Hitting the rev limiter at speed?

BookEmDanO · July 12, 2011, 05:04:41 PM

I'm new to Ducati, not to motorcycling. What kind of top speed should I expect out of my 97 m750?
The reason I ask is because I was getting out to stretch her legs a little bit, found a long, straight country road and opened it up. At about 101-104 mph (indicated), the bike "lost power". Now, this isn't to say that the whole thing shut off. What I mean is that I still had the throttle WFO, but I began to decelerate. At first, I thought I had snapped the throttle cable. However, after I coasted to a stop, I was able to continue on as if nothing had happened.

I don't think I hit the rev limiter, but it's hard to say w/o a tach (my only real gripe about this bike). Any thoughts?

zarn02 · July 12, 2011, 05:22:27 PM

'97 M750 will be carbed, and won't have a limiter, so that won't be it.

I'm not sure about top speed on the 750.

(Someone better versed will surely come along.)

Howie · July 12, 2011, 05:28:38 PM

Top speed should be just a bit shy of 120. Of course, this if for a perfect engine, stock gearing, level road, no head wind and a slim rider in full tuck.

BookEmDanO · July 12, 2011, 06:09:40 PM

Good point about the naturally aspirated engine. I didn't think about that.

I was fully tucked, but I'm certain this engine is far from finely tuned.

Maybe the previous owner did the 14t sprocket??? Time to go count teeth...

Speeddog · July 12, 2011, 06:20:17 PM

'97 M750 does not have a rev limiter, at least an electronic one.

You probably ran the bowls dry, fuel pump couldn't keep up.

Howie · July 12, 2011, 06:29:35 PM

Quote from: Speeddog on July 12, 2011, 06:20:17 PM
'97 M750 does not have a rev limiter, at least an electronic one.

You probably ran the bowls dry, fuel pump couldn't keep up.

I just re read the original post, since the didn't just top out, but started decelerating you probably nailed it Nick

the_Journeyman · July 12, 2011, 07:16:11 PM

M750 published top speed was 115MPH or so. I'm not sure if that was drag or mechanical limit.

JM

The Bearded Duc · July 13, 2011, 01:13:46 AM

I've ran my 750 to about 110 indicated (still not as fast as the 620!!). Felt I still could have gone for more but the "holy crap" factor kicked in.

Sorry I don't have anything to offer technically, just wanted to brag a bit.

bikepilot · July 13, 2011, 05:24:10 AM

I'm not certain about that year 750, but even most carbed bikes have an electronic rev limiter built into the CDI box - they just cut spark. Bikes have had these since at least the early 80s. A rev limiter wouldn't require that you coast all the way down to a stop, it'll just cut spark when the bike goes over the limit, as soon as rpms are below the limit, spark comes back. This is why you see a bunch of popping/flames from old bikes when squids hold them WOT in neutral....

Do you get the same power loss at that rpm if you wind it out in 2nd gear real quick? I wonder if maybe your float bowls ran dry - maybe a fuel restriction somewhere and it wasn't flowing enough to the carbs to keep up with the fuel rate the engine requires at those speeds.

Howie · July 13, 2011, 08:40:22 AM

Carbed Monsters don't have rev limiters.

MongoReturns · July 13, 2011, 11:33:22 AM

Quote from: howie on July 13, 2011, 08:40:22 AM
Carbed Monsters don't have rev limiters.

Yes they do, but you can only hit it once

I've zinged mine up to 9k on false neutrals; very disconcerting.

My 750 did 120 indicated before I went two up in the rear sprocket. It's like 112-115 now, but it's really not happy to do it. Stupid no 6th gear

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Hitting the rev limiter at speed?