From 107 to 128

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freeridenick
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Re: From 107 to 128

Post by freeridenick »

gilson wrote: Tue Mar 23, 2021 7:25 am I know very little about fuelling and this might be the most stupid post but I was reading this old post and in point 2 it mentions float height causing fuelling issues around the 4k/5k mark.

I'm embarrassed to even mention it as its probably completely irrelevant considering that you have different cars etc. Just trying to help.

I'm sure you'll sort it in the end.

https://r.tapatalk.com/shareLink/topic? ... source=app

Carb Tuning guide (setting up a Dynojet or Factory Pro kit)
Thanks, I've been reading that again quite a lot. The float height isn't adjustable on the stock carbs or the Mori ones and the floats are good. I've not compared these and the stock carbs to see whether they are the same or not, but it's one thing to consider. Without adjustment I've no idea what solution there could be.

I'd like to sort this but I think this bike and me are close to the end of our road. It's booked in at the local Dyno centre Monday week. We had a good chat today and he was shocked at the chart. Could be one thing or it could be a combination of loads of small things. He's going to check as much as he can during the day, between other work, and then we'll run it up on the Dyno in the evening. If there's no clear path to resolving it then someone else can have a go. Between this and everything else I have I should be able to buy a reasonable bike that works, or a half-decent horse (serious consideration).
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gilson
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Re: From 107 to 128

Post by gilson »

freeridenick wrote:
gilson wrote: Tue Mar 23, 2021 7:25 am I know very little about fuelling and this might be the most stupid post but I was reading this old post and in point 2 it mentions float height causing fuelling issues around the 4k/5k mark.

I'm embarrassed to even mention it as its probably completely irrelevant considering that you have different cars etc. Just trying to help.

I'm sure you'll sort it in the end.

https://r.tapatalk.com/shareLink/topic? ... source=app

Carb Tuning guide (setting up a Dynojet or Factory Pro kit)
Thanks, I've been reading that again quite a lot. The float height isn't adjustable on the stock carbs or the Mori ones and the floats are good. I've not compared these and the stock carbs to see whether they are the same or not, but it's one thing to consider. Without adjustment I've no idea what solution there could be.

I'd like to sort this but I think this bike and me are close to the end of our road. It's booked in at the local Dyno centre Monday week. We had a good chat today and he was shocked at the chart. Could be one thing or it could be a combination of loads of small things. He's going to check as much as he can during the day, between other work, and then we'll run it up on the Dyno in the evening. If there's no clear path to resolving it then someone else can have a go. Between this and everything else I have I should be able to buy a reasonable bike that works, or a half-decent horse (serious consideration).
Hi Nick, I really feel your pain. You've put hell of a lot of time and money into this bike.

Let's hope they sort it at the dyno. Vent on here as much as you want to. We are here to help and support.

Good luck.
No bike (yet).
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sirch345
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Re: From 107 to 128

Post by sirch345 »

freeridenick wrote: Tue Mar 23, 2021 5:22 pm
gilson wrote: Tue Mar 23, 2021 7:25 am I know very little about fuelling and this might be the most stupid post but I was reading this old post and in point 2 it mentions float height causing fuelling issues around the 4k/5k mark.

I'm embarrassed to even mention it as its probably completely irrelevant considering that you have different cars etc. Just trying to help.

I'm sure you'll sort it in the end.

https://r.tapatalk.com/shareLink/topic? ... source=app

Carb Tuning guide (setting up a Dynojet or Factory Pro kit)
Thanks, I've been reading that again quite a lot. The float height isn't adjustable on the stock carbs or the Mori ones and the floats are good. I've not compared these and the stock carbs to see whether they are the same or not, but it's one thing to consider. Without adjustment I've no idea what solution there could be.

