GK76 SP carbs, TPS and air box sensor

[willandrip]

What I will add is my experience of these engines re ; spark plugs.

A bike that has stood for a while or is hard to start can often be coaxed into life by substituting a conventional
electrode type plug for the stock twin electrode that seems very easy to foul.

Once up and running the twin electrode plug may be replaced.

If you place a stock plug in the lead and earth it you will see that the spark seems very weak at cranking rpm even with a booster battery,substitute it with a single electrode plug and it will zap it out of your hand.
They don't run well at higher rpm on single electrode plugs though, unfortunately.

[xstian]

The bike is a 93'. The previous owner has had the bike running. I might try these standard carb, he seemed to have more success with them. Is it okay to run standard carbs with a SP CDI?

[willandrip]

The bike is a 93'. The previous owner has had the bike running. I might try these standard carb, he seemed to have more success with them. Is it okay to run standard carbs with a SP CDI?

You were lucky to get both sets of carbs !

[xstian]

I've got 4 sets to be honest, but 2 of the sets only look fit for spares.

[rgvsp]

The SP also uses a different signal generator. I've converted my standard to SP specs and it would not start without the SP signal generator.

viewtopic.php?f=53&t=20774&start=160

[Variablevalves suck]

Like I said it might never run correctly unless all sp parts are fitted.

[xstian]

The previous owner said he had had the bike running. I'll look into this signal generator.

I assume if its not an SP version, I'm either going to have to swap it for an SP one or change the CDI and loom?

[willandrip]

From the linked thread the PO states;


"Re: No idle at all after carb rebuild








PostWed Aug 21, 2013 4:26 pm

Quick update......

I received all my o rings and seals from Thailand (thanks Blair) and set about fitting everything, paying special attention to getting things seated properly etc. it made absolutely no difference!
So..........I pulled a set of carbs off my spare bike, having resisted doing so because of them not being SP carbs and unbelievably, it started and ran perfectly!
At least I know for sure that its all carb related and can rule out other things, having changed the coils, pick up and plugs twice. Really wished I hadn't been so hell bent on using the SP carbs and tried another set earlier.

So the question is now......what could be wrong with these carbs. Crack in the body possibly. "

So he had it running fine on non sp carbs.

I see he is still a member on here and maybe would be willing to participate.

[rgvsp]

I had mentioned that SP's have different signal generators, they also have different intake cams. If the bike has the stock intake cam and stock signal generator I'm assuming you should be fine. I think you'd only have a problem if you mixed and matched the two.

[xstian]

Its all a bit confusing. The previous owner told me he did have is running fine on the sp carbs once, but he decided to have them cleaned in a ultra sonic bath. When he put them back on he couldn't get the bike to run on them again.

I tried the standard carbs yesterday but they pissed out fuel, so they need a bit of work before I can try them. Before I waste my time rebuilding them, has anyone tried running standard carbs with the SP CDI?