Set the advanced timing to around .235" BTDC using the dial indicator method. That gave me around .006" BTDC for the fully retarded position when I removed the doughnut.
Question: Is this fully advanced setting supposed to get me back to the book's setting of .016" when I let it go back or ? I understand from the post, here, that most of the time the bike is up at or over the 2500 rpm and by then the full advance should be in play, anyway
My points disc was badly bent with I got the bike. I've done my best to straightened it out but tightening down the two locking studs causes the timing to change. Spent some 4 hours on this and this is the best I can do until I replace that plate.
Anyway, took the bike for a ride this afternoon (Shell 93 in the tank) and was extremely pleased. Straight section of level road (91 degrees and humid out) and I was easily able to get her to around 55 mph (my odometer read 60 but is off by 5 mph to the high side) and probably could have gone higher but I ran out of road. This is way more than I would ever be going but nice to know it's there.
No backfiring when I let off the throttle just a smooth drop in speed. Also had no knocking of any kind. Really just seemed to run like the wind.
Question: I always check my plug as I can tell much about the bike this way, My plug looks good. Right where it should be color wise. Can I assume, then, that based on this and the lack of any knocking or backfiring the bike is running properly... not too hot or approaching piston damage?
I do notice the motor runs way hot. Not seen this kind of heat with my Honda's. I read where Cubs will do that. Some will even just stop altogether until they cool down. I don't plan on pushing it, either.
Sounds like you have it pretty close. If it starts (no kick back) and idles okay, I don't think I would stress out about the fully retarded position. Keep a close eye on the plug. Have a look at this article. http://honda-tech.com/forced-induction-16/***-basics-reading-spark-plug***-3063102/ Sometimes you can see the timing mark pretty clearly, other times not so much. Keep an eye out for "pepper flakes" showing detonation. Running somewhat retarded can lead to overheating. Might try something like this to get an idea how hot it is getting. http://www.harborfreight.com/hand-tools/thermometers/infrared-thermometer-93984.html
"Pepper flakes" are little specs of carbon on the white insulator part of the plug. The plug reading link I posted has a picture. They indicate detonation is pulling little pieces of carbon from the top of the piston. Even worse is little specs of aluminum, meaning the piston is self destructing. I'd try measuring the temp on the cylinder head. Maybe someone with more experience will chime in, but I'm thinking something in the 250-300 range would be about normal. Would also check the oil tank temps. Maybe something in the range of 150-200 on a hot day.
I'm not sure this article you site really pertains to my little Cub. The article is about tuning high performance cars running 110 octane racing fuel. I just cannot relate what they are showing to what I normally see.
I'm always looking for a nice dark coffee color on my 4-stroker plugs. Never had a bike plug that had the porcelain remain white. All go towards the brown range and these bikes run perfectly fine that way.
Like the idea of the thermometer, though. Looked into another HF model years ago but they were found to be way off for this purpose. Would only read black surfaces with any kind of accuracy.
At least I can use it to keep an eye on things. Compare one of my bikes to the other to build some kind of range of normal operation.
Rear mud guard chopped ? Or was this a bathtub model ?
The front-lower mud-guard-stays could be fitted lower on the forks . If there are no lower-lugs , it may be a model, that uses these studs in the oil drain holes .
Your measurements show a lot of extra rotation in your AAU . ( are these strobe numbers ) So it can , now timed at 32º , over retard at low rpms , It may be nothing . The counter weights and such , when running may not allow this retard to ever be seen , or seen much . , or It might get off the line a little better if it was advanced a bit , say to 34º
Could the ' overheating ' just be the smell of old-oil wafting off the bike for the first time in forty years ?
If you are generally happy with acceleration, no flat spots , you only need to do a plug-chop , for over-lean , at a high-load-rpm . (An under load , high rpm snapshot )
A plug chop will show plug-colour from the rpms when the plug was last run .
Find a spot for a high-rpm , 3rd. gear , loaded straight away run .( 4th gear, sure , but its easier to find a 3rd gear spot ) Then Simultaneously , kill engine and pull clutch . Roll to a stop . Pull and check plug color as quickly as possible without burning your fingers .
Rear mud guard chopped ? Or was this a bathtub model?
I was told by someone on the Cubsite forum that the front fender is not for this year Cub. He was making a big deal about it not being all original.
Frankly, I can care less.
Just won a trophy Sunday for Best British Daily Rider at the BritJam so at least there are others who found the bike to their liking. Was attracting much attention all day long. One of only two bikes not restored to new condition and seems that was appreciated by many... as I felt it might be.
The front forks are not working. Took a few hard bumps and cracked the muffler where it joins the pipe. Had applied a patch there anyway. Weak from corrosion. Need to order a new one from the UK... and fix the forks.
I was told by someone on the Cubsite forum that the front fender is not for this year Cub. He was making a big deal about it not being all original. Frankly, I can care less.
I concede your point . And apologise for offering my unsolicited opinion , it was not meant as a rivet-counter criticism . I dont know enough , nor is it my style to demand year by year correctness . My cub retains the dings and patina it has earned over the years . ... still , your front mudguard would , in my eye , look smarter , it it was round like the tire . And the stay showed better triangulation . ... and a full back mudguard would fill in the middle of the bike , Possibly making it look more finished ?
Congratulations on the award and getting the bike back on the road .
Re: T20 Tiger Cub: help with setting advance, please
#613445 08/18/151:14 pm08/18/151:14 pm
No harm done by any means. Appreciate all the help.
Some time ago, I did try and pull the rim in to possibly use those oil drain studs but nothing doing. It would not bend at all. That steel is just too thick. Would have to have it re-rolled on a "big wheel".
As to the rear fender, it appears it was cut back. If it did continue it would hit the oil tank. Not sure if it was like that OEM and the missing shroud was used to conceal it or it too is wrong for this bike.
On another matter... the exhaust flange that screws into the head has stripped some of the threads inside the head. It is moving side to side. The threads on the outside of the flange are fine. I have used that water-based exhaust patch... steel mixed with silica (glass) to seal up mufflers (used it on this bike) and that should work here (good for up to 1600 degrees F) but if you know of something better.. some kind of high-heat silicon cement you can recommend... Once I make that fix it may be stuck there forever so want to do it right.
My muffler cracked on the way home from the show Sunday. It had corroded through just after the inlet port. Used to be home to a mouse.
Anyway, was able to source a Norman Hyde Toga silencer for this bike on eBay for $130. They have a nice sound to them and seem to be well respected in the biz. No longer make one for the Tiger Cub so guess I was lucky to find one.