A possible reason for slower takoff after warm up

[patthesoundguy]

I finally got to tear my 84 spree down and pull the cylinder and have a look see and give it the 7000KM or 4300mile service it deserved. It ran fine before but It would sometimes have a slower take-off when it was warmed up. Someone had asked thise question back in the summer I think but there was no real answer, This may explain why that is.

The bore was mirror like, no place for the oil to go. The piston looks pretty darn good for being in there for that long and never being serviced.


minimal carbon build up and some blowby but not bad. I have the piston and grove cleaned up and the bore honed up.
New taz stock piston and rings on the way, but Im going to run the original set-up untill the new arrive just to see the difference. And I ported a little while I was there too. No real exhaust work yet as I want to feel what the intake work did then go at the exhaust port and raise it. Just cleaned up any casting flaws for now.

gotta love diamond dremel bits.

[motormike]

What am I seeing Pat ?
What is the possible reason for slower take-off after warm-up ?

[patthesoundguy]

A worn cylinder. If there is good compression and no air leaks and the bore is in that kind of shape, it could be it. Ill heat cycle it a bunch and do a break in and run it and see how it goes. Its funny, I tore it all apart just to replace a busted exhaust stud and look what I did a whole ton more. I figure trying to get better perfomance is not going to work if the major parts of the engine arent up to snuff so its fun to expearament along the way. I have lots of fun planned for that little scoot. I have a used 44mm bbk to play with then Im going to order the 48mm bbk. My nc50 express is all "kitted" up with the 70cc kit new head, reeds, intake and carb with a MLM pipe ordered, my spree deserves the same love.

[patthesoundguy]

Getting things put back together
Got something fixed that was bothering me
Before

uploadfromtaptalk1352578465201.jpg (160.7 KiB) Viewed 4393 times

After

uploadfromtaptalk1352578417882.jpg (154.58 KiB) Viewed 4393 times

uploadfromtaptalk1352578465201.jpg (160.7 KiB) Viewed 4393 times

all that is needed is to match the reed block out put to the case so very minimal amount of material needed to be removed

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[patthesoundguy]

All that made for one happy spree! It is breathing so much better for sure. And nice to have new exhaust studs which was why I tore it down. Its a nice night for heat cycles nice and cool. Ive gotten 5 cycles so far.

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[motormike]

.........I wanna ride that Express. Spree happiness is a very good thing...
After you have this break-in complete, I'll be interested in a before/after statement....
My Aero 50 could also be described having sluggish take-off after hot,
but after a quick warm-up, she hits a ton and wheelies quite gracefully....

[patthesoundguy]

I did 7 heat cycles and did a little light running around the hood varying the throttle and it runs very well indeed!! it has more pep for sure. I didnt need to give much throttle to cruise at 20 mph with ease. the porting was well worth the time. the piston slaps, but it always did that anyway. That should stop with the new piston coming from Taz. And I would love to let you take the express for a blast, it would make you giggle. I still have to port the reed block on the express but it is runing so nice I dont want to take it apart unless the spree is in one piece which it will be by tomorow morning, ill be back to wor on the spree after I get back from my gig in a few hours.

[patthesoundguy]

Alright its really starting to break in now, it has a real tangible pronouced power band which was never the case before. It comes on a little over 3500 rpm and doesnt quit. Going up the hill before it hit a brick wall at about 25mph now it climbs in speed going uphill. Its a whole new scooter. Cant wait for the new piston

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[thekingof7]

I was one of the guys asking this question and never really getting anywhere.
A couple of us had proposed the idea of an issue of a dirty carb being exasperated by the auto bystarter kicking in.
I might need to take the plunge next riding season(Wisconsin) and throw a new cylender and piston on there.

[patthesoundguy]

I knew it wasnt a carb and bystarter issue all along. Becase the lack of power would be well after the the bystarter would have any thing to do with anything. It would have less get up and go after an hour or so and it still had the top speed more or less. You might not need a new cylinder but its so cheap to pick one up with the new gaskets with piston and rings.
http://www.ebay.com/itm/HONDA-NQ50-SPRE ... 69&vxp=mtr

If you want to renew on the cheap, just pick up a cheap brake cylinder hone and hone the cylinder, clean up the piston and ring groves, replace the base gasket, port like I did and you will restore a whole bunch of performance. what I did cost me so very little, I replaced the piston clips $5, the base gasket $3.5. I keep base gaskets on hand along with piston clips and exhaust gasketsand a head gasket or two, because I always need them. I actually used the new base gasket as a template to cut one so I dont have to keep buying them just to experiment and fix little issues with out having to order parts and wait.

[swimmingfree]

i no you have a tach what was your max rpm before and what is it now???
swimmingfree