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
D7 Gear box problems
Avatar
Pootle
Southampton
Top Gear User
Club Member
Forum Posts: 55
Member Since:
September 19, 2013
sp_UserOfflineSmall Offline
1
November 8, 2020 - 9:18 am
sp_Permalink sp_Print

My recently rebuilt D7 engine was jumping out of third under duress and also it was difficult to change down from third to second without going through to neutral. My the gears are from a D1/3 so thinking it was a weak spring under the ball bearing on the selector plate I stripped the engine. While waiting for a new spring I decided to take everything apart and was surprised to find the amount of wear on the shaft the selector plate rotates on, may be enough to account for the reduced spring pressure. It’s an area worth looking at when rebuilding a gearbox. Whilst looking at my collection of selector plates some have deeper recesses for second gear than others, I’m guessing this was introduced in an attempt to stop the D7 second gear jumping. 1F6EBF6C-AC29-40D3-A7E9-B47BD65D5ACC.jpeg

Avatar
cocorico
Central France
Top Gear User
Site Member
Forum Posts: 3293
Member Since:
June 23, 2013
sp_UserOfflineSmall Offline
2
November 8, 2020 - 9:36 am
sp_Permalink sp_Print

Yes, we recently discussed this very problem, with lots of input from Sponge on the effects of wear in that component and how to ameliorate it. It's also described in FAQs, ** Please log in to view **, specifically post 5.

Avatar
Pootle
Southampton
Top Gear User
Club Member
Forum Posts: 55
Member Since:
September 19, 2013
sp_UserOfflineSmall Offline
3
November 8, 2020 - 10:23 am
sp_Permalink sp_Print

I had a suspicion this wasn’t original thinking but as I had it in bits thought I’d mention it.

Avatar
sunny
Norfolk
Top Gear User
Club Member
Forum Posts: 1657
Member Since:
January 9, 2013
sp_UserOfflineSmall Offline
4
November 8, 2020 - 10:25 am
sp_Permalink sp_Print

the  thing  is  its  a CRASH   gearbox     not   modern  sikrowmesh       second  gear  is   for  geting   to  therd gear   & back to  first gear      

something    we  tend  to  forget  wen  riding   all  this  dont  help   much  so  go  carfull   

Avatar
GlenAnderson
Dover
Top Gear User
Club Member
Forum Posts: 248
Member Since:
August 27, 2013
sp_UserOfflineSmall Offline
5
November 8, 2020 - 2:09 pm
sp_Permalink sp_Print

To be pedantic, it’s a constant mesh gearbox. 

Anyway, yes, that bit’s knackered. It will certainly have contributed to your selection problems. 

I think that it’s a sub-assembly that is often either left in place, or removed and refitted complete, and seldom actually gets investigated at rebuild time. 

Bantams are so often owned by the inexperienced that now, sixty to seventy-odd years after they were built, it’s more uncommon to open one up and find it ok than it is to unearth utter bodgery. 

Avatar
Sponge
Lancashire (A chip shop somewhere near Preston)
Top Gear User
Club Member
Forum Posts: 341
Member Since:
November 6, 2016
sp_UserOfflineSmall Offline
6
November 9, 2020 - 4:01 pm
sp_Permalink sp_Print

Yes, that 'pin' is well worn. Exactly as I have described. The selector plate jumps up on the ball and the bike jumps out of gear. 

If you replace the worn pin and firm up the spring with a shim it ought to resolve, it certainly worked on 2 of my bikes. To be sure I would also give everything a good clean up and a thorough inspection under strong lighting. 

Well done for diagnosing the problem. 

    

Forum Timezone: Europe/London

Most Users Ever Online: 223

Currently Online: rusty1, Number6
5 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Top Posters:

cocorico: 3293

Cornish Rooster: 3109

bart: 2689

Blue Heeler: 2546

David Dale: 2349

Sprung Chicken: 2301

Piquet: 2063

Mags 1: 1863

jess steele: 1674

sunny: 1657

Newest Members:

user

Forum Stats:

Groups: 9

Forums: 48

Topics: 11010

Posts: 97755

 

Member Stats:

Guest Posters: 1433

Members: 3001

Moderators: 0

Admins: 3

Administrators: Bantam-Super, JMD, Stoo63