Japanese Import 650 Maxim, '81

K-moe, my mikunis look a little wider, 39.9mm in fact. They did look like they were stretching the maifolds a little, so We have found the first issue with these. Can you confirm 38.1 for me please? I'm contemplating machining these down, if not exactly to Hitachi 32 dimensions, at least close to it, and I have to be certain (well as certain as a cast body can allow I guess?)
Oh, and if it's not asking too much, the depth (or width if you like) of the mounting from front face to shoulder.
Thanks

 

I can confirm the diameter is as written. The mounting depth is registered by the retaining groove. There is a rib of material inside of the boot that engages the groove. I measured the groove setback from the face of the carb outlet to the midpoint of the groove.

 

Sorry, I wasn't being clear. By front face to shoulder I meant the extreme point of the mounting, to the carb body, just in case the Hitachi is longer here, and I need to make added allowance. Ultimately I should fetch one of the manifolds home to do this, job for tomorrow I guess.

 

The distance from the face of the bore to the nearest part of the carb body is 14.33 mm (+/- ~0.3mm. I just had time to take a quick measure, so it might be off by a tad).

 

Plus or minus .3 will do me k-moe, thanks. I've stripped one carb set down to nothing (the gummed up ones which will eventually go on the bike), the other set I kept as a rack, in the process of rebuilding these to try on the bike. Two sets means I have pretty much got a good set, the water filled set had a lot more miles on them, and suffered from a range of issues, but should be fine using bits from the other set - things like the float valves, diapgragms, float chambers.
Once the rh switch comes I'll have a go at firing it up.

 

As in other post, cranked it over today, ordered coils which didn't arrive, so job for next week.
Quick question kmoe - do you know if the mikuni and hitachi are the same diameter at the inlet? There's a set of - oo, what are they called, rubber adaptors? Between the carbs and airbox on ebay.

 

That I do not know. I don't have any Mikuni carbs on hand.

 

Ok, could you take a calliper to your Hitachis and let me know what diameter they are? Much thanks. I'll take a chance on length, there seems enough adjustment in the airbox.

 

There probably isn't as much 'give' as you think. The air box 'boots' have a lip each side to secure them in the box If you're lucky you might be able to shift the box for/aft a few mm.

 

Well it's not certain, but it looks like this japanese spec was a Midnight Maxim - the clinchers would seem to be the stanchion covers between the upper and lower fork trees. I had previously noted and ignored as of not any consequence the black rear footpeg mounts with gold paint inlay, black fork bodies, black mudguard, gold swingarm bearing covers.
I guess the question is, does this change anything re my rebuild? Do I carry on with the flat bars, seat and moving the footpegs back, or is this model one that should be restored to original? This will mean some welding since the rear frame section has been hacked off by the PO, and to be honest would not give me the bike I wanted when I bought it.
Oh, it says nothing about "midnight maxim" on the registration document, but given it was a Jap import this probably shouldn't suprise anyone right?
Also forgot about the black pipes and gold wheels and disc centres.

 

Midnight Maxims are quite desirable in original condition, and quite uncommon, even in the U.S.

 

Yay!
It runs!
Fitted the new coils, the rebuilt (but not really church cleaned 600 Mikunis (no filters), 600 rh control switch and my fuel can rig. At first crank she fired up, ran a bit fast, but after a few tweaks it ran very well. So well that I filled the original tank, connected it up and took the midnight for a spin around the works.
Admittedly a fairly careful spin (no front brakes and very little rear), but on the uphill section gave it some beans and it fairly flew.
So now I have to:-
Order rear brake shoes, front pads, tyres (do I change the rear wheel for a seca?), handlebars with grips and bar end mirrors, headlight, rear brake lever, seat hoop, head bearings.
Then I need to make or buy:-
Seat, footpegs and linkages, rear mudguard, number plate mount, stop and tail light, indicators.
Need to strip and rebuild:-
Cam cover to check cam chain and valve clearances, brakes, wheelbearings, the mikunis that have been to church need machining to fit the inlet manifolds, head bearings, front dampers, rear units as far as possible.
Not much to do then...
Still grinning though

 

Good result! Enjoy the rest of your resto!

 

Thanks, made a detailed list of to do's and to get's today, its a long one. Hopefully I can get most stuff this side of the pond so don't have to pay import taxes and freight and vat...
Front end, carbs, seat, footpegs, rear end will be the order, I think.
Still not sure whethero kick the seca rear wheel idea into touch. Anyone done this?