I'd like to sort this but I think this bike and me are close to the end of our road. It's booked in at the local Dyno centre Monday week. We had a good chat today and he was shocked at the chart. Could be one thing or it could be a combination of loads of small things. He's going to check as much as he can during the day, between other work, and then we'll run it up on the Dyno in the evening. If there's no clear path to resolving it then someone else can have a go. Between this and everything else I have I should be able to buy a reasonable bike that works, or a half-decent horse (serious consideration).
It would be a shame not to finish what you started, especially (as Gilson said) after all the time and money you have put into your dream bike. You're so close too.

As frustrating as it is, I really wish you well in getting this problem fixed.

Good luck from me too,

Chris.
MK_WF
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Re: From 107 to 128

Post by MK_WF »

People speculated that different vacuum would create a different slide position yielding to the observed rich condition.

But this isn't controlled by the vent holes - they only control how fast the slide reacts to changes (more/bigger holes = more dynamic, less/smaller = more damped)

Something that wasn't mentioned was the springs above the slide. The membrane area and spring force control the slide position as a reaction on a certain vacuum signal.
Do you have softer springs to test? That would open the slide higher and allow for more air. In combination with a reduced needle position that could lean out the required rpm range.

At that stage of tuning, I wouldn't bother with carbs anyway. Converting to EFI is no rocket science and in the Megasquirt community there were examples of big twins being converted in the past.
Bye
Martin
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Stephan
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Re: From 107 to 128

Post by Stephan »

dynojet slide springs are softer and you can buy them for reasonable price through dynojet dealer. Just find out the part number listed in dynojet kit. At least this was possible few years ago.
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freeridenick
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Re: From 107 to 128

Post by freeridenick »

I've been going over all this quite a bit in the last few days and I've got myself a plan I feel good about.

The bike is now wearing my old carbs and airbox that I know worked well. If that doesn't work then it'll be a timing check and back to basics. I'll double check the timing is at least close before it goes in on. If there's no good news, more than likely I'll drain the fluids and mothball it for a while before I do anything. I might even do that if it ends up running well.

Thanks for all the support and advice. From busting the old engine to finding this one, the hassle of stripping two bikes along with fettling and renovating parts, and then the forks, I'm feeling pretty drained. This last year of sh1t hasn't helped my general state of mind either. Some time off gives me a chance to do some other stuff and recharge. I'll be having a good sort out of all the bits I've accumulated too. I've got at least two bike's worth and it's cluttering my head as well as the garage. Time to get rid of everything that isn't going to be immediately useful for this bike.

Thankfully in that pile of parts are different slide springs, jets, and a few other bits, that I can try and see if they make any difference to the fueling.

Sent from my E5823 using Tapatalk

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lloydie
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Re: From 107 to 128

Post by lloydie »

Putting away for a while and come back at it fresh is a good option when your banging your head on the wall .
Hope you get it sorted again tho
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sirch345
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Re: From 107 to 128

Post by sirch345 »

freeridenick wrote: Sun Mar 28, 2021 6:06 pm I've been going over all this quite a bit in the last few days and I've got myself a plan I feel good about.

The bike is now wearing my old carbs and airbox that I know worked well. If that doesn't work then it'll be a timing check and back to basics. I'll double check the timing is at least close before it goes in on. If there's no good news, more than likely I'll drain the fluids and mothball it for a while before I do anything. I might even do that if it ends up running well.

Thanks for all the support and advice. From busting the old engine to finding this one, the hassle of stripping two bikes along with fettling and renovating parts, and then the forks, I'm feeling pretty drained. This last year of sh1t hasn't helped my general state of mind either. Some time off gives me a chance to do some other stuff and recharge. I'll be having a good sort out of all the bits I've accumulated too. I've got at least two bike's worth and it's cluttering my head as well as the garage. Time to get rid of everything that isn't going to be immediately useful for this bike.

Thankfully in that pile of parts are different slide springs, jets, and a few other bits, that I can try and see if they make any difference to the fueling.

Sent from my E5823 using Tapatalk
You're sounding more positive now Nick, and you have a plan too, so that is good :thumbup:

Chris.
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fabiostar
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Re: From 107 to 128

Post by fabiostar »

sometimes a rest from it is as good as a change Nick :thumbup: :thumbup: i still think the carb change will bring good news :thumbup:
the older i get,the faster i was :lol:
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gilson
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Re: From 107 to 128

Post by gilson »

Your positivity is great to hear. A plan always tames the anxiety.

