NTX650 or NTX750

[Ivan_J]

Hello guys.
I have a dream, to own Guzzi enduro.
Now I have opportunity to buy one.
Here in Bulgaria's s/h market have one 650 and one 750.
For sure it will be the one in better condition. But I want your opinions.
Now I ride my beloved Yamaha SuperTenere 850. My ride is 70% bad country roads, 10% highway and 20% offroad.
My worries are about rear swingarm mounting point. Will it stands my ride? I 've hear about broken gearbox cases. Are there any projects for enforcement plate, to mount swingarm to frame besides to gearbox case?
If both bikes are at same condition(prices are identical), which one to choose? I want strong low and midrange, low consumption, comfortable and strong bike.
I suppose difference between them is only engine size and cosmetics.
I have tried only 750, but different bike, not that for sale.
Both are relatively away from me, so I must choose at first try.

 

[chris a]

I'd go for the 650 but that's because I've got one and appart from the engine having slightly more horses prefer the earlyer styling with the high front mudguard and no plastic shielding on the front brake disk.The 750's have the advantage of better front brakes .
Given the amount of road use and also that you are NOT going to thrash it on the rough stuff I don't think you'll have a problem with the swinging arm mounting points.As far as I know the ususal problem is the Uni drive joint blowing up and taking out the s arm and or back of the gearbox.If you keep a regular check on it and make sure it's not worn then the problem "shouldn't occure" One remedy additional to that in usage in France in the day was to have better and slightly shorter shocks fitted.The marsocchis fitted to mine as standard are stiffer than a marine's c--k !
Teo lamer's in Holland also made a steel sleave reinforcement to fit the UJ tunnel ...probebly cost the earth and if you have fabricating skills wouldn't be difficult or expensive to make to make
I'd also fit some crash bars ....

 

[Ivan_J]

Thanks, Chris.
The ugly disk shield and under tank fairing can be removed fairly easily.
Crashbars are esential for that kind of engine.
Do you have ridden both 650 and 750. How can you compare engine power? Two more horses are not the big thing if torque is less and at higher rpms. Regarding this site http://www.motorcyclespecs.co.za/model/ ... 0%2090.htm 650 have only 4,7 kgm at 6000 rpm and 750 6,1kgm at 4700 rpm which is a way too strong pull.
I have tried 750 and compared to my SuperTen(77 hp @ 7500 rpm, 80.4Nm @ 6000 rpm) it pulls with same strenght. Never tried 650.
I don't care about max speed, I don't like to drive fast - at highway at 110-130 km/h.
Fuel consumption must be as low as possible because of high fuel prices and long distances I like to travel.
I WILL going to thrash the bike on the rought terrain, thats in my blood.
Shorter shocks are not option as far as rear end travel is very limited as stock. If I can, I will put long travel shocks.
I know many parts on guzzis are interchangable with some italian cars, so I hope U-joints also will be and it will be cheap repair.
The 750 I test has awful shocks - it was hard as a rock, it bumps on every roughness of the road. Is this normal for standart shocks or these were shot?
I know Honda XL600 will suit better on my riding stile, but I' m in love with Guzzi's italian beauty(it's ugly but I like it).
I have a month or so to decide, so I will appreciate every opinion. Thanks.

 

[chris a]

Very hard shocks seemed to be the standard for the 650's at least.Not ridden the 750 so i can't comment about it ...the 650 is perfect for me but I do much more road riding than rough stuff.
Both these bikes are pretty rare outside of italy so you will have a job finding people having experiance of both.
As far as I know, and I've owned various guzzi's for the last twenty five years, there are some UJ rebuild kits but having gone down that route once and having it blowup on the fast lane on the motorway at over 150kph I would not use a reconditioned one again.
I honestly think that thrashing these bikes over the rough will bring tears: that's why the factory baja's have a big bloc swingingarm,uj and drive box adapted.The early Dakar private entries all seemed to fail because of this design fault.
It would be far from impossible to do but expensive to modify an NTX to BAja spec and I have played with the idea.I'm pretty sure that I know just the man to do the job money being no object as he's one of the best know guzzi restaurers in france and lives about 50km away...Barnabe likes a challange,only speaks french and doesn't suffer folls at all !!! .One of his freinds had the UJ burst on her TT650 and that was the last time she ever rode on the bike.He bought it and has rebuilt it with shorter shocks and a grease nipple in the new swinging arm for UJ lubrification. Longer shocks as fitted as standard stress the UJ more and increase the likelyhood of a grenading.....
Unless you want to spend a good few thousand euros on modding a standard bike I think a yam or honda might well be the way to go for you.You could also go for it in an unmodified state but I reckon you'll find the weak spot pretty quickly .

