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Post by bennwedge on Nov 4, 2011 19:01:47 GMT -5
HI all,
I recently purchased a scooter from my young cousin which i am going to use to save money. It was somewhat bodged when i got it, The electrics had been played about with , electric start did not work, the exhaust studs had been snapped off and exhaust fixed on with metal repair gunk and copper wire and it had cracked fairing.
I went through all the electrics and have fixed the starter motor and have fitted a new head and standard 40mm piston. I also bought a new full power performance exhaust and a ramair filter.
The problems i have been getting is with the ramair foam filter installed the scooter would bog down when accelerating under load and stop.. so i have taken it off for now and put the old one back on. I took the scooter for a long ride today and after about 15mins of riding i had a blast on full power and the engine just cut out and died. 10 mins later it started up again. does anyone know whats going on? I think its getting too hot and seizing up . i was wondering how i can solve the problem. the carb is a gurtner py 12 and has and 80main jet fitted i have it set up to factory settings on fuel/air mix (1 1/4 turns) . i also think i have a problem with the idle adjustment at the moment it is fully in and the scooter hardly ticks over. i have had the carb off and cleaned it and used an airline. I really want to tune this little scooter to make the fastest 50 around and would really like some advice. back when i was 16 i had a aprillia rs50 that did 75mph and would really like to hit 70 with this one.
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Post by 90GTVert on Nov 4, 2011 19:19:39 GMT -5
It sounds like you need a larger main jet. The heating up and seizing as well as the bad bog with an open filter can all be indications of a lean condition.
Try adjusting the idle mixture to get your idle speed to increase. Go 1/8 - 1/4 turn at a time and let it settle, repeating until you find the highest idle. Adjust the idle speed screw as necessary.
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Post by Fox on Nov 4, 2011 19:21:51 GMT -5
If you have any air leaks like a crank seal or intake seal then the scooter will run lean or erratic causing it to "soft seize"
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Post by bennwedge on Nov 4, 2011 19:35:29 GMT -5
cheers for the advice. I think i will do a plug chop tomorrow and check for air leaks. what size jet do you recommend i try?
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Post by 90GTVert on Nov 4, 2011 19:36:53 GMT -5
Just a guess, maybe a 90. If you go back to the ram air filter, larger than that.
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Post by stepthrutuner on Nov 5, 2011 12:27:57 GMT -5
I'm guessing your Gutti is air cooled (I think the F12 was available in l/c & a/c versions) ? IMHO the path to a true and reliable 70mph would involve (prices probably within 15%): 1. A quality 72cc mid race, maybe cast iron but probably nikasil coated Al cylinder......$300+ 2. 21 mm or larger carb and tuning parts.....................................................................$160 3. 10 - 15% upgearing and/or overrange transmission................................................$100 - $500 4. Appropriate mid race pipe.........................................................................................$350 5. Full circle race crank (you won't see 70 w/o seeing at least 11 -12,000 rpm)...........$250 6. Roller/spring tuning....................................................................................................$80 7. CHT (cyl. hd. temp.) gage (optional but could save you hundreds potentially)........................$100 8. Reeds/cage/intake...................................................................................................$150 Others may dispute these prices but I am considering good-to-excellent quality parts prices. If you can get lucky and find some good used parts you could cut the cost's considerably. You could spend a lot more too for top quality parts too. The crank could be optional if you only used the top end speed sparingly but that's no fun.  If you set your goal to just 65 mph you could save a bunch on the cyl., pipe, crank, gearing and intake/cage (maybe $600-1000) |
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Post by bennwedge on Nov 7, 2011 17:36:39 GMT -5
thanks for the replys . cant wait to start tuning this little machine up although think its gonna take some time. having a 30yr old vw bus aswell which is burning a massive hole in my pocket. I took off the filter and carb earlier and noticed there was alot of fuel in the airbox . so i checked the reed valve and its not closing properly. do you think this is the reason i cant adjust the idle properly and why it keeps soft seizing at wot?
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Post by 90GTVert on Nov 7, 2011 17:57:32 GMT -5
It could be your idle issue, but I don't think it's the soft seize culprit. I still think that's a lean condition. If the reeds don't close it's more likely to run rich.
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Post by bennwedge on Nov 10, 2011 19:14:58 GMT -5
hi all . right i need some advice about where to go next. I got a new reed valve today fitted it and my idle/ starting problems have vanished so thats good. i also bought a selection of jets 75-120. I took the old jet out of my gurtner carb and it was a 62 ( not the 80 i thought it was). So i fitted the 80 jet along with my ramair filter. The throttle needle is on the middle setting and the mixture screw is set to the factory 1 1/4 turns. The scoot now sounds really throaty and when i go for a ride the revs start off really good then it bogs down alot in the mid range. Once you get passed the mid range it picks up again and i can get 60mph. My question is ..........do you think this is the right size jet? if not do i go higher or lower? or have i not set the carb up properly?Thanks
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Post by 2strokd on Nov 11, 2011 1:47:31 GMT -5
Try setting your needle higher by moving the clip down a notch.
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Post by bennwedge on Nov 15, 2011 13:41:38 GMT -5
well thats bloody annoying. No sooner had i sorted this scooter out. I get up this morning ,get dressed open the front door put my crash helmet on and ..............oh..............oh dear.........my lil scoots been stolen!!!!!!! .............................BASTARDS!!!!!!!!!!! now im sad ive only had it 3 weeks and have really enjoyed cruising around on it . oh well looks like my scooter adventure has hit a brick wall for the time being. just hope it either turns up and is not smashed up or the insurance company give me a decent payout
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Post by 2strokd on Nov 15, 2011 14:13:25 GMT -5
DANG IT!!!! F$cking thieves :rant: :swear: :censored: :bfg: Hope you get good in the end brother.... Bring that shit inside next time if ya have to  |
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Post by 90GTVert on Nov 15, 2011 14:23:23 GMT -5
Sorry to hear it. Let us know what comes of it. |
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Post by bennwedge on Nov 21, 2011 17:52:10 GMT -5
well i had a phone call from the police today. They have found the tax disc and one of the rear side fairings about a mile away near some woods. I know the side fairings do not come off ( rusted bolts) so im guessing that my lil scoot was crashed after racing around in the woods. Ive done a google earth search of where my parts were found and the is a dirtbike track very very close. think im going to be taking the dog for a long walk round there tomorrow.....fingers crossed
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Post by 2strokd on Nov 22, 2011 8:18:47 GMT -5
Dang it... Thats no good man. Ide do the same as you. Bad thing is. If its made it that far, they have probably destroyed it?
Hoping the best man! Maybe you can catch em on it?
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