Author Topic: SPR jetting question  (Read 270 times)

SeaR1ck

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SPR jetting question
« on: April 09, 2018, 07:46:38 PM »
Now that I'm done working on the Tzm i can get back to my spr.

Got some new jets and carb o rings n bowl gaskets. The bike is stock cept for the sugo unleaded cdi and the pipes silencers.

So what i'm wondering is when i pulled the carbs apart. The jetting specs where all stock cept for the power jets. They was slightly richer than stock.

Stock if i remembering is # 55/60 the one's in the bike where 75/80. 

Why was this done? The powerjet richens the mid/top was it because of the sugo cdi and the stock jetting not rich enough?

The bike was also running no boost bottles and has the sugo plugs. Which i'm going to be putting the boost bottles back on.

The air solenoid jets where also stock and i dont want to mess with that right now.

Guess i'm parinoid and don't want to run it lean and lock it up. Gonna be a street ride so it has to run on our 92 pump gas we have here which is equal to 95 ron.

Those with experience with this cdi the stock jetting is fine?

ybk

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Re: SPR jetting question
« Reply #1 on: April 10, 2018, 02:46:13 AM »
How does the bike run at the moment with the stock carbs and 7K CDI? Does it pull cleanly?  Have you checked what the plugs look like? Are the powerjets hooked up to the loom? I am also interested in getting SPR stock carbs working with the sugo box, will be doing the same at some stage with mine.

SeaR1ck

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Re: SPR jetting question
« Reply #2 on: April 10, 2018, 03:43:50 AM »
When i got it, it was running fine but i didn't ride it much. The guy i got it from was running it on premix and not off the mechanical oil pump it has no oil solenoids has the older pump setup.

Guy also took off the carbs and fucked up the sync so it was a little boggy off the bottom cause of it. The power jets where connected.

When i pulled the carbs apart there was a little bit of dirt in them and there was fuel in the air boots. Some of what i'm dealing with is undoing thier crap.

I only pulled the lower plug it looked okay if anything a bit rich. I couldn't remember the name of the pipes earlier it has jackals on it.


ybk

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Re: SPR jetting question
« Reply #3 on: April 12, 2018, 06:45:52 AM »
Plug looks ok yeah. Been thinking about this - swapping out to the sugo cdi and pipes shouldn't really require a big jetting change. They are jetted conservtively from the factory and assuming youíre close to sea level stock jetting should suffice. Are you running stock air boxes?

The sugo carb internals are quite different from the stock ones, my assumption is that itís to compensate for the powerjets now working as well as the VAJ system now being disconnected (the spr only has one vaj block that feeds both carbs so that makes it a bit more simple.) 

If you leave the powerjets disconnected initially then itís only the air jets that have changed since adding the sugo cdi. The sugo cdi only adds some advance so from there it should be easier to get a working baseline.

As a sidenote Iím not 100% sure about the powerjets - as far as I know older SPís dont have PJ connectors on the stock loom so they just hang there. The SPR stock loom has the PJís connected already with provision made for them. The connector is also different than on other SPís(I think). Maybe someone with an older SP can chime in. Here is the SPR loom powerjet connector :
 [ You are not allowed to view attachments ]

I managed to get a frankenstein sp with a sugo cdi and spr carbs to carburate cleanly (not necessarily optimally, need a dyno for that) so Iím sure this would feasible. Just thinking out load a bit...

Smithy3XVC

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Re: SPR jetting question
« Reply #4 on: April 12, 2018, 02:41:51 PM »
The SPR is the only model with the type of PJ connectors as in the picture.
The earlier models without PJ connected to the ignition box had a link loom that connected both PJ connectors together.
It was taped to the main loom but you rarely see them now.
I think this was to prevent dirt getting in the connectors and to stop people worrying about unused connector block. Handy if you did fit a SUGO box to a road bike, it gave out the connectors to use....

If my memory is not playing tricks my SPR has two VAJ solenoids. One on the oil tank and one on the thermostat bracket.

I'll confirm tomorrow, it is dark now in the shed.  ;D

SeaR1ck

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Re: SPR jetting question
« Reply #5 on: April 12, 2018, 05:16:44 PM »
My SPR only has the one vaj upfront.

So if i'm understanding this the sugo box advances the mapping functions the power jets. But stops the vaj from working and the oil solenoids. Why you must run the older style throttle cable and oil pump.

It also doesn't have the speed restriction as well.

ybk

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Re: SPR jetting question
« Reply #6 on: April 12, 2018, 09:59:26 PM »
Thats right. The sugo manual tells you to block the air jet inlets on the carbs:

SeaR1ck

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Re: SPR jetting question
« Reply #7 on: April 13, 2018, 06:13:38 AM »
I forgot yes I'm running stock air boxes on it.

Smithy3XVC

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Re: SPR jetting question
« Reply #8 on: April 13, 2018, 10:36:33 AM »
Checked in the shed. Bike has two VAJ valves, both connected up to the stock wiring loom.

I checked my two spare looms and they are both the same as the one on the bike.

The parts book only shows one, so I don't know why mine has provision for and has fitted both valves.

I was running really well before I shipped it back to Australia and then stripped it to clean up the engine which looked like it had been in undersea storage for a month.

Looks heaps better now but it is not on the high priority list to get rebuilt at this time unfortunately.

ybk

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Re: SPR jetting question
« Reply #9 on: April 13, 2018, 10:01:47 PM »
 ?:-|Weird, both my spr's only has the one up by the powervalve motor. It has 2 outputs, one for each carb which is different than all the other models. Odd that someone would put an extra on on yours?

Edit : autocomplete typo
« Last Edit: April 16, 2018, 09:19:34 PM by ybk »

SeaR1ck

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Re: SPR jetting question
« Reply #10 on: April 16, 2018, 07:31:22 PM »
I just ordered a gasket set from the gasket guru so i can swap out the reed block manifolds and put the boost bottles back on.