 

[Ivan_J]

Thanks again, chris.
Mind says "go for Honda", but heart wants Guzzi.
Same with italian cars - they can ruin your savings, but you love them.
If I'll love it, I'll showw off here. If went practical, I'll renew my account at XL600.de
Cheers,
Ivan.

 

[chris a]

Your more than wellcome Ivan,
I know exactly what you mean about the heart dictating the mind : my love of the NTX intially cause me embarrasement as it was os high in the seat as I've got shortish legs and can't stand not being able to flat foot on a bike.As a result I had to get the seat cut down and recovered , fit shorter shocks ( though as I explained that does have other benefits) and drop the forks a bit.The next part of the project is to upgrade to better front brakes -the single PO5 as standard on mine are laughable but I've now got a larger fully floating disk and four pot callipers with corresponding master cylinder to fit but I need to get the spacers and adapters made which will have to wait till winter.

 

[Ivan_J]

Are there any market for NTX650?
I can buy one in mint condition. But if it's not "my bike", can I sell it in Europe?
In Bulgaria there is no market for Guzzis, so I must sell it abroad.
What is normal price for that bike?

 

[johnno]

i always feel that if i rode hard enough for long enough my 750 engine would blow (never let me down yet and runs brill) .My 650 just wants to rock and roll all day long with no worries . I enjoy both engines for different reasons the 750 is for laid back cruising and the 650 is for supermoto fun,fun,fun .Hope that helps

 

[Ivan_J]

i always feel that if i rode hard enough for long enough my 750 engine would blow (never let me down yet and runs brill) .My 650 just wants to rock and roll all day long with no worries . I enjoy both engines for different reasons the 750 is for laid back cruising and the 650 is for supermoto fun,fun,fun .Hope that helps

I comare 650 and 750 reduction ratio. Gearbox and bevel gears are the same, just primary reduction gear have different ratio. 650 drives at higher rpms than 750 for constant speed. Can you tell me whats the rpms at 5th at 100 km/h?
It can lead to higher fuel consumption for 650. Whats you readings about that?
Thanks.

 

[migcorso]

Hi from NW of Spain with another NTX750 used for both road an off-road.
I would not worry about ntx engine, the problem is gear box and transmission. It's too weak for this engine, and torque is too much for that design.
I had two u-joint failures, both in highway after hundreds of km at 120 km/h, both with old, not checked bikes. In second failure i put new u-joint (and remake gearbox, of course ), after then run in highway with out problems and also in off-road, but previous to depart to long travel i mount and umount all rear shaft and u-joint to see if all is ok.
I agree with I cris_a long shocks are bad idea with u-joint, even worse in highway, high number of revolutions i think increase hot and stress in u-joint. This is a common problem in Stelvio also, see this:
http://xa.yimg.com/kq/groups/10584229/5 ... uzzi%2Epdf
The ideal would be a long variable shock, short for road and long for off-road, perhaps someday i will mount someone like this http://www.ammortizzatori.net/anopic.htm

Another thing, old models after big mileage make noise in 5 and 4 velocity, because a bad lubrication in gearbox sprockets. After 2002 models (breva) these is corrected, but old models can suffer this problem. Check bike and if noise transmision change in five, is bad sign.

And yes i complete agree... "Mind says "go for Honda", but heart wants Guzzi" but motorbike is a thing without mind only heart .

