Topic: Tips on getting the barrels on a CB400f with 466 kit

[Waveblaster]

Hi

I was interested in hearing from the brains trust as how folks have managed to get the barrels down in the least painful fashion with the 466 kit on a cb400f. The chamfer is well and truly machined away. two sets of hands might be helpful

Cheers

[MoMo]

yes two people helps as well as piston holders to keep them from wobbling

[Bodi]

There should be a whisper of chamfer left but not enough to help much. If the rings are gapped properly they should go in with finger work around as the barrels drop down. I have found a few 466 rings way too long, they wouldn't even go into the cylinder to gap.
Block up #2 or #3 around TDC (just a stick the right size under a piston) and carefully work the jugs down to whetre the top ring is about to go in. Push a ring (gap in the right spot) into the groove and wiggle the barrel assembly a bit until i slips in. Then get the other piston's ring in. Move down to the second ring. The thin oil rings are delicate so take it easy there. Once all rings are in drop the barrels a bit and remove the stick, turn the crank and assist the barrels to move down as the 1-4 pistons come up into it. Repeat the ring fiddling insertions. Do 2/3 first so you can work around 1/4 in the much reduced space under the barrels, it's pretty hard to do 2/3 last.
You can use hose clamps as ring compressors. My experience is that in the time it takes to get them on and off I can have the barrels done and down. If you have reservations about doing it with fingers then get the clamps. Just barely tight, and well oiled.

[MoMo]

There should be a whisper of chamfer left but not enough to help much. If the rings are gapped properly they should go in with finger work around as the barrels drop down. I have found a few 466 rings way too long, they wouldn't even go into the cylinder to gap.
Block up #2 or #3 around TDC (just a stick the right size under a piston) and carefully work the jugs down to whetre the top ring is about to go in. Push a ring (gap in the right spot) into the groove and wiggle the barrel assembly a bit until i slips in. Then get the other piston's ring in. Move down to the second ring. The thin oil rings are delicate so take it easy there. Once all rings are in drop the barrels a bit and remove the stick, turn the crank and assist the barrels to move down as the 1-4 pistons come up into it. Repeat the ring fiddling insertions. Do 2/3 first so you can work around 1/4 in the much reduced space under the barrels, it's pretty hard to do 2/3 last.
You can use hose clamps as ring compressors. My experience is that in the time it takes to get them on and off I can have the barrels done and down. If you have reservations about doing it with fingers then get the clamps. Just barely tight, and well oiled.

exactly the same sequence I use and well explained by Bodi...Larry

[Waveblaster]

thanks for the replies . Given your responses I will attempt it more convincingly tomorrow.

[Don R]

My machine shop put the chamfer back with a die grinder. It helped a lot. This was an 836 but it's the same  deal. Take your time and be patient.

[Jore]

Could it be done using some pvc as makeshift clamps? I'm a few weeks away from installing a 466 and want to know all the possibilities. As for the ring gap, how big should it be?

[Bodi]

I don't know the correct ring gap offhand. It should be specified in the piston kit instructions but it's calculated from the bore size, there are guideline specs online.
Too large and you get more blowby through the gap than is ideal (not so good). Too small and the engine seizes when it gets hot (very bad). There are some good youtube videos on ring gapping, but you just set a ring in the bore and push it down with the piston so it sits square to the bore. Measure the end gap with feeler gauges and file off enough to get the spec gap. There are filing jigs for folk that do it a lot, but freehanding it works OK. File towards the inside of the ring (smooth to dead smooth file or India stone) and keep the end as square as you can.
Use hose clamps if you feel you really ring compressors. They are cheap and they work, and are easy to remove afterwards. How would you get a piece of PVC pipe out of there?