Dies after hitting bumps

[mitsukid124]

I'm having a few different issues with my 86 Honda spree nb50.

first: I have been noticing that whenever I hit a bigger bump my spree wants to die. It'll start to slow down and when I pull the throttle I have no response for about 5 seconds and then it'll go back to normal. I can also sit down on it hard and it'll die. I can even pick up the back end slightly and drop it and it'll die.

Second: I have noticed that whenever I am at 3/4 to full throttle and I let off the throttle to slow down it bogs down and if I try to give it any throttle it doesn't do anything. It slows down from about 25/30 to around 10/15 mph before I can get any throttle response. Also when I'm at full throttle I notice something weird. It feels like it'll cut out for a second or two, almost like the moped chugs. it'll do this anytime I'm at full throttle.

third: It just today started to sputter when I go to take off and doesn't have power until about 5 mph.


I think this is all somewhat related and I think it is fuel related but I'm not sure where to start looking.
Please help!

[mitsukid124]

Where are all the grounds that I should check?

[Trafficjamz]

This is not the first time this has been discussed.

http://www.hondaspree.net/phpBB3/viewto ... 3&p=183088

IIRC this is a carb/bystarter issue

[mitsukid124]

The bumps have been, yes. The other issues I can't seem to find anything on.

[Trafficjamz]

The bumps have been, yes. The other issues I can't seem to find anything on.

The other issues sound like an air leak to me. (lean bog)

Is your air box and filter all sealed up tight?

[mitsukid124]

I think so, how can I know for sure though? I might be ordering a gasket for the cover and a new filter.

[ClemSpree]

IIRC this is a carb/bystarter issue

Same here and I happen to be replacing a stuck open bystarter on a scoot that has the same problem. IIRC, fuel splashes into the choke system on the air side and kills motor.

Other issues could also be related to the bystarter as well, test and check wires. They are available cheap.

[mitsukid124]

I tore into the carb today to clean out all the ports and what not. I came across something I though was weird. In the hole the bystarter's collar is supposed to be able to move in, I foundthat part way down the casting looked bubbled out and I don't think It can move at all. I'll try to get a good pic of this.

[mitsukid124]

Well I cant seem to get the pics on here but whatever. It looks like the guy I bought it from used a bolt that was too long to bolt the bard on and pushed a bump into the bystarter port so the needle would act like it is constantly in the cold position. So it looks like I'm parking it for the winter until I can get a carb.

Another question though... would this rich state be able to cause all of my symptoms?

[mousewheels]

If this is a Spree or Elite SB50, look at the outside of the carb body by the mounting bolt nearest the bystarter.

If the wrong carb mounting bolt (long one) is installed on the bystater side of the carb, it can strike and deform the inner round bore in which the bystarter air valve travels.

When the carb is installed, the bystater is cold, (thus open), and is now stuck open by the deformation of the carb body.

>> Another question though... would this rich state be able to cause all of my symptoms?
Yes - That's the pre-conditions along with the old style carb body which make the issue of engine dies on bumps occur.

On the same thread Tjamz linked, but a little earlier, I describe the stuck open/bump behavior. (Link)

[mitsukid124]

Ok, I understand that now. But would it cause the other symptoms as well?

[mousewheels]

Ok, I understand that now. But would it cause the other symptoms as well?

first: I have been noticing that whenever I hit a bigger bump my spree wants to die. It'll start to slow down and when I pull the throttle I have no response for about 5 seconds and then it'll go back to normal. I can also sit down on it hard and it'll die. I can even pick up the back end slightly and drop it and it'll die.
>> Most here are pointing at the stuck open bystarter <<

Second: ....Also when I'm at full throttle I notice something weird. It feels like it'll cut out for a second or two, almost like the moped chugs. it'll do this anytime I'm at full throttle.
>> Sounds like '4 stroking'. When too rich 2 cycles sometimes fire every other cycle and can toggle between running correctly, and being too rich to fire every stroke.

third: It just today started to sputter when I go to take off and doesn't have power until about 5 mph.
>> Sputter points to too rich

IDK for sure. Gather up all cheap/easy info you can. I'd probably verify there is no carb float needle or float level issue. What's your plans? If replacing the carb to fix the bystarter issue, wait and see if that fixes the other issues.

[mitsukid124]

If I measured my float correctly it sits almost perfectly at 12.2mm like it is supposed to. Also the float and float valve both look to be okay, I wanted to test the float in water but I'm not exactly understanding that whole thing. Sorry for seeming like such a noob, I'm more of a FI guy that works on cars, mopeds and carbs are new to me.

As far as plans, I think I'm going to fill the indent on the outside of the carb with jb weld and then grind out the bump in hopes it wont go through the wall in the carb.

If that doesn't work, is this site know at all?

http://wincycles.com/Carburetor-Honda-S ... _info.html

I don't want to cheap out on a knock off, but I don't have the cash to go straight to Honda.

[mousewheels]

>>If that doesn't work, is this site know at all?
IDK about the website, but have bought from wincycles on eBay.

Wincycles is where my clone carbs came from a couple years back. Looking at a Spree carb rebuild kit site you linked, their carbs still differ somewhat from Keihin carbs internal parts. Here's a link to some pics of a clone carb

[ClemSpree]

I just did this with a cheapy bystarter, I'll provide the link after I know if it functions in a true cold start. All the running problems were similar(but not as constant/consistent) and all are gone.

Might be a few days, I didn't have any exhaust gaskets so its gooped up with some furnace rope filler and I want it to dry well:)