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V7 Special gearbox return spring

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GUZZIPETE View Drop Down
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    Posted: 02 Sep 2018 at 15:01
Changed a weak but unbroken return spring a couple of weeks ago. The gearbox is now not selecting well at all. The spring tension seems unequal forwards and backwards, with the greater tension in the backward (down change direction). So it will jump out of first on the merest amount of overrun. 

When I change up, the lever doesn't spring back up ready for the next upchange. I've had it apart twice since first changing it with the same result both times. I'm not sure if I have done anything inadvertantly whilst in there, or if there is a coincidental fault. The only possible issue I can think of involves the pawl and gear which is visible on the RH side. I don't think I moved anything there, but beginning to wonder now.

I thought this would be a simple job!LOL
1971 Moto Guzzi V7 Special
1974 Laverda 750 SF2
1979 Laverda 3CL

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Dave P. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 02 Sep 2018 at 18:33
Hi Pete. I'm guessing we are talking here about the four-speed box? Have you tried turning the eccentric adjuster in the back of the gearbox? It may be that the new spring needs a different setting to the old one.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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GUZZIPETE View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GUZZIPETE Quote  Post ReplyReply Direct Link To This Post Posted: 02 Sep 2018 at 21:38
Thanks Dave. Yes, it's a standard 4 speed. 
I hadn't thought seriously about touching the adjuster at this stage, as I didn't want to alter a 'base-setting' and add possible further complication to the fault finding. I've never had to adjust them on any of the bikes before, so I don't have experience of how much effect it has. I can see that the eccentric is quite pronounced, so can understand how it could affect the spring tension. I will try some adjustment and report back. 
I think you mentioned before that you have changed your spring before on one of the bikes, did you have to make an adjustment after that?
1971 Moto Guzzi V7 Special
1974 Laverda 750 SF2
1979 Laverda 3CL

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 02 Sep 2018 at 21:47
Hi Pete. When I rebuilt the four-speed that I got from Gutsibits I took Greg Bender's advice and modified a five-speed spring to fit. He reckons that the later spring is better. So as I was working from scratch I had to experiment with the eccentric adjuster until I got it right. It's not difficult to do. The instructions for modification and fitting are on his website. Let us know how you get on.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GUZZIPETE Quote  Post ReplyReply Direct Link To This Post Posted: 02 Sep 2018 at 22:09
That's interesting Dave. I have a 5 speed spring, so I'll have a look at that article on Greg's site.
1971 Moto Guzzi V7 Special
1974 Laverda 750 SF2
1979 Laverda 3CL

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GUZZIPETE View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GUZZIPETE Quote  Post ReplyReply Direct Link To This Post Posted: 02 Sep 2018 at 22:26
This sounds like it could be a good tip for pre-setting the adjuster too Dave, on Greg's site.

"When installing the small triangle shaped rear cover plate, set it in loose and check the 5 bolt holes that secure the selector cover. If they don't line up true, loosen the 19 mm lock nut on the adjusting screw and rotate as required to line the bolt holes up. This insures that the shift lever may stroke in both directions when shifting."
1971 Moto Guzzi V7 Special
1974 Laverda 750 SF2
1979 Laverda 3CL

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 2018 at 09:52
Ah yes! I'd forgotten about that.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Amboman Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 2018 at 14:33
Make sure that the spring isn't a bit too long and isn't scraping against/catching on the rear cover. I've found it necessary to trim the "prongs" of the spring so that it didn't. Also, in a few instances I've had to bend the 5 spd. spring in order to remove "slop" from the shift selector.

I had been using the 5 spd. spring, but have now gone back to using the 4 spd. spring again.
Charlie
'69 Ambassador,'71 Ambassador,'73 Eldorado,'75 Eldorado police,'76 Convert,'77 Morini 3 1/2 Strada,'81 Ducati 500SL Pantah

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Post Options Post Options   Thanks (0) Thanks(0)   Quote GUZZIPETE Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 2018 at 15:41
Thanks for those points.

The spring was too long, I had to grind the ends off a little.

I have of each of the springs, so I will look out slop with the 5 speed, and use the 4 speed if it's an issue. Hope to get back into it tonight.

Pete.
1971 Moto Guzzi V7 Special
1974 Laverda 750 SF2
1979 Laverda 3CL

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Post Options Post Options   Thanks (0) Thanks(0)   Quote GUZZIPETE Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 2018 at 22:11
Fitted the 5 speed spring and worked on 'tuning-in' the selection with the adjuster tonight. It feels more positive at this stage, but always difficult to tell on the bench.
Will finish re-assembly and road test it tomorrow.
Charlie, why did you revert to the 4 speed spring I wonder?
1971 Moto Guzzi V7 Special
1974 Laverda 750 SF2
1979 Laverda 3CL

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 2018 at 23:36
The trimming of the "progs" was what I was referring to when I mentioned modifying the five-speed spring, they are too long. I thought that the later spring felt stronger so I'm also interested in why Charlie reverted to the four-speed version.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Amboman Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 2018 at 14:01
The only reason I went with the 5 spd. spring in the first place was due to due to a period of unavailability of the 4 spd. spring. I always disliked having to trim and bend the 5 spd. spring to make it work, the 4 spd. spring was a direct fit, so when they became available again I went back to using it.

How many 4 spds. have suffered a broken return spring? In my 35 years of owning Guzzis, I can't say I've heard of one. How many 5 spd. springs have broken? Dozens! It took Guzzi three tries to make a spring that didn't break.
Charlie
'69 Ambassador,'71 Ambassador,'73 Eldorado,'75 Eldorado police,'76 Convert,'77 Morini 3 1/2 Strada,'81 Ducati 500SL Pantah

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Post Options Post Options   Thanks (0) Thanks(0)   Quote GUZZIPETE Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 2018 at 15:30
I can see your logic there Charlie. I'll see how I get on with the 5 speed, now that it's in there, but might revert to the 4 speed if I don't have success in sorting the initial issue.
1971 Moto Guzzi V7 Special
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1979 Laverda 3CL

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 2018 at 23:32
Hmm, that puts a different perspective on things. I'll leave the five-speed spring in there but if it fails I'll go back to the original four-speed. I carry one on the bike anyway and with the four-speed box you can if you have to change the spring on the side of the road. Pity the later gearbox doesn't have that facility. Every day's a school day.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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GUZZIPETE View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GUZZIPETE Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 2018 at 21:43
Road tested the bike tonight, but it's still not right. The gear lever is still biased to the rear, so that when I change up a gear,  the pedal is not springing back up ready for the next gear without some help. This also means that it will easily jump out of first. I will have another go at moving the adjuster, but this time I will try to adjust it so that the bias is the other way, rather than setting it for what felt like an equal loading in either direction.

I don't know about changing it on the roadside Dave, but I will be able to do it in my sleep soon! LOL
1971 Moto Guzzi V7 Special
1974 Laverda 750 SF2
1979 Laverda 3CL

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