Author Topic: CB400F Engine Rebuild (Read 14160 times)

Bodi · « **Reply #75 on:** December 10, 2019, 03:03:21 PM »

Fine if you want the extra displacement but expect some carb tuning work..
There will be no rebore option from 466: that's as big as the bores can get with safe wall thickness... so no more displacement without a barrel and case bore out and oversize liners.
466 was originally the one overbore available for the Yoshimura 458 kit. Most buyers just went for the extra 8cc figuring they would not wear the bores out, and probably few did.
If you ride the bike enough to need new clean bores your option is to get replacement liners or a good used replacement barrel section.

jakec · « **Reply #76 on:** December 10, 2019, 03:28:33 PM »

Interesting, I figured would only need to replace the cylinder sleeves if needed at all, not the cylinder section of the engine as well. Also I was under the impression that you wouldn't have to change the jetting at all? That's something I read on here.

jakec · « **Reply #77 on:** December 12, 2019, 10:11:09 AM »

Please view the album of photos below, showing the bearing surfaces on my crank and journals...

https://imgur.com/a/LNHMR3K

Worst looking areas can be seen below:

Redline it · « **Reply #78 on:** December 12, 2019, 11:55:53 AM »

Quote from: Bodi on December 10, 2019, 03:03:21 PM

Fine if you want the extra displacement but expect some carb tuning work..
There will be no rebore option from 466: that's as big as the bores can get with safe wall thickness... so no more displacement without a barrel and case bore out and oversize liners.
466 was originally the one overbore available for the Yoshimura 458 kit. Most buyers just went for the extra 8cc figuring they would not wear the bores out, and probably few did.
If you ride the bike enough to need new clean bores your option is to get replacement liners or a good used replacement barrel section.

and starting from a worn standard bore, "if" you can find all the new parts, it's about the same cost to either go up .25 or first over using the $500.00 pistons pins vs the cruzimage $135 pistons, at $85 a hole to .25 over and then to .50 over, then to .75 etc before getting to that dimension for the 466 size. that's how i understood it at the machine shop. (or can they just set the boring bar to hog out a millimeter or 2 and still be 85 a hole? i'm kind of doubting that.)

jakec · « **Reply #79 on:** January 15, 2020, 09:35:24 AM »

I contacted APE regarding the spots on my crank to see if they thought the crank needed polishing, but I never heard back from them. So my rebuild has been stalled since the holidays.

I was in the shop near me dropping off my top end parts for vapor blasting, and I mentioned the issue and the oldest guy there said he doubted the crank would need work, and I could bring it in and they would take a look. So I'm waiting until I bring my last set of parts for blasting and I will see what they have to say.

bryanj · « **Reply #80 on:** January 15, 2020, 10:15:46 AM »

Crank looks fine in pictures , one shell has physical damage but all are fine for wear

jakec · « **Reply #81 on:** January 15, 2020, 10:33:58 AM »

Bearings are fine to put back in, you think? I thought they looked pretty messed up (but I don't know, this is my first time looking at crank bearings).

bryanj · « **Reply #82 on:** January 15, 2020, 01:47:09 PM »

Only bad shell is bottom row third from left with a scored line on it and if i was pushed i would use that one as well

jakec · « **Reply #83 on:** January 15, 2020, 02:36:00 PM »

Thanks, I will keep that in mind and hopefully go to the shop and see what they think as well. Hope to sort out this bearing issue soon so I can order the rest of my parts!

Kelly E · « **Reply #84 on:** January 15, 2020, 02:57:15 PM »

Jake, there is a machine shop at the NW corner of the Ballard Bridge in the yellow building. It is called AutoSport and they do all of my machine work including motorcycle engines. They work on a lot of old stuff. Ask for Terry, he is one of my riding buddies.

jakec · « **Reply #85 on:** January 15, 2020, 03:22:08 PM »

Ok I will go to them for decking, boring, & sleeve pressing. Thanks for the tip!

jakec · « **Reply #86 on:** January 19, 2020, 03:36:48 PM »

This morning I started to test the bearings to try and find their position. Stopping for lunch now after my first pass at it.

Case stamp: BBCCC
Bearing marks: D4J (x1) D4F (x4)

First try I put the only set of "different" bearings (D4J) in the far left (#1) journal & marked all bearings 1-5.

Results:

.003, .002, .002, .002, .003

bryanj · « **Reply #87 on:** January 20, 2020, 12:42:46 AM »

Going back a bit the tool you asked about is a cylinder bore gauge and you dont need it

jakec · « **Reply #88 on:** January 20, 2020, 09:09:25 AM »

Thank you. I got time to do two more measurements.

