Advice Please

[Exponent]

Hi guys

I need some troubleshooting advice please.

I am experiencing a stutter especially when setting off. It almost feels like when your bike lets you know it is time to switch to reserve. This disappears after a while (almost as if it is better when the engine has warmed up properly and after the throttle has been properly tested. When the bike has stood for an hour or two it is back, but in a lesser degree.

It also seems as if the bike battles to maintain at a constant throttle, when cold it is terrible and at running temp it give a little nudge every now and then. It almost feels like you have to constantly accelerate to maintain smooth engine performance.

Can anyone point me in a direction where I can start looking for the problem?

[mrbill5491]

Hi guys

I need some troubleshooting advice please.

I am experiencing a stutter especially when setting off. It almost feels like when your bike lets you know it is time to switch to reserve. This disappears after a while (almost as if it is better when the engine has warmed up properly and after the throttle has been properly tested. When the bike has stood for an hour or two it is back, but in a lesser degree.

It also seems as if the bike battles to maintain at a constant throttle, when cold it is terrible and at running temp it give a little nudge every now and then. It almost feels like you have to constantly accelerate to maintain smooth engine performance.

Can anyone point me in a direction where I can start looking for the problem?

What is the maintenance history on the bike.

[Rob S.]

I think it would have to be carbs and/or boots.

The experts will chime in soon with recommended fixes.

[Exponent]

What is the maintenance history on the bike.

Hi Mr Bill

I bought the bike about two months ago from a guy who had already left for a job overseas, so the info on my bike is sketchy at best. Apparently is was standing a while, but runs great otherwise except for the stutter.

I have done an oil and filter change about 400 km ago.

[Exponent]

I think it would have to be carbs and/or boots.

The experts will chime in soon with recommended fixes.

Hi Rob

My git tells me carbs, but my mechanical experience is zero

Here is a pic of the carbs from the air filter cavity - can you pick up anything?
Carb LH 4 Close up.jpg

[BigD_83]

Other than being a little wet and oily looking, not much to see there.

It's really the inanrds needing addressed, as it sounds like you have a small block in the idle/low throttle opening circuit. This is supported by the fact that it gets a bit better at more open throttle settings.

A full strip and dip, with a valve adjustment will probably be the resounding advice.

[Exponent]

Other than being a little wet and oily looking, not much to see there.

It's really the inanrds needing addressed, as it sounds like you have a small block in the idle/low throttle opening circuit. This is supported by the fact that it gets a bit better at more open throttle settings.

A full strip and dip, with a valve adjustment will probably be the resounding advice.

Thanks Big D, I was dreading and looking forward to that advice.

Guess I better start getting the carb kit together and source some shims

[Steve]

Guess I better start getting the carb kit together and source some shims

Don't bother sourcing any shims until you know what you have and what you need.

.

[mrbill5491]

Hi Mr Bill

I bought the bike about two months ago from a guy who had already left for a job overseas, so the info on my bike is sketchy at best. Apparently is was standing a while, but runs great otherwise except for the stutter.

I have done an oil and filter change about 400 km ago.

Okay, you need to start here and read. http://www.thegsresources.com/_forum...K-HERE!!/page9 Go to the bottom of page 9 and start there.

[Steve]

Go to the bottom of page 9 and start there.

How can he go to the bottom of page 9 when there are only three pages?


Oh, yeah, you still have your options set to the forum default.

.

[chuck hahn]

No need to buy any KITS. get the intake manifold orings and one CV oring kit from Robert Barr at cycleorings.com. 1 kit does all the carbs and fuel tees.

Intake manifold orings are on page 3 of his website. Measure the id of the old ones and get the appropriate size

DO NOT EVER grip the float seats with pliers to get them out OR apply heat to loosen the orings seal. There is a screen inside the seats and heat will melt the plastic that holds them in place. Squeezing the seats will make the holes out of round and the needles will jam up and not work. Use a fine knife to gently get the seats pried out. Be patient and work them out by prying between the brass shoulders and the carb body itself.

Lastly..go here and get familiar with the CV rebuild tutorial. Get new rubber plugs for on the pilot jet holes and new bowl gaskets too. A can of Berrymans from Walmart, a can or two of carbs spray and get to rebuilding the carbs. Check the valve adjustments and use a new cover gasket. Do these things and youll be amazed at the life the bike has left in it.

Carb rebuild is on the right side and look for a manual from the list

http://members.dslextreme.com/users/bikecliff/

[Big T]

Walmart's in SA?

Flyboy can let you know what type of chemicals you can get in SA

Is it me, or does the carb boot in his pic look like it's melted?

[chuck hahn]

Yamaha carb dip....whatever.........pot of boiling water and Tasmanian Devil pizzzzz...just get them cleaned out.

[Brendan W]

Hi Rob

My git tells me carbs, but my mechanical experience is zero

Here is a pic of the carbs from the air filter cavity - can you pick up anything?
[ATTACH=CONFIG]36600[/ATTACH]

Before getting involved in a full carb strip it's always worth trying the ' lite' option. If it is dirt it may not be fixed - yet and draining the bowls a few times, running fuel through on prime and a few taps with a rubber mallet or hardwood stick will dislodge dirt.

[chuck hahn]

But if theres "dirt" getting to the carbs you need to go upstream to the tank and fuel lines. Tank may need cleaned, derusted, and a tank liner to prevent future heart ache. Fuel lines do degrade and the rubber sluffs off and make things get gunked up.

I would suggest that the ENTIRE system be gone over AND the carbs dipped and new orings. That way all possibilities have been addressed and dealt with.

"lite options" are like putting band aids on shotgun wounds...