Gt200X5

[Suzukix5]

Hi , first post and already asking advice ! I have a 1979 X5, rebuilt crank and new topend. Ran in and dynoed, all figures good and 80+ mph seen on the road. But never happy running on left hand pot till it gets upto about 5000 rpm. Makes you think pilot jet which seemed likely when it had a 30 instead of 20 in there. I swapped back to standard 20 and no better. Carbs ultrasonic clean, float height correct. No difference, swapped plugs and leads over still off on left cylinder. Over oiling, swapped oil pump for another I had, same issue! Anyone come across similar and how did you sort it? Thanks

[daxman]

Over-oiling? Is it noticeably smokier out of teh LHS exhaust?
Could it be something in the oil feed - faulty check valve? Pure guess work on
my part I hasten to add.

[Suzukix5]

Hi , oil petrol mix dripping where downpipe joins silencer. Plug wet which could be unspent fuel. Not sure this model has check valves like on older Suzukis. Oil just goes straight into the barrel same as X7 engine. I am going to see if I can rig carbs up to opposite cylinder and see if problem follows it, if not can rule carb out. After that might try premix and not use oil pump. I have also ordered a CDI to try . Big headache !

[daxman]

I'm not sure its possible to use only pre-mix due to some CCI feeds being direct to bearings. Others on here will know better..
Have you got equal compression on the two cylinders?

[GTandcbr]

Hi and welcome to the forum. Dont be tempted to use premix as these engines have to be modified on the crank if you do so. The oil pump squirts a heavier dose of oil to the crank and a lighter dose to the cylinder walls. Premix will also affect the temperature in the cylinder maybe resulting in piston crown damage. I'm not familiar with the carbs on this bike but is it possible that the choke is stuck open on that cylinder causing it to overfuel? Do you have in line fuel filters? Its a good idea to fit these on an older bike as clean carbs can block in seconds if a tiny bit of crap in the tank gets sucked in. It is also a cause if the float needle shut off gets dirty too affecting the float level.

[Suzukix5]

Thanks to all replies and will take on board what you say about premix . Compression even on both cylinders, no inline filters but will give it a go. Choke is plunger type, let's more fuel in rather than restricting air. Looks OK but is on the side affected by poor running so worth a look. Will update when I have played some more.

[GTandcbr]

So just re-read your first post. When determining the problem with engine performance, its important to note that it is the throttle position not the speed of the engine when the problem occurs . I.e. you say under 5000 revs. It is possible to wrap some masking tape around the twist grip and mark the position of the throttle into 4 so you can identify when the problem starts and ends.

[Craig380]

It's highly unlikely to be the CDI as the X5 and X7 ignition is 'wasted spark' and the single coil always fires both plugs at the same time. If one plug is firing fine and the problem did not swap sides when you swapped plugs & leads, then that pretty much eliminates the ignition.

I think you're on the right lines with the choke plunger, it could be weeping. The left hand carb slide is the right way round, yes? Cutaway facing the airbox?

One final thing to check is, do you have a good, clean BARE METAL earth point for the battery? On my old X5 in the early 80s, it suddenly developed a stutter / misfire at midrange rpm. It would start fine, and run great until it warmed up, then it would start the misfire. New plugs, caps and several carb strips didn't sort it, until I happened to notice that the part of the frame the battery earthed to had surface rust. Cleaned it up back to metal, and problem solved. The electrics weren't earthing properly.

[Suzukix5]

Slides are right way round, had them on and off loads ! Will look at choke and the earth is a good tip thank you. CDI, getting rarer so don't mind picking up a spare while I can get hold of one. Do get the feeling it's something simple but there usually hardest to find. Advice much appreciated