97 1100 Sporti Timing Chain Tensioner

[MedicAndy]

My 97 Sporti rides great, but the engine sometimes has a jerking motion, which cuts the engine off when stopped on a stoplight, unless I let the engine idle at around 1200-1400 rpm's, which keeps the engine from cutting off when this jerking happens. I can feel a distinguished jerking motion coming from the engine, followed right after by the engine cutting off. I also notice the same engine jerking feeling when I'm riding at a constant lower speed. This jerking feeling goes away as soon as the rpm's go above 3k, or when I'm riding faster that 45 mph. This bike only has 7400 miles on the engine, so I'm pretty sure that the original timing chain is still good. However, I was told that this jerking motion could possibly be due to a worn out timing chain tensioner. I bought me a new chain tensioner, and I was wondering if anyone knew if I needed to take the chain off in order to remove the old tensioner and to install the new one, or can the chain remain in place for the removal of the old and installation of the new tensioners? I will replace the old chain, if the currently installed chain needs to come out in order to to install the new tensioner. 

I'm only asking, since it seems that it will take some special tools to remove the timing chain, tools that I would need to buy.

Andy








upload pictures online privately
 

[swooshdave]

97s still have carbs? Start there. Not saying that with Guzzi's reputation during those years that it couldn't be the tensioner...

[Antietam Classic Cycle]

I seriously doubt it's the tensioner at only 7400 miles. Sounds more like an injection "glitch" to me. Maybe a slight adjustment to the little potentiometer in the ECU? Did wonders for my Centauro, which had similar symptoms. 

[MedicAndy]

97s still have carbs? Start there. Not saying that with Guzzi's reputation during those years that it couldn't be the tensioner...

My 96 is a carb, all three 97's are EFI's

[MedicAndy]

I seriously doubt it's the tensioner at only 7400 miles. Sounds more like an injection "glitch" to me. Maybe a slight adjustment to the little potentiometer in the ECU? Did wonders for my Centauro, which had similar symptoms.

I have to admit that I don't know much about these bikes. For instance, I know that this bike has the Will Creedon chip, but I don't know what the "little potentiometer" is? Is it the plastic screw that controls the fuel mixture that is located next to the chip?

[LowRyter]

Carl Allison, long time Guzzi guy here, mentioned that the timing chain did indeed cause driveability problems for his Sport.  I discussed it with Carl after riding a bike with similar problems as you described after the owner had been through ignition and fuel injection troubleshooting but couldn't cure it.  Carl went through all the normal stuff until figuring it out.

Sorry don't know how to inspect the old one or install the new one.  Hope that it fixes the problem. 

[Scud]

I installed one of those recently on my V11 Scura. I needed a super-deep socket - I think it was a 32mm.  If the Sport is the same as the V11 engine, then you will need to remove the chain to install the tensioner.

[Chuck in Indiana]

This was a common problem with the early fuel injection. As Charlie says, idle mixture (affects running up until about 3-4000 rpm) is adjusted by the trim pot next to the chip. Standing on the left side of the bike, 8 o'clock is full rich, 4 o'clock is full lean. Don't try to force it past those points, it'll break. Probably best to use a plastic screwdriver, although I never did. Something else to think about is a brass temp sensor holder. The computer doesn't get a good temp reading from the plastic affair. It will also break if you are not careful..

[Doug McLaren]

I had very similar symptoms on my 98 Sporti at about 20,000 miles. I changed the original tensioner for a "Valtec" type as it didn't seem to be doing much tensioning, the spring seemed to be very weak. Also make sure valves are spot on, the throttle bodies are in balance and the TPS is adjusted correctly. In addition check the exhaust manifold nuts and the intake rubbers.

Mine also has a Will Creedon chip and I'm running with the standard exhausts. The symptoms have all but disappeared, I just get the odd cough and a fart when the engine is cold.

[Howard R]

I'm going with "fuel problems are electrical" because my '96 will do pretty much the same, and it has carburetors.  It will occasionally cough and as the OP says it will also stall if the idle isn't set high enough.  What I do have is the Digiplex electronic ignition.  It's triggered from the flywheel and only has 4 "lumps" for the pickup to see, so I think the brain box will sometimes not see a lump or just forget to fire a cylinder.  A few more RPMs and it's all fine, so I think the best solution is proper idle and just ride the thing.

Your Motorcycle May Vary.

Howard

[bmc5733946]

Yes loose timing chains can cause this problem, so can tight valve clearances and low idle speeds, idle speeds can be affected by high resistance and or opens in spark plug caps. Valve clearances and idle speeds are adjustable without much if any disassembly, I would look there first. I can't remember if this bike has flywheel triggered ignition, if it does schmutz (that's a technical word) on the pickup can cause early firing and other problems as well.

