Idle and Throttle Sync Test

[Pio412]

Just to ask,....have you checked the Exhaust Pipe-to-Head Flange Bolts?

Good point. Have you put on new crush gaskets? I found that you could reuse the old ones a couple of times but after that you need to replace them. I have no idea if that is the issue but it is good to do.

Spot On, SgtCall.
An exhaust leak at this point in the System can be the cause of several performance issues. Depending on how big the leak and if it's one or both cylinders, it can cause RPM changes at Cruise Engine RPM ( little load) or while Accelerating, Misfiring/ Power Loss/etc. ( under more load). At Idle it may not even be detectable! (again, depending on how big the leak and if both cylinders).

I recall several times on the Purple Board, guys going nuts trying to fix mysterious symptoms,... Repeated Adjusting/Tearing into the Carbs and Fuel System/Pump, etc.......... spending loads of time on the Ignition/Electrical System checks,......only to find it was Loose/Leaking Header Pipe Gaskets.

Being SO easy to check,...It's now my FIRST item on my trouble-shooting list for these symptoms such as pio142 reports.

I appreciate the help from everyone.

With countless hours looking through past posts of similar issues I already came across that header bushing being an issue and looked them over already.. they were already tight and had no visible or audible leaks. plus I don't think they've ever been removed considering this bike only has 7000 miles and it being fully stock.

But when I get a chance I'll look them over again while it's running and report back.

[sgtcall]

I appreciate the help from everyone.

With countless hours looking through past posts of similar issues I already came across that header bushing being an issue and looked them over already.. they were already tight and had no visible or audible leaks. plus I don't think they've ever been removed considering this bike only has 7000 miles and it being fully stock.

But when I get a chance I'll look them over again while it's running and report back.

If I remember correctly, according to the service manual, you are supposed to change them every time you remove the head pipe. But like I said I re-used them a couple of times before putting in new ones.

[Pio412]

So i ran it yesterday and absolutely no leaks form the headers. she idles and revs very nice. even taking off from a stop shes smooth.

Rode it up the street and it just surges when given steady throttle like it needs a throttle sync. But its pretty damn close and im pretty sure it should be riding just fine with the sync i did (in video)

like i said before with half choke it seems to eliminate the surging...…..

guess I'm taking off the carbs to clean them very thoroughly.

[Designer]

So i ran it yesterday and absolutely no leaks form the headers. she idles and revs very nice. even taking off from a stop shes smooth. Rode it up the street and it just surges when given steady throttle like it needs a throttle sync. But its pretty damn close and im pretty sure it should be riding just fine with the sync i did (in video)

like i said before with half choke it seems to eliminate the surging...…..guess I'm taking off the carbs to clean them very thoroughly.

Not always does an exhaust leak become evident by sound due to the Pipes and others noise. Did you check the tightness of all 4 Head Bolts? If so,. . The "First Step" is done and it's not that issue.

Okay,...but,....before tearing into the Carbs and all it entails,....I would run at least two tankful's of gas treated with Sea Foam or Berrymans B 12.
Then see what you get.

[Pio412]

So i ran it yesterday and absolutely no leaks form the headers. she idles and revs very nice. even taking off from a stop shes smooth. Rode it up the street and it just surges when given steady throttle like it needs a throttle sync. But its pretty damn close and im pretty sure it should be riding just fine with the sync i did (in video)

like i said before with half choke it seems to eliminate the surging...…..guess I'm taking off the carbs to clean them very thoroughly.

Not always does an exhaust leak become evident by sound due to the Pipes and others noise. Did you check the tightness of all 4 Head Bolts? If so,. . The "First Step" is done and it's not that issue.

Okay,...but,....before tearing into the Carbs and all it entails,....I would run at least two tankful's of gas treated with Sea Foam or Berrymans B 12.
Then see what you get.

Hey Designer,

Yes i checked the tightness of all four bolts and they're tight. I didn't wanna risk snapping them off but made them tight enough.

And i did put a bottle of berrymans b12 through it a few weeks ago and ran through it, No change...

[Designer]

Hey Designer,
Yes i checked the tightness of all four bolts and they're tight. I didn't wanna risk snapping them off but made them tight enough.
And i did put a bottle of berrymans b12 through it a few weeks ago and ran through it, No change...

Thanks for giving us this Update. The more Information you give us Fellow Riders, the better of help we can be.

Quick question,...when you say it "surges" at Steady throttle,

.... Rode it up the street and it just surges when given steady throttle like it needs a throttle sync.
like i said before with half choke it seems to eliminate the surging...…..guess I'm taking off the carbs to clean them very thoroughly.

