Author Topic: My GF broke her 400F ... Carnage pics on page 2. (Read 11476 times)

Scott S · « **Reply #50 on:** January 13, 2014, 03:59:43 PM »

The engine never seized. She's ridden it since that day.
I wasn't there, so I can say how low the oil was. I believe that it was not draining back from the head fast enough and they overfilled it. It was then that it puked.

The breather is on top of the head, but routes to the air box. It was then coming from this vent/separator/collector and down onto the swing arm.

Tim2005 · « **Reply #51 on:** January 13, 2014, 04:14:29 PM »

It seized on those pistons by the look of it...must have freed off afterwards. The overfilled head thing isn't really viable either tbh, the camchain tunnel is about 1 inch by 4 inch & oil can always drain down there from the breather chamber. Most mysterious....

It'd be best to inspect this motor very carefully before putting a lot of new parts in there, this isn't adding up- low mile 400s really aren't known for problems like this.

Scott S · « **Reply #52 on:** January 13, 2014, 04:24:19 PM »

Everything from the case up is coming off for rebuilding. What else would you suggest to look at?

Bike never seized. She rode it until they noticed oil on the swing arm and tire. Parked it and put it on the truck. I cranked it up myself a couple hours later. She put another 100-150 miles on it since that day. Only smokes when the throttles close...you know, letting off the throttle.

fmctm1sw · « **Reply #53 on:** January 13, 2014, 04:24:47 PM »

Are the wrist pins frozen? I had an old XR100 that did that to the piston.

Stev-o · « **Reply #54 on:** January 13, 2014, 05:39:56 PM »

Are you getting the cruzinimage eBay kit?

If you're having trouble finding someone to bore it, there is a guy in FL that does it for $150.

Scott S · « **Reply #55 on:** January 13, 2014, 05:43:19 PM »

Yes to Cruzinimage kit. I think my guys in Charlotte have a machine shop that can do it.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #56 on:** January 13, 2014, 06:43:08 PM »

Smart move to do the kit. From the look of those piston skirts I wouldn't trust the cylinders with just a hone. Plus the bore may have been too loose to begin with. What else would cause the heat/scalding/rubbing damage to the skirts?! And a few extra cc's for a lady that likes to use a bike for it's intended purpose never hurt. My take is the last top end job wasn't done right. The riding she did should have been well within it's boundaries.

If you are unsure about the machine shop send it to one of our guys that have been doing SOHC4's for 40+ years. They all SAY they can do it but do they know how to correctly drop cylinders, rebore the jugs, press in the new sleevs and then bore them while NOT affecting the cylinder next to the one they are working on?!

bryanj · « **Reply #57 on:** January 13, 2014, 08:41:01 PM »

Pistons, rebore and stem seals are a must, now to the work you did not want to hear about!!!

The 350/400 and notorious for the cam chain tensioner horseshoe siezing on the pivot pin when the chain goes slack, also the springs on the tensioner plunger go weak and the plunget sticks in the bore plus the pinch bolt siezes in the thread in the case.

All these mean the bottom end off and you are over 50% of the way there so do it now.

The Horsehoe has been discontinued by Honda but I think TTR400 was making them in stainless and there is a man in UK making them, if you need more info PM me. Not cheap but well worth doing to get a nice running motor

Scott S · « **Reply #58 on:** January 14, 2014, 04:24:27 AM »

I am aware of the cam chain tensioner problems. In fact, I specifically asked my shop to check them out.

He says the tensioner is moving freely and any noise I was hearing was probably piston slap. I ordered a new cam chain and the two guides from David Silver Spares yesterday.

I'm trying to do this one right this time. She loves the bike so much and is SO much more comfortable on it compared to her FJ600, it's worth making it right.

Stev-o · « **Reply #59 on:** January 14, 2014, 05:00:20 AM »

How many miles on this motor? I breezed back through the thread but didn't see it...

Scott S · « **Reply #60 on:** January 14, 2014, 05:57:03 AM »

I'm not sure and the bike isn't at home right now.

I do know that it was used for track days for a while and has the safety wire holes to prove it. I think it was just worn slap out and that the last ring job probably wasn't done correctly.

On the cam chain guides: The ones in there are OK, certainly usable. But, since we're this far in and plan on keeping the bike, I decide to spend an extra $102 and get all new stuff.

DustyRags · « **Reply #61 on:** January 14, 2014, 10:49:59 AM »

Wow, hell of a story. In for the follow- any idea what sort of power you were getting pre-rebuild? Be curious to know what sort of improvement the overbore does.

