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Blood Sweat Tears and Grease => Engines => Topic started by: Sderbyshire on Jun 01, 2018, 04:34:19

Title: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 01, 2018, 04:34:19
Hi everyone, iím back after a period away from messing with my 360.

Have an oil weep from the head to barrels join, both sides, so am going to strip the top end down and potentially bore and install gs850 pistons.

Looking on ebay there are new aftermarket pistons available, or old engines.

Which should i go for as i think NOS are pretty rare these days?

Iím competent with a spanner but havent rebuilt an engine before, so want to keep this simple......

From reading threads on here and hondatwins i think i need to bore the barrels, and deck the pistons by adding a copper base gasket of the appropriate thickness?

Anything else essential?

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 03, 2018, 12:36:45
Took a break from decorating to tear down the 360 motor!

All went very well, no problems at all.

Previously iíve only uad the rocker box off but judging by the red Ďgasket sealerí on the base gasket someone has been here before?

So now i need to source a pair of gs850 piston sets and then have the barrels opened up to suit.

I want to keep this simple so am not changeing anything unless i need to, any suggestions as to what extra work is essential/worthwhile while i have the top end in bits?

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 03, 2018, 13:42:10
You'll need a new head gasket for the larger bore, I recommend solid copper for head and base, better heat transfer. You'll need to get bore done first so you can check clearances to order correct thicknesses to get around 0.040" piston to head clearance
You WILL need heavy duty clutch springs with bigger motor, they are barely adequate for stock engineIt's a REALLY good idea to do various oil system modifications, need clutch and generator cover gaskets as covers have to come off.
 If you havcent looked through Miniature Ninja's build you should, he's got pictures of various mods and it will beeasier than looking through my 360 build/blog to find the informationWhen it's all done you can treat it as a very reliable high rpm Triumph 500, will be about same size, weight and power output but with an extra couple of gears and a higher cruising speed (80mph is generally no problem)As for after-market or used, doesn't really matter as bore should be matched to piston size, use 0.0015"~0.0017" piston to cylinder clearance
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 03, 2018, 13:53:48
I've recently "completed" my 378 build, although I have yet to fire it up pending finishing the wiring. Last week of School for the kiddos has been holding things up for me.

notes and comments:
I ordered custom copper head and base gaskets from coppergaskets.us  (https://coppergaskets.us/shop?olsPage=products%2Fhonda-cb360-copper-head-gasket-69mm-x-042-106mm-thick)as PJ said you need to have the new pistons in the bored out cylinders to measure how far up they stick out so you can get gaskets made in the correct thickness. so steps: 1- buy pistons 2- have cylinders bored out to match pistons with proper piston/cylinder clearances 3- install and measure deck height 4- order gaskets 5- put it all back together again (dont worry, you will do this about 10 times before it's all done)

my build has some other complications as I have also gone the route of larger valves and some other things - but suffice to say that while you've got the engine apart it's more than worth it to take care of some of the oil passages that plague these engines, that will add some time and effort to the build but absolutely worth it and most likely necessary too.

any reason you took down the motor?
there are things that should be done to it - like tensioner replacement, filter cleaning.
my engine was as clean as a whistle inside and by doing a "simple tear down" I ended up doing everything in the book to this motor! LOL it's an addiction
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 03, 2018, 14:49:43
Thanks both for the constructive replies.

Iíll look into the oil mods and make those, filter cleaned out not long ago.

Iíll also read minatureninjaís blog, as iím unsure exactly how to calcilate what base gasket thickness iíll need. Will then buy copper as recommended.

Thanks again!

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 08, 2018, 10:24:33
Hi all

Awaiting delivery of a pair of aftermarket gs850 pistons from Japan...... so tore the head apart and opend out the exhaust ports to more closely match the ex gaskets.

Couple of pics attached.

When the pistons arrive iíll have the barrels bored out to suit, i went for 70mm pistons.

Meantime iíll read up on the oil mods and get those done ready for reassembly, 10 times !

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 08, 2018, 11:11:53
Should be interesting. Doesn't 70mm give you a 391?
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 09, 2018, 04:40:21
Iíve had a search but struggling to find the 360 oil system mod info.

Could someone point me in the right direction please?

Thanks

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 09, 2018, 06:22:29
Is this the oil mod that i need to do to improve oil flow to the head?

Seems to be a very small opening out of the edges of the transfer piece, just removing the Ďstepí ??

Steve
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 09, 2018, 16:01:36
Is this the oil mod that i need to do to improve oil flow to the head?

