So, replaced head gasket on project bike, which fixed the coolant issue. Had the carbs cleaned, put them in, synced them up. but seems to have fuel issue. cant get it to idle smoothly, won't rev past 6 to 7, ignition breaks up after 5, and has a massive bog. Any suggestions?

 

I am no expert on this - but have gone through some of what you describe in the last month or so. When you say had carbs cleaned, and you synced them up - what procedure did you use? I ask because I had to remove all jets and clean with carb cleaner and compressed air to get the bike to idle well on all 4 cylinders..it took two separate cleanings til the jets were free and clear... and I did not need to do a sync to achieve pretty good results... did you happen to see if the pilot screws were exposed and can be turned? I got good results using the setting of 2 1/4 turns out... also did you check to make sure you have plug wires on correct plugs? There are 3 jets in each carb, and one handles the rev range for idle to about 4 or 5K, then the main jets handle the rev range above. The idle jet can not be removed and it is tough to clean.

 

I had a friend of mine clean the carbs. He did it thoroughly. I adjusted the pilot screws to 2 and a half, and that fixed the idling. But it still bogs and wont rev past 7. What the guy before me did was put a hollow canister on the bike with no baffling, and what I'm thinking is that there is no back pressure, which is causing it to starve for gas. I'm gonna see if I can get a stock canister, and see if that does anything. So if anyone has a stock canister they are looking to get rid of, I would be interested.

 

Just a quick heads up... if you are still using the stock header and have a slip on aftermarket muffler that you are looking to replace, you can use an F1, F2, or F3 muffler with no problems.. I only tell you this because I was in the same spot you are in, and I could not find a decent F1 OEM muffler, but found lots of F2 and F3 OEM ones on eBay. I put a perfect F2 muffler on my 89 600 for about $30 including the shipping! It sounds so much better and you are right, it does run better, too. The mounting points lined up pretty well and it looks good, too.