EW Pistons

[Clive]

Hi All,
The mid winter O/Haul has revealed as expected that the cast iron pistons are at last at the end of the road the gudgeon pin bosses are flogged out and with insufficient material left bushing is out of the question.
So my question is ,is there a modern piston available as a substitute ie.low expansion material which will fit the bill.
Perhaps someone out there can help with this problem
Regards
Clive

[Chris]

Hi Clive
      I believe that members in Australia have purchased pistons for the EW 350 from JP Engineering. Ltd. Well known piston manufacturers based in Australia.  Chris.

[Clive]

Thanks Chris ,
yes i know about JP pistons but was rather hoping someone had tried using something out of the vast Japanese range as we do for the mark bikes, which for me has transformed my MK3 no more oil leaks etc.etc. and more power !!
Regards
Clive

[trewblu]

Clive
Have you looked at the Yamaha range ?? I know that XS 400 pistons fit a 600 EW
the numbers are 2LO-11631-00-YO     And Y850322Y and 153546-1
I know a bloke in CH Ch who has  1927 EW fitted with these, if you want to give him a ring email  me off line and I can supply his name and pH #   Cheers Geoff

[Clive]

Hi All,
At long last the EW is back on the road and going very well.
The pistons i chose are from a Donor Honda CB750 , a small shamfer needed to be turned on the outer diameter of the piston crown and a few thou. from the top . as they just touched the blind head at TDC. the small ends needed attention as well ,bushes removed and opened up to 15mm very little material left and a special  tool made to press them back in so they didn't collapse ,then a fixed reamer just to clean the hole[ i know the purist's wont like this] , so the pin would pass through a nice sliding fit.
After a number of trips i had to keep adjusting the tappets which i thought was strange then it dawned on me !! no more oil going out through the combustion chamber to cushion the valves so am now running an additive and all seems to be well .
The pistons where matched for weight and the engine runs so much more smoothly hardly any vibes at dare i say 50Mph down hill  first ever never went over 45 before with the Cast iron pistons the foot boards vibrated too much.
I am going in a 100ml rally in a few weeks time so will get a few more miles in before then just to make sure
Regards
Clive

[Ian]

Clive, great its running well. I am not sure of the specifics of the oiling system on the EW but I presume its still a total loss system ? With the OC we used Honda pistons but put a dummy ring in where the oil scraper goes so that it still burns oil - only compression rings fitted. What do others do in this situation ?

[graeme]

My experience with the veterans is to leave the oil ring out altogether - my 3 1/2hp bikes have Hillman Imp pistons fitted. These machines have wet sumps, but were obviously designed to burn some oil - I have never had trouble with valves disappearing into the seats, and as many would know, the outfit works very hard indeed! I would hate to think how many miles that bike has done over the last 30 years or so, but it would be many, many thousands.
By the way, I am having a great time at the National Veteran rally in Albany on the solo 3 1/2 - I will post some pics.
Cheers, Graeme

[Ian]

Lucky bu**er !! How many bikes turned up ?

[graeme]

Over 80 entries and more bikes - and it's great veteran riding territory. Enough hills to challenge some without forcing too many to walk!

[Clive]

[Thanks for the input guys will carry on for a few more miles and see what happens ,the valves have settel ed down and another 20 mls today no adjustments needed . The plugs are a beautiful colour never seen them so clean . The oil system as you all know is a total loss, the over flow from the timing case has been re- directed over board outboard the RH running board as i am playing safe and over oiling at the moment .with a few more miles will cut the flow rate down so i am not dumping so much overboard!!.
Regards
Clive

[Clive]

Just to let you all know the EW preformed flawlessly in the Auckland rally this weekend i collected 3rd in the vintage class and a great time was had by all .
A number of people remarked how well the bike pulled up hills and the lack of smoke out of the tail pipe!!!  60miles in the morning and 40 in the afternoon the only part that suffered was my BOTTOM
Regards
Clive

[oily bloke]

Hi everyone,
My first question so here goes. Which model CB750 piston is useable for the EW350. I presume the F1/F2 sohc?
Cheers
Andy

[Clive]

