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 Post subject: Re: Dyno Interpretaion
PostPosted: Tue Feb 24, 2015 1:43 pm 
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It would be nice to find out what the lobe centres are,I would hazard a guess that they are around 114 or so.
Hopefully some of the more experienced can give some comments.
Paul


Last edited by huit on Tue Feb 24, 2015 7:16 pm, edited 1 time in total.

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 Post subject: Re: Dyno Interpretaion
PostPosted: Tue Feb 24, 2015 4:02 pm 
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Sorry Jeff, I digress. Lets try associate the dyno figures to the real world. The following may be of some use.
I am using the same P grind cams in the TT2. Along with smaller 36mm carbs, 41/35 valves, 10.6-1 compression, so apart from the capacity increase there is a suitable parallel. Cams are timed for 106 degrees on the inlet.

It really picks its feet up at 8,000rpm, giving useable power at well over 12,000 -- and beyond. However, the gear shift light is set for 10, 600 and limiter cuts in at 11,000 in an attempt to relieve temptation !

I would suggest the 750 dyno reading (assuming the cam timing, leak down etc, are OK), is simply a matter of re-jetting to find both the missing revs and associated power, much as Palmer suggested in the first response.


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 Post subject: Re: Dyno Interpretaion
PostPosted: Tue Feb 24, 2015 7:39 pm 
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Location: Chicagoland
This is all very helpful. I've never done these kind of diagnostics before so have to pick up a few things and get at it. Once I can do that I will report back and let you all know what's going on. We might be able to fiddle with the jetting this spring but I'd like to ride it some before opening things up. I don't have unlimited and cost effective access to the dyno. Maybe I find a way to make it up to them, like slap a big MCC logo on the bike!

I'm jammed at work for the next couple of weeks and will out of town but not off line. Very interested in hearing everyone's ideas.

Regardless of what we find, I may plan to do a major rebuild off season next year. At least a more thorough disassembly and cleaning.

Thanks,
Jeff


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 Post subject: Re: Dyno Interpretaion
PostPosted: Tue Feb 24, 2015 9:40 pm 
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Not much to add other than follow Palmers list off the first post. I might say check the valve timing before the jetting. Ive seen some "interesting" timing on Reno motors. As pointed out the Ducati spec is 106 LC on the intake for the P cam. Reno built quit a few strokers so those spacers point toward that. That would certainly lower the peak HP more towards what you are seeing. On the subject of 02 sensors they can take short exposure to leaded race gas but will gradually drift and go bad. Calibrate your instruments. I find it useful to measure sparkplug temps at the gasket to balance the 2 cylinders more so than reading plugs. That combined with O2 at the back of the pipe seems to dial things in quickly.
-Cranky-


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 Post subject: Re: Dyno Interpretaion
PostPosted: Tue Feb 24, 2015 11:20 pm 
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CrankyRoller wrote:
Not much to add other than follow Palmers list off the first post. I might say check the valve timing before the jetting. Ive seen some "interesting" timing on Reno motors. As pointed out the Ducati spec is 106 LC on the intake for the P cam. Reno built quit a few strokers so those spacers point toward that. That would certainly lower the peak HP more towards what you are seeing. On the subject of 02 sensors they can take short exposure to leaded race gas but will gradually drift and go bad. Calibrate your instruments. I find it useful to measure sparkplug temps at the gasket to balance the 2 cylinders more so than reading plugs. That combined with O2 at the back of the pipe seems to dial things in quickly.
-Cranky-


Cranky Thanks! I'll be right over!!


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sat Feb 28, 2015 5:40 am 
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Location: Quebec
I have just received my Innovate Motorsports #3845 air/fuel ratio gauge. I will install it on my 750F1 to adjust the Dell'Orto carbs.

What is the best position on the exhaust pipe to install the threaded female dowel (is this the right word ?) on the exhaust system (bought from Steve Munro, engineered by Mike Weber if my memory does not fail) ?

I suppose that the threaded dowel must not protude too much into the exhauts pipe.

Another question from a novice : is it possible to weld a steel dowel on a stainless steel pipe ?

Thanks for any advices Glynn and other members of this forum.

Gilles


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sat Feb 28, 2015 2:46 pm 
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I welded a lug on the inside of the collector pipe at the rear of the engine. This kept the Llamba out of harms way as it protruded from the pipe almost horizontally into the curved pocket to the lower rear of the crank cases. Locating it in a front pipe can clearly only give a reading from that particular cylinder. I guess there is no reason it can't be fitted within the exhaust either.

Welding rods are available for dissimilar metals, but maybe easier to turn up a stainless collar (M18 x 1.5 thread) The Llamba tip only needs to read the gas so doesn't have to sit well inside the pipe and interrupt the gas flow.

Cranky is right, the earlier style narrow band sensors proved a problem with race fuel, methanol etc, (and even silicon gasket sealant). However, the new generation of wide band sensors are designed to cope with just about anything you wish to burn.


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 11, 2018 4:07 pm 
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Palmer wrote:
Jeff,

Yah, looking at the dyno graph looks a little weak. The air/fuel ration doesn't look ideal. The power appears to be dropping off early but without knowing much about the engine build it's hard to say. Couple of things I would do if it was mine would be:
1. Check compression
2. Do a leak down check
3. Check the timing with a light
4. Adjust jetting to get 12.5 A/F through most of the pull
5. Check the cam open and close with degree wheel
These would at least tell you what you have without having to tear it down. Once you get more details it may become a little more clear as to what the motor needs. Hope these suggestions help.

Palmer


It's been a while. I made half-assed attempt to sell the bike and I'm glad it didn't go. I'm working now to get it track ready and picking up this thread.

I've been getting into this a bit.

1) The plugs are pretty blackened so it's running very rich.

2) I've checked the compression and get 150psi on the vert cylinder and 140 on the horizontal.

3) Did a leak down on both and it is very solid 96% give or take on both cylinders.

--Going to check the timing but I'm asking a noob question. If it's off, what's involved in adjusting it? do I take off the entire left hand cover? I found the page in the manual for checking the timing but can't find where it describes adjusting it.

It's got a new clutch too. Wasn't much left of the old one.

More to come.....


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 11, 2018 7:18 pm 
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I'll chime in first.

Yep, if the timing needs adjusting everything on the left side to get to the pickups must be removed. Fun getting things oily.

RE compression: Have you checked the lobe centers of the cams to see if they are the same? One could be advanced/retarded compared to the other (and where you think the centers should be), and that can effect compression; I believe advancing or retarding a cam can result in more or less compression depending on when the intake valve closes. Or, you might find slightly different intake valve durations. Just a thought.

MikeV


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 11, 2018 8:58 pm 
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Mike, how would I do that without taking things apart?


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