Hi guys,

It seems I’m having some issues with my stock 1vj.

The engine had some maintenance, new piston, headbolt repair due to the std issues and the head is overhauld. Anyway it ran fine for about 200km and suddenly at a nice afternoon start it starts to splutter. I’ve checked everything, well not all as the issue is still there.

All electrical tested, measured - coil, stator plug new sparkplug, checked all the wiring even checked the valve clearance. Cleaned the carb twice still running bad.

So it’s idling fine, but when you blip the throttle it’s stalling. Burp When slowly increasing gas it’s running rough but it will go its still a bit popping etc. What kind of part is this in the carb? As I’m assuming it’s a carb issue.

Cheers Nick.

Most likely.
What settings do you have at the moment?and can you make sure for definite the choke piston is fully to the right when off?
Before you pull the carb apart do the fuel level check too.

The carb is overhauled by Motoritz and went perfect for the first 200km. However I checked the float level and the choke. There’s is a fixed choke installed and that also was ok for 200km. Could it be the advanced system which is behind the lh case? Or a loose nut on the rh side?

Here’s a video. At the end it happens.

https://youtube.com/shorts/uFlA00Vj99M? ... rCfQm9PYO_

Sounds like she’s just under fuelling on a snapped open throttle, I think mine needed just a little more fuel height, and I went up a pilot jet size to 48. The fuel height was most important though. Then she picked up cleanly on the throttle from crawling along at under 2000 rpm, from behaving badly like that. Originally though, someone had put a choke piston with a needle on it in there, and it was causing havoc. Always allowing air through and adding the extra fuel. She’d stall with a jolt to the bike.
Why not try a fuel height of 6-6.5mm below and see what she’s like? Although I’d do the east thing first, and wind out the pilot screw a 1/4 turn each time and see. If you get to 3.5-4 turns out, go up a size.
Of course , I also changed my stator, some years back too. also a massive difference.

Cleaned the carb again today. Checked also float height measured 6 with the tube and 25,5 on the bowl. Still running shit. Pulled the sparkplug and that’s a bit black, seems a bit rich. Played a bit with the pilot screw 3 turn out now and running much better.

Didn’t went out for a run, but could this be the issue? Carb is rebuild 200km back and went all ok.

Fixed. The mass cable from the cdi was chafed by the frame. Found it with measuring and wiggle. All good now.