Six-Day loading up problem HELP!

[penton117]

Hi Guys,
Can anybody help? I recently built a '72 Six-day. The motor is stock, second-over bore, original porting, unmodified piston and original Bing carb. The only mod is to the tail pipe, which has had the outer muffler removed and a silencer put on the end of the stinger. Anyway, The bike starts easy enough and if kept in the powerband sounds quite crisp. Inspection of the plug after doing a plug-chop shows the main (a 140) to be about right for my altitude of 1,000' above sea level. The problem is when riding it, it tend to load up if you bog it at all. The only way to get around the track is to really keep it reving. I have dropped the needle all the way down, to no avail. Any suggestions on needle type, slide cut-out, pilot jet size or anything else that might help sure would be appreciated.


 

[Doug Wilford]

117, You are looking at a lot of variables, I will try to give you a few things to consider.  You say it starts easy.  Does it idle?  You say it bogs. at what point of transisition of the carb are you in, coming off idle, mid to wide open, is the float level set properly, try a 135 main jet,is the choke plunger sealing when off?   Hope this helps, these are just a few of the things that can be double checked.

 

[Randy Kirkbride]

Doug,
Glad to see you're back in action.

 

[hrbay]

P117, I spent a month last week trying to sort out a Bing 32. Turned out to be a leaky float needle. GC

 

[SoCal996]

I had the same type problem  and found the float wasn't set correctly. Adjusting the float solved the problem.

Brian

 

[john durrill]

penton117,
 did you find out what was giveing you the loading problem?
John D.

 

[penton117]

Thanks to all for the tips. I have yet to figure this out, but will consider everyones pointers this weekend. Thanks again

 

[FMF MX]

My 125 Husky did the exact same thing. It was a sticking float needle. I suggest a carb rebuild from Doug, and your problem should go away.

Bart Carrigan

[imported_n/a]

Jake Fischer would be thrilled to sell you a new carb!  

Glenn

 

[john durrill]

P117
 while you have the carb apart check the bleed hole from air boot side of the carb to the back of the needle jet. make sure its clean and not partialy blocked,
 if you have the vaporizer that is half cut away, the cutaway should face the engine.
 sometimes it would get blocked with aluminum
or what ever the carb body is made from. that vaporizer is knerled ( sp is wrong )  and will cut as its seated so it wont turn. the shaveings can block the hole and give you the simptoms you have. the choke plunger has a plastic end that seals the choke circuit so it only operates when the lever is depressed. the plastic falls apart on them over time. we made up a replacement with a thin neopreen washer and use gasket paper behind that to get the hight right. glued it in place with yamabond and it will work fine till you can get a new one from bing. used a set of gasket hole punches to make up the disks from the neopreen washer and gasket paper. if that circuit is not sealed off when the bikes running it will give you fits.
 check the timing. use a light if you can. another off chance is the motoplat is doing something strange. they can give you almost any simptom you can dream up when they fail.
John