I hope this isn't seen as a thread hijack, but what tyres do you prefer for the track?

The tyres I have on there at the moment are slight squared off Bridgestone BT16 Pros, which are on ebay for about 160 a pair. This is a very good price considering that's the price for just a front supercorsa pro.

All these tyres will be far better than I can ride and in the case of the top priced tyres, probably a waste.

Are there any others I should consider? I have tried slicks and they felt great but not this time. I do have warmers but during Covid where access to electricity at the track is limited, it's not always guaranteed.

Any recommendations please?
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freeridenick
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Re: From 107 to 128

Post by freeridenick »


gilson wrote: I hope this isn't seen as a thread hijack, but what tyres do you prefer for the track?


Any recommendations please?
I've only used Super Corsa scrubs. About £80 a set and they are way better than me. SC1/SC2, front/rear is the common combination, but I've found SC1s both ends works for me on warm days and SC2 on colder ones.

Generally they've only done a race or qualifying and I get at least three track days out of a set. I started pushing that too as I was assuming they were no good after wearing to the wear indicator but I never felt them lose grip. I've got three sets if you're interested in trying them. I won't need that many this year, or next.

Folks reckon they have about six heat cycles in them before they go off so basically six track days if using warmers. I'm just going to use what I have until I feel them start to slide from now on.

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8541Hawk
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Re: From 107 to 128

Post by 8541Hawk »

freeridenick wrote: Mon Mar 22, 2021 8:43 pm Lift holes, what about lift holes? Rereading the carb tuning guide reminded me that the HRC slides only used one hole. The ones with the Mori carbs had three, so I plugged one, but would the Mori stacks allow a much greater vacuum than stock? Enough to lift the slides too early and cause a rich condition just off the pilots and into where the needle operates? Therefore I need to plug one more hole and try that?

The Mori needles are much fatter than the DJ and FP ones with a much steeper taper. They have a longer straight section too. Presumably to stop this midrange richness.

I checked the diagrams when I rebuilt the carbs Tony but will check again. When you say vac lines do you mean from the air cut off valve to the small metal tube?
Sounds like the Mori needles are very similar to the HRC needles. For the lift hole question, HRC recommend running a single lift hole on the short stack only. The kit came with 2 slides in case you were running 2 short stacks. If you do this then you also need to raise the needle on the other carb .5mm (one shim). The reason for this is that while the slide with 2 lift holes moves faster, it also doesn't lift quite as high under a steady vacuum signal. :thumbup:
Loud pipes don't save lives, knowing how to ride your bike will save your life.
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freeridenick
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Re: From 107 to 128

Post by freeridenick »

So the Dyno session started OK, with the old carbs and airbox leaning out the rich condition in the mid-range. So it seems reasonable to think the springs in the Mori carbs are just too strong. We'd just started working with the airbox and Mori stacks when the engine lost power and we could hear a ticking noise from behind the flywheel. So that's it, I've no clue what's wrong with it but it's game over for a while at least. We're not on speaking terms and it's under covers out of sight while I have some time away from it. On the plus side I've started to have a clear out so there'll be some bits and pieces going up in the sales section.
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AMCQ46
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Re: From 107 to 128

Post by AMCQ46 »

I feel your pain, this has been too frustrating.


time to take a step back and think / drink
AMcQ
tony.mon
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Re: From 107 to 128

Post by tony.mon »

This sounds like a two-pipe problem. (Read: more than one bottle of decent port, having thrown the cork away upon opening. Or maybe three bottles of ever-more-expensive wine).
Start with the cheap stuff.

Deeeeep breath- it's just a mechanical thing.
It is all explainable, and understandable. Just not now, and today.

Don't let it beat you, or you'll be beaten forever.
But don't be too proud to ask for help.


I've been where you are now. There will be a better day. :|
It's not falling off, it's an upgrade opportunity.
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