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How is this possible?

Posted: Fri Aug 27, 2010 8:07 pm
by abalmer
I am working on a 1988 SB50 honda elite. I cannot get it to start. I have tested the spark and it is good. I have good compression around 145. I cleaned the carb jets and reassembled. I tested the petcock by sucking on the vacuum line and the gas starts to poor out, so I am guessing the petcock is working normally. I have compression, gas and spark shouldn't it have no choice but to run? What else can I do to get this thing to run? Thanks.

Re: How is this possible?

Posted: Fri Aug 27, 2010 8:23 pm
by da808nanospeed
how about hook up for the gas and vacuum lane and ignition switch?

Re: How is this possible?

Posted: Fri Aug 27, 2010 8:29 pm
by Bear45-70
da808nanospeed wrote:how about hook up for the gas and vacuum lane and ignition switch?
Image

Re: How is this possible?

Posted: Fri Aug 27, 2010 11:25 pm
by mustangwagz
Your muffler aint all plugged up is it?

How did you check for spark? with a screw driver inserted into plug wire? (crude method, but does work) or did you pull plug and check it that way? Check your plug gap..could be wrong.. ya gotta think, if that plug aint exactly gapped right, or even has cracked porcelin, its gonna not fire inside the cylinder. Inside a cylinder is a rather harsh environment, so spark sometimes isnt present internally, but then when pulled out into the earths natural atmosphere, works just fine?

as far as the petcock thing goes, id say thats working fine, try leaving the fuel line attatched to carb, suck on the vac side and let the carb prime itself.. (as in fill the bowl) You can verify the bowl is full by then opening the bowl drain to see if gas comes out..

You got compression so that would eliminate the reeds being stuck open (right bear?)

If EVERYTHING i typed is all good (Dont forget muffler..) then uhh...maybe look at timing? thats only other thing i can think of.. You might have a sheared key..but i dunno how often that happens on these scoots. (happened ALOT on my alcohol race kart)

Ahhh yes, one other thing..Do you have air box hooked up? I know the spree wont run properly with the air box n such unhooked, so i can only imagine ther others are the same way!

Re: How is this possible?

Posted: Fri Aug 27, 2010 11:51 pm
by fastplastic
does it start for a second and stall or nothing at all

Re: How is this possible?

Posted: Sat Aug 28, 2010 12:25 am
by Bear45-70
abalmer wrote:........................I cleaned the carb jets and reassembled....................
Cleaning the jets does not mean the carb is clean. Also you have only proven you have fuel to the carb inlet. Not in the carb. Open the drain after you try to start the engine, if there is fuel in the bowl then you have proven that much, but you still have not proven there is fuel getting into the engine. Do you have the air box and filter on the engine?

Re: How is this possible?

Posted: Sat Aug 28, 2010 6:31 am
by Munstah666
mustangwagz wrote:Your muffler aint all plugged up is it?

How did you check for spark? with a screw driver inserted into plug wire? (crude method, but does work) or did you pull plug and check it that way? Check your plug gap..could be wrong.. ya gotta think, if that plug aint exactly gapped right, or even has cracked porcelin, its gonna not fire inside the cylinder. Inside a cylinder is a rather harsh environment, so spark sometimes isnt present internally, but then when pulled out into the earths natural atmosphere, works just fine?

as far as the petcock thing goes, id say thats working fine, try leaving the fuel line attatched to carb, suck on the vac side and let the carb prime itself.. (as in fill the bowl) You can verify the bowl is full by then opening the bowl drain to see if gas comes out..

You got compression so that would eliminate the reeds being stuck open (right bear?)

If EVERYTHING i typed is all good (Dont forget muffler..) then uhh...maybe look at timing? thats only other thing i can think of.. You might have a sheared key..but i dunno how often that happens on these scoots. (happened ALOT on my alcohol race kart)

Ahhh yes, one other thing..Do you have air box hooked up? I know the spree wont run properly with the air box n such unhooked, so i can only imagine ther others are the same way!
I would second this advice.

Re: How is this possible?

Posted: Sat Aug 28, 2010 11:08 am
by abalmer
Thanks for all the replies. Its a brand new plug and I gapped it correctly. I checked the spark and it is there. I have the airbox and filter tightly connected to the carb. As for the muffler being clogged how can I test this? Just put my hand over it while I try to start it? The engine won't run at all. I think im going to take the carb off and make sure everything is clean like advised.

Re: How is this possible?

Posted: Sat Aug 28, 2010 11:13 am
by Trafficjamz
pull the spark plug out and put a little gas/oil mix in the spark pug hole.


reinstall plug and try to start it.

if it starts then stops, clean the carb again. :thumbwink:

Re: How is this possible?

Posted: Sat Aug 28, 2010 11:36 am
by Bear45-70
Having fuel, air and compression is no garrantee an engine will run.

You have to have the right amount of fuel (not to lean and not to rich) and the spark has to be at the right time for the motor to run.

Check the timing.

Re: How is this possible?

Posted: Sat Aug 28, 2010 12:43 pm
by abalmer
I put some starting fluid in the cylinder and it did the trick. I guess it needed some help pulling the gas into the cylinder. I figured that the piston going up and down from me trying to start it would have been enough of a vacuum to pull in the gas. But after I added the starter fluid it works great and starts easily after I turn it off.

Re: How is this possible?

Posted: Sat Aug 28, 2010 2:43 pm
by mustangwagz
Glad you got it running!

Tip of advice though, DONT USE STARTING FLUID ON 2 STROKES! lol you Can cause major damage to internal components. use a bottle of 2stroke gas. like in a spary bottle, Windex style or something with that style bottle! Just a tip! haha

Re: How is this possible?

Posted: Sat Aug 28, 2010 4:05 pm
by abalmer
Thanks for the tip I did not realize it is bad for the engine. Ill take your advice for sure.

Re: How is this possible?

Posted: Sat Aug 28, 2010 5:50 pm
by Bear45-70
abalmer wrote:Thanks for the tip I did not realize it is bad for the engine. Ill take your advice for sure.
Starting fluid is actually ether and it does two bad things.

1) It washes the oil off the cylinder walls and the piston and rings, means no lubrication between moving parts.

2) It explodes and if it explodes before the intake port close it will ignite the mixture in the crankcase causing the reeds to be destroyed.

Re: How is this possible?

Posted: Sat Aug 28, 2010 11:57 pm
by fastplastic
[quote="abalmer"] I figured that the piston going up and down from me trying to start it would have been enough of a vacuum to pull in the gas.
umm if thats the case your rings are fired/cylinder walls, but your carb is dirty or not cleaned correctly would be my guess so clean /re-clean your carb