pilot screw

kzken750 wrote:

all valve guides are new and the valves have been professionally seated. Not sure what you mean by the thumb test on the slides.

Put your thumb over the large opening on the top of the intake of the carbs. Lift the slide then put your thumb over the opening, let them go and see if they fall fast or slow. That lets you know if there's a leak up there. 
Steve
 

Like Steve say lift slide and then hold thumb over hole. It should drop real slow

Thanks for all the replies and interest given to this thread. 

Did the thumb test and the carbs are fine. I went down one on the pilot jet and it ran worse so I quickly changed it back. The pilot screws are now three and a half turns out. Still, it runs great with absolutely no hesitation while under power. Just trying to cruise at any speed and it will seem to surge or slightly buck, not sure how to accurately describe it.  The pick-up coil is new from the factory and the timing advancer seemed to work fine when I put it back in after the rebuild. Simply at a loss what to do here. So much time and money spent on this project. 

Surging while running at a steady speed is commonly a needle issue.  Dynojet sells a kit for using pods, that comes with different needles.  

kzken750 wrote:

Thanks for all the replies and interest given to this thread. 

Did the thumb test and the carbs are fine. I went down one on the pilot jet and it ran worse so I quickly changed it back. The pilot screws are now three and a half turns out. Still, it runs great with absolutely no hesitation while under power. Just trying to cruise at any speed and it will seem to surge or slightly buck, not sure how to accurately describe it.  The pick-up coil is new from the factory and the timing advancer seemed to work fine when I put it back in after the rebuild. Simply at a loss what to do here. So much time and money spent on this project. 
 

With that many turns out on the pilot fuel screws it would suggest that you could go one size bigger on the pilots then readjust the screws to a more normal +one turn setting.
 

Injected wrote:

kzken750 wrote:

Thanks for all the replies and interest given to this thread. 

Did the thumb test and the carbs are fine. I went down one on the pilot jet and it ran worse so I quickly changed it back. The pilot screws are now three and a half turns out. Still, it runs great with absolutely no hesitation while under power. Just trying to cruise at any speed and it will seem to surge or slightly buck, not sure how to accurately describe it.  The pick-up coil is new from the factory and the timing advancer seemed to work fine when I put it back in after the rebuild. Simply at a loss what to do here. So much time and money spent on this project. 

 

With that many turns out on the pilot fuel screws it would suggest that you could go one size bigger on the pilots then readjust the screws to a more normal +one turn setting.

 

There is something wrong if the bike surges like described.  3.5 turns open is the functional limit, but we don't even know the pilot circuit is causing the problem in question.  

kzken750 wrote:

thanks for the response. but what do you think is causing the feeling of the bike surging when I try to maintain an even speed? I have gone up twice on the pilot jet and there are 3 washers under the needle. I started with two and didn't feel it was right. Went down to one and it was worse. Went to three and as I said the bike runs great under power. Its just that it doesn't want to cruise smoothly. 

 

Sounds like you could use a richer needle or a Dyno Jet tuning kit. You would get much more response from a different taper on the needle than the spacers could give. Cruising speed would be mostly on the pilot circuit so it may also be lean there as well which might explain the surging. 90% of riding is done on the pilot system, over all jetting points back to a correct main jet size.

thanks for all the replies, it is much appreciated. I was off in the mountains in Arizona hiking. As far as the pilot jet goes I have installed the largest one available for that bike. The bike does have a dyno-jet needle.  It was installed after the Yoshimura pipe but before the rebuild with the Wiesco kit.  To the best of my memory the dyno-jet people said they had no data for a Wiesco bore kit. I guess I will have to dig deeper.     thanks guys

Is it possible to increase the spring tension on the plungers to stop them "fluttering" on a constant throttle ???

Wookie58 wrote:

Is it possible to increase the spring tension on the plungers to stop them "fluttering" on a constant throttle ???
 

I believe the flutter may be caused by the hole in the bottom of the slides that any DynoJet kit instruction manual tells you to do.

 

thanks yet again for the replies.
I had another talk with a representative from dyno jet yesterday. It was very helpful and informative. As I mentioned before they have no data for a bore kit. The kit for my bike will not help me as the main jets I have installed are already larger than what comes in their kit (of course they will sell me additional larger ones). I also have already installed a tapered needle when I did the first jetting at the install of the yoshi pipe. Other than that, the instructions get right back to moving the needle up and down. The rep also explained to me that not many people drill the slide lift hole as it is not always necessary. I was advised that that is done to improve throttle response. The throttle response on this bike is incredible. So, it gets back to the surging. Then it gets back again to the placement of the needle. To repeat, I started with two washers under the needle. Going down to one it ran worse. Going up to three it ran better. I'm going to try four. I will also buy four new spark plugs so I can get a better look at how it is burning. I'll let everyone know how this works out.     thanks 

P.S. As far as the spring tension I'm not sure if that could be beneficial. I will ponder that thought.

Seems to me that you could cover the holes drilled in the slides with a little dab of gasket maker or sealant to see how the carbs act without the holes. If it is worse or no better, the stuff can be scraped off. If it is better, a more permanent plugging could be used.