R100RT stuttering at speed

[tomatotum]

Hi, I have a stuttering R1100 RT, only does it at speed when rolling on and off the throttle at speeds 60mph and above, the faster the bike the bigger the stutter.. it hesitates when rolling off and again when rolling back on again.

 

Is smooth as silk at lower speed and idle. I've replaced fuel and air filter and cleaned plugs checked HT leads, and balanced carbs..

 

Any other thoughts??

[myshkin]

Hi, I have a stuttering R1100 RT, only does it at speed when rolling on and off the throttle at speeds 60mph and above, the faster the bike the bigger the stutter.. it hesitates when rolling off and again when rolling back on again. Also, I am not clear what you mean by stutter. Is it missing, detonating or surging or ????. If the bike is R100 could be timing, plugs or carb diaprahms. R1100 I would suspect the fuel.

 

Is smooth as silk at lower speed and idle. I've replaced fuel and air filter and cleaned plugs checked HT leads, and balanced carbs..

 

Any other thoughts??

Well, is it an R100RT which has carbs or an R1100RT which has fuel injection? If it is the former then I would check timing and plugs, if the latter I would suspect the gas especially given the reports I heard on BBC about the poor quality gas (ethanol) which cost hundreds of motorists huge expenses for damage to emission components of the engine.

[tomatotum]

Thanks for your note, it's a R1100RT 1996 injection model, not sure that it can be the fuel since I only use ESSO or BP due to the historic problems with supermarket fuels.. So any other ideas?

[ShovelStrokeEd]

OK, so your running at 60 or above and apply throttle and the bike stutters. By that, I assume you are talking about either an actual miss or a reluctance to accept throttle.

 

Something like this, assuming a healthy ignition system, is usually caused by a lean condition. A simple test would be to back off the throttle slightly (not as much as you applied) and see if the bike recovers or at least does it less.

 

Working on that premise, we have some things to look at.

A clogged fuel filter can do this. You can pass enough gas to run under a certain load but at higher loading/fuel flow requirements just not enough gas gets through.

A bad injector with a poor spray pattern or even an inhibited flow rate can do it.

Throttle cables grossly out of synchronization will produce this, might be as simple as a small pebble stuck in one of the pulleys or a badly streched cable.

Throttle position sensor going bad is another possibilty.

 

You have some testing to do. A mutlimeter can do the TPS, a pressure gauge is needed for the fuel filter thing. A bucket and a safe, well ventilated area for the injector spray pattern test.

 

There is a wealth of info available (albeit difficult to find with the search engine). Noodle around in the FAQ at the top of this forum. Others may chime in with some more detailed testing techniques.

[Jim Moore]

Make sure all your fuses and relays are pressed in completely. I had a similar problem once, caused by a relay working its way out of the socket.

[Calvin (no socks)]

Some more information from you will help diagnose the suspect items.

 

How long has it been doing it?

What level of fuel in the tank when problem occurs?

Smooth at idle usually lets the injectors off the hook.

clogged or blocked injectors always show up at idle.

An electrical high tension loss will show up on accelleration but not on de-accel.

A fuel starvation/areation will produce results as described. Have found clogged filters and hoses slipped off of connections in tanks and loss of fuel pressure.

A pressure test while problem was occurring would confirm or redirect diagnosis.