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 YAMAHA ZUMA BUGEYE - 70cc would not cold start. 
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Joined: Fri Apr 06, 2018 3:03 pm
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Location: montreal
scooters and mods: 2008 bws 70cc, pipe,
Post YAMAHA ZUMA BUGEYE - 70cc would not cold start.
Hi guys, new to forum but not motors. here's the problem.
I bought a 2008 yw50 not running with piston that was scored and cylinder head as well. I could not get it to run, figure low compression so Got a naraku 70cc kit (105 psi compression now; is that good?) and placed a 94 main jet, 44 slow, new bh9hs plug, checked reeds for issues, all good and seal perfectly, sealed intake tube so no leaks, cleaned carb completely so thats good too. she wont start cold on its own unless I block the carb filter side (no filter on it)...sorta choke it with my hand, it burps some fuel then it will run and run well. air screw is at 1.5 turns out (tried 1, 1.5, 2, 2.5) seems to respond well once warmed up. can start it again and again when warm. let it sit for a while and she is back to no start...choke it and vroom. the enricher works off the bike tested, the circuit for the enricher had 12v when running. what am I missing? HELP...daughter wants her scoot. :catholic:


Fri Apr 06, 2018 3:24 pm
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Joined: Thu Mar 20, 2008 5:27 pm
Posts: 14871
Location: portage wi
scooters and mods: 08 zuma dual headlight tmod rally kit cutom red paint koso mirros red anodized trans bolts
Post Re: 08 with 70cc kit, wont cold start
105 is low
Second what brand jet God only knows where you are at as to doesn't sell a 94
3rd put the Airbox and filter on you can not properly tune the stock carb to am open or no filter
4th unless it has a nolgy hot wire you need a resistor plug
5th when you tested the enricher off the carb did you replace the print when you put it back on

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2008 zuma dual headlight mod koso mirrors liquid cooled polini corsa kit leo vince zx stage 6 variator rally kit custom red paintFUEL INJECTEDsoon to be 100cc
2008 stella olive custom ported 177 cc kit dechromed ford tear drop tail light alive and breathing and awaiting cosmtic surgery thanks to an trump cager
1985 elite 150 how long can i leave it stock


Fri Apr 06, 2018 10:40 pm
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Joined: Fri Apr 06, 2018 3:03 pm
Posts: 4
Location: montreal
scooters and mods: 2008 bws 70cc, pipe,
Post Re: 08 with 70cc kit, wont cold start
thanks jmkjr72, here are some responses to comments;

1st what is a good compression and why would a new head and piston not be correct compression, any ideas?
2nd jets are from a polini kit (362.0003) has 80,82,84,86,88,90,92,94,96,98 main
3rd I did not get original box with bike, have an aftermarket foam style filter, should I find and oem?
4th what is a good plug for this setup (bh8es?), the plug was given to me by the local scoot tuner store
5th when you state replacing the print, can you explain <print > please? if you mean the rubber oring gasket, no it seamed fine.

thanks for all input, every bit helps


Sat Apr 07, 2018 6:09 am
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Joined: Fri Apr 06, 2018 3:03 pm
Posts: 4
Location: montreal
scooters and mods: 2008 bws 70cc, pipe,
Post Re: 08 with 70cc kit, wont cold start
my mistake, it is a BR9HS plug I have in it...sorry for confusion with resitor type.


Sat Apr 07, 2018 6:39 am
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Joined: Thu Mar 20, 2008 5:27 pm
Posts: 14871
Location: portage wi
scooters and mods: 08 zuma dual headlight tmod rally kit cutom red paint koso mirros red anodized trans bolts
Post Re: 08 with 70cc kit, wont cold start
120 or higher
You bought a cheap brand did you check ring end gap and piston to wall clearance
Read my thread why use the right jetsjust because it fits doesn't mean it flows the same and the numbers don't match from one brand to another
Yes get an own air box that would be why the last bite failed it ran lean as duck
Br8hs for cast iron br9hs for al unless the kit says otherwise
Yes you need to replace the print every time you pull the enricher

_________________
2008 zuma dual headlight mod koso mirrors liquid cooled polini corsa kit leo vince zx stage 6 variator rally kit custom red paintFUEL INJECTEDsoon to be 100cc
2008 stella olive custom ported 177 cc kit dechromed ford tear drop tail light alive and breathing and awaiting cosmtic surgery thanks to an trump cager
1985 elite 150 how long can i leave it stock


Sat Apr 07, 2018 6:41 am
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Joined: Fri Apr 06, 2018 3:03 pm
Posts: 4
Location: montreal
scooters and mods: 2008 bws 70cc, pipe,
Post Re: 08 with 70cc kit, wont cold start
ok...so the problem was the head cover that I received from naraku was not the correct one for the head, changed one that a friend had with oring type now have 125psi. I put an ngk coil on and she starter right up first crank, did some tuning and at 1.5 turns out on a-m, ran very well and plug was perfectly jetted at 92 from color. although I had spark it was not enough.

thanks for the comments.


Sun Apr 08, 2018 5:06 pm
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Joined: Sat Aug 05, 2017 6:33 am
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Location: Calgary, Alberta, Canada
scooters and mods: 2009 BWS 50, 70cc BBK, Dellorto Racing carb, Technigas exhaust
Post Re: 08 with 70cc kit, wont cold start
Glad to hear it worked out. Thanks for the final update on your solution!


Fri Apr 20, 2018 7:48 pm
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