Muncie

As a bonus was talking to a mate about building the drive setup for this how i was going to use chain etc..... he goes nah that'll be shit use these, so will be rolling a 30mm cog belt as a primary drive hmmm wonder if i can get them to sing in a high C ! Some assembly required but ive now got access to a lathe at work so will be a piece of cake. Oh and also access to a tube bender so the frame should be decent looking. Have been looking to see if i can run any of my toys in the junior dragster classes at Meremere Dragway. Its a possibility but there's specs to build too more reading needed and im probably too old which means handing over to my kids...... yeah nah maybe will have to see what this handles like.

So no photos for this update but a few weeks back i took too the inlet manifold with the die grinder as it was only designed for a 30mm carb, opened that up till there was no more dags or wall thickness Picked Up some new Ngk BP6ES plugs threw those in filled up with E85 and took it for a hoon under cover of darkness (remember those headlights?) In short goes fucking well power band is now a bit further up so less sketchy getting moving can roll in to a wheely really easy without nearly dying. Amazingly even with the massive carb and electric pump that could feed a v8 it feels like it is getting starvation eg 50-60ks it goes flat if you back off and then nail it again it zings straight through to 80ks then dies off again. Will see what i can do to help free up the fuel lines as there is a few small areas. Go ped tanks have tiny fuel pickups. Fuel consumption is pretty up there did 10k ride last night and used a litre. Oh and back tyre threw a chunk of rubber off where petrol had dripped on it think this time I'll try get a 10" wheel under it seems to be just about enough room under there.

Looks like a flash as goped house to me!

So this thing has been pretty rock solid and has just taken abuse for hours..... until my daughter whos a bit lighter and a bit more fearless got on it and held it at max rpm for about 3 minutes till it started to hop so bad i called it. Nothing major big crack across engine mount after a sleeve shifted on tyre after got almost gooey. Zapped it up good to go again. My boy has drifts sorted now! Sorry about sideways vid......

Hope you have a rear disc on order? Do fuck all for slowing down but wonders for saving a case of the wobbles while on one wheel.

Would highly recommend stripping the carb down and scrubbing everything with soapy water and a dish scouring pad inside (the green type you would use on non stick pans) Everything will be full of soot and grit the float chamber will probably have hard lumps of lead and varnish in it. I do mine in a bucket while watching tv.... rinse with meths and leave to dry for a bit. Just did one today.

Hmm yup if it lives about here i can refit the factory airbox holesaw a place for carb to poke its head out and get to the tuning nut by hand. If only i had a holesaw set or a laser cutter to make some flanges..... Only 30cm of inlet plumbing should make it punchy!

Great thing now is im back to using a blowthrough configuration. On E85 this carb would ice up for sure my scooter grows ice on the inlet manifold just on a 50/50 mix. So blowing nice warm air from the turbo through will produce a cooling effect from evaporating the fuel hopefully negating a need for an intercooler. I also wont need to worry about feeding fuel through the turbo and grenading that under my ass if it backfires through inlet.

The origins of these carbs are from a Triumph 2.5tc the later shape that got a longer manifold. Could never get them to run right they would be fine puttering round but wind the car out you would just hit the wall engine would loose power. 20 years later figured out why! Tiny piece of swarf was rattling around in between the ferrules of the line that connects the jet to the float bowl.

Built an SU carb today. This is the one that i put through the ultrasonic cleaner at work its looking pretty mint now. @sr2 was kind enough to donate the the float chamber i was missing, that got a refurb and assembled and fitted to carb. Also happens to have a 4mm pushlock for a boost reference. Boom complete carb!

Did some more mucking around with this today found engine to be struggling against the closed position of the VGT on the turbo, small tweak to the stop and its way happier it was affecting it at idle and choking it when revved. and it actually spools up properly now with no load it spools and blasts copious amounts of air at about 3200-3500 rpm then hits the 3800rpm limiter. Hoping with load that'll come on earlier and a actuator will keep it there by variation of the vanes angle. The actuator on the turbo runs on a vaccum signal not pressure so hopefully i just need to swap that out with a conventional pressurised wastegate actuator. Ignition wise theres a few things i can do to ditch the rev limiter, 1. switch to the single cylinder coils to maintain CDI (Expensive) 2. switch to the earlier non CDI v-twin coils like on my other engine 3. Build something custom, probably best option as I'll need different timing to a naturally aspirated engine to get the best out of it. Could maybe build a speeduino or megasquirt and just run ignition only and have option for EFI at a later date.