Scott S · « **Reply #62 on:** January 14, 2014, 03:28:37 PM »

I'll be sure to ask my girlfriend for a seat of the pants dyno report when it's done!

george · « **Reply #63 on:** January 14, 2014, 09:08:43 PM »

Quote from: Scott S on January 13, 2014, 05:43:19 PM

Yes to Cruzinimage kit. I think my guys in Charlotte have a machine shop that can do it.

Hey Scott , I needed a really bad cylinder bored quick when I was visiting on Lake Wylie last year and met some awesome long time old school machinist from CLT. They took pride , did a great job and didn't sound annoyed when I said moto engine ! I absolutely cannot praise them enough .
Sorry I missed you while I was in RH , next time !

http://www.carolinasautomachine.com/

Scott S · « **Reply #64 on:** January 15, 2014, 05:06:36 AM »

I'll have to ask the guys at 2Topia Cycles who they use. It could very well be the same shop.

I can't say enough good things about Nate and Bill at 2Topia. I do most of my own work, but the last six months or so have been a killer at work, so I let them do a few things for me.
It's hard to find a shop that will work on vintage iron, let alone knows what they're doing. Excellent work at very fair prices.

https://www.facebook.com/pages/2Topia-Cycles/196010633808627

tomkimberly · « **Reply #65 on:** January 15, 2014, 06:13:39 AM »

From the pics and written discriptions it appears the PO changed the ring size but never rebore the engine nor replaced the pistons.

Do the next over bore (what ever it is), new pistons, new rings, and this bike will run like a bat out of h*ll.

I have two CB350F's, they both love running at 8 - 11 k all day long.

Tom

Scott S · « **Reply #66 on:** January 15, 2014, 06:44:29 AM »

I agree, Tom. It's getting the 466 kit and the head will get some attention, too.

RAFster122s · « **Reply #67 on:** January 15, 2014, 08:06:33 AM »

The key is pressing the new sleeves in properly so you don't end up with a liner dropping later. Even good shops who "know what they are doing" can screw it up. It isn't cheap to fix and is frustrating to have to redo it. David

Oddjob · « **Reply #68 on:** January 15, 2014, 08:30:08 AM »

I don't think those are the next size up in rings with standard bores, to me the end gap you can see looks like they are the right size for the bore but bloody worn. I suspect that the thrashing your GF gave the bike was just too much on what was essentially a worn bore with worn rings, this caused a ring failure, you can see the top ring hasn't been sealing properly by the amount of carbon between it and the 2nd ring. It's possible the second ring was doing all the compression work itself and had been for some time. Eventually this had to go and go it did. When it did go on the ride it caused massive crankcase compression, this caused the oil in the engine to vomit out of the nearest and easiest place it could find, the breather pipe. The heat of the engine and the heat of the oil made the failure more likely to happen.

Rebore, which I know your doing anyway, check head for valve seating, just in case and as Bryan says replace the stem seals, most little puffs of smoke you can see on startup and over run are usually down to those.

It was ordained that the engine would fail and I'm certain the PO didn't replace the rings and he should have done. Shame but it could have been much worse.

754 · « **Reply #69 on:** January 15, 2014, 08:47:19 AM »

What oil brand was in it at the time?

Scott S · « **Reply #70 on:** January 16, 2014, 03:06:38 AM »

Castrol motorcycle oil.

Scott S · « **Reply #71 on:** January 21, 2014, 04:37:47 PM »

Just a quick update. Stopped by the shop and had a look at the horseshoe. It's definitely NOT stuck and very, very little evidence of the cam chain touching it. The shop owner also said the chain was tensioned properly when he disassembled the motor and passed the "pull test" when checking free play on the cam gear.
I will replace both guides while we're in there, though.

Most likely, we were hearing piston slap.

Stev-o · « **Reply #72 on:** January 21, 2014, 06:18:50 PM »

That's good news. Did you ask them who will bore?

Scott S · « **Reply #73 on:** January 24, 2014, 04:31:35 AM »

Crap. Sorry...I forgot.

Scott S · « **Reply #74 on:** February 04, 2014, 09:01:52 AM »

Quote from: Jerry Rxman Griffin aka MuthaF'er on January 13, 2014, 06:43:08 PM

If you are unsure about the machine shop send it to one of our guys that have been doing SOHC4's for 40+ years. They all SAY they can do it but do they know how to correctly drop cylinders, rebore the jugs, press in the new sleevs and then bore them while NOT affecting the cylinder next to the one they are working on?!

Jerry, you should have an email.

News:

Author Topic: My GF broke her 400F ... Carnage pics on page 2. (Read 11476 times)