hi guys, Picked up an 50cc 08 plate NRG - great little scooter ( normal ride is a Triumph 800). Looked thru this forum - seems very helpful so hoping someone can help me out as have a problem that's doing my head in. Good news- Starts on the button, idles fine, choke works then settles down to 1500rpm idle, can rev to 9000 easily. Bad news- pulls away at 5000rpm, reaches 20mph then revs drop to say 7000 and bogs down when applying throttle,with less throttle then revs drop to 5000rpm and eventually applying throttle has no effect except making a bbuuurh noise. Have noticed sometimes if revving from idle the revs take 30 seconds to drop from 3000 to 1500rpm - lean running??? Leave it to cool down 5 mins then all above reapplies. Changed plug, choke voltage actuation all Ok, cleaned air filter, replaced old fuel, cleaned carb and replaced float, fitted new pet cock ( vac operated pump). Any ideas why it will Rev freely initially when pulling away then 'bog down'. (Previous owner fitted 65 jet and a technigas exhaust and said it used to work fine - loads of service history with 18000 miles) This was fun but now frustrating, help!
Hello Pgray and welcome to the scooter shack. stock jets are around the 53-56 on that model depending on the year . 65 jet is going on a 10% upjet rule, so that around the ball park area. one thing is the airfilter ? is this the stock airbox or has the old owner put an open airfilter on, if its an open air filter its running lean theres just to much air getting pulled in for that jet size, we would usually leave a stock airbox on for derestriction and only upgrade for a 70cc bore kit. if your running an open airfilter your 65 jet is a bit weak .
Hi & thanks for quick response - air filter wise it's completely standard... A little dirty so have ordered a new standard one due this week. Guess this means jet is about right? N I'm new to 2 strokes so a bit stuck and don't fancy going ordering lots of new parts until there's a theory to test out. Thanks again
Sorted.... Just for anyone who's interested - the problem was as simple as fuel starvation after wot. Vac pump pumped fuel however the clear plastic line was very yellow and swollen so was not able to spot the air bubbles. Replacing both the vac line and the fuel line solved it.
great news and good to hear a replacement vac line and fuel line worked out, maybe a good idea to throw a fresh inline fuel filter on to so that whole area of the fuel delivery system is in tip top working order