Ive also quit working on spacecraft recently and now work for a tool company so should be able to get my hands on all the tools i need to up my game shortly. Last employer might explain why ive gone so overkill on my scooter and this thing...... ive seen some things! Inspiring.

Done some research and can get dual V belt drive pulleys 1 for engine and 1 for a jackshaft for about $40 did think about cog belts but alignment and lifespan might suck.... This thing is getting built with rulers string and an eyecrometer although yuck i think it'll be a good stop gap to just get it working. Will then run a 3/4 jackshaft so i can fit normal go kart centrifugal clutches probably 2 of them 2 sprockets and chains should be bullet proof enough. My other v twin hasn't killed a clutch yet doesn't slip despite been fed 25+hp and ive given it an utter pasting for 2 years and only been rated to 11hp, it does kill chains though. This should work ok and belts will stop the v twin from hammering the chain. Talk me out of it??

Finally got around to doing an oil drain from turbo back in to sump today its just into an existing oil drain as there is 2 on these motors, will see if theres enough flow but so far turbos not smoking and spins for about 30 seconds after engine stops. Ive also rigged up an oil pressure gauge as before i knew there was some pressure but not if it dropped off with revs feeding turbo. It maintains about 45-50 psi so bang on. Ran it for about 30 minutes today to see if anything leaked oil and to really get the turbo nice and heat soaked. It can move plenty of air thats for sure! Especially banging the limiter. Now to save coin buy parts and get it done about $600 would have it moving under its own power.

@Kimjon if you pass your wire through a tampon it scrubs the dust and some oxidation off the wire before it gets into your rollers and makes them skid. Old panel beater Barry trick that seems to work.

Fuck it im painting this purple aliexpress special is on its way. I have a stash of paint i bought for a car ages ago that i gave up on may as well use it. Can blow this thing apart in an hour now, all the wiring is on plugs and comes away with the engine or front forks. @Kimjon you still want to swap fuel tanks?

Did quite a lot today pulled all the control cables out re did all the wiring, got the kill switch to go and tidied up the headlight wiring a bit more added some more earths. Realized frame was bare so whipped out grinder buzzed off all the stray blobs of weld sanded her back and blew a fresh coat of zinc over it. Left it in sun for an hour then blitzed it with some gun metal grey, weird seeing this all glossy and clean the scars from when i crashed it are gone. I think its kind of finished......

Rumour has it the rev limit is built in to the coils wonder if some coil on plug arrangement can be done... Apparently gx390 coils are the same but do not have the rev limit functionality, they annoyingly are quite pricey too from NR Racing.

Something i have in my head that wont affect getting it running but will be a pain in the ass is the electronic rev limiter that kicks in at 3800-4000 rpm, thats right in the fun zone! If anyone is a small engine guru and knows how to disable it let me know? It should do 5000rpm with no issues with the turbo and big carby probably more so i want to sort it.

Unbolted all the factory Honda governor and throttle gear today ive already gutted the governor out but left the arm on the block as was a pig to get out and would leave a hole for oil to leak from. Anyway shoved engine forward because i could and realized the seat position is mint! Will need guards around exhaust but to be fair heatwrap and a simple tube cover will be enough to stop your leg getting burned. Chain or belt drive will need guarding too but i could comfortably ride this.

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Engine can come forward a good 100mm easy but seat position isn't terrible as it is.

Decided to have a play with the turbo back to the inlet manifold of engine. It occurred to me how much extra work it will be to have it blow through. So dummied it all up draw through and stood back..... makes everything so much easier think I'll just do it. Just going to do 2x 90 degree bends off inlet manifold as its 2 barrel and straight in to the 2" tube.

Something like a 3 piston air con pump converted to run as 2 stroke would be cool and real compact. https://hackaday.com/2019/12/04/building-an-engine-with-an-a-c-compressor/ You could actually build a grunter with your 2 stroke knowledge though.

Soldered the lot together went for a light hoon and had a weird lack of revs available snipped diode out, back to normal. Have ordered 2 more diodes but at least the wiring is all done, have bunged a generic kill switch on bars for now.