When held at Steady Throttle,..does it first loose RPM/Power then regain it....or does it feel like a Surge in power from Steady State Throttle ?

[hillsy v2]

Surging on partial throttle like that is a sign of erratic fuelling. A lot of the time this can be caused be worn needle jets but with such low mileage that's (almost) unlikely. Worth checking though - especially the front carb which lies flat.

How long has this bike been sitting? I'd be guessing quite a while considering the low mileage. Quite possibly dirty / varnished pilot circuits.

[Pio412]

Surging at steady throttle meaning, the rpm's go up, then down, steady, then up and down etc. like starving for fuel on one carb or like symptoms of a bad sync.

[Lechy]

Check that the rubber boots air box to carb are seated correctly and securely on the air filters.

[Designer]

Surging at steady throttle meaning, the rpm's go up, then down, steady, then up and down etc. like starving for fuel on one carb or like symptoms of a bad sync.

Check that the rubber boots air box to carb are seated correctly and securely on the air filters.

Good Call there Lechy. That was my first thought after reading the symptoms Pio412 reported of the RPM going up from steady state throttle. Let's see what he gets.

[Pio412]

Just had a chance to run her today. Checked the boots... all are seated properly, check all around with a light. Sealed perfectly. No cracks through either when I had them off a month ago. The o-rings are seated on well too.

When I took her for a ride, it was 35 degrees F out. Warmed her up and drove around the block. Tested my theory again. Ran it with the choke off sputtered but once I gave her heavy throttle ... fine. later I pulled the choke halfway out, starting from a stop.... pulled away smooth as butter, and I kept constant throttle as well while going 25-30 mph and no sputtering or surging at all. Adding some choke fixes the issue.

Just a note - front float height is 9.1mm and rear is 27.7mm - and all jets are stock.

[Lechy]

Take her on the highway and give her a good hard spanking. Blow the cobwebs out of the system. Try a lower octane fuel.

[Designer]

Take her on the highway and give her a good hard spanking. Blow the cobwebs out of the system. Try a lower octane fuel.

Pio412,...before you take Lechy's advice,...I might suggest you run more Berrymans' through the system. Sometimes it takes a bit for that kind of product to "work things out",...so to speak.

Just had a chance to run her today. Checked the boots... all are seated properly, check all around with a light. Sealed perfectly. No cracks through either when I had them off a month ago. The o-rings are seated on well too.

Before you had them off a month ago, did this "surging' issue appear just after that, or was it present before you took them off? And,....For what reason did you take them off please.

[Pio412]

Okay so yes when I bought the bike the guy said it needed the choke to run. So I figured... ok just need the carbs cleaned and a throttle sync. So I thought. When I first cleaned them and synced them I thought, sweet I fixed it good to go! But I never rode it long enough to take the choke completely off and ride it. And then later, I realized when I rode it without choke when it was fully warmed up it was still surging and sputtering and thinking it was lacking fuel or the sync was off, which I know it's not because the sync is near perfect and I throughly cleaned the carbs with carb cleaner ( yes... everything had been check as stated before, seals, diaphragm , floats, needles replaced, etc and compressed air. Maybe throw them in an ultra sonic cleaner.???

[Herb]

You are running lean, not sure if it is the main jet, the needle setting, float level, or a problem with a slide.

[Designer]

You are running lean, not sure if it is the main jet, the needle setting, float level, or a problem with a slide.

That was pretty much my thoughts too. Especially after he reports no difference after the Berrymans b12 application along with the choke (and it's effect on Fuel/Air Mixture) "fixing" it. It certainly isn't an erratic fuel delivery.

[Herb]

A lean condition won't show up on the high rpm part of the carb sync. It will show up at steady throttle under load.

[Pio412]

Quick thought- could a battery issue cause the problems I'm having? As I stated in a previous post I did replace the battery but what if it's going bad already (faulty)? Since these are battery dependent bikes?

[hillsy v2]

Quick thought- could a battery issue cause the problems I'm having? As I stated in a previous post I did replace the battery but what if it's going bad already (faulty)? Since these are battery dependent bikes?

It's possible. Test the voltage at the battery terminals when the bike is running. You should see 13V or so at idle then 14+V at revs.

[Designer]

Quick thought- could a battery issue cause the problems I'm having? As I stated in a previous post I did replace the battery but what if it's going bad already (faulty)? Since these are battery dependent bikes?

Possible,...but,..Let me ask,...do you experience any lack of Battery Power when starting? Do your Lights get dimmer when you turn them on, but do not start the Engine right away?