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Messages - K2-K6
1
« on: May 28, 2024, 03:05:54 PM »
"According to the Denso site the plugs you need are Denso-X22ES-U "
Honda contemporary manual agrees with this as alternative to NGK D7EA Dave.
Denso 24 = NGK 8 heat range. With Denso 27 = NGK 9.
2
« on: May 28, 2024, 11:48:36 AM »
Topic debated before, assembly of front brake caliper and the lubricant to use in this assembly.
From 1970 CB 750 Honda workshop manual;- Verbatim "Note : Use silicon sealing grease (temperature range of -67~ 392 F (-55 ~ 200C). Do not use molybdenum grease known as brake grease. "
This accompanying a schematic of caliper showing the application point as both recess that accomodate active and fixed pads.
Also from Honda workshop manual 1978 CB 750 (last of SOHC bikes, with illustration of the K7 caliper in arrangement parallel to all the previous 4 cylinder motorcycle calipers;- verbatim "Install a new piston seal. Coat the piston with silicon grease and install it. Apply silicon grease to the brake pad outer circumference and install."
This, in my appreciation of it, is that Honda direct the use of this grease only in assembly of the caliper.
Anecdotal view, I've been using silicone grease in this way for some time. Part of this is that it appears to be the only common one I can use in system with mineral oil, or conventional dot fluid or silicone based fluid.
Interestingly, I dont get brake squeal in any system when using this method. It seems to offer the most competent piston return over significant period of use, being all but impervious to water ingress when exposed to poor working conditions too.
Both cycle disc (working on two four and six piston calipers) that have very concise demands in preventing drag by piston contraction when releaesd, also cars & bikes when placed on mot rollers to test, these having notably extremely low drag before brake application.
3
« on: May 28, 2024, 09:21:01 AM »
They are a pretty durable chain and generally don't display premature wear when used with decent service schedule.
There's schematic in the official manual showing where to measure and asses to chain. Described with vernier caliper in depth measurement from face of oil pan mating surface up to a point on the tensioner arm.
4
« on: May 27, 2024, 06:41:50 PM »
Yes.
Sump pan off and you'll see the "tensioning" wheel from underneath just in front of oil pump.
5
« on: May 27, 2024, 08:05:16 AM »
I'll have to get a look at that issue Dave, should be interesting. It is one of classic representation of production engineering from that era I feel, the 400 Four that is. Thanks for the scans Ash, read through then as got up too early this morning  Mr Curtis gives correctly the name of "wet OR dry" abrasive paper, I note A friend working in sales for 3M years ago always corrected the mention of "wet & dry" through gritted teeth, as it can't be both at the same time 
6
« on: May 25, 2024, 10:30:53 AM »
Likely within a minute to 90 sec would be a practical estimate.
But fresh build, plugs out and turn it over with no compression to get the oil distribution competent before starting is worthwhile.
If you don't want to spin too long on starter, then push it around in second gear with plugs out to get oil circulation throughout would supplement this process.
7
« on: May 24, 2024, 01:18:15 PM »
I'd complete an more in depth version of Bryan's assessment.
If you've transmitted any grit or other debris into the bearing by cleaning, then they can sound bad.
Really wash it independently (only tgat shaft and bearing) with something like paraffin, then clean that all with strong mix of washing up liquid to completely remove anything that's in the bearing.
Completely dry it with compressed air or hairdryer, then you can recheck for any unwanted radial movement.
Now put clean engine oil into bearing and assess what it's like for smooth movement.
It generally takes alot to wear them, any unwanted grit makes them feel awful if not cleaned out.
8
« on: May 24, 2024, 10:00:07 AM »
Very nice work Dave, hopefully you'll get the exhaust you want to complete it.
The picture of Sheene on early RG 500 behind the bike, I saw the first one he rode UK meeting at Mallory Park and have some pictures somewhere as we were allowed to wander around the pits at that time.
9
« on: May 23, 2024, 04:12:07 PM »
Good informative overview - many products I wasn’t aware of.
Sent from my iPhone using Tapatalk
There's far more than I thought too Using supermarket snack crisp etc isle (or multiples of) as example, there must be considerable margin in these canned product to attract so many into developing and marketing them to the bike riding sector.
11
« on: May 22, 2024, 08:55:34 AM »
A bit of a fraught existence then for the engine in previous ownership Hopefully you get all the details sorted and back to more cohesive running.
12
« on: May 22, 2024, 08:52:51 AM »
Data says stroke of 450 is 57.8mm ..... in comparison to a 650 Bonneville @ 82mm, which is a huge difference in linear piston speed and giving the short stroke Honda an easier time, in kinetic terms, at any rpm. Both about 70mm bore too.
Crank rotation faster, but pistons moving slower sounds stressful, but mechanical effect is more gentle.
Also 360 degree crank vs 180 to give significant difference in balance at half stroke point in rotation.
13
« on: May 21, 2024, 08:19:16 AM »
Could be wrong, but some details on that piston appear odd against what I recall as normal.
Looks like .... the top valve clearance "pocket" has been recut, with evidence of original visible near to edge, then another pocket located inwrads.
Is there some bits missing from ring land at about 2 o'clock ? Those little triangle marks, or just carbon and indented ?
The turning finish is quite "rudimentary" especially in the centre, and makes them look like a modified piston possibly.
The official Honda manual for F2 indicates to put the "offset "O" mark on piston faces to exhaust side (forward)" quoted directly, it gives a picture of the O location consistent with your piston too. But if you're really unsure, then assembly with representative gasket and use plasticine to check valve pocket clearance by rotation of crank would be definitive in assessing them.
14
« on: May 19, 2024, 09:28:09 AM »
Very interesting within Honda, is that they've built so so many different types in configuration and application, all good to compare design traits etc.
The three mentioned above all allmin the same area in regard to bhp per cylinder, more importantly loading (torque) and speed all being close to specify a bearing for use in.
The detail in your thread about prototype 750, the small original big ends suggest it either started as a roller bearing crank or sized upward 8f origin in plain bearing, to control crank twist perhaps.
Around that time were the car engine 4 cylinder too, with roller bearing crankshaft.
15
« on: May 19, 2024, 08:50:29 AM »
Yes, you'd definitely need a "depth" hardened surface to run rollers or balls on, thats in comparison to plain bearing arrangement.
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