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Putting back together a 400 thats been apart for a while and ended up here when it seemed like I was on the stick with only appx 800ml installed but 1500 is clearly marked on the case. 800 is appx what came out of it.

I compared the 77 400 stick with a 75 350 stick and they appear to be interchangeable, both plastic tops, same threads.

400 110mm oal 107mm to low 97mm to hi

350 110mm oal 107mm to low 96mm to hi

All of these are measured from the bottom, internal, flat surface of the cap. Cheap tape measure however but should be close.

Of interest may be that the 400 was likely running with only 800ml, we drained and saved it, for quite a while, maybe its whole life, 11.7k mi. No damage or wear to the internals was noted while it was apart. Bike performed perfectly until the left seal failed.

I will be draining the 350 to double check it and satisfy my curiosity.

This is not a recommendation to run the oil low of course but may ease your mind if you find one low. I say that if Chuck is running 1500ml, run 1500.

Jebus, now we cant trust the arrows? This is going to be as bad as the reversed slides thing, and that damn choke tube:)

Yup, always a special experience to ride a two stroke.  Younger guys that have ridden any of my typically stockish bikes always return with a smile.  Even my cb350 obsessed buddy loves the 400 but is always suprised by the lack of engine braking.

+1, be happy it was the side that doesnt blow things up.  I'm in the same predicament but left side.  Ignore advise given on this board at your own peril:)

Buy an old cheap Ninja 250 or a scooter if you dont have anything to ride in the mean time, yeah, I know its not the same, at all:)

I think there is a good walkthrough around here with pics for either the 350 or 300.  I have something saved, somewhere, and assume it was from here.

I'm not one for choppin em up but it looks good to me and if it was already a hill climber, may as well go with whatcha got:)

On home builds or just stuff that may not be real suitable, rider in position, u need someone to balance you,  bouncing some weight on footpegs and having another helper eyeball the eveness of the front and rear of the bike as it goes up and down, speed and displacement.

Adjust with whatever is available to get it balanced, you can also do with only one helper and bouncing while rolling slowly.

If up and down is relatively similar, the bike should be rideable. If one end wont cooperate, the rider will have to adjust. Too soft is probably generally preferred over too hard, wallowing vs skipping.

For my most recent war on a single, we used damn near boiling kerosene as a soaker and worked on getting a tiny bit of clearance at the base, then worked the crank back and forth "slapping" the cylinder on the base, semi vigorous but mostly just trying to use the mass/inertia of the cylinder to set up some vibration. Also, once we had clearance, we could sneak super hot kerosene on the underside as well.

If this is a total rebuild, drilling the piston could be an option, no?  If its stuck on the studs, tho, maybe not useful.

I remember reading on an antique tractor board that an alternative method is to chuck the engine into a lake for a year or two, theory being that the water would slowly dissolve the rust and would not rust further since there is very little O2 available.

We did throw a dead quad motor under water for about 2 years and I was suprised that it came out looking better than it went in and there was plenty of oil/grease in the places you would want it.  If there werent holes in the cases, it could have been dried, oiled and used.

YMMV and all that, dont believe everything you read on the internet:)

Well, after how many years, I finally understand why you were suprised that SV coils were high.

Never really looked into specifics for coils, just tried to mach em up close. Know way too much about em now:)

On the plus side, I think these 6v ones are mostly down around 1 so it shouldnt be a problem to find one to test with.

I suspect carburetion as the primary suspect but while its apart, may as well check everything and get it as good as it can be

Thanks for the explaination.

hmmm, I may need a low ohm for some testing on a 6v, no battery, points scoot and the 400 is down anyway...

IIRC, chinese scoot coils are real low primary, 1 or less? and about 6k secondary, SV spec is 3-5 and 25k iirc.

I will probably try an SV for science but I think my spec is 1.5 and 10k so might not do a whole lot, we'll see

I've got a whole 74? not 75 350 I could let go, rusted and locked up but dont really need it and its 95% there, mostly bought it for spares since theyre getting expensive and I'll need em eventually.

Have not taken the heads off yet. Semi near Pittsburgh Pa but over in OH, PM in case I dont see this thread again.

I love the common "only going to go up in value" remark. Seems to me that if you were so sure of that, you should keep it:)

That said, two strokes, vintage italian scooters and pinball machines have all done pretty well for me except for the actual selling part.

Seller did say that the price would only go up

How bout that, actually worked. Im not a facebooker so no link but Im sure u can find it.  Looks pretty complete.

This was forwarded to me and I kinda dig it but dont need it.  Bad forwarded pic attached hopefully, yea it looks like he took a pic of his computer screen, does seem to work so wont complain.

I didnt read everything so heres my armchair, up with the rear, down with the front, lower bars.....

Orrrrrr....... just take it to the track as is, we ran plenty of dudes on Harleys and sport tourers around and they all had fun. The faster guys ran out of bike 1/2 way through the day but they still had fun.

Take the tools to the track that you need to make likely adjustments, if its 3 sessions, you have 40 min every hour to futz with it.

Orrrrr..... just ride the bike as it is and ride around whatever problems it has, I'm thinkin ur gonna be way up on that tank, motard style.

It'll be fun, just go:)  Take a spare bike if you think it wont be good for the full day.