Seems to be a very small opening out of the edges of the transfer piece, just removing the Ďstepí ??

Steve
Yup, that's the way I did mine (well duh, that's my photo) but also the way PJ had done his. Basically you're just removing some of the restriction this bypass part has, allowing more oil through the ports and less dumped out the bypass.
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 09, 2018, 16:18:59
You'll want to open these ports 1/32' more...

(http://i1086.photobucket.com/albums/j449/trek97/oilhole.jpg)

Then the clutch basket...

(http://i1086.photobucket.com/albums/j449/trek97/clutchmod1-1.jpg)

And try to find a CJ pickup.  Although, you can get away without a CJ pickup with good oil level maintenance and limited side stand idling.

All those pics are photobucket, which means they may not be showing up unless you have the fixer extension.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 09, 2018, 17:49:04
Thanks both!

Iíll dremel the bypass as per your photo Minatureninja.

Irk, what size holes are you suggesting i drill in the clutch basket?
And what sise is Ďopening out by 1/32í , do i drill that or file it bigger??

Thanks again

Steve
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 09, 2018, 19:23:32
They're the oil passages bringing oil to the top end.  I can't remember exactly what size the holes are now, but you're just making them slightly bigger- 1mm or 1/32" bigger. 
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 09, 2018, 19:28:42
Thanks both!

Iíll dremel the bypass as per your photo Minatureninja.

Irk, what size holes are you suggesting i drill in the clutch basket?
And what sise is Ďopening out by 1/32í , do i drill that or file it bigger??

Thanks again

Steve
I drilled the headbolt oil holes out to 3/32 and used either a 9/64 or 5/32 bit for the clutch basket (basically just what fit between the splines)

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Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 09, 2018, 21:29:15
Thanks MinatureNinja

Whats the point of the clutch basket drillings?

The pther two mods allow more oil flow to the head, but i dont see what the clutch basket holes do?

Steve
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 09, 2018, 21:38:39
That and the HD clutch springs help clutch performance, especially with the bore. 
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 09, 2018, 23:32:25
as Irk said, it improves performance

it does this because it allows the oil in the clutch to flow out of the plates at RPM when the clutch is disengaged and run much cooler. cooler oil = better performance overall
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 10, 2018, 00:26:33
It makes clutch run cooler. Oil flows through the plates all the time engine is running, (it's a 'wet' clutch) this mod directs more.  oil through the center plates so they are less likely to overheat. When you pull clutch in plates disengage and oil flushes any 'dust' It's used on 200+bhp bikes so it must do some good  ;D (although I've been doing mod since 1970's, kinda sucked trying to explain it to 'experienced' mechanics)
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 10, 2018, 04:31:41
Excellent, thanks guys.

I understand about the clutch being cooled by the oil, although iím more of a Ducati dry clutch man really!

HD springs ordered and iíll get my drills out :-)

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 10, 2018, 04:47:31
Ps, also ordered a CJ360 pickup on ebay.

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 12, 2018, 04:21:19
70mm pistons arrived from Japan in less than a week!

Off to the machine shop today 😎
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 12, 2018, 20:22:02
Ps, also ordered a CJ360 pickup on ebay.

Steve
WHAT?!?!?! I've been scouring the Ebay for months for one of those!! :(
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 12, 2018, 20:25:52
WHAT?!?!?! I've been scouring the Ebay for months for one of those!! :(

As annoying as it is, you have to get them as soon as they post.  I got mine within 20 minutes of the listing being posted.
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 12, 2018, 22:46:59
They never stopped CJ cam bearings failing so it's only needed if you don't ever check oil level plus park on side stand on highly cambered roads and leave bike idling for extended period. It would probably be easier to weld over the original pick up and extend it into center of case or even just make a complete new pick up?
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 13, 2018, 00:44:56
They never stopped CJ cam bearings failing so it's only needed if you don't ever check oil level plus park on side stand on highly cambered roads and leave bike idling for extended period. It would probably be easier to weld over the original pick up and extend it into center of case or even just make a complete new pick up?

I have a spare CB pickup, so I may take that up and make a modified one. I am meticulous about checking proper level and change intervals because I know how important that is to engine life for anything (plus being a former Marine has taught me that equipment maintenance is key to survival)
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 13, 2018, 03:35:24
Iím a little jubious that the pickup will be genuine CJ..... lets see what turns up!

Meantime iíve done the oil mods, and taken the pistons and barells to the shop 😀

Also contacted CopperGaskets to line them up for base and head.

Iím awaiting a gasket kit and viton valve seals, the ones in the old kit i have seem crap, then i think iím ready to assemble.

