help needed to get my bike to start and run

[Frankyboy]

hello people, first time writing on a forum, ever! I have a Yamaha sx650 us custom 4G7, and am having problem getting it to tick over and sometimes even to start. any help anyone can give me would be much appreciated. firstly i am working from a Haynes Manuel and there seems to be three different types, the A, B and c, and i am unsure as to which model my bike falls under, it can make a difference to value clearance (inlet and outlet mm). if anyone can shed some light on that that would be great. i original signed up here to the site to access a pdf, with a detailed list on model info, (which aged by bike by a year and told me the 4G7). but didn't tell me which cosponsoring model i should use from the Haynes Manuel.
The main problem I'm having is that it has started but run lumpy I have set the exhaust @ .006 inch, inlet @ .002 inch checked the point setting with a strobe spot on taken the cab to bits and cleaned it, believe I have done everything that should but still have the problem of not starting or when it does it does not run for long and back fire through the cab seem like one side. It has been sitting in my garage for about 10 years under cover
any help thanks guys
Frank

 

[fredintoon]

Hi Frank,
clean the carbs. If you already did that, do it again. Especially the slow running and choke systems, those tiny little passages are the first to get blocked up and the most difficult to get clean.

 

[Frankyboy]

Thanks for your advise getting there slowly, i think my cam change was one link out redoing it now. I have an other question I have 2 x orange rubber seals in my cylinder head kit which I am not sure were they go they are roughly the diameter of the cylinder head gasket but very thin any help thank you

 

[nj1639]

Slide the rubbers over the lower part of the cylinders that extend beyond the finned jugs. They fill a gap between the cylinder and the engine block....used along with the gasket. You'll see where and why if you look.

 

[XSLeo]

www.amckayltd.com/carbguide.pdf is all you need to get your carbs right. Read it, download it, read it. Read it a few more times. Now remove your carbs and follow the steps in the carb guide.
Don't buy anything until you tear down, clean and inspect what you have. You might not have to buy anything. Most kits get the float bowl gasket right, sometimes the float valve is workable, not much else in the kits are usable.
There are 3 major divisions in the engines, the very early were the 256 engines. They uses a needle bearing on the piston pin as well as a longer rod and shorter piston than the next engines did, the 447. They added the E-start and made changes to the rods, no needle bearings and a shorter rod, longer piston.
In Europe they sold the 533 engines, They were different from the 447 in a long rod short piston, I think they were even longer than then 256 rods. There were many changes over the years, some minor, some major.
Up in the TECH section you will find threads on history and getting to know your bike.
There are many things to find and read in the TECH section.
I have a Haynes book. In the front it starts with the 256 engine. A lot of the info applies to the later engines too. As you go through each section it talks about some of the changes over the years.
Your bike will fit into the 77-83 areas of the book.
Your 4G7 is a number most of us disreguard. We go by the year and model. Your bike is an 80 which was the first year for the TCI and BS34 carbs. some models, the SG had mags, the G had spokes.
On the valve clearances, they changed them often trying to quiet the valve clatter. Most have found that .003 I, .006 E works well. I think the .003 inch = .075 mm, the .006 is .15 mm.
Leo