Problem Blipping Throttle? (2003 Monster 620sie)

**yantheman** · 28 Jan 08, 09:30 PM

Hi, not sure which section to post to, hope this is the right one, so here goes...

My bike is a 2003 Monster 620sie

I rode the bike yesterday on the M11 for a bit(not sure if it was even related), and on my way back, at the exit from A406 to A104(to Walthamstow), I changed down from 5th to 3rd, blipped the throttle, released the clutch, gears engaged very smoothly, then from 3rd to 1st, blipped the throttle, I heard/felt a click sound coming from the right throttle and the engine didn't rev up(at this time, clutch lever fully pulled in), blipped the throttle again, engine revved up, clutch released, gears engaged(liked it should be).

Engine about 110C at the time, everything seemed ok, about 3-4 sets of lights, in 3rd, change down to 2nd, blipped, engaged smoothly, then from 2nd to 1st, blipped again when the clutch in, only click sound and no response from the engine... blipped again, engine rev up, clutch release... and then fine all the way home.. the engine at anytime was nowhere near the limit, doing may be 50mph at 3rd gear

I am sure this is not normal, anyone has any experience on this? Is this a normal glitch or the something wrong with the bike?

The same thing happened last week in busy traffic, only once though. The "click" felt like something kicked in to stop the engine revving up...

Any ideas what happened?

**Steve GD** · 29 Jan 08, 05:57 AM

Yantheman, I am sure someone will be along soon to offer advice and suggestions about the throttle problem. In the meantime, welcome to the site

. Some pics of the bike would be nice, by the way...

**yantheman** · 29 Jan 08, 10:59 AM

thank you steve

I will try to get some pictures in the next few days..

**Ghost** · 29 Jan 08, 11:12 AM

Just reading through your post, there is a lot of detail I can't help but wonder if this is a carburation issue. I am not familiar with this model but if the carbs had an accelerator pump it would appear that you are losing the responce that a pump would be giving you.

Phil

**V90** · 30 Jan 08, 12:38 AM

I think Ghost would be right about it just being a fuel issue if it had carbs but the 620 is injected. The noise is very likely a spit-back through the throttle bodies, and not a mechanical noise, which a service may fix - fuel set-up, valve clearances and perhaps compression check to show if valve not seating. If the throttle is blipped a bit slower instead of snapping it open quickly it may stop the spit-back - no substitute for a proper service though.
All guesswork without seeing bike of course so no guarantees

**brian91cfr** · 30 Jan 08, 08:43 AM

is the throttle free to turn when this happens or doas it stick in the closed position ? then click and work ok after that.

brian

**yantheman** · 30 Jan 08, 12:05 PM

Brian - hi, the throttle twistgrip is all smooth and free moving, no tight spot or binding or anything like that, it was like twisting the throttle and it moved, "click" sound from somewhere and had no response from the engine. After that, I twisted the throttle again the engine revved up like normal. It felt like the engine momentarily ignored the input of the throttle...

V90 - hi, pardon my ignorance, what is spit-back? Someone on the UKMOC mentioned the possibility of the "butterfly value clicking"?

Any input would be much appreciated

**V90** · 31 Jan 08, 01:11 AM

By spit-back I mean a backfire in the inlet tract usually indicating a weak mixture. The weak mixture burns slower than required and is still burning on the exhaust stroke when the inlet valve opens on valve overlap hence the 'pop' in the inlet side. If this is happening then the bike needs servicing so the fuel delivery is correct - tps set, throttle bodies check for balance, mixture set with gas analyser and checks for air leaks on inlet side. If it is running really weak then the valve clearances can also have an effect as tight clearances increase the valve event so inlet opens earlier.
I'm sugesting this as a possibility if it really is nothing mechanical causing the click but I hope you appreciate that nobody has heard the bike so we're all guessing and hope that one of them is right! Have you tried my suggestion about blipping the throttle a bit slower rather than snapping it open?

**yantheman** · 31 Jan 08, 11:13 AM

Thanks, I tried yesterday blipping the throttle gently and that "clicking" didn't happen. I've noticed it only happens between 2nd and 1st gear and if I snapping the throttle (not violently , but briskly). I can almost reproduce it everytime now.

I think thats a very reasonable assumption that the bike need servicing. I bought the bike last December with 1200miles on the clock, belt changed in mid December and serviced by previous owner(not sure what had been done, the receipt didn't say) the last known confirmed full service including belt change, valve check and oil change which was backup by receipts was in end of 2005...

Does it matter if the bike really hasn't been ridden much?

**V90** · 31 Jan 08, 11:42 PM

Ok, it does sound like the bike is running weak so ideally you need to find a decent Ducati dealer(..and there aren't too many of them!) to have the fuel system set up properly. There is a thread on here about dealers so depending where you live you may see a recommendation for one near enough.
The bikes are set to run weak from the factory to pass the emissions tests anyway and you don't know who has fiddled with it before you got it and made it worse. My workshop manual says that the CO is initially set at 1.5% but recommends for improved performance the CO should be between 4% - 6%.
Did you mean 12,000 miles and not 1,200? As the service history is a bit vague I would change the oil and filter and also air filter. One big issue about not using the bike is there is a theory that because the belts are stuck in one position they take a 'set' where they bend around the small pulleys and this shortens the life - I believe that Gates who make the belts do agree with this. I don't use my bike much in winter but have the back wheel off the floor and occasionally rotate the back wheel with bike in gear to move the belts. Another issue is that having an engine stand with old oil is not good as the contaminents can cause corrosion so best to change oil before the winter if not being used for perhaps 3 months. Before I start my engine after it's been standing I remove valve covers and squirt some oil over cams/rockers and also down bores then rotate engine to pump a bit of oil- easy job and it makes me feel better.

**yantheman** · 01 Feb 08, 12:29 AM

hi, it was 1200miles on the clock when i bought it. I am the third owner. The first owner rarely rode the bike and had been sitting in a garage with regular short runs and startups. The second(previous owner) owner had the bike for a few months but again hardly rode it.

I am sure the bike has been serviced last October with belt change although the receipt didn't list the work carried out. I think I may take the bike to Rosso Corse in London, a lot of people have recommended this Ducati specialist in.

Thanks again for your response.

**StevieB** · 20 Jun 08, 11:32 PM

My new M696 was doing the same , and at the 600 mile service the fuel / air ratio was discovered to be too lean . The mixture was richened a bit , and it seems to have improved now . It might be an avenue worth investigating!

**yantheman** · 21 Jun 08, 07:52 PM

Thanks for the reply... It still happens every now and then. I must take the bike for a service and check the mixture and TPS as well.