My rebuild thread

[Guest]

Don't worry about the mixture screws too much until you have them sync'd up nicely.

Once they're in sync, you will probably find it's a whole different story.

Before I sync'd mine, I thought the slightly uneven header lengths on my 2 to 1 were requiring me to have a different pilot in each carb. After the sync it was just fine and dandy with the stock pilots.

As for the sync tool, don't worry what the gauges read, just make sure they're accurate to each other and when sync'ing, all that matters is that each side reads as close to the same as possible.

 

[Mr Rogers]

hey i know its been a long time since i've posted but thats because my bike has been running like a dream! I just finished doing a valve clearance adjustment and everything is looking golden. But, i've run into another problem. I'm trying to diognose it but i can't be sure since the bike has never done this before.

So... i filmed a video for you guys!

http://www.youtube.com/watch?v=bnvkfauqPZw

IF you look closely you can see that i'm really revving the throttle but the rpms stay right around 2k. and if you listen closely you can hear that the exhaust sounds really funny like its puttering when normally it has a very clear sound to it...

Any advice from you guys would be awesome thanks!

John

 

[Guest]

Your only running on one cylinder and the other isn't kicking in at all or one is really rich and the other is keeping it going.

Check for spark on both sides.

Pull one plug cap and put a spare plug in ground it and see if the engine will run on one cylinder or the other.

After listening to your video with headphones i can tell there is one point where you rev'd it the highest and that was the only time it kicked in on two cylinders for just a second.

You either have a problem with:

Spark
Fuel
valves


Could be just a bad plug or coil or ignitor etc...

Could be one of the diaphragms are not seated properly.


Prime just allows gas to flow constantly.

ON and RES are supposed to be vacuum operated but the diaphram could be leaking and allowing one cylinder to suck gas in.


You could have a stuck needle valve, so its flooding that one cylinder all the time.

 

[Guest]

Yup, that sounded somewhat like mine did today when it ran on one cylinder on the way home again...

In my case I'm pretty sure I have a dodgy connection relating to the right coil or power feed to the Dynatek as it's always that cylinder that stops, and then it will start again for no apparent reason.

 

[Mr Rogers]

Ok so i checked the spark plugs for spark and i'm only getting spark on my right side. on the left side the plug looks like it is fouled since it is all black and smells of fuel. it's not wet though. I'm going to switch the plugs so the good plug is on the bad side and see if the coil is still working properly. If it is working i'll get a new plug to replace the old fouled on then i'll try asap to get a carb sync so that i don't just ruin this plug as well.


When you say diaphragm, do you mean the black bellow looking thing in the top section of the carburetor? or is this within the engine? i'm certain that all of the shims were seated properly before i stitched her back up but maybe something happened while riding?

 

[Guest]

When you say diaphragm, do you mean the black bellow looking thing in the top section of the carburetor? or is this within the engine? i'm certain that all of the shims were seated properly before i stitched her back up but maybe something happened while riding?

Yup, that's the one, top of the carb

When you do the valve adjustments, they recommend you turn the motor over a few times (by hand with all shims in place) then measure each one again to be sure they're seated correctly after replacement...

 

[Mr Rogers]

I did measure all of the clearances (after turning the engine over a few times) and they're all in spec. I'm pretty sure the diaphragms are still in place. I'm going to see how the bike is running with the new plug then have the carbs synced by a friend of mine.

i've got a question about the carb syncing though. should i change my mixture screws back out to 2 turns out then adjust the sync screw between the carbs?

 

[Guest]

Don't bother with the mixture screws until after you've sync'd your carbs.

Once the carbs are sync'd, then check your mixture screws and set them according to the highest idle method.

Then reset your idle and do the carb sync again...

 

[Mr Rogers]

is the sync needed a second time? i had them synced last night and i was surprised to see how far off they were! but now they're right on. will the mixture screws effect where the sync is?

 

[Guest]

is the sync needed a second time? i had them synced last night and i was surprised to see how far off they were! but now they're right on. will the mixture screws effect where the sync is?

It's more precautionary than anything, but essentially if you change the sync it can affect the mixture, and conversely if you change the mixture it can affect the sync.

More than likely you won't find much difference, although if they were badly out it may need further adjustment.

 

[Mr Rogers]

hmmm i think that's a good idea Pete! i've been riding the bike a bit today and i can tell a considerable difference in power in the bike. it's much smoother.