Hi Andy ,
Yes my pistons came from a 1976 750k they just needed a skim off the top and the top edge  radius-ed so they clear the combustion chamber head opposite the valves .
All my cylinders seem to be different lengths so individual checking is required , its a good opportunity to up the compression ratio slightly which i have and the bike has responded according . The only other mod is to open up the small end bush too suit .
Hope this helps
Regards
Clive

[oily bloke]

Thanks Clive, The old EW might just see the light of day again after all.
Cheers
Andy

[LATDOUGNUT]

Hello from Latvia,
I have the following message for those who are looking for good and reasonably priced new pistons for EW 350 Douglas. I recently came across a Japanese website offering piston kits and ordered and received 2 pistons @ US$ 50 each + postage US$20 direct from Japan.
The piston designation is CG150 CHINA (KG9 AH0960X) 4-stroke -- they seem to be made specially for some Chinese Honda model, but they could be the same dimensions as HONDA CB 750. Comp height OK, pin diametre 15 mm. They need skimming off of the top edge. Standard piston size is for 62.0 mm bore and they can supply 8 oversizes -- i.e. up to + 2 mm oversize!
The pistons are provided by:
UEDA MOTORCYCLE PARTS CO.,LTD【TKRJ】
Mr. Toshihiko Sakano
 2-9-18 Nishitanabe-cho,Abeno-ku,
 Osaka 545-0014 Japan
 Phone   ：81-6-6694-2045
 Fax     ：81-6-6694-2046
 E-Mail  ：tsakano@tkrj.co.jp
 Web Site：tkrj@tkrj.co.jp
I would appreciate some guidance from those who have fitted HONDA CB 750 pistons on running clearances to be used, also whether I should use the original modern steel composite oil ring.
Thank you.

[Clive]

Hi Lat-doug-nut
I fitted CB750 pistons to my EW, i left all the rings on !! there are some owners  that leave the oil rings off as per the original . In order that i didn't have to bother about running in i gave them good clearance to start with ,004 th for the front and .006 for the rear . The engine  was transformed and transports me along 97 Kgs as it never did before , May be you could try a thou. less on those figures i would be glad to know how you get on.
Regards
Clive

[LATDOUGNUT]

Hello Clive,

Thank you very much for your guidance on EW running clearances with modern Japanese pistons. I will do as you say to make slightly smaller clearances and will use a Flex-Hone to finish off the cylinders -- this abrasive tool practically eliminates the usual breaking in period and most importantly it removes the torn metal from the cylinder surface after rigid honing and makes the cylinder surface friendly to rings and they bed in very soon.

Unfortunately the winter has set in here (Nortern Europe) so I will only be able to try my EW machine on the road hopefully next summer. I am actually rebuilding the engine from scratch, -- new  bigends, new gear rings on cams, new bearings, new clutch sprocket and linings, etc. Will then report back on progress with the new pistons.

I also intend to fit chrome-moly-vanadium valve seats and modern valves to my EW. I think some automotive valves (with chromed or phosphated stems) should  fit this engine fine. My old valves are too worn and rusty and the seats are pocketed...

With best wishes,

LATDOUGNUT

[Clive]

Hi Lat-Doug-Nut,
With all the work you are doing to the valves and seats definitely fit the composite oil rings.
How are you repairing the cam gears ?
Are you turning off the old teeth and making a new ring with new teeth and shrinking on and or a little welding!  or are you pushing out the old cam from the gear and making all new gears and fitting the old cams or making new cams ? be interester to know how you go about it.
Regards
Clive

[LATDOUGNUT]

Hello Clive,

O.K. I will describe below some of the tricks and materials I used to rebuild my EW engine and there is still quite a lot to do to get it finished, luckily it is winter here, so I can carry on the work without distraction.

I have been using tough steel rings which I shrank on the camgears (after they were machined down) -- hot with 0.05 mm interference fit and then machined new gearteeth on the rings. I understand Douglas used raw steel without heat treatment (case hardening) for cam gears. With this hot shrink fit and smooth and precise surfaces no tack welding is required. The steel I used is a type which kind of work hardens.

