1971 T500 Main Jet

[Vintageman]

debby,

Good point. Now I look again the cycliders are a different part# for example the 72 J LH is 11220-15100 (15101) and the KLM for LH is 11220 15300 (15301). I must be going blind or loosing my mind (or both). I thought the were the same first couple times I looked.

So you actually compaired a 70 cyl with a 74 cyland you see intake ports are different?
So would need jugs as well as intake changes to reep the extra 10%. For now 44HP it is unless some day I find a set of cyclinders.
Thanks

[tz375]

44HP - is that the advertised number? I wonder what the real number is at the rear wheel. Back in the day they used to quote gross HP at the crank and that always included all manner of "adjustments".

The 750 supposedly made 67 or 70HP but at the back wheel, the average number was closer to 50. Dynojet dynos seem to give higher numbers than say Factory dynos, but the difference between what is measured at the rear wheel and claimed HP was significant.

[Vintageman]

It is funny you say that. These old bikes are really slow compared to today for sure. It's funny how much fear 2 strokes give when someone hears them. The perception is that they are very fast.

I have a little GT380 with chambers. I was driving along and someone with a newer Yamaha R1 was following me. Well, we go into a bend where the road also widened and I started to accelerate starting from about 30 mph and the legal limit is now 55 MPH. I see him going for the pass and about to prove his point as to who is faster.

When he went by me, as of course he would, It was the first time I ever heard an R1 hit the Rev Limiter. He actual was so afraid he felt he needed to take his R1 so far into its ability and beyond to pass me that he needed to hit rev limit before he would shift again.
How cool is that! He was unknowingly showing me respect!

I sure would like to get my 75 T500 to be 10% more at least. It looks like I need new Barrels to0. Well I did get a set of Jemco chambers. That should add some power if not 100% perception there is a hole bunch of ponies!

[srech77]

Hey all -

Was following this thread, and thought someone could give advice. I've been working on getting my 75 Titan running, I had new pistons installed (.5mm over), and have rebuilt the carbs with one of those keyster kits, but I now realize that is a source of problems, and explains why I can't really get the bike any farther than the driveway. I no longer have the factory jets, and have ordered some 110 main jets from jetsrus. I ordered 110s because I'm using some UNI foam pod filters. I do have an airbox in good condition with a rubber boot, but I think the boot is designed for the earlier models, because it doesn't really fit around the carb inlet, and holds the carbs at a slight downward angle, so from this thread I'm assuming it is a pre 73 boot. Anyway, I'm wondering if someone can tell me if the 110s are a good choice considering the pod filters. I have read anywhere from 105-120 if you add pod filters. The carbs also have the keyster pilot jets installed (#30) and like I said I don't have the originals. The carbs still have the original jet needles and floats... but the float needle was also replaced with keyster. I feel like I'm getting close with everything, and any advice would be appreciated.

Just as a sidenote, I have replaced the points/condensers, timed the bike, am rebulding the petcock (which was pretty dirty), added new fuel filters, and know that I am getting spark to both cylinders. I have also added new plugs, cleaned out the oil injection lines, and the bike has a new fuel tank, oil tank and a few other things; also has new header and exhaust gaskets. I haven't received the 110 jets yet, but that's kind of the last piece of the puzzle I'm waiting for to see if I can get the bike running well.

When I had it started with the 150s in it, it idled so-so ... but I noticed the right exhaust pipe was noticeably cooler than the left, but seemed to heat up more if I choked the carbs. The left one was too hot to touch (which I assume it should be), while the right header pipe was cool enough to wrap your hand around for a few seconds ... I thought maybe this was a timing thing or it was "missing," but the pistons are new, and timing is spot on, and I know I'm getting good spark to both cylinders. So I can only assume this is a carb issue (air/fuel). Just thought that might help someone trying to provide advice. Please let me know if I can provide any other details.

What do you guys think? Thanks in advance.

[srech77]

A little off topic, but does anyone know anything about the exhaust baffles on the T500s? Like where you can find replacements, or how they get cleaned, or how often? any of that stuff ... thanks.