Honda Spree and Elite 50 Forums

if all is stock with the box you shood not have to block it at all ..... some thing is funny try moving the pin up and see what happens.. some one has done some thing to the carb ( put a difrent pin in ) or you have a air leek ????
swimmingfree

My thought was air leak too, but I've sprayed carb cleaner on all the suspect areas with the engine idling and no increase in speed, so it appears to be tight. So is teh exhaust. Puzzling.

OK, I tried driving a while with the partially-restricted intake. It actually ran well for 3-4 miles. Then it died as I slowed for a stop sign (worked fine at several other stops). After that I could not keep it running for more than 30 seconds or so at a time. Limped back home. At the home stretch, I ran WOT for 20 seconds, then chopped the throttle. The plug looked good to me, tan-brown.

OK, so now I decided to go through other stuff just to eliminate any other issues. Compression was 100 psi, a little below spec, but not all that bad in my opinion - what do you think? Timing was dead on. Reed valves looked very good. Pulled the fuel line, opened the petcock with vacuum, verified that fuel flowed freely. Pulled the fuel screen anyway and blew out with compressed air. I put masking tape all around the air box cover seam just to make sure it was sealed. I tried the needle in all three positions.

I will get a new carb gasket kit, just to be sure, but I don't think that is the problem.

I can't think of anything else to check or do, other than try a bigger jet. What would you do?

Thinking about this some more, I'll supply a partial answer to my own question, of what to do next.

When I block the intake, that restriction increases vacuum in the airbox and carb. That increases fuel through the main jet.

Conversely, what could cause vacuum to be reduced? If the exhaust were restricted, less air would flow out of the carb, so that would reduce vacuum in the carb, and reduce fuel flow. Low compression would also flow less air through the carb, would it not? I think I will pull the exhaust tomorrow and check for blockage in the exhaust and exhaust port. With the exhaust temporarily removed, I should get more air out, more vacuum, and more fuel, no? Maybe it will run temporarily with no exhaust. It is worth a try, to point me in the right direction. My neighbors will love the sound of that test!

I would appreciate any feedback on what number constitutes "good" compression - does my 100 psi demand a remedy?

Your 100 PSI is not your problem.

Bear45-70 wrote:Your 100 PSI is not your problem.

thanks

Pulled the exhaust and saw no restrictions or undue buildup in the exhaust port. The engine ran the same without the exhaust - it would only run at open throttle with the intake restricted.

The local Honda dealer says he has the 70-size jet listed in the Wikispreedia reference chart in stock, but not the 68, so I will give that a try hopefully tomorrow. Gasket kit is on order.

can you post photo ???? most of us use imageshack to do so .. i wood like to see the inside of the air box and a close up of the peace between the carb and the manifold ..
swimmingfre

OK. Thanks for looking.

you need that clamp tite ... and you can plug this to hand choke it
By freeswimming at 2012-03-21..

do you have the brow thing on right and are the rubber o rings on as well
swimmingfree

Thanks swimmingfree. I don't have a cover seal. I did not know there was one until you asked and I just looked at a parts diagram. Glad I included the cover in the photo. I will get one.

I have manually choked as you described to get the engine started on occasion, usually after replacing the carb (I do use vacuum on the petcock to get fuel in there, but it still hesitates to start sometimes).

It looks like the airbox cover seal is still there

Yes, you're right - it is. One corner of the cover looks like it is not completely tight - it will drop a fraction of an inch if I press down on that corner. Could just be the seal compressing. I'm not sure now if this seal is the issue.

Carb-manifold spacer. This one and the carb o-ring looks good; it looks like they compress slightly when installed. But I do have carb gasket kit and airbox cover seal on order.

the O ring gose to the motor you can put it on upside down so put the bolts in then the sacer so you cant see the ring and then look to make the hole is line up .. then the carb..
swimmingfree