Douglas - For Sale Items

Douglas 1913 Model P motorcycle

Douglas - Wanted Items

Douglas 1915 3 Spd-Gearbox and Clutch

Support & How to Join

Side Panel Notices

Quick Comments

Reminders, links to interesting topics, bump your own topic, quick comments or any short message of interest to members. Try it out!
Please note - 500 character current limit


Today at 01:04:34
Welcome to the new site!

Recommended viewing for a fast start...
 - Quick Tour of the Front Page
 - Quick Tour of the new Attachments

Please see the bottom post in this topic for more info.

That darned t35 misfire.

Started by george sutton, 06 Dec 2009 at 17:43

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

george sutton

 :cry: With regard to the topic of my t35 misfire which began on 28 0ct., and the snippets that later appeared .those that gave advice i thank you,particularly Eddie, god bless him. The' saga' however is far from over.  In the words of the now famous song, 'I dreamed a dream''. yes i dreamed a dream that if i bought that lovely looking t35 off the websight icould get the pleasure at 77 that  i had when i was 17 and owned one.  BUT, the dream has now crashed.   having just refurbished both heads with new valves, guides , and springs, the problem of spitting back, and failing to run properly after 15 minutes or one mile run is finally obvious. Why did i get so far before i found out ?  because i was told that the oiling up of the head was due to over size rings being fitted on the rebuild, and it would need running in ! So ,off with the head yet again, But now being suspicious of poor work , i removed the barrel also. THERE it was ! Although i' miked' up the bore size the two 1.1/2'' long ex. rusted streaks of pitting of at least 0.002" deep in the upper half of the bore told the story, that i feared. Now my dream has crashed.  The bore/s are STD, and will take honeing of 5 thou, or even 10 thou.  BUT 1 can i get oversize domed pistons ? Or is any one making them?.  The bike and its problems are not knew to this club, i know, But i am determined not to see it end up in bits at the bottom of some old garage, not after all the work and money spent on it !    note,  I did a rebore on a mk.3 to 10 thou. o/s in 1950, and it ran brilliantly for 8 yrs, CAN it be done on a mk1, given the pistons , PLEASE,PLEASE help before my coffin arrives.


I do know that oversized domed pistons were available from Hepolite at some time in the past, as I have a pair of +.030 oversize in my T35 now and they work fine. I've tried to find other alternatives in case I need larger ones in future and have found that while Honda CB750 and Suzuki GSX 650 pistons can be made to fit the bores with minor modification, they are not domed as much as the originals or the Hepolite replacements. Theoretically it is possible to weld material on to the crowns of the Japanese pistons and then machine them down to shape, but that would be a poor second choice to obtaining purpose-made pistons.

george sutton

thankyou Aggettd,   I'm hoping to be lucky, in as much i have located a pair of new pistons complete. they are standered size (which is better than my old flogged out ones ) and with a gentle honeing i MAY get away with it ? got to get them in my hands first, thanks again, Denis