puzzle number 2

[jezman]

Hi guys on to puzzle number 2 on this thing !!! Chasing the gremlin. So to recap. Got it down to a throttle problem. Was not running over 3000rpm and backfiring stripped carbs cleaned them and as lloydie suggested checked vacs. So to cover my back new VAC hose balanced carbs set fuel screw on front to 2&1/4 and rear to 2&1/2 turns set TPS so it was reading 494 from about 980. Fired it up and found front slider wasn't moving took top off and rubber wasn't sitting right. Fired back up now its backfiring soon as i blip throttle in rear carb!!! Visibly through butterfly and it's puthering smoke out of rear carb and exhaust for ages after I cut it off!!!!

Saw a French guy on here having a similar problem and I think he found it was ignition pulse sensor. Checked that its reading 625ohms Haynes says between 610 & 620 no massive difference the ignition pulse on my old engine is reading 614.
Just waiting to get. It painted but not painting till its running right.
Cheers guys if I'm being a bit dim but built it all back up on my own and refusing to take to garage at final hurdle!!

[bazzashadow]

sounds like timing if it firing back through the carb

[jezman]

I thought it could be timing at first so checked both as I had fitted mcct's and both looked spot on.

[lloydie]

Did you refit the air box to test it


Lube, no lube, it's your choice .

[jezman]

Yep fitted airbox just took top and filter off to check on backfire.

[jezman]

Just to mention big thanks to gabi for coming having a look and flicking his "magic" touch was a pleasure to meet and chat and hope to see him soon at a meet.

[artee]

Is it sorted?
Its always nice to read the solution to any problems.

Roger

[jezman]

Not 100% sure yet seemed to cure itself of the main spitting and farting but seems to still be a bit of lag on whipping throttle open. not had it out for a run yet to test properly waiting for wheels and body work to come back from paint shop.
will put update when its mobile.
going to try running it with standard cans first then chuck the carbon microns on to see if they are the issue.

[gabi81]

If not done I will come down on bike and we can see what's what on mine and match it to yours
Let me know