 

[Ivan_J]

Unfortunately the 650 which is in perfect condition(just from pictures) is sold.
Now I have to choose from several Honda XLs and an NTX 750. I'll choose the one in best condition. Sadly there are no parts avalable here for guzzis. So if the bike needs some repairs, I'm not gonna get hands on it.
Next week I'll go to see all the bikes I found on ads localy.
migcorso, whats the fuel consumption of your NTX750?
Thanks for replies.

 

[migcorso]

Between 6 and 7 liters/100 km depends on throttle BUT ntx needs 98 octane and lead substitute, this is more $ than 1 liter up or down.

Vsss

 

[Michael H]

Interesting thread. Didn't know about the U joint problem and certainly something to have checked.

Need some guidance on NTX650 engine probs.
In short I've broken one piston - the rim that goes around the crown, nearest to the spark plug.
Other piston has got some scoring on it. Cylinders still in good condition as are valves.

Problems started over New Year. I took it for a long 300km ride. Was going pretty steady (read fast) for a period of 20-30 mins. Bike died. Roadside mechanic took plugs out and advised that the left plug needed replacing - the electrodes had almost welded over to the central pin on the plug. Left the bike to cool for 20 mins and it was drivable again but kept rpm down below 3000 rpm to do last 30km or so of ride.

Couldn't locate proper plugs in the town I was visiting nor since I returned home. They don't stock parts for Guzzis in Cambodia. Been riding it intermittently since New Year and last week gave it a bit of a thrashing for a short stretch. Couple quick gear changes and upped the revs for a blast when heard some distressing noises from left hand cylinder. Able to nurse the bike to a pair of reliable western mechanics. They showed me the broken piston a day or so later. We need technical specifications to check engine tolerances for crank etc. The rest of the engine seems in good nick - just the pistons gone. Whilst it's off the road I inted to get all new bearings, seals and gaskets. Plus the U Joint will be checked. If anyone can point in the right direction to a pdf of engine tolerances can be found, preferably in English, be v grateful.
Cheers.
M

 

[Michael H]

Also - can anyone comment on availability of pistons for the NTX650. Is it advisable to change from stock to Wiseco or another brand? Thinking of whatever is most reliable/durable.

Any other modifications to the bike that would keep it purring nicely?

 

[chris a]

All the engine specs are the same as a v 65 appart from the ignition timeing and carburator bits...best have a look over at http://guzzitek.org/gb/cadres_gb.htm.They have all the relevent manuals there...possibly only the NTX one in Italien.
If I were in your shoes I'd fit a set of gillardoni piston and cylinder sets and blueprint them for valve to piston clearence ...your likely to unleash a few hidden horses there but it means trimming down the barrels which is only doable on a new set.The pistons might need a trim too.Ed Millich is currently THE MAN for small bloc tuneing and you could contact him at http://guzzipowered.forumcircle.com/ if you have big wads of spare cash to spend and want to get her really going.
Mine runs nicely on straight 98 without additive .It's not going to get ethanol until I have no choice !
Keep us posted on how you get along

 

[sign216]

Michael, you're in Cambodia, right? I would stick with stock pistons, although they might be impossible to find. Custom is expensive, and fit is always a question, but it might be your only choice.

American brands like Wiseco are likely to be $$$. Since the Orient is known for its motorcycle industry, perhaps there is a local piston manufacturer that will produce a piston to the specs you need. If you can scour the internet for right shop manual for your engine.

Joe

 

[Michael H]

Thanks gents.

Most local shops are geared up for small capacity bikes - Daelim from Korea made copies of Honda Super Cub and those bikes are everywhere along with a full range of modern Honda/Suzuki/Yam moped/scooters. There are lots of bigger Japanese dirt bikes - Honda XRs, Bajas, Degrees, AX1s etc. Suzukis, Yamaha and Kawasaki less common. No one with old Guzzi parts though. My bike's from 92 and anything will have to be ordered in. Will probably stay with stock barrels and see if can get pistons for them.

Did have a few teething problems with electrics and had been able to get that sorted.
Plus the clutch had to be replaced and that was done locally although not sure what clutch is in there as requires a pretty strong grip to pull the clutch lever in.

Fingers crossed it will be back on the road in 6 weeks or so - depending on freight!