dyno, given a certain well known, well sorted VJ23 does low 60's at the back tyre). If the single disc isn't up to it, I've got a set of Mk 1 Aprilia RS250 wheels that will go in, giving me a 4.5 on the rear, and i'll fit up a second brembo and 320mm disc (and suitable master) - Ducati 916 spec brakes on a 130kg 250 is probably overkill though.

Edited December 14, 2017 by Gammaboy
fixed pics

[Maggotbreath]

Awesome!

[Swiss Toni]

+1. 

[Gammaboy]

Must get around to rehosting the pics. Got the Zeel wired in yesterday, which is major progress - only been sitting around for ~15 months! Need ot do a couple of other tweaks to the loom, run some extra wires for future proofing and the map selection switches, then drop motor, mod airbox (again), put it back together and wrap the loom. There's a few other little things to do once that's done, but getting closer.

 

[Gammaboy]

Have temporarily bodged the images back into functioning.

Dropped motor on the weekend, discovered the airbox clearance was actually ok.

Messed around with some jetting changes the other night to copy the jetting setup that some others are running (Kit needles, different solenoid air setup with no restrictor in the line), and randomly discovered that the shorty bellmouths that I'd just taken off the RS36s on the Kat fit the Mikunis on the VJ23. Will grab a photo at some point.

To do list is slowly getting shorter.

Also dummied up some brackets for the front guard - dogleg one is the current line of thinking.

 

Edited August 4, 2017 by Gammaboy

[Mar71n]

Just read this through, wow.

[Gammaboy]

Dummied some Mikuni bellmouths onto the VJ23 carbs:

 

[Gammaboy]

So, this is still happening - finally got the longer res hose sorted, and shock went off to the guy who did the forks last week (should arrive today actually) for some magic.

Had some shed time with the Mito last weekend - after spending some time macking up the template for the big one piece semi-complex alloy bracket to hold up the back of the guard, I was sat there staring at it and had a realisation of how easily I could use both mounting holes on the front of the forks, and use some 3" long bits chopped out of a already folded bit of sheet alloy sitting in my scrap box... anyway, will try to finish that install this week and snap some pics.

Threw an almost new 998 front disc on it too - the stocker measured out at 2.5mm thick! Even with the alloy centre, the new disc weighs as much as the worn out 916 style disc that has a stainless centre!

Once the shock is back, I need to sort the velocity stacks, modify the heads to sort the squish (deepen chamber and skim the head), wrap the loom and sort the throttle cable, then throw some tyres at it and it's ready to rock...

Edited September 10, 2017 by Gammaboy

[Gammaboy]

Orrite, a couple of sets of Alpha 13 scrubs are on their way, so that's tyres sorted.

Shock arrived back from rebuild during the week, it's mounted up, just need to tighten up the hose clamps for the reservoir mounting, and I also got 1/2 an hour in the shed to finish up the mounting of the front guard brackets.

Ignore the black anodised button heads, I'll sort something better for the actual fitup.

Bracket looks like so:

and will be sikaflexed and riveted to the guard like so:

It'll make fitting/removing the front guard a minor pain, but how often do you do that?

Anyway, much neater than the huge bridge bracket i'd dummied up for the back of the guard.

[Gammaboy]

Ok, some minor progress.

I picked up an Aprilia RSV4 radiator (lovely thing, tapered and curved) to investigate slotting it in for extra cooling capacity, unfortunately at this stage it looks like a ballache to modify and fit - because it has reduced curvature compared to the original rad, there's a tonne of chopping required. Luckily it was lightly damaged and cheap.

So I reverted to the original plan, and looked at a bunch of different oil coolers - annoying the Ducati ones that looked good for the job had odd end tanks, but the RSV4 oil cooler turned out to be spot on.

It has raised a question of plumbing however. I have 2 Mito rads - one is bog stock, and is a dual pass rad. The other has been modified to single pass by knocking out the divider plate, and fitting a outlet on the other end. The stock one is pictured here with the oil cooler as a mock up.

