J30a V6 Bike Carby Engine Build

[Kakapo76]

Well guys and gals, decided to try the back to the future route with a new engine build. I picked up a J30a for $500 and had it shipped down to Rolleston. I have a couple of sets of 38mm Mikuni's that are going to be modified into a multi (6) carb set ITB style.

I have stripped the engine of all of the unnecessary gear (this weighed 23kg!  ) and by unnecessary I mean intake manifolds, runners, cast iron exhaust, EGR crap,  loom etc.

Obviously I need to build manifolds etc etc- will report on the net weight loss eventually.

The plan is to modify a Chevy v6 dizzy to mate up with the intake cam on the Honda- its got a nice bracket I can weld to the new dizzy and I will control spark with old school vacuum and mechanical advance. Just waiting for Amazon to deliver this.
 
I am going to arrange the carbs in a sort of cross flow style so there is a almost straight shot from the carb down the runner into the head. This will increase the height of the engine so will be faffing about trying to make it as tight as possible but still ok to work on.

Cooling will be closed loop with a HE.

So far the engine is proving to be as compact as my turbo toyota so am going to see if I can make it as light as possible and as simple as possible- Mohawk this is a work of Homage  I have been listening ....

I will track the build as per normal and am happy for any suggestions as this is mainly for fun-

The specs state that this particular model has 210 HP at 5500 and 246 torque at 4600 rpm This would make it similar to my turbo 1800- so will make a great comparison.

The Goals:

1. Do something I cant find documented on the net (Bike carby v6)
2. Make a small compact v6 that is so simple its almost reinventing the wheel.
3. See if a modded Colorado can handle a small v6 without spitting the dummy.
4. Make 4 cylinder turbo hp, naturally aspirated with the same or less weight all up.
5. Fit it into my existing boat for comparative hooning.
6. Last but not least make a nasty sounding ITB roaring , exhaust snarling v6 like Honda never did- I am thinking v6 Jaguar crackle and

[Jeff B]

I hope you didn't order the dizzy for the odd fire v6 chev...(the older one 90 deg without balance shaft)

[Jeff B]

Is that the old 1998ish model j30? That had dizzy already?
I picked up this later model one for $100 and will do similar project (one day) but will leave injected
 
Have a Saco impeller (212 turbo style) and a longer wear ring and spacer for Hamilton single stage that shouldatch nicely

[Jimmy Jet]

Cool project. Will be following. Vacuum advance is redundant in a marine engine situation. Go full mechanical if you can or disable the vac.

[Kakapo76]

Hi Jimmy

I misspoke- checked my Amazon account and this is the one I ordered.

https://www.amazon.com/gp/product/B06VV49N6N/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I wanted an internal coil as well- the goal is to cut down on everything to a bare minimum- it was cheap so hopefully will do the job. I can block off the vacuum port easily.

[Kakapo76]

Hi Jeff,

Yes, mine is the older model with the dizzy but it was electronically controlled so no advance so far as I can tell? I wanted the j30a4 to get the integrated exhaust port heads but down here we are getting absolutely bent over on price- Local Honda wrecker wanted $1800 for a j35 and $1500 for a j30 

This will be a bit of a Frankenstein - it should be fun though.

[Jeff B]

The later j30a4 has caps in back of heads where a dizzy can be attached but I don't think the camshaft has slot or drive for dizzy like the older putt bomb j30 does?
What are the carbs off? Yamaha?

[Kakapo76]

Yep mine has the slotted camshaft- the a4 doesn't, so that would mean pulling the cam out and machining a cam, another level of complication I want to avoid and the main reason I went for the putz version. Carbs off a gsxr 750.

I looked at a heap of 4age builds and while lots of people went with R1 carbs (40mm) there was a lot running off r6 carbs (36 mm) and the only advantage to the bigger carb was performance at very high rpm-8k plus, so my logic dictated that the smaller carb would be fine because I intend to top out at peak hp 5500 rpm, I also believe the slightly smaller carb will better behave at low speed.

[mohawk]

Sorry i asked on your other thread..... are you sure that distributor rotates the right direction for mounting off the back of the head ?

[Jimmy Jet]

I think Mohawk is right. The cam is rotating anti-clockwise at the back of the head and Chev distributors rotate clockwise. The pickup will probably work but I don't think the advance will. Well spotted Mohawk.

[Kakapo76]

Bollocks! That's a pain if you are right- good spotting indeed- I ordered it without the engine in front of me and didn't think about it at all-

Any suggestions as to a Dizzy anyone that turns in the correct direction? I don't really want to buy a race dizzy so anything from a six cylinder works for me.

[mohawk]

Ford or jeep i think... but will need too shorten them overall

[mohawk]

Triggering should be ok but advance will be back too front.... might be able too flip over weight plate but not ideal

[Jimmy Jet]

A VERY brief search shows the Ford 3.8 V6 is counter-clockwise. Triple check this info. Pertronix are decent distributors but not sure if they do one for that engine.

[mohawk]

Look at running it off the front or toothed belt on the drive block if your stuck. 
Jeff belt drove one on his second build but not my cup of tea