Author Topic: V50/V65  (Read 2989 times)

Offline misterswizzo

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V50/V65
« on: July 02, 2017, 01:09:44 AM »
I have a 1981 V50. My favorite mechanic suggests that it may be possible to simply swap the engine (which has an unidentifiable noise and only gets about 30 mpg) for a V65 engine that I can get really cheaply. Does anyone know if this is an easy engine-for engine replacement or does it require more extensive work?

Offline Huzo

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Re: V50/V65
« Reply #1 on: July 02, 2017, 03:28:13 AM »
Firstly welcome to the forum, love your name ! Dunno about your nice Guzzi, but many here will, you've come to the right place.

Offline Rick4003

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Re: V50/V65
« Reply #2 on: July 02, 2017, 10:06:45 AM »
You should check SED's thread on installing a 650cc in his Monza, there should be some good info for you there. You might be able to fit a 750cc in it too.

Sent from my SM-J105F using Tapatalk

Moto Guzzi 850 T5 (850 sport) - 1985
Moto Guzzi Ambassador - 1967
Yamaha FZR 600 - 1996 - SOLD

Offline misterswizzo

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Re: V50/V65
« Reply #3 on: July 02, 2017, 10:53:15 AM »
The 650/ Monza thread caught my eye. I'll have to give it a closer look.

Theres a story behind the name but I always say that even the most abbreviated version isn't worth the time it takes to get to the punchline.

Thanks

Wildgoose Chase Moto Guzzi

Re: V50/V65
« Reply #3 on: July 02, 2017, 10:53:15 AM »

Offline Psychopasta

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Re: V50/V65
« Reply #4 on: July 02, 2017, 02:38:17 PM »
Definitely come to the right place. SED's thread will be great, also check out anything by Chuck in Indiana.

- P
V50 Monza 1981
Triumph Tiger 2012
Ducati Diavel 2014
Triumph Bonneville Bobber 2017

Offline Rick4003

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Re: V50/V65
« Reply #5 on: July 02, 2017, 07:57:12 PM »
You should also check this thread. Although the pictures seem to have gone. Must be something about this photobucket thing.

http://wildguzzi.com/forum/index.php?topic=81033.0

-Ulrik
Moto Guzzi 850 T5 (850 sport) - 1985
Moto Guzzi Ambassador - 1967
Yamaha FZR 600 - 1996 - SOLD

Offline SED

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Re: V50/V65
« Reply #6 on: July 09, 2017, 02:41:38 AM »
Great project! Glad you are finding the V65 Monza thread helpful.

The engine is a straight fit in the frame, but there are some details.  Check the crank endplay before you swap because the crank thrust washers on the early V65s would wear quickly causing problems. All the small blocks have valves that have a reputation for dropping their heads at ~20,000 miles. The solution is to replace with new V75 valves and single coil progressive springs - they are a straight fit. (If the V65 engine has dual coil springs it almost certainly has original valves - replace both valves and springs.)

If you are keeping your transmission you will need to swap the clutch disk as the input shaft on the V65 is larger.  The V65 has different timing marks (8* vs 10* as I recall) so you may want to swap the flywheel too. 

You will need the V65 intake manifolds and carbs. The cylinders are 3 fins longer putting the top of the carbs higher and outward compared to the V50 and the V65 manifolds give more room for the throttle cables into the carb tops. Guzziology recommends removing the accelerator pump and drilling the atomizer larger and the mod works great on my bike.

The different intake manifolds mean you need to use the V65 airbox or pod filters.

The stock V65SP gearbox has higher ratios than the V50 'box and the Lario and V75 higher still.  If your bike is a V50III it is an easy swap, but if you have a V50 (not sure about V50II) the output splines are different and you will need to find a V50III drive shaft (the V65 & 75 shafts are longer).

This is what I can remember now.

BTW Steam Driven on Wild Guzzi has put a V75 engine in a Monza frame but the cylinders are longer so throttle cable clearance at the top of the carbs is even tighter.  Steam Driven was super helpful to me and has good information in the archives.

Cheers,
Shawn
 

   
1983 LeMans III
1981 Monza
1947 Ariel Red Hunter
1939 Ariel Red Hunter
1937 Guzzi GTV

 

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