MOPED ARMY

Im thinking about a spacer, the fact that the transfers dont open all the way bugs the crap out of me, especially since I only need to raise them like a mm to get my blowdown right (and even then I still wont be getting all the flow that my intake/carb is capable of). And Ive contemplated finding a puch piston or something that has the ring ends away from the exhaust, I really want to widen it, but can't anymore. I hear you can move the locator pins, so if I figure that out I may go that route. I'll post stuff back here too. I'm not the type to horde any possible advances I might make lol (edited)

Well, decided not to go with a spacer because I didnt want to play with my exhaust timing anymore for now. Decided to do some work to the piston instead. The pics are from my phone and do no justice to it. It actually looks pretty sweet. I went along the lines of what some people have done to the exhaust side of their piston to increase duration, but I spent like an hour just getting the shape right on this. I tried to make it swept so that the carter flow isnt really affected (this was one of those times where the fact that I have OCD really helped...):

Ok, ran that port job from the second picture tonight, along with the piston chamfering. Also, note this is with many other mods. Setup is as follows:

1992 A35

Stock cylinder, ported to pic above (with piston mods also)

Custom intake

Malossi 4-Petal Reeds

HPI CDI ignition (just put it on today, started first kick)

Mikuni VM18 carb (Jetting: 70 main, 15 idle, 4F18 needle at leanest setting)

UniPod air filter

Case matched

Techno Circuit Exhaust, Baffle removed

Tried out 26:28 gearing tonight (this is setup for racing in the Cherry Valley Cup)

Holy crap, runs like a whole different bike. The porting changes mixed with the gearing... jesus. Wants to wheelie off the line and into second, just a little into second gear it hits the pipe and rockets up. Still haven't hit top speed, didnt have enough room and I was on gravel (aka scary shit).

Also, this is in the works:

And before you ask, no, its not gonna fly apart. I welded the outer rim of the two hubs together where they meet, can't see it in that pic. Just did this on a spare bell, Im gonna throw it in and see what happens (if it explodes, it explodes). (edited)

Going from a 22 rear to a 28 also has a lot to do with the wheelie off the line. I'll bet it turns some insane rpm's at wot.

The major downfall to the tomos racing on that track is getting it to shift down. Having short gearing will cause you to shift faster with the stock gears (in my experience). The straight will be your best and worst part because you'll be in second gear going into the turn, but you will catch up quickly with proper gearing.

what frame is that?

that intake and carb position is sick!

Yep, tomos colibri with crossbar added. I couldnt get gas to the carb with the tank in the stock position so I had to do it (didnt really want to). Intake was made by myself. I would put the carb at an angle but Im always weary of doing that... just me I guess. I need to make a better intake with a radius to it rather than that angle, but I dont have a mandrel bender and I havent had time to do the sand/squash pipe method.

And boy, timing the HPI is cake compared to the stock points system. I hated having to put the flywheel on and take it off, put it on, take it off, etc. And you dont have to worry about the points gap either.

Ok, thought I would resurrect this thread. That second port job I posted way back when is a beast when coupled with the right pipe. I ran it at the last NEMA race this season with a new custom pipe I designed, along with down gearing some more to 24/28. Absolutely friggin rocked. My top speed was most definitely higher than it had been with the techno circuit (even with the lower gearing) and mid range acceleration drastically increased (to the point where it wants to throw you off the bike when the pipe hits... anyone is welcome to ride the bike if they don't believe me haha). Also note that I changed out the clutch springs to 30lb on BOTH clutches, much much better. I just got finished this evening raising the exhaust duration some more... Ill post a new port map when I get it done. I'm hoping to get my RPMs up to at least 13K+ by the time I'm done (Probably will end up gearing at 24/31 when I'm done too, top speed will be similar but I'm more looking for the get-up-and-go).

Also, don't use this gearing or porting for everyday use, this is race only stuff. Although the acceleration is pretty fucking sweet...

You do realize that I have run the cylinder as it was and it ripped right (and I was only at 172* exhaust duration which is kinda conservative)? Ive widened the exhaust port as far as I can without hitting the ring ends, I havent relocated them yet. And I milled the stock head to compensate for any compression loss, plus I have a high comp head to throw on since I did the most recent work to compensate even more. Also, the port itself is very straight from what work I did to it, and it is polished to mirror smooth. I can't do much more or I will cut through the casting (I'll have a hole pretty much).

Not trying to be a dick, but do you actually know anything about porting? What are your port durations from what you did? What pipe are you running? If you just hap-hazardly port and don't match different variables, your bike will run shitty. I planned out what I did and I was very happy with what I did. You wouldnt want to port your bike like mine unless you planned on racing it, for general use my setup sucks.

I had thought about using a puch piston, but I would have to cut in the windows and all that jazz again. I sometimes sort of regret cutting out the bridge in the intake because I could have gotten a single ring piston with the ring end 180* from the exhaust, meaning no need to relocate the ring end guides. But, with how light the piston is now, I think I'm fine with two rings... It's done well so far.

Oh, and I have the cylinder with me now, I just havent had time to sit down and do the map. I'll get that up ASAP.

As of right now, yes. But, I raised the intake port almost 2mm and the piston chamfering I did fixed the problem of the transfers not fully opening. I don't own a right angle pencil grinder to work on them unfortunately, If I did I would raise them a bit to get my blowdown where I want it, as well as widen slightly for more port flow area. Although, they are enlarged where they meet the case (I case-matched to the enlargement as well).

what exhaust would you suggest I get for it when I have the cash.

Well, it depends on what you want to get out of the bike. I dont really have any experience with pipes because the only one Ive ever bought was the techno circuit. It was ok, but not the best for what I wanted. It has a good mid-range though, and is relatively inexpensive. I have built my performance pipes though (designed for the cylinder).