Problem With My Top End
- Thread starter CranbrookKid
- Start date
CranbrookKid
New Member
Thanks for your extremely helpful post mapbike, I'll need to try that.
Yep, that's what I've done.
CranbrookKid
New Member
I've ridden my bike with the clip on the needle at the very top and without an air filter and it seems to run very smooth and vibe free up until WOT at which point it stumbles and slows down. The spark plug is dry and is a dark caramel color, but it's still too rich to run with the stock air filter. If I had the time to use the method mapbike used I'd do it but I don't so I've ordered three jets from sick bike parts sized .68 mm, .66 mm and .64 mm so hopefully that'll do the trick.
mapbike
Well-Known Member
Ditto...
I've found that when the main is correct then if the needle clip is to high it will lean the low throttle mixture so much that it makes the engine harder to get started and idle screw has to be turned in much further than usual.
A small propane torch or electric cook top, small sloid core wire solder and a $4 set of wire gauge bits from www.widgetsupply.com and that jet can be any size you need, very simple process if a person has about 10-15 min to do the mod. Thats about all it takes, bit if someone doesnt have the time or the tools sbp is an excellent way to go and then is just a simple jet change until you get it right, only problem is you end up buying jets you didnt need if you biy more than one which is almost a have to when you dont know what you need.
Map
CranbrookKid
New Member
Yep, exactly mapbike. You've actually described my bike to a T about the starting etc. I got three dif. size jets, hopefully that'll have my bike running great.
Old Reliable
New Member
What? The big spring is for heat dispersion around the clutch cable sheath. The thinner spring is for the clutch engage assist. You definitely need the thin long spring...
mapbike
Well-Known Member
The smaller spring actually serves no good purpose.... all it does is make the clutch lever harder to pull and actually cause more wear and tare on the clutch cable, I recommend leaving that spring off always unless you want your clutch harder to disengage and dont mind putting more wear on the cable and lever.
Map
CranbrookKid
New Member
Well I've changed the jet size to .68 mm and the bike runs much better. I've had to change two of my head studs from SBP because they were too short and I stripped the thread twice. When I opened up my head I noticed it had a lot of carbon build up considering I only ran it for about 25 miles after I did the head work. Maybe because of the oil I was using?
mapbike
Well-Known Member
Glad to hear it's running better for ya Cbkid, if its still 4 stroking a lot you may consider trying a .66 jet and if you have access to Opti2 oil in your area that wil be a nice improvement as well for lessening the cabon build up on your piston and heads combustion chamber if the gasoline there is a good grade, we dont have very clean fuel here, lots of additives and even running Opti2 @100:1 my pistons and heads are carbon-ed up more than I would like, but all my engines run nice so I don't worry about it and Opti2 at 70:1-100:1 sure makes for a nice running engine when it's tuned right little to no smoke and less oily smell.
Map
CranbrookKid
New Member
I'm also pretty happy with the way it runs. I'll definitely be playing with jet size when the weather warms up. No stores 'round here sell Opti2 so for now I'll be using Lucas semi-synthetic at 40-50:1 as recommended.