So, the question I'm facing, is do I plumb the sub radiator in in parallel with the modified rad, making it one big single pass system, or do I plumb it in as a triple pass system?

[bluedog59]

I would plumb it so it flows hot into both rads. My thinking is that you will get quicker flow into a bigger core area ( where it can start to be cooled, 2 access points rather than 1) and it will slow the flow through the rad, giving it more time to "heat exchange".   

[Gammaboy]

1 hour ago, bluedog59 said:

I would plumb it so it flows hot into both rads. My thinking is that you will get quicker flow into a bigger core area ( where it can start to be cooled, 2 access points rather than 1) and it will slow the flow through the rad, giving it more time to "heat exchange".   

Yeah - i posted about this on another forum, and another poster reminded me about the whole heat transfer being driven by the temperature delta - which is something I of course knew cos I used it to do some back of the envelope capacity calculations for the RSV4 rad on a warm day here - you can shed a fuckload more heat when the hotside is 100* than when it's 55* - particularly when ambient temps are 30* (Delta is 70 degrees vs 25 degrees)... however, the more i think about it, the more i'm convinced the only difference the flow paths will make is the flowrate through any given tube in the cores - the 3 pass will result in a higher coolant pressure drop across the core, and resulting higher pressure at the cylinder heads which may prevent steam bubble formation, but ultimately a lower flow rate across the system.

I'm convinced the boring shite I'm doing at work at the moment is removing my ability to think like an engineer.

[Blubber]

Can't you fit a thermostat to switch on the lower radiator?

Give you extra cooling when needed, but quicker warm up when cold.

[bernardo]

The heat dispersed is based on the log mean temperature difference, which depends on the direction of travel of the cooling and the cooled fluids. There's lots of calculators on the net. I used to be able do do this stuff from first principles but my brain  hurts even thinking about it.

[Gammaboy]

15 hours ago, Blubber said:

Can't you fit a thermostat to switch on the lower radiator?

Give you extra cooling when needed, but quicker warm up when cold.

Extra weight and unecessary bullshit to add to the bike.

14 hours ago, bernardo said:

The heat dispersed is based on the log mean temperature difference, which depends on the direction of travel of the cooling and the cooled fluids. There's lots of calculators on the net. I used to be able do do this stuff from first principles but my brain  hurts even thinking about it.

Yeah, I used to be able to do it from first principles too, but what we term multi pass in bike and car radiators isn't multipass in the terms of classical heat exchanger design - classical heat exhanger design would place the passes stacked in the direction of cooling air flow, so each core sees hotter air as it travels through. The reality is that both are single pass cross flow heat exchangers of equal area, the difference is just the cross section and local velocity of the coolant.

The more I look at the oil cooler, the more I think I should have bought a Panigale bottom rad to cut down... might investigate if cutting down the RSV4 rad and putting it on the bottom of the modified stock rad would work too. The oil cooler has much larger passages, more wall thickness everywhere and wider tube pitch vs a real radiator...

[Gammaboy]

Rough dummy up of the RSV4 rad sitting behind the mito rad so that it's at the same height as the Oil cooler.... Might be a goer - winds up as more rad than just the RSV4 unit.

Edited April 13, 2018 by Gammaboy

[Gammaboy]

A quick dummy up on the bike last night. Need to take to the fairing with the grinder and take a couple of quick measurements, but it looks like I might just stick with the oil cooler core.

 

[Gammaboy]

After 4 evenings of straightening fins and cleaning the junk (fine gravel and rubber) out of the RSV4 oil cooler, and attacking the Mito fairing with the grinder, I have a solidified plan.

Cut/bend bracket to hang the cooler from the bottom of the main rad using OEM rubber mounts (which will annoyingly blank some airflow to the upper rad), cut/bend bracket to mount to the lower cylinder head and steady the bottom of the cooler, add inlet/outlet to the cooler and outlet to the rad, use a Y piece on the cooler outlet to run to the pump. Have also figured the thermostat/filler neck re-work up at the top end, that's just waiting on the weld on filler neck to show up. I'll need to heat the fairing a little to soften it and flatten where the end tanks of the RSV4 cooler go, but that's easy as. I have to mount the cooler backwards, as the bottom mount fouls the bottom cylinders plug otherwise.  I also need to knock up a baffle to stop airflow disappearing between the coolers.

