Well I decided to get a nice pipe for my yam jog r,& some jets to sort out the change, I have a feeling the 'manifold bolts' are coroded to the extent that they will just shear off,any ideas of getting them out with the barrel still insitue,or should I go for getting the motor on a bench,off the bike. Might have to shelve the tune up untill the spring,then go for a 70cc kit,no big problems with that,but interested in ideas that might work. (not a will they won't they shear off thread),just throwing it out there to see what ideas people with experience have. Also,as & when I get the rusty beggars out,I will copper ease the threads in the hope that the the bolts dont hold in their threads after a gentle re-tap .or make up some studs & use brass nuts. Any thoughts?
try using a wire brush to clean off,and use abit of heat to expand the metal .may loosen off for you..
Yep,thanks Hexlec,I can feel a new pot being in order & leaving the tune until then,just a shame as its a good engine only got 2600 miles on it,& wanted to try tuning a 50 before I jump it up to a 70,just those rusted bolts... I know I can strip it down, drill out the old & go from there with new oversised bolts,or as I said stud it,partly I threw this one up for others who no doubt will come across the same hurdle,& maybe get my sparkly new pipe on to see what it opens up,(I am impatient by nature)!
Well one bolt came out ok,the other I sheared off,so I flushed the stubb up with the manifold,centre punched it & drilled it out to 7mm,got a nut & bolt with washers & used that,so it will be easy next time to remove. Got to get to the carb over the weekend to jet it up. I need to fit stronger clutch springs,after a quick fire up & very short run the clutch engages before the motor comes on the pipe,(doppler sr3),making pull away a tad slow,I put in lighter variator weights after fitting a polini 9 roller,& it definately pulls better & longer than before I fitted the pipe,so will get the jetting sorted out on the standard gutner carb (12mm),going to try a 70 jet to see how I get on,though it does not feel like its that lean on the carb even with the pipe deristricted,so someone might have played with the jets before I got the scoot. I may go for a 70 sport setup with 17.5 carb,but I will see once I have set this up right on its original barrel.
i have a jog r , and a polini 9 roller variator (4g rollers) and a 17.5 mm carb (80 jet), sport exhaust and a 70cc kit. it flies its well worth it m8.
Thanks h.hubbyy,i think I will get the 70 kit,what 17.5mm carb are you using? I think I rather a mild 70 than tweaking the guts out of the 50,the crank has only 2500miles on it so it could take it,just learning the scoot tuning at the moment,I work with chainsaws for a living,so I understand the basics of two stroke carb setup,albeit we tune our saws to start 4stroking at max revs with no load,& its all done with a high & low screw so much easier to fine tune. I have a husky3120,the largest capacity saw out there at 120cc,now that one flies into the wood,even on a six foot long bar,bit of a beast to use when climbing & having to chog down a large stem!
Well that was a task getting the carb off,be easier next time,anti tamper hose clamp on the manifold...so The dremmel came out to get a slot cut in it for a screwdriver,after seat & seat box removed to gain decent access, took out the existing main jet,(60),& settled on the upjet at 80,seems to run well now,nice sounding keen 2 stroke tone to it,top speed is up about ten mph clock reading,giving me a fairly consistent 50mph reading,it accelerates much better,though slightly less weight in the rollers,or maybe a stronger contra spring will improve it further,but it is nearly set up right. I Changed the clutch springs over to stronger ones,& it pulls away on the pipe now,holding the gearing on peak power with just a very slight dip on the revs at about 30-35 going up a gentle incline,or when the variator is hot after repeated pull aways.
