[Joshua Cosimi]

Hello all, long post but need to describe some key things.

I've been working on my bike for about a year now and have had many issues that I've diagnosed and mostly repaired or replaced. I have gotten to the point that I've only got it to start once and after that I had taken the carbs apart and couldn't get it to start ever since. I've read just about everything I could find relating to the issue of fuel for the carbs. Everything that I've tried hasn't gotten me anywhere other than the same thing. I had done a carb clean and replaced all the seals for the internal components as well as changing the original parts for new ones in a carb rebuild kit. I found later that that kit wasn't working so I cleaned the original parts till I could see easily through them. I also bought new float valves and the clip just to be sure that wasn't the issue. I currently have ran out of ideas other than that maybe it's in need of a valve adjustment since sometimes while turning the bike over it will get caught and not move. Other than this thought I did set the pilot screws to 2.5 turns from completely tight and made sure the float bowls were at 17mm for both. I also switched from my completely rebuilt vacuum petcock to a manual yamaha one to see if maybe it was being starved of fuel. I'm unsure if it made a difference but that's the main thing I've done recently. Other things I've done is change the flywheel to a 2nd gen as the original problem was that the 1st gen had broken magnets all over. I followed the documentation listed by FOG. I removed evap crap on the top and currently have all vacuum ports blocked on the carb to work the the removal. I can list everything else after people help clarify things as well I can share photos with a Google photos link.

 

[FlipFlop]

Ignore what you have done and start from the beginning 1 step at a time.

Sounds to me you need to be more methodical about your diagnosis. Air, Compression, fuel, spark.

Carbs good boots in stock air box. Proper settings and verified. Getting good fresh fuel.

Sparkalators are being sparky.

Compression is good and even.

Make sure the stuff you stripped was properly removed, and no vacuum leaks.

 

[Joshua Cosimi]

Well I'm getting fuel, getting spark, compression I'm unsure how to properly test but I'll look it up. No vacuum leaks except rusted exhaust I suppose coming from the muffler maybe. Otherwise nothing else. I've properly cleaned and removed old gaskets before putting on new ones. I've also drained the oil maybe seven times or more. Only recently have I found that there may be gas in the oil so that could be carb related. Fuel should be good but after putting in additives in the new fuel to help with the carbs it has partial started but wouldn't run for more than a few seconds. I did also find after draining the oil yesterday that only the oil from the flywheel side seemed to have gas. I had opened that side first to see if there was any noticeable difference from how it has looked prior when i last had seen gas in the oil. When I found gas the last time I drained it all and found it was all the same being milky and smelling of gas. But this time after draing from the stator/flywheel side i found itt smelled like gas and was milky. I drained the rest from the oil pan in a separate container but found that it was not milky or had gas in it so that's a whole other thing. So my next steps will have to be compression test and probably a valve adjustment.

 

[Joshua Cosimi]

As far as I know I've replaced almost every seal except the clutch and anything in the heads or shifter. As for compression it seems to move just fine with no resistance until it builds up pressure and gets stuck until it release the air when turned by hand.

 

[Joshua Cosimi]

Update I bench synced the carbs and added new oil to the system. I was able to get it to run with full throttle open but it would die after a minute and if I let go of the throttle it would die. When attempting to start with out throttle it would not run. Using choke at first helped until it got up to temp, so I didn't use it later on still had same results. Also I noticed my rpm needle isn't going up like it had along while ago so what does anyone suggest I do?

 

[yorkie]

@FlipFlop said

Ignore what you have done and start from the beginning 1 step at a time.

Sounds to me you need to be more methodical about your diagnosis.

totally agree start over and do it properly and methodically asses all the work you did and and determine it is correct.
you said you changed the flywheel for gen 2 and modded it for the gen 1, was it correctly and precisely done. are the trigger strips identical to the gen 1 all other trigger material was removed. you could remove it place on a flat surface on top of the gen 1 timing marks and keyway exactly aligned. to verify the fly wheel is correct.
any mistakes will adversely effect the engines running. make sure you have it correct if it is you can discount it as an issue and move on.
do a compression test of the engine next. if ok move on I suspect the main problem is the carbs, there just not clean enough or set correctly forget the 17mm BS do a wet test on the float levels make sure all jets and pathways are clear.

there is a saying if you find yourself in hole. "stop digging"