I have also repaired the original EW tappet guides by using  phos. bronze valve guide liners. Please see the attached photo. The guides are bored out in a lathe chuck with a special drill/reamer, a sleeve is air driven in with a special tool and then a tungsten carbide ball is driven through the liner to calibrate it and to fix it in the tappet guides. This type of repair has been around for a while and is used extensively for quality repairs of valve guides in automotive engines. I have even used these guide liners to repair some of my girder forks – very efficient, quick and long lasting.

I had to calibrate the diametre of the worn tappets first of course. I did it with a diamond file and using a special abrasive stone lapping gadget I bought from the USA. It can also be used to lap down to size valve stems in a lathe. It took me a couple of hours to achieve a satisfactory finish and equal diametre throughout the length of the tappets.


By the way I received fitting recommendations from TKRJ regarding running clearances for their 62 mm HONDA piston I am using for my EW. They say 0.055 -- 0.065 mm. That is for a modern air cooled cylinder. I fitted mine with 0.08 mm front and 0.12 mm rear cylinder clearance. I have Flex-Honed the cylinders so they will not require any extensive break in period.

This is it for the moment.

LATDOUGNUT

[LATDOUGNUT]

Clive,

I have machined out the counterbores in the EW cylinders and fitted new chrome-moly-vanadium valve seats using a special heat transfer liquid „Fluid Weld” (Patented and made by Seallock International in the USA) it keeps the seat in place and fills all voids and also transfers the heat as if the seat and head materials were integral. It is very good stuff even when re-sleeving your old cylinders, by the way. It is not anaerobic and can withstand heat up to 1500 degrees Centigrade (yes 1500 - no mistake).

I of course fitted „RAPID” phos. bronze valve guide liners/sleeves to the EW cast iron guides. These liners/sleeves will last a lifetime and they allow closer tolerances and retain oil in special pores. When they are worn out – there is a special tool which allows you to split and remove them and replace with new liners/sleeves!
 
I had to hone out the rods with a diamond hone to clean up the deep scoring left by turning bearing rings. The original rings are thinner because of the bigger diametre rollers. I used 1/4" rollers and consequently thicker bearing rings. I tried to achieve maximum contact between the rod eye and the bearing ring. I even made the ring 1 mm longer  so that the chamfered and rounded side which is first pressed into the bigend eye is pressed right through and then ground away on the surface  grinder. As a result the ring seats in the bigend eye bore 100% and also Loctite is trapped in the honing crosshatch and helps retain the ring against turning. I made new crankpin sleeves in through hardening ball bearing steel and shrank them on the crankpins. A boron carbide Flex-Hone helped here to remove 0.01 mm from the bigend eye to achieve a perfect fit – the rod must pass on over the rollers without binding and of course there must not be perceptible up and down movement in an assembled rod. The little ends received very thin bushes and before fitting them I countersunk the eye from both ends, so that the ends of the very thin bush could be bent over into the countersinks using 2 balls and a hammer. Thus I ensured that they will never start turning in the rod eye. No I did not use a reamer for calibration of the bushes, but an other Flex-Hone to open them up enough for a good push fit of the piston pin. Working slowly with the Flex-Hone and frequently checking the diametre you can achieve a perfect result and avoid spoiling your work, like it sometimes happens with a reamer!


LATDOUGNUT

[Clive]

Thanks Latdougnut,
A great summary of your repair --O/Haul  of the EW engine. I hope others are reading your post as the repair schemes you describe will be of lots of help to others around the world and hopefully will inspire others to adopt some of your engineering prowess and get a few more of these interesting machines back on the road .
The use of Rapid valve guide liners is of particular interest to me as i am in the process of O/Hauling a set of early 2 3/4HP forks with no bushing and very little meat to work with and this could be the repair for this job.
As Christmas is around the corner and the temperature in the mid 20s c, we in the  Southern Hemisphere  are riding our Bikes, Christmas Parade tomorrow so the clutch will take a hammering Rally on New Years Day and so on .
So to you and everyone else a very Merry Christmas and a Happy New Year
Keep firing on both cylinders

Regards
Clive

[LATDOUGNUT]

Hi Clive and All,

A Happy Christmas to you all!

LATDOUGNUT