I've had to change the mixture screws on booth carbs to improve the color on the spark plugs. For some reason i can't figure out how to do the highest idle method correctly. I've tried to do it but it doesn't seem like the rpms are changing at all... maybe i'll try it one more time now that the carbs are synced.

Eventually i'll get it all right! one thing that is concerning me is that one of my carbs is still burning rich and i've got it set at about 1/4 of a turn out. So i'm thinking i need a new one.

 

[Guest]

hmmm i think that's a good idea Pete! i've been riding the bike a bit today and i can tell a considerable difference in power in the bike. it's much smoother.

I've had to change the mixture screws on booth carbs to improve the color on the spark plugs. For some reason i can't figure out how to do the highest idle method correctly. I've tried to do it but it doesn't seem like the rpms are changing at all... maybe i'll try it one more time now that the carbs are synced.

Eventually i'll get it all right! one thing that is concerning me is that one of my carbs is still burning rich and i've got it set at about 1/4 of a turn out. So i'm thinking i need a new one.

I have troubles with the highest idle method too. Stock I was able to do it, but not with the pods and pipe... Once I get the rest of the carb circuits tuned properly I'll be revisiting the mixture settings with my Colortune.

Still running rich on one side... are you sure your pilots are both the same size? Have you checked to make sure your mixture screws are still intact? I've heard of the tip breaking off, so if one has broken off then screwing it in may not reduce the fuel as expected...

 

[Mr Rogers]

i'll pull them out and check. my brother has my calipers but i may be able to eyeball it.

I've heard of that colortune plug. it sounds like a very good tool to have!

 

[Mr Rogers]

ok so both of my mixture screws are still intact and they are the same size. I still have the issue of having my left carburetor burning rich.

You say i should check my pilot jet and make sure it's the same size as my right one?

I should tell you also that i pulled the mixture screws out and swapped them and set them to the same number of turns and I'm getting the same result. Right burns properly and left burns rich.

 

[Guest]

The only things I can think of that would have different mixtures at idle are:

• air leak on the leaner side
• pilot circuit blockage on the leaner side
• larger pilot on the richer side or smaller pilot on the leaner side
• tip broken off a mixture screw
• missing O ring off a mixture screw

There may be other reasons I'm not thinking of though...

Oh, are the holes for the sync adaptors sealed properly? That could give you an air leak...

 

[Mr Rogers]

hmm my mixture screw o rings did look a little worse for the wear... but is it likely that the problem would persist when i swapped them?

thanks a lot pete you've been a lot of help and I appreciate it!

 

[Guest]

If it was the O rings you'd think the symptom would follow the O ring... but if they're dodgy you'd be best replacing them anyway.

When you did your carb clean did you get all new O rings from www.cycleorings.com at all?

And glad to help if I can...

 

[Mr Rogers]

yeah all the orings are new and from cycle o-rings... thats why I'm wondering what's up with this one on my mixture screw... it seems like it has deteriorated really fast.

I've got a question: when you do a valve adjustment and expand the gaps throughout the bike so they're on the loose end(.102mm) would that result in richening the the bikes combustion?

because i think that the left side always burned slightly more rich than the right. but after this valve adjustment it became a real problem.

Could the valve adjustment effect it so much that i would need to buy new mixture screws?

Right now i'm thinking that i need two replacement screws since even the right one is only one turn out. I read somewhere that it's best to have them out two or more.

I'm probably going to sit off the bike for a few days...

 

[surviverguy]

ok so both of my mixture screws are still intact and they are the same size. I still have the issue of having my left carburetor burning rich.

You say i should check my pilot jet and make sure it's the same size as my right one?

I should tell you also that i pulled the mixture screws out and swapped them and set them to the same number of turns and I'm getting the same result. Right burns properly and left burns rich.

Are the fLoat heights the same? Is the fuel level in the bowls the same? Is a float needle sticking? Does fuel pour out of the overflow?

I didn't read all the posts////....just read your last post....

 

[Guest]

As for the mixture screws, they're either broken or ok, should be no need to replace them, just the O rings if they're bad.

As for how far out they should be, factory says 2 from memory but tuning will have them at different positions, although typically they would end up further out than in... you are counting the turns right aren't you? I have to ask that because I didn't once...