A55 going for 50/50

Soooooo I got this streetmate that I'm trying get 50mph (or real close atleast) with the stock cylinder. It's got the a55 homoet pipe, custom intake to match a phbg 19mm, geared at 26x22. It was going 41mph, then I ported, I cut the intake down 2.7mm and widened it 2.4mm, have not touched the exhaust port yet but plan to widen that up too once I get the proper bits for my dremel. After porting the intake I got a 3mph gain getting me to 44mph.

People have said the carb is too big, but I've tested using the stock carb (properly jetted) with the larger intake and had worse results.

Someone drop some knowledge where I should go from here. I'm thinking maybe regearing to 27x20 will get me some more topend but I'm trying to keep a little low end because I weigh 250 and the hills in Austin are not chill, but that may not be possible with this setup and I'm ok with that

Thanks

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Re: A55 going for 50/50

touch your exhaust.

Re: A55 going for 50/50

I don't think I've ever seen a streetmate I liked until now

Re: A55 going for 50/50

I would stay with 27x22 or 26x22 for the torque if u ride in a hilly area. Use some 200 grit sand paper on that exhaust port then get 1000 or 2000 grit and polish it up. You'll get most of your power from case matching, carb, exhaust port and pipe don't forget high compression head. See what u can do with your timing to that will get power also. But remember change onething at a time cause it will affect everything eles. Fyi when u get into 50mph zone your going to have to change your clutch setup cause power can be gained from them with different linings I use kevlar. Its strong enough to handle the power without slipping 2 much. Stock spring for first yellow on second. My bike GPS on a hot day 50mph and that's as far as I'm willing to push it.

Re: A55 going for 50/50

I've widened the hole on my exhaust to match the pipe but I don't have bits long enough to port it just yet.

Re: A55 going for 50/50

Sand paper and files takes longer but can be done

Re: A55 going for 50/50

What do you mean "see what you can do with your timing" Mysterious Tomos A35 ? I was thinking playing with my timing might help but I don't know what specific timing to shoot for, for gains...

Re: A55 going for 50/50

Ignition curves helps keeps the temps cool as the ignition can advance or retard depending on what u setup.

Re: A55 going for 50/50

Re: A55 going for 50/50

Different cdi boxes have different curves. Some retard for easy starting then advance as you wot instead of a set limiter rpm effect by stock cdi boxes.

Re: A55 going for 50/50

I wouldn't play with timing just yet unless your running high temps over 400

Re: A55 going for 50/50

My temps have been right at 300 which is kinda cold for me.

Re: A55 going for 50/50

No Dr. No. That is way overpriced. You can find those pencil grinders for like 20 bucks. Who cares if its bad quality and you only get one or two uses, because it's only gonna get one or two uses total.... anywho I got some long shank bits coming that'll do just fine

Re: A55 going for 50/50

Yeah I bet that works real good on the transfer ports raise them up

Re: A55 going for 50/50

Bringback2Ts Plz /

what do you call it when two bored idiots are contemplating the same thing? 26x22 is stock gearing on my ST and it does 40mph. Pulled me up every hill in Duluth, MN last year while every one overheated and broke. Anyway, I was looking into doing the same until I decided to leave it alone and found these threads in my quest:

https://www.mopedarmy.com/forums/read.php?7,2964145,2964145

Edit: Also that Streetmate would be a great chopper candidate. (edited)

Re: A55 going for 50/50

Nishad Datta /

what are those tires you got on there?

Re: A55 going for 50/50

I’d drop the rear to a 20t, port the exhaust and do the old flat tile and sandpaper truck on the head for a little more compression. Should get you a few more mph

Re: A55 going for 50/50

Nishad, these are the tires. They sit a little higher and might effect your kickstand. Mine was bent anyway so I went with a sideboi kicky

https://www.treatland.tv/ProductDetails.asp?ProductCode=sava-H05-16x3.25-tire

https://www.treatland.tv/ProductDetails.asp?ProductCode=sava-MC51-17x2.75-tire

Re: A55 going for 50/50

50/50 is cool and all but to be honest, in Austin, you're probably gonna want a kit, especially with that heavy street mate.

The stock cdi is rev limited to about 8500 rpm, if you build it right you will hit that. I don't know how much gear it can pull because of the weight, but that's gonna be a big deal, you get into a situation with the ported a55 cylinder where it can't get into the rpm it could otherwise pull. I built one a few years ago that ran high 40,s but never quite got to an honest 50. It was geared 24x26 (I think?) and was owned by a skinny 19 year old kid, even then, when it got a hill it would pick up a lot of speed and could do 52 or 53, but otherwise hit a hard wall 48 on the flats. Still it was a good bike and fun to ride around in town. Tecno estoril, phbg19, high comp head. Less is more with the porting. They don't need much.

