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1978 Honda CB400TII Engine Swap Suggestions

1039 Views 8 Replies 4 Participants Last post by  longdistancerider, 
M
So I'm a dummy.. an idiot... a noob.. whatever you want to call me I deserve...

I decided to take a ride to Windsor Ontario from Toronto the other weekend... about 400km give or take.. without checking or changing the oil before hand...
I'm sure you can probably guess where this is going... but if not.. my engine is toast.. seized.. whatever

Its sitting in Windsor now, with a friend who's a mechanic and is into bikes and works on bikes etc.. So yay to that... He basically told me I could either rebuild which would take probably more than 20 hrs in labor and even then it might not last...
OR I can swap out the engine which would only take 3-4-5 hours of labor.... I think I'm going to go with the latter and swap out the engine..

So my question.. please does anyone have any good suggestions for which engine to swap out for.. I've been reading that a CB450 and/or CM450 would bolt right into the frame without much work.. or should I look into another CB400 engine? or is there another option that would work?
There are a few I've got my eye on already that are all reasonably priced.. some in the US off ebay for 4-500$ CAD without shipping.. which would probably be more like 6-700$ CAD and some I've found through kijiji(Is kijiji in the US? If not.. its like Craigslist but better) for 2-300$ without shipping.. Those are in Canada and shipping would probably be much much cheaper than international shipping.

ANY any ALL suggestions are helpful! Please be specific with which year mentioned etc if possible, it would only help me.

Thanks everyone! Hope I can get it back on the road before winter hits!
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dtsmjr8dan
I sent you a PM.

The 450 swap would be good to do. Stay in Canada for the transplant though. I've driven hundreds of miles to get what I have. Well worth it.

I am swapping a 1882 CM450 into my 81 CM400.

Direct swap.
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M
dtsmjr8dan said:
I sent you a PM.

The 450 swap would be good to do. Stay in Canada for the transplant though. I've driven hundreds of miles to get what I have. Well worth it.

I am swapping a 1882 CM450 into my 81 CM400.

Direct swap.
Click to expand...
Ye I'm trying to... I'm going to get a hold of my mechanic and talk to him a bit tonight. And give him your contact and see if there is anything that can be used.
Thanks!
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Old Okie
Many rears ago, when I was younger and crazier, I seized a CB77/305 engine.
It seized because I went too fast for too long. This happened on the Kansas/Oklahoma border,
at night. The engine locked up and locked the rear wheel. I pulled the clutch
and coasted for a long way, I was going about 100mph when it seized. I finally slowly let the
clutch out and the engine started. I had no choice but to try to make it home.The engine rattled
and smoked all the way to Oklahoma City, 165 miles more or less.
Being nearly penniless I elected to rebuild the top end myself. Got her done with the help of
a mechanic at the Honda dealership. Bored to first oversize, new pistons, rings and pins and she
ran for many more years.
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Old Okie said:
Many rears ago, when I was younger and crazier, I seized a CB77/305 engine.
It seized because I went too fast for too long. This happened on the Kansas/Oklahoma border,
at night. The engine locked up and locked the rear wheel. I pulled the clutch
and coasted for a long way, I was going about 100mph when it seized. I finally slowly let the
clutch out and the engine started. I had no choice but to try to make it home.The engine rattled
and smoked all the way to Oklahoma City, 165 miles more or less.
Being nearly penniless I elected to rebuild the top end myself. Got her done with the help of
a mechanic at the Honda dealership. Bored to first oversize, new pistons, rings and pins and she
ran for many more years.
Click to expand...
Moral of the story?...

Oil that ish up always? lol
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Old Okie
The cause of the seizure, according to the Honda shop I frequented, was
lack of lubrication in the piston area. They said if you are going to go that fast for
any distance you should close the throttle occasionally to pull oil up to the cylinder walls.
Makes sense to me. I am older and wiser now, I hope, and I do not ride that way any longer.
I may not be totally sane, I rode my BMW R100RT all out to 120mph on the speedometer
and ran the CX500 Turbo to an indicated 128mph.
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dtsmjr8dan
Hopefully, it's only the pistons to the wall seizure. That would be an easy fix. These engines have poor oiling to the left rod bearing. If the rod is seized to the crank shaft, Another engine is best.
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Old Okie
What can be done to improve the oil supply to
the left rod bearing???
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longdistancerider
The oiling problem for the left rod is in the design. The right main bearings feeds the right rod and supplies the right side of the head. The left main bearing feeds the starter clutch and supplies the left side of the head. The center main feeds the transmission, balancers and the left rod. Only solution I have would be to get the crank drilled for the left main to supply the left rod.
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