 

[Gammaboy]

So, progress has been stalled while I wait for a mate to sort the laser cut piece for the radiator hanger, and while other stuff (kids mainly) have chewed up my free time... however I've started getting back into it again - managed to get some lathe time the other day to start making the holder for the heads so I can skim them in the lathe to set the squish and machine the chamber to get the compression right, and last night sat down with the wiring loom and chased through 2 wiring diagrams, the Cagiva one (which is the most infuriating thing to use - instead of colours it has numbers, which you then have to cross reference - on a different page!) , and the VJ23 one, which is a) for the road loom, not the race loom i'm using, and b, it's in Japanese... luckily, i remembered the google translate app on the phone does live translation of text via the camera. Anyway, picked up an error I'd made 6 months ago (last time I looked at the loom), which if I'd gone through with I would have blown a bunch of time wondering why there was no ECU power, and figured out the last 2 connections that had been bugging me, so hopefully I'll sort that this week.

Just need to finish the head holder and centering piece, machine a couple of barbs for the radiator connections, get the bracket and barbs welded up, skim the heads and then I can screw it all back together...

[Gammaboy]

More wiring last night, mostly unfucking some stupid layout stuff i did when I first blended the looms 8-10 years ago - like I had this wierd loop running off the side of the loom that came back into the main loom 6" further along - I did this because I didn't want to extend the TPS wiring, but when I built the airbox, I grafted on much longer TPS wires from the damaged road loom I had... so I shortened 2 wires, relocated the connector for the right hand switch block, and now the loop is gone. Now I just need to shorten the powervalve motor wiring that I'd looped up at the same time - the race kit loom has enough length to put the powervalves up where the roadbike's headlight lives, so it's about 18" too long!

[Gammaboy]

So, wirings pretty much done, need to refit it and just check everything before wrapping it all up. Have managed to get some lathe time, finished the head holding fixture so I can set the squish and chamber volumes... Also had the laser cut blanks for the sub radiator mount show up - first one I didn't quite get the bends in the right spot, second one was bang on. Have also turned up some of the new spigots for plumbing in the sub rad. Just need to finish the custom thermostat housing bits, and get it all welded up.

Getting closer....

[Gammaboy]

Managed to get a little workshop time, machined the new thermostat housing top (conical bit) and finished up the lower housing, and modded the y piece to fit... Just need to get the filler neck and outlet barb welded to the upper, the y piece welded, and the radiator barbs welded... And trim the excess flange on the upper. Lump of 3" bar stock to show how the thermostat housings started... so much fucking swarf.

[Gammaboy]

Figured I should write a list of shit to do somewhere, if i write it down it'll be easier to work through.

necessary purchases:

1) Oil solenoid set (unless i figure out repairing a damaged barb) and oil lines

2) New front brakeline

3) Oil pump (if I fuck up the barbs swapping them back)

4) Oil tank (and cap and sensor if I can use the Tyga one)

5) Welding time

6) fasteners for front guard etc.

7) battery

 

Things to do:

1) Swap barbs back across to unmodified oil pump

2) Mount oil solenoids and plumb it all in.

3) Make lower mount for sub radiator

4) Skim heads and adjust chamber volume.

5) Finish coolant barbs, get radiators/thermostat/Ypiece welded.

6) Sort moving oil tank (again!) - possibly use Tyga oil tank - may include moving battery mounting.

7) Shorten Clutch Cable

8) Sort throttle cables

9) modify airbox/move air solenoids

10) new front brake line, fit new pads

11) Rebuild/replace rear master

12) Finish mounting front guard

Edited September 20, 2018 by Gammaboy

[Captain Chaos]

so it's almost done

[Gammaboy]

lol. Yeah, I just need to get my shit together.

Currently losing most of my time to renovations at the moment though.