#2: Moved D4J bearing over one to #2 journal. Moved all other bearings over one journal. New order is 21345 top and bottom.

results: .002, .002, .0175, .002, .003

#3 D4J bearing in same journal, moved all other bearings over one again. New order is 51234 top and bottom.

results: .0175, .0175, .0175, .002, .002

My understanding is that the clearance from new should have been .0008 - .0019 and the maxiumum acceptable clearance should be .0032. I would guess I am aiming for the middle of that range.

My assumption is that since four of the bearings are marked the same, they are the same thickness or would have started that way from new. I am also assuming that top/bottom alignment is not very important since they are all the same bearing. I am keeping the original bottom/top bearings in their respective case half during these tests.

jakec · « **Reply #89 on:** January 20, 2020, 08:58:24 PM »

More trials.

#4 order: 21534
Result: 002, 002, 0175, 002, 0025

#5 order: 21435
Result: 002, 0175, 0175, 002, 002

I felt that I was getting close so I decided to try the same order a second time.

#6 (same order as #5)
Result: 002, 002, 002, 002, 0025

What’s noteworthy about this result is it’s the first time I got a reading on the center bearing other than .0175”. Also, the only outstanding measurement is the #5 bearing, which had previously given an .002” reading.

Not sure it’s conclusive but it’s very close. Four of the five bearing-journal relationships have duplicated these measurements in another trial. The measurements given by bearing 5 in the #5 journals have not been duplicated, yet. However, human eyes looking at this plastigauge, I’m sure I could get the result eventually, if you know what I mean.

jakec · « **Reply #90 on:** January 26, 2020, 09:54:37 AM »

Just a small update I now have all parts vapor blasted. I did the car wash & air compressor treatment yesterday.

jakec · « **Reply #91 on:** January 29, 2020, 06:36:59 PM »

I dropped off my top end parts for machine work. I need to supply them with valves seals before the install the valves. I have two gasket kits, one is the 4into1 brand, the other is cruzin image which I got with a parts bike (unopened). I'm wondering which set is higher quality and which I should use. In both kits the valve seals are dark green.

bryanj · « **Reply #92 on:** January 29, 2020, 10:51:39 PM »

Dont matter, they probably all come from the same place

jakec · « **Reply #93 on:** April 03, 2020, 11:56:59 AM »

I have my parts back from top end work ($$$) and I also had everything I needed to start the engine rebuild. So started the bottom end last week. I mated the cases up last night. Currently I can keep moving ahead and put the engine in the frame, maybe tonight or tomorrow, and build the top end in frame. I am a little stuck on the gear shift mechanism right now, not quite sure if I have it right or if I'm just being overly cautious.

I have a post asking about the gear shift here.

http://forums.sohc4.net/index.php/topic,181664.0.html

Here are some photos, I have the bottom end parts in with the new TTR400 cam chain tensioner

My application of the hondabond, and finally assembled lower end.

jakec · « **Reply #94 on:** April 04, 2020, 04:29:38 PM »

I broke a piston ring (lol).

I'm using 0.50 over pistons from Cruzin Image. Does anyone know if I can use any piston ring (like genuine Honda) or if I need to get another one from CI? This was the second to last ring (cast iron one I think) out 20-ish on the four pistons.

Just wondering because my package from CI took a pretty long time last time.

jakec · « **Reply #95 on:** April 04, 2020, 09:08:13 PM »

https://www.cruzinimage.net/2018/09/24/75-77-honda-cb400f-0-5mm-oversize-piston-ring/

Found this, should have ordered a spare set when I first got the pistons

Motorrad · « **Reply #96 on:** June 04, 2020, 08:03:47 AM »

Hi,

i have a question from my side.

When reading your documentation i saw, that you had a broken screw.
How did you get rid of the broken screw ? I am happy about a nice soultion for that problem.

Your pic : https://i.imgur.com/HLbJrwm.jpg

Best regards
Dietmar

info@softwarekoch.com

jakec · « **Reply #97 on:** June 04, 2020, 09:16:37 AM »

I tried drilling it out with a reverse drill bit and using an extractor, but I gave up halfway through drilling the hole, because I realized I was sending the case in for vapor blasting anyways, and could ask the shop to do it for me at lower risk. So I paid some extra labor to have them finish the job for me.

jakec · « **Reply #98 on:** June 10, 2020, 11:39:33 AM »

Engine has been sitting in the bike for 2 months while I waited for piston rings. I got the rings last week and i plan to install the cylinder on the engine after work today. Can anyone with experience confirm assembly?

In between case & cylinder:

1x Base gasket
2x large dowel
4x cylinder sleeve O ring

In between cylinder & head:

1x head gasket
2x oil jet with O ring
2x large dowel with O ring
2x large dowel

Nothing goes in the non-circular holes at the front corners? What is the point of the oil holes there? It seems like there is not corresponding hole on the underside of the head.

bryanj · « **Reply #99 on:** June 10, 2020, 10:50:23 PM »

Should be O rings in the base where oil feeds up

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Author Topic: CB400F Engine Rebuild (Read 14160 times)