'70's Ambo 4 Speed Questions?

[Tom H]

I have a few questions about the 4 speed trans. I'm trying to figure out if the 2 transmissions that I have are normal or if something is wrong with them.

Let's say that your sitting at a traffic light, the crossing is 5 lanes wide. When I start up in first, I can go all the way across, but I have to let the engine come back to just about idle before I can go to second. The down side to this is that I have lost a bit of speed and it bogs when I'm in second. If I don't pause for a moment, it makes nasty noises as I go into second. If I just go a few lanes and shift earlier, it shifts "OK?" but is bogging in second due to not enough speed for the gear. Is this normal with the 4 speed?

Right now I have a 5 speed and the 5 speed rear end in the bike and it goes through the gears well, except for first which takes a bit of slipping the clutch compared to my Eldo. The Eldo you can just about give it a bit of throttle and dump the clutch, the Ambo takes a bit more finesse that I can live with.

I'm thinking of converting it back to the 4 speed setup. So is this the way the 4 speed box works? Or do I need to strip them down and shim something like the shift drum?

I hope I gave enough info. Thanks for the opinions and help!
Tom

[DARKHORSE]

Hi Tom, I have a 71 Ambo and it shifts pretty much as yours. I dont have a problem letting out the clutch though.  Maybe check your tune and keep your idle at 1000 rpm.  With the four speed pretty much if it aint broke don,t bother it. I would like to try a lightened flywheel in mine next. would probably make a big difference in the Ambo. Cheers.

[Tom H]

DARKHORSE, thank you.

And to be clear, with the 4 speed I can give it a bit of throttle and just about dump the clutch like the Eldo does. Heck even a bit quicker with the low first gear.

Tom

[Antietam Classic Cycle]

If I don't pause for a moment, it makes nasty noises as I go into second. If I just go a few lanes and shift earlier, it shifts "OK?" but is bogging in second due to not enough speed for the gear. Is this normal with the 4 speed?

No.

[arveno]

My 4 speed shift well , actually shift better at higher rpm.

[bigbikerrick]

Something isnt right with your transmission. I have ridden an ambo, and it shifted through the gears nicely, just like my eldo, with one less gear.
They do require a certain positive technique to shift properly, but what you describe sounds abnormal to me.
Rick.

[Rod]

I have a 4 speed Ambo and a 5 speed Eldo. The 5 speed shifts beautifully, the 4 speed is clunky and noisy. That's part of the charm :-).  But it shifts fine, nothing like what you are describing. I can rev it right up in every gear and it takes off like a rocket (in relative terms) when I release the clutch, I don't "dump" it.

Make sure you are holding the shift until you release the clutch, as described in Greg Bender's recommendation on shifting loops:
http://www.thisoldtractor.com/moto_guzzi_loopframe_transmission_-_shifting_technique.html

They are easy to rebuild. Sounds like yours needs it.

[Tom H]

It sounds like most of you say that it should shift from 1st just about like my 5 speed always has. I've had both bikes since 1980 and the 4 speed never shifted into second like the 5 speed. Even tried another 4 speed and it did the same thing. First to second never has been smooth, but the rest of the gears changed pretty much like the 5 speed.

Sounds like I will have to pop it open and see if I can see anything. Could shimming the shift drum get rid of the problem?

Thanks again,
Tom

[John Ulrich]

For sure shim it.  What I found was.. I needed to put a thin shim on both ends of the drum instead of a thicker one on either end. 

[guzzisteve]

I've had a few Ambo's and they seemed to shift fine. My 700 that I ride all the time has always shifted a bit clunky and didn't like being rushed. While trying to sort out a engine oil leak coming out of the bellhousing I put in a light flywheel. It is 30% lighter than a LeMans. It shifts like butter now. I have 2 more 4 speeds from the other 700's but never tried them.
I think John has the right answer, factory left the drum a bit too loose but centered.

[luthier]

Throw some G70 nulon in the 4 speed box. Sounds like it's a bit sticky in there.

[garbln]

My 70 Ambo is a clunky shifter but it likes to be wound up a little in first before shifting.  Remember this is an engine speed  transmission so the trans input shaft should be close to the engine rpm when letting out the clutch or you will get a bit of a lurch.  With the heavy flywheel it takes a little more time for the engine to slow down after revving up after first gear.  I have also found with my transmission a timid shifting foot results in bad shifts.  Trying to ease into a gear doesn't work well at all, just bang the shifter with your toe or heal with a bit of force and you are good.  This is all assuming the clutch is set up properly of course. 

[Tom H]

Thanks again for letting me know how your 4 speed feels. Looks like I'm going to have to play with them a bit. For now my 4 speed is on the back burner since other things have come up that need my time.

Thanks again!!
Tom

[Antietam Classic Cycle]

The 4 spd. in my '69 Ambo with 110,000 miles on it (never rebuilt or even opened) shifts better than any other vintage Guzzi transmission I've experienced. They definitely got it right during assembly 50 years ago!

I definitely do not "bang" the shift pedal, there is no need to. I simply pull in the clutch, push the pedal down with my heel or toe and hold it down while I release the clutch. In my experience, that last bit is very important if you want a Loop 4 spd. transmission to shift properly.