1974 twin cam special

[Coopers]

I have rebuilt a 1974 special but I could not find a good gearbox builder or spares in New Zealand.  The current Renault box is a bit noisey but worst the gear change is poor. 3rd to 2nd is virtually impossible with any speed on and 5th is very agricultural to select .Any suggestions for a solution. Will any other box fit, is there anything in the States that might improve things, who supplies spare parts?

All suggestions welcome

[BDA]

The first thing to check is your linkage. Usually the first thing to go are the plastic top hat bushings at the bottom of the shift lever. After that, check the u-joint and the rod end near the bell housing, then the u-joint at the back of the tranny. SJ Sports Cars in England sells brass replacements for the plastic bushings. I assume they can help you with the u-joints too. The rod end should be a pretty standard part.

I am not a gearbox expert (as if I am an expert at anything!) but if yo have a synchro problem, I suspect the hardest to find is the 5 gear since the gear is a NLA part. I have seen them in the US EBay. I don’t know the availability of the other synchros. You may be able to find them at Renault parts specialist in Europe.

There are some knowledgeable owners in OZ If not NZ. Hopefully you can hook up with one of them.

Good luck and and keep us posted!

[jbcollier]

If the transaxle is noisy, stop driving it.  Right now.  Some parts are made of pure unobtainium.  New Zealand is absolutely car and bike mad.  There has to be someone who can help.  I'm in Alberta Canada and I have two ex-New Zealander friends who may be able to come up with a recommendation.  They know Graeme Crosby and have supplied him with quite a few bikes for his specials.  I'll ping them right away.

[Coopers]

 :ttiwwp:thanks guys, I clamped the gearbox end of the linkage and had very little play at the shift lever end, feel sure it’s either the indent mechanism or just simple cone wear on the synchromesh

[BDA]

I just noticed you are a new poster...   

When you say that gear change is poor, do you mean it is vague? While your method of checking for linkage slop seems reasonable, I would check each individual joint. Again, the plastic top hat bushings at the shift lever is where I’d start.

If by “5th is very agricultural to select” you mean it requires more effort than you expect to get in the fifth gear gate, that is because of the detention mechanism that adds resistance to it being shifted into R and 5. I believe r.d. enterprises sells the detention cam (or possibly someone in NZ could make you a spare freeing you to experiment with the profile (did that make sense? ).