Brian

[rodekyll]

Just for argument, I'm gonna go with not enough inertia at low rpm and overrun.  Needs more flywheel.   

[MedicAndy]

Thanks for all of the great replies! I will check the valve's gap settings, change the air and fuel filter (just to be sure, all of this was suppose to been already changed / set by her last owner), and adjust the fuel mixture to begin with. I will then still change the timing chain and tensioner. I'm pretty sure that there are a couple of great running 1100 Sport's out there, so I need to find that sweet spot, to get this, and my other bikes right. The injectors are balanced, and the rpm's are set at 1k. I probably could keep her from cutting off if I were to increase the rpm's to 1200, but I don't want to rev / idle the engine this high when I'm stopped somewhere at a light or stuck in stop and go traffic.

Andy

[fotoguzzi]

Valves too tight..

Yes loose timing chains can cause this problem, so can tight valve clearances and low idle speeds, idle speeds can be affected by high resistance and or opens in spark plug caps. Valve clearances and idle speeds are adjustable without much if any disassembly, I would look there first. I can't remember if this bike has flywheel triggered ignition, if it does schmutz (that's a technical word) on the pickup can cause early firing and other problems as well.

Brian

Everything he said.. I wouldn't bother the timing chain at that mileage but if you must you'll need a 3" deep 32mm socket.

[Chuck in Indiana]

I probably could keep her from cutting off if I were to increase the rpm's to 1200,

Actually, Guzzi specifies 1150 from memory.. always suspect. Too low of an idle is really hard on the clutch splines on the big block drive train.

[John A]

Actually, Guzzi specifies 1150 from memory.. always suspect. Too low of an idle is really hard on the clutch splines on the big block drive train.

And running with any load on the engine below 4K rpms will hammer out the splines

[rodekyll]

And running with any load on the engine below 4K rpms will hammer out the splines

So you recommend revving past 4k before dumping the clutch?   

[John A]

6500 would be better, but 4K should do it If your not breaking parts your not putting out enough power

[Howard R]

Actually, Guzzi specifies 1150 from memory.. always suspect. Too low of an idle is really hard on the clutch splines on the big block drive train.

Found this in the shop manual for Centauro/1100 Sport-i, on setting up injection, TPS, and TB balance:

13) Check that at the minimum the RPM is equal to 1200 +/- 50 RPM.

so Andy just needs to up his idle.  (That doesn't sound the way I intended. )

Oil pressure at idle will be a lot better, too.

Howard

edit: stupid �

[5154guzzi]

 Yes, to your question, the sprockets and chain need to come off to remove the oem tensioner.  It is not the same as the pictured one you attached on your original post.  It has a long piece of steel strap, similar to the style of the earlier tonti non automatic tensioner rubbing blocks.  It is bolted the same way,  to the case just above the front main bearing, behind the chain. I just looked at it and cant see it being slipped out with the chain in place.

 Howard and others nailed the real problem.  The Creedon chip and idle between 1100 and 1200 got rid of the annoying hiccup and constant dying at stoplights on my ol Sporti.   Hotrodding a friends sporti motor as we speak, the oem tensioner and chain don't look bad at all after 28,000 miles, just put  a much bigger cam in it along with carillos, cp pistons and major headwork.  It had a bad exhaust valve and seat that were limiting the top end to 144mph.  Anyway,  the extra oil flow as mentioned with the higher idle is a good thing, save cracking the timing cover to all of the other common issues are ruled out.

[Kiwi_Roy]

A couple of owners mentioned that you need an extra deep 32mm socket, I tried in vain to find one.
Just buy a regular 32mm 3/4" drive. it easily passes over the shaft.

Protect the shaft with a couple of layers of masking tape then turn the socket with a pipe wrench or grind a couple of flats for a 12 inch wrench.

Of course if you have access to a welder just cut a half inch drive socket and extend it with a length of pipe.
For some reason the bolts were too long without the old tensioner bracket so I cut it off and scratched a note for the next owner.

At 80,000 km the old chain showed little sign of wear, Im sure it would be safe to run to 250,000

[rodekyll]

I'll say for the umpteenth time -- get a set of plumbers sockets.  The kind you install basin valves with.  They are dogbone arrangements with a different hex on each end, one of which fits very closely.  Use the dogbone on the nut and put a suitable normal socket on the other end.  Remove with rattle gun and reinstall with torque wrench. 

[Howard R]

What RK said.  I have used these a couple of times, they will "nest" together for more length to clear the crankshaft nose, and get down to a "normal" size socket.  Then a rattlegun takes it right off.  These are pretty stout, the wall thickness is over a millimeter.  Just make sure you get one the right size.  They seem to run in odd 32ths, 1 9/32 inches converts to 32.5 mm.




image hosting anonymous


Howard