Carb Spitback Help??? its getting to me now.
Posted: Sun May 04, 2014 5:44 pm
https://www.youtube.com/watch?v=rgsl3Ny ... 0KOSmKJYqA
I hope the vid turns out OK.
Muggy 185 Jetex normally through the air box. JL Snail
I was a bit previous with my statement about spitback on my wandering timing thread.
I have gone back to basics and am now running static timing at 17DBTDC. it was wandering all over the place but after a new BGM stator and CDR its stable. I did try an M Tech again but it was running like a dog so it came off again.
So after 3 weeks of buggering around Im back to square one. So much spitback it wont run with the carb rubber on. The rubber now has 2 holes that let the spitback escape but its straight down onto the pipe. It starts and runs but not with the rubber on. The vid is a reamed out 26mm that is not set up but its spitting the same as the 22mm I have run since I built the engine.
The problems all started when I lost some top end. I stripped it to find stuck rings round the ring pegs. The plating had come off in several places so it was sent for replating with a new piston. Got it back, rebuilt and holed the piston with what may have been a loose carb manifold.
At that time I opted to rebuild and use an M Tech with a view of getting it to run cooler. Of course I checked all the top end and was advised to go for a wider ring gap? and a bigger squish. I was all over the place with the settings on the M Tech but it ran OK but I seemed to be hitting a brick wall on revs. I was trying to run at 17-15 on full chat but had problems dropping out of the pipes power band changing from 3rd to 4th. so the M Tech came off. It was then that I noticed the spitback as it was a sod to restart.
The cream deposits are from the spitback on my rear runner after a very short ride with no rubber on.
3 weeks ago I rebuilt the top end with new rigs going for a smaller ring gap. and the squish was 1.2. The spit back was unchanged. It was an unmolested barrel with no porting.
Any ideas guys or does anyone have any info about measuring the port timings. I did notice the piston goes down about 4 mm below the exhaust port, I expected it to be level with the bottom edge.
I hope the vid turns out OK.
Muggy 185 Jetex normally through the air box. JL Snail
I was a bit previous with my statement about spitback on my wandering timing thread.
I have gone back to basics and am now running static timing at 17DBTDC. it was wandering all over the place but after a new BGM stator and CDR its stable. I did try an M Tech again but it was running like a dog so it came off again.
So after 3 weeks of buggering around Im back to square one. So much spitback it wont run with the carb rubber on. The rubber now has 2 holes that let the spitback escape but its straight down onto the pipe. It starts and runs but not with the rubber on. The vid is a reamed out 26mm that is not set up but its spitting the same as the 22mm I have run since I built the engine.
The problems all started when I lost some top end. I stripped it to find stuck rings round the ring pegs. The plating had come off in several places so it was sent for replating with a new piston. Got it back, rebuilt and holed the piston with what may have been a loose carb manifold.
At that time I opted to rebuild and use an M Tech with a view of getting it to run cooler. Of course I checked all the top end and was advised to go for a wider ring gap? and a bigger squish. I was all over the place with the settings on the M Tech but it ran OK but I seemed to be hitting a brick wall on revs. I was trying to run at 17-15 on full chat but had problems dropping out of the pipes power band changing from 3rd to 4th. so the M Tech came off. It was then that I noticed the spitback as it was a sod to restart.
The cream deposits are from the spitback on my rear runner after a very short ride with no rubber on.
3 weeks ago I rebuilt the top end with new rigs going for a smaller ring gap. and the squish was 1.2. The spit back was unchanged. It was an unmolested barrel with no porting.
Any ideas guys or does anyone have any info about measuring the port timings. I did notice the piston goes down about 4 mm below the exhaust port, I expected it to be level with the bottom edge.