Re: A55 going for 50/50

I'm getting to about 8200 rpm which makes sense at 44mph so not quite at that limit yet but close. I have a gila kit that's getting built up on a different a55 engine and going on a custom colibri, but am short on funds for it, in the meantime I'm messing with this for funs. Just want to see how far I could take a stockish setup with me on it. I'm starting to think I might run it a bit leaner and try to get my timing a little more advanced if I can by swapping to a35 stator and whatnots. My temps are low, (barely touches 300) but the plug is the right kind of brown. so idk if that will help or put me in the danger zone. I'm gonna just try a warmer plug first and go from there

Re: A55 going for 50/50

@Graham, so I have always heard they have a rev limiter but in my testing I can't find one. And I've tested a handful. I remember at one point a friend had one he claimed had a restrictor and we put a Vespa sytle cdi box on it and he claims it went away. And I know they had at least two different ignition systems based on having different magnet placement and trigger setups so maybe the early type do. But I've got an 08 still and I tested it and even though I still run the 77 "derestricted" box it made zero difference in my testing.

Re: A55 going for 50/50

raise the exhaust port up 3 mm in the cylinder... don’t make it wider then polish the in side of the port ..

then strip down to your underwear..

it’s helps

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Re: A55 going for 50/50

Did 45 on a stock a35 jug with just some intake cleanup and exhaust widening and shaping. I did all the work with some small files and sandpaper hot glued to the end of a flathead screwdriver. Took a little time so I did it in my livingroom watching tv. So worth the effort. Pretty lowkey setup 15sha / 26x22 / biturbo

Take time, do work, go fast.

Re: A55 going for 50/50

> Jesse Stephenson Wrote:

> -------------------------------------------------------

> @Graham, so I have always heard they have a rev limiter but in my

> testing I can't find one. And I've tested a handful. I remember at ...

That's interesting, I'm assuming it's the later model with the trigger style cdi. I built one and was at like 46 and hit a hard wall. It was for a customer, he rode it, thought it was great, we never went any further. Math worked out to almost exactly 8500, I always assumed it was a rev limiter but never chopped up the wiring harness to prove it.

Re: A55 going for 50/50

@graham the a55 all have the trigger type, even the new run. The a35 have falling wave trigger, but everyone one I've tested has revved to whatever the motor will handle, my stock 08 a55 would turn 10,500rpm on the stand, no change in timing, static the whole range. The 77 box is exactly the same, maybe some version is different, like is said I know they made slight variations. But far as I have tested on many bikes, no such restrictor exists.

Re: A55 going for 50/50

EH 📣FCC of the QCB /

I built a streetmate for my neighborhood a few years back. He wanted it Army green and his Helmet to match. 🤪. It was god awful but I was mid 40s with the 15 carb and a treats pipe. It was like 1st or 2nd run streetmate. I remember checking the dates. I wonder if the early runs used boxes from the a35s that were comparable. I lowered and widened the intake I want to say like 1mm lower and 1mm on each side. Raised the exhaust 3 mm and went as wide as the ring land would let me. To him it was a 60mph bike and he told everyone that. Some how he sold the bike for 3k. Don’t ask me how🤷🏼‍♂️.

That bike seemed like it had a rev limiter Jesse. In my limited TOMos experience the other two A55s that I helped Jon from out club with (Peaches and Peaches 2.0) were both around 50. I know they were GPSed years ago on a long stretch and hit it but I can’t memeber. Both had external trigger type never seemed to hit a limit like an A35 would. Peaches had similar porting to the streetmate and a PHVA17 with a treats pipe. It would hall ass. But like Tommy said we dropped to a 20T rear also. Peaches 2.0 Has a VM18, MLM Cali Pipe, and a Parma Box. But the interesting thing is that the revs were basically the exact same. It did not rev out any higher.

Re: A55 going for 50/50

More to revs than just the box. Everything plays a part.

Re: A55 going for 50/50

Yeah, I wonder if there is something about the a55 cylinder that hits a wall? I dunno it was weird, the bike would pull hard and then just start 4 stroking like crazy, felt exactly like a rev limiter. Jetting made no difference, even being on a hill up or down, made no difference

Re: A55 going for 50/50

> Graham Motzing Wrote:

> -------------------------------------------------------

> Yeah, I wonder if there is something about the a55 cylinder that hits a

> wall? I dunno it was weird, the bike would pull hard and then just start

> 4 stroking like crazy, felt exactly like a rev limiter. Jetting made no

> difference, even being on a hill up or down, made no difference

I had the same problem with a55. But never felt the same situation on the a35. I also have the same issue with my garelli vip. It gets to 28mph but just four strokes at the top and bogs down. No jetting seems to help or added.or restricted airflow. It has a big chamber pipe so it should have plenty of leg to stand on.

But crap now I'm thread jacking. Has this bike gotten close to 50mph yet?

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