T upgrade

[sixpack]

good day to all----newbe here---i own a well running 75 850T, and looking to improve on performance---i recently saw a pair of 1000cc round fin barrels on e-bay that appear to be a direct bolt on ----my question is what other considerations should i be looking at if i were to mount the bigger jugs---bigger carbs/cam---ect.---or should i leave well enough alone????----cheers-----bob

[WCGuzzi]

Bob - between this and other Guzzi forums, you will find a lot of information and opinion on your question. If it were me, and the bike is running well, I would not open the can of worms. Instead, I would use the T for what it is good for, and have another bike to go fast upon. If you opt for the larger displacement you will have plenty of company. All kinds of Guzzisti out there. Welcome and please post pics. dennis

[john zibell]

About all you would get is more vibration and maybe a little more power. The 850 is a sweet engine and I'd leave it alone. In my opinion, you would get more useable performance from lightening the flywheel than by increasing displacement.

[Rafael]

The easiest and probably the most effective way to get more power out of your T is to get PHF/M carbs . The round slide pumper carbs provide a mild acceleration improvement over the square slide carbs. Upping the size to 36mm from 30 will provide the most improvement, along with performance mufflers and air filters. The selection of permanence mufflers for old tontis is less than it was in there time, but I'm sure you can find something out there. I would only lighten the flywheel if you upgrade the motor; lighter rods and pistons.

The hole in the 850 block is smaller than the 1000 block. You'd have to have the 1000 sleeves trimmed to fit. That's what I did on my T-3, ended up with 850 base gaskets and 1000 head gaskets. Gilardoni makes retro kits.

[sixpack]

Bob - between this and other Guzzi forums, you will find a lot of information and opinion on your question. If it were me, and the bike is running well, I would not open the can of worms. Instead, I would use the T for what it is good for, and have another bike to go fast upon. If you opt for the larger displacement you will have plenty of company. All kinds of Guzzisti out there. Welcome and please post pics. dennis

as usual a very helpful website----most replies lean to leaving the top end alone---sounds like good advice--i should have given a better hist of the bike in my 1st post---the bike was rescued from a local Craigslist post with three year old tags on it ---priviest owner must have been a drunk as there was lots of driveway tipover rash---every light lens from turn signal to head light was hammered ---allowing me the freedom to freestyle the rebuild see pics for light choice -----once i qualified the cylinders bores (thanks to hist. post this forum)----i lit it off she settled down without any big noises ---which gave me confidence to saddle up for the 1st torture test----immediately experienced a slippery clutch (probably why the bike was parked 3 years ago)---after crabbing the frame (again thanks to this forum) i installed a new clutch and bravely set out on my 1st road trip a 300miler ---the bike made the trip but the trany complained the whole way with false neutrals, misshifts ,no shifts---- anyway got it home and put myself through 5speed school ---with some shimming sealing and removing 5lbs from the flywheel i was back on the road----since then the bike is becoming my favorite mount over a T160--two Commandos---couple of Triumph twins and a Rapide---many thanks for everybody,s input ---hope to see you on the road---bob

[sixpack]

About all you would get is more vibration and maybe a little more power. The 850 is a sweet engine and I'd leave it alone. In my opinion, you would get more useable performance from lightening the flywheel than by increasing displacement.

Good day to you John---Bob here (sixpack)---took your advise and scored some pumper carbs on e-bay--although only 30mm---the seller claimed they were on a 1000cc bike ---my question to you is can you prescribe the correct internals for fitment on my 75 850T????---also when running the bike at a brisk pace in 75 degree weather here in sunny So. California i pull over and the temp of the rear end only allows my hand on the rear end for about 6 seconds before thing start to get to warm----i drained and renewed the 90wt three times in 3thou mi to try to purge the unit---is this normal temp????----cheers ----bob

[pete roper]

Baware! Early 850T's sometimes came with bevelboxes with the 'Level' plug in the wrong place! Far too low!!!! Riding any distance will screw the gears.

Drain the box and refill by measure rather than using the plug. From memory they take 385ml!!!!

Pete

[Series4]

And don't forget the moly additive for the rear rive when you change the oil

[john zibell]

I agree with Pete and never trust level plugs. Always add oil by measure. Skip the moly in the rear drive, just use a good synthetic 75W90 gear oil. I've seen moly contribute to bearing damage. No other manufacture recommends moly for that reason. It is good for gears, but bad for bearings. Specification is for 250cc of lubricant in the rear drive.

[Amboman]

I agree with Pete and never trust level plugs. Always add oil by measure. Skip the moly in the rear drive, just use a good synthetic 75W90 gear oil. I've seen moly contribute to bearing damage. No other manufacture recommends moly for that reason. It is good for gears, but bad for bearings. Specification is for 250cc of lubricant in the rear drive.

Not 250cc on a "deep sump" 850T (shared with the V7 Sport, Eldo and some very late Ambos) rear drive! 360cc is the correct amount for that rear drive design. 340cc of gear oil and 20cc of moly. Original bearings in my 100k miles '69 Ambo, moly used all of it's life, bearings are like new (as are the gears). YMMV.