Will post pics when stuff arrives.

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 14, 2018, 11:36:11
Well the ĎNOS CJ360 Oil Pickupí arrived, and yes itís genuinely not the same as the CB360 one, and looking unised and a bit rusty!

I shall clean it up and install.

With the pressure relief mod, clean oil pump, drilled clutch basket and oil ways drilled out to 2.5mm ( they were 2mm) i think im ready to button up the right case?

Steve
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 15, 2018, 14:50:42
Sounds like it, you got the heavy duty clutch springs in there?

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Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 16, 2018, 10:10:14
Yes, hd springs installed.

Ps, thereís another cj360 pickup listed on abay by the same seller.....

Steve
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 16, 2018, 15:20:28
Yes, hd springs installed.

Ps, thereís another cj360 pickup listed on abay by the same seller.....

Steve
Cool thanks.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 20, 2018, 08:52:00
Collected barrels and pistons from the machine shop this morning, and so couldnt wait to test fit and measure up for gaskets!

With a new base gasket in place and the barrels bolted down iím seeing :

Pistons sticking up .045 from the barrels
Base gasket measuring 0.018

So if i went for a base gasket at 0.063 from Lani then iíd have pistons perfectly flush with the barrels.

A 0.042 head gasket would then give me clearance of 0.42.

Is this correct and the right approach?

Steve



Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 20, 2018, 09:10:13
Yep.  That's the way to do it.
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 20, 2018, 11:16:08
Yep, numbers work out
Did you check gasket after it was compressed? I doubt if it would be more than 0.001" but it's generally easier to clamp cylinder down without gaskets then work out what combination will get you closest to 0.040" clearance. Having thickest gasket on base is a real good idea as there is way less pressure 'down there'.  ;D I'm really interested to see how a 70mm bore turns out. When I did my CJ250 to 70mm I used GS1000 pistons and flycut the head. Using stock 360 head gives a different combustion chamber shape and probably volume? I was actually on TV with it in 1995 (or 6?) There was an event at LLandow  Circuit with a RWYB 'sprint' Thanks to the 'magic' of television, I was filmed during a run then it was cut into the Welsh Champion drag racer doing a huge wheelie off the line making it look like I was 'winning (even though filmed on different days) only another 14 mins, 55sec to get my full '15 minutes of fame'  ;D
 
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 20, 2018, 11:24:33
Thanks both.

I did measure base gasket after removing it, so had been compressed.

Iíll order the copper gaskets and hopefully get rebuilding soon!

Iím a little unsure on piston rings.

I have a three part oil control ring, being two thin rings and a Ďwavyí centre, and two thicker compression rings.
Both compression rings are stamped Ď100í on what i think is their upper face. One ring is black edged and one silver.

Have you seen this before?, iíve not take a picture yet nor contacted the seller.

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 20, 2018, 11:29:18
Rings are completely normal, marked as 1.00mm oversize. Expander ring goes in between side rails. Make sure ends are butted and not overlapping (sometimes they look 'too tight' assembled correctly) Side rsails don't haver up or down face
Top ring is chrome face, second ring is 'black'
 Numbers up.
 Oh, stagger the oil ring rails and have gaps 'opposite' the 'join' on expander,(I only go about 1/2" either way)  it only makes a tiny difference but can seal 'better'.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 20, 2018, 12:01:20
Fantastic, thanks CrazyPJ!
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 23, 2018, 06:10:30
Gaskets ordered from Lani at Coppergaskets, he was very prompt in responding and in making and posting the gaskets too!

While i wait for those to arrive iíve painted the head and barrels, and built the head back up with new Viton seals.

Cant wait for the gaskets to arrive so i can rebuild and fire up the CB389 😀
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 23, 2018, 14:06:00
Moving right along there. I had quite a bit less meat on my build, and that's what I did went with a thicker base gasket. You could probably get away with shaving some off the case but gaskets is more reasonable solution.
Factory valves and guides?

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Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 23, 2018, 15:34:15
Stock valve guides are actually real good. It's only if you fit oversize stainless valves the guides need changing (something they don't tell you when you buy stainless steel valves, the stemscan  gall in cast iron and need bronze guides) Really though, it isn't worth the extra expense of oversize exhaust valves but the+1 (35mm) intakes will make all the port work better as it's already oversize.With a '390' is should be good to 'cruise' around 85~90 with top end around 120 on stock gearing (17/34) I got confused the other day with the CB550 591cc 'kit' and 70mm 389.46cc of 360 (35x35x3.14159x50.6x2 = 389.4629)