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 Post subject: Re: Dyno Interpretaion
PostPosted: Sat Feb 21, 2015 5:40 pm 
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Joined: Mon Jan 21, 2013 4:36 pm
Posts: 185
so it's a race motor, not a std f1 motor? put that sort of info in the first post.


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 22, 2015 12:45 am 
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Joined: Mon Dec 27, 2010 12:00 am
Posts: 48
Location: Chicagoland
My apologies. I mentioned the origins of the bike in a couple of other posts. sorry if you missed them.

My intent was to get some unbiased feedback on the dyno output.

Jeff


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 22, 2015 7:28 am 
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it's not possible to give unbiased feedback on a dyno run. it either makes as much power as it should, or it doesn't. sounds like you think it doesn't. it will make more if it is leaner, but i'd say not enough more to make you happy. what were you expecting? what does a comparable motor make on this dyno? my 750 motor made 76 on one dyno and 67 on another. so that's another bias to the result.

if it's still too low, then really it's time to check into the motor. cranking compression, leak down, etc.

looks like a std cam motor too, peaking at the rpm it does. maybe it lost its big cams along the way and is now a dog because of it.


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 22, 2015 9:42 am 
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Joined: Mon Dec 27, 2010 12:00 am
Posts: 48
Location: Chicagoland
brad black wrote:
maybe it lost its big cams along the way


yeah, maybe but the seller represented otherwise as was establish member on the pantahead list. It's a small community and there's a certain level of trust.

right now i'm just going to have fun with it. Besides, I'm probably not so fast anymore either. You know the saying, "The older I get, the faster I was"


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 22, 2015 12:15 pm 
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Joined: Thu Oct 14, 2010 11:23 am
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Hello Jeff. Can you pull one of the cam end caps off, and read the letters on the end? There will be an O on the front, and a V on the back. But what else is there? This will help ID the cams. By the way, the name of the original owner's (Baker) son is Geoff. Now and then he posts on the site about his F1. MikeV


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 22, 2015 6:19 pm 
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Joined: Mon Dec 27, 2010 12:00 am
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Location: Chicagoland
Mike,
Thanks for the info about Geoff. It would be great to connect.

In the meantime, I did as you suggested and pulled one of the cam cover and this is what I have, what do you think?

You can also notice that the head studs are inside the nuts a turn or two. There's a big thick gasket at the bottom of the cylinder so it likely cylinder volume is not stock.



Image


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 Post subject: Re: Dyno Interpretaion
PostPosted: Sun Feb 22, 2015 9:39 pm 
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Location: Sydney, Australia
There is the "P" stamped on the cam that everyone was hoping to see :!: It identifies it as a Montjuich camshaft so that should be a good start to building a race engine. ;)

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 Post subject: Re: Dyno Interpretaion
PostPosted: Mon Feb 23, 2015 2:00 am 
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Joined: Thu Oct 14, 2010 11:23 am
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Yes, you have Montjuich cams. So that means one thing you do not have to look for assuming they are good --- race cams.

But the gasket is a bit puzzling. Now I wonder if the engine has a 64mm (851) crankshaft instead of the stock 61.5mm 750 crank; an increased stroke would require something like that. 2/23 thought: Or, maybe it had a 64mm crank and now that is now gone. Have you done a hot-engine compression check? If you do that don't forget to prop the carb slide open.

Well, Palmer gave you a good list to check. It would seem you could find some missing HP somewhere.

Ain't it fun figuring out what is in an old race bike? Pantah Good went through this same thing a few years ago.

Good luck,
MikeV


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 Post subject: Re: Dyno Interpretaion
PostPosted: Mon Feb 23, 2015 6:21 pm 
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Joined: Wed Mar 21, 2012 9:56 am
Posts: 112
Like Brad says, 76hp on one dyno or 67 on another. There is no difference between measuring the dyno curve in horse power or banana's, as long as you are on the same dyno. I have also used the temp sensor on the down pipe to gauge the difference in jetting between the two cylinders, and it works well. There is a popular misconception that a Ducati is merely a twin cylinder engine. In many ways it is really a twin engined engine.

Regarding combining the use of both the air/fuel ratio mixture and the temp sensor meter. I have found by jetting for the leaner mix and theoretically more power (13.5-1), the head temperature soars to new heights using the temp meter on them straight after a race. In view of this I aim for between 12.5 and 13 on full noise for a degree (pardon the pun) of comfort. Please bear in mind though, I am referring to a 600 race engine which spends almost every second of its working life enjoying this level of abuse.


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 Post subject: Re: Dyno Interpretaion
PostPosted: Tue Feb 24, 2015 12:26 pm 
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Joined: Thu Oct 14, 2010 11:23 am
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Thanks for the added comments Glyn.

I still think the most striking thing about the dyno runs is that the engine is out of breath at around 7500 RPM! I would think a 750cc with 40mm carbs, 41/35mm valves, Montjuich cams, some porting, high-compression (assumed) pistons, and all the other normal builder tweaks would pull well past 9000. So, what is amiss?

MikeV


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