My CB-1

[cb0y1]

yeah I replaced the slow jets with new #35 and it still does it.

[Kai Ju]

I've had a very annoying lean surge on my F3 engined CB1.5 and finally found the reason. The carb vent hose, for the float bowls, was routed to end behind the airbox.
It is now routed to end down by the water pump/ countershaft sprocket.
The bike has never run this well. Unbelieveable difference.
Worth checking.

[Kai Ju]

Off topic, how do you like that Sahara tank on the XR.
I've got an '02 but set up for the street with 17" wheels and have access to one of the Sahara tanks and I'm debating whether to try it or not.

BTW, I don't know if you've seen pics of my CB1.5 but I also have the front covers cut out but have them backed up with screen. Once you find screen that you like, double stick tape works awesome to hold in place. Just lay it along the perimeter and work the screen into the tape with a wooden dowel.
Any questions, let me know.
Here is a pic

[cb0y1]

I love the range on the sahara tank,  off road I get about 220mi out of a fill.  the trade off is access to the carb is shot, needs to be removed to get to the spark plug, and its really heavy up top when full.  Whats the range on the 1.5?

[Kai Ju]

The range on the CB-1.5 is about 110 to reserve which leaves about half a gallon/20 miles or so.
Which is about the same for the XR650 R/SM which gets about 45+ mpg.
I've installed a fuel valve on the left side of the fuel tank so I run the right side dry and then turn the left side on as reserve.

[Drewski]

Some nice loking powdercoating there OP, my frame's suffered badly this winter and needs sorting desperately. Out of interest, where did you hear about this over heated intake air issue? I allways thought warm air was better for intakes, probably due to the amount of cars I've seen where the airfilter scoop is directed to somewhere hot on the motor like the exhaust manifold.

[a_morti]

Off topic, how do you like that Sahara tank on the XR.
I've got an '02 but set up for the street with 17" wheels and have access to one of the Sahara tanks and I'm debating whether to try it or not.

BTW, I don't know if you've seen pics of my CB1.5 but I also have the front covers cut out but have them backed up with screen. Once you find screen that you like, double stick tape works awesome to hold in place. Just lay it along the perimeter and work the screen into the tape with a wooden dowel.
Any questions, let me know.
Here is a pic

That's beautiful. A great job!

[cb0y1]

Heat is always the issue on a gasoline engine.  Cold air is more dense and therefore you can put more fuel in it to make more power.  With the radiator right in front and the hot engine right under side plates, and a gas tank, there is only hot air available for the intake, especially in traffic.  Also hot air can contribute to detonation.  Only exceptiion to this rule is Diesel engines which run on controlled detonation so it really doesn't matter much with them.

[cb0y1]

So after hitting the exhaust pipes with a lazer thermometer to find the weak cylinder and listening closely to the engine, I found #2 had a pin hole in the plug cap.  Wrapped that in self fusing tape to insulate it and tried it again the ticking was gone and the engine studder is gone too.   Happy days are here again.

[Kai Ju]

thanks a_morti, I'm pretty happy myself with how it turned out.

cb0y-1, great find. So the ticking was probably the plug cap grounding out against the valve cover.