A A A
Avatar

Please consider registering
Guest

Search

— Forum Scope —






— Match —





— Forum Options —





Minimum search word length is 3 characters - maximum search word length is 84 characters

Register Lost password?
sp_Feed sp_PrintTopic sp_TopicIcon
2nd gear jumping D7
Avatar
NeilSh
Second Gear User
Site Member
Forum Posts: 10
Member Since:
August 11, 2020
sp_UserOfflineSmall Offline
1
October 16, 2020 - 1:01 pm
sp_Permalink sp_Print

I have the problem of 2nd gear jumping on my 1966 D7 Bantam 175. I have seen this on ebay ** Please log in to view ** it says in the blurb it should fix the problem.

Does anyone have experience of fitting this and does it work? Would I have to take the engine off the bike to fit this?

Avatar
Stoo63
GLASGOW
Area Rep
Forum Posts: 978
Member Since:
April 19, 2018
sp_UserOnlineSmall Online
2
October 16, 2020 - 2:19 pm
sp_Permalink sp_Print

Neil, this is a subject which crops up very regularly. In fact it's so common it's even in the FAQ. ** Please log in to view **   It's due to the modifications made to the D7 shafts after the earlier ones had splines on the shaft. Lots of previous topics on the Forum will explain the issue. The solution is to source some earlier shafts with the splines and replace your D7 ones. That cog on eBay won't help in any way and you could probably buy the internals for an early gearbox for that price. Bottom line is that you're gonna have to split the cases to see what shafts you've got, so you might as well have replacement shafts at the ready to fit...

 '55 D3 Battery; '58 Square Four (project); '59 D1 direct lighting plunger; '59 Tiger Cub; '60 5TA;  '76 FS1-E; '97 Honda Sky SGX50.

Avatar
NeilSh
Second Gear User
Site Member
Forum Posts: 10
Member Since:
August 11, 2020
sp_UserOfflineSmall Offline
3
October 16, 2020 - 5:59 pm
sp_Permalink sp_Print

Thanks - thought that would be the case. Will source some earlier shafts with splines.

Avatar
GlenAnderson
Dover
Top Gear User
Club Member
Forum Posts: 173
Member Since:
August 27, 2013
sp_UserOfflineSmall Offline
4
October 16, 2020 - 6:40 pm
sp_Permalink sp_Print

The D7 engine I had in my D1 for a while used to jump out of second, usually at the most awkward of moments. Now I know why. laugh

Avatar
Sponge
Lancashire (A chip shop somewhere near Preston)
Top Gear User
Club Member
Forum Posts: 316
Member Since:
November 6, 2016
sp_UserOfflineSmall Offline
5
October 16, 2020 - 11:09 pm
sp_Permalink sp_Print

There is another reason why they jump but usually in any gear. That is the pin that holds the selector mechanism together gets worn and the selector quadrant can then jump over the detent ball.  Anybody stripping their engine down to replace their gear shafts would be well advised to check this pin make good as necessary and insert a shim behind the spring to tighten it all up.  Some folks deepen the notches in the quadrant but its not necessary.

I have several D7s and all are running the original stock gearshafts but with my little mod to the selector assy. The only D7 engine I have that jumps out of gear is one that was built by somebody else. Its on my list for surgery sometime before spring 21.

Happy to explain in more detail and simpler if this confuses anybody. If anybody is interested that is ?

It has been a long day.

Avatar
stubaker58
Sunny Felixstowe
Area Rep
Club Member
Forum Posts: 544
Member Since:
June 13, 2015
sp_UserOfflineSmall Offline
6
October 17, 2020 - 12:48 pm
sp_Permalink sp_Print

Hi Sponge,

I for one would be interested in your thoughts, especially with some pictures to help my understanding!

regards.

D7/14 hybrid (4 speed with D7 crank etc.) on the road, D10 Bushman awaiting rebuilding.

Avatar
Stoo63
GLASGOW
Area Rep
Forum Posts: 978
Member Since:
April 19, 2018
sp_UserOnlineSmall Online
7
October 17, 2020 - 12:59 pm
sp_Permalink sp_Print

Absolutely, Stu. The more info on this prob, the better. Maybe a stiffer spring would help too. I've tried unsuccessfully adding an extra washer before to take up some "slack"

 '55 D3 Battery; '58 Square Four (project); '59 D1 direct lighting plunger; '59 Tiger Cub; '60 5TA;  '76 FS1-E; '97 Honda Sky SGX50.

Avatar
cocorico
Central France
Top Gear User
Site Member
Forum Posts: 3296
Member Since:
June 23, 2013
sp_UserOfflineSmall Offline
8
October 17, 2020 - 1:09 pm
sp_Permalink sp_Print

I think it is this area Sponge is referring to.

IMG_1871.JPGIMG_1872.JPGIMG_1873.JPGIMG_1874.JPGIMG_1875.JPGIMG_1876.JPG

sp_PlupAttachments Attachments
Avatar
NeilSh
Second Gear User
Site Member
Forum Posts: 10
Member Since:
August 11, 2020
sp_UserOfflineSmall Offline
9
October 18, 2020 - 10:02 pm
sp_Permalink sp_Print

Sponge - would be great if you could explain a bit more. Does this mean I should hang back on sourcing some earlier shafts with splines if I check this pin, make good as necessary and insert a shim behind the spring to tighten it all up?

Forum Timezone: Europe/London

Most Users Ever Online: 223

Currently Online: ZZ, Stoo63
12 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Top Posters:

cocorico: 3296

Cornish Rooster: 3122

bart: 2757

Blue Heeler: 2624

David Dale: 2388

Sprung Chicken: 2369

Piquet: 2117

Mags 1: 1887

Munchkin: 1844

jess steele: 1705

Newest Members:

_3438

Forum Stats:

Groups: 9

Forums: 48

Topics: 11037

Posts: 99216

 

Member Stats:

Guest Posters: 1435

Members: 2837

Moderators: 0

Admins: 3

Administrators: Bantam-Super, JMD, Stoo63