DIY portmapping HOW?

[ja-moo]

Without a real squish band, 140 psi.

[tz375]

That begs the obvious question of : With a real squish band on an air cooled motor running street gas - say 93 Octane?

[ja-moo]

There seems to be some variable, as the RD's with corrected heads still only run 135-140 psi. On the Kawis it's 150-155 psi on premium pum gas. I only get 91 with Ethanol here.......

[dyrberg123]

Without a real squish band, 140 psi.

The heads are Kawa h1 55% squish, 1mm gab..

[ja-moo]

I forgot, long thread....lol. Go for 150 then. You can always drop it later if there is a problem.

[dyrberg123]

[Vintageman]

Those H1 heads squish look like they have real flat/shallow angle. Did the H1 piston have the same shape dome as T350?

I suppsoe if you checked with solder or something you would have know if clearance was even along the squish area of head to piston.

[dyrberg123]

Those H1 heads squish look like they have real flat/shallow angle. Did the H1 piston have the same shape dome as T350?

I suppsoe if you checked with solder or something you would have know if clearance was even along the squish area of head to piston.

That is also what i will do, but first i will Work over the barrels, install them. Chek squish the solder way, is that is okay i will take a compression test to see where we are. At the moment the head turned upside Down holds 18cc , but i suspect they have to small a clearance. I as you probably know bought the set from ebay, but the barrels where scrap, and on 4th over - not 5th. And the pistons tapered the wrong way, and the barrels where with many scrapes below exhaust port on the walls. I took it to my local cylinder shop, they said he had either had it running on extremely dusty roads without filter, or could also come from glas Pearls from blasting Blocks - cylinders etc. To make all worse the squish OD was only 62mm, but the bore was 63mm Never mind, i have a set of barrels - std size, never bored out, nice looking. So i will hone them lightly, add new rings, port them, and then if neccesary recut the squish on my lathe. And when i have succes, purchase a set of 1st over wiseco, bore the barrels, and run the bike like i bloody stole it. Summer time here i come

But i have really learned alot on this project. Thanks to all of you.

[Vintageman]

Save the barrels. even though Suz only made 1.00mm over piston.

Paul Miller has offered a 2.00mm (must get real thin) and 1.5mm Wiseco. He had some customs made by Wiseco here in USA. Not sure if he did for T350 or was NOS. He did custom for Gt550 for example. These T350 cylinders are getting real rare and someone should make a run with Wiseco. 0.25mm 0.75mm 1.25mm, 1.5mm

Speak of this. Why not offer a 1.06mm or 1.07mm for example so all one needed to do is hone a little off to fit. I think you see some mfg. do this for MX bikes (Vertex?). Wiseco actually goes smaller than OEM piston for they need a little more clearance.


Speak of honing, my experience, soon as you hone even just a few in and outs with a medium stone grit you loose about 0.001" off wall so 0.002" total. And if you go nuts and try to remove all scratches well do the math. Dang, I hate when people who sell jugs on eBay hone the shite out of them before they sell. "Look no scratches" :roll"

Now I just use some 320 or 400 grit paper and lightly sand or scotch brite. I also ordered finer ball hone like 400 just to peel off very little just in case I can't control myself. I would rather have some fine scratches left then piston slap. Bull crap you need coarse hone lines to hold oil. Best is ring seats then cylinder walls get that nice slipper glaze... so smooth frictionless engine. And there is of course oil on stuff as you run. Chamfer the bottom of piston skirt to help get it there.

Smooth up those port edges. Ever see what factory says they need to be like for T350?

Also, it looks like some of the piston coatings do help tighten up gaps as one benefit . It will wear/fit, but, does hold the slap noise down. I have >2000 miles on my R5 with Wosnners, they were coated on skirt from factory and the coating is still there ! Various types out there now and can build up a little. As usual , long reply somewhat off topic

[dyrberg123]

I think the over sizes from Wiseco is 0,5mm 1mm 1,5mm 2mm, and that was what they where on, +2mm, so 63 bore. So just to the bin, unless thay couls be resleeved. But i have several sets of barrels to the 350, so that is not the problem. But i am considering if it is possible to fit Yam R5 pistons in it. But i have to find the data for those somewhere. But that must be later, not i just want to tune this 350

[Vintageman]

they where on, +2mm, so 63 bore.

Sorry i misread

if it is possible to fit Yam R5 pistons in it. But i have to find the data for those somewhere. But that must be later,

. Hmmm. I have some R5s somewhere. another topic for later.

I just finised and T350. I can say your post made me relook at some things and may do a couple more tuning changes too before I install engine.

Thanks good luck.

[dyrberg123]

they where on, +2mm, so 63 bore.

Sorry i misread

if it is possible to fit Yam R5 pistons in it. But i have to find the data for those somewhere. But that must be later,

. Hmmm. I have some R5s somewhere. another topic for later.

I just finised and T350. I can say your post made me relook at some things and may do a couple more tuning changes too before I install engine.

Thanks good luck.

Thanks. Could you meassure the R5 piston for me? Just for future Projects? Pin size, total height, height from pin to edge of Crown, height from pin to bottom of piston. height from edge to Crown top?

Cheers

[Vintageman]

It may be a while.... have R5 , DS7, DS6, RD400, and CS5 parts in multiple boxes... ran out of room in garage ... put Yam stuff in cold storage last fall (new shed 12' x20' built last year).... packed like a Sardine can! Never big enough.

When I pull out summer stuff I'll be able to access Yam parts... still have a lot of snow and well below freezing still. Done some great snowmobile rides last few weekends but, ready for summer.

Motivated/distracted by this post was curious about rod length too to see how R5 / DS7 compare port timing to Suz 305/350/250 engines.

I wonder if anyone on USA2Strokers.com or AirCooledRd.com had that info. Mostly Yam stuff there. So I was briefly searching there for port timing ... did not find ala search (no surprise) did not ask either. Too much Suz projects now, need to finish. when summer come here its short need to be ready

Was there enough meat on the T350 intake bridge to bore beyond 63mm to 64mm? My cylinders had spots in the bridge liner casting that were a little thinner in places.

[dyrberg123]

Hi,

I do not know why those spots are there, it must be for helping the oil in ome way, but at 63 there is still material left. I have some t350 cranks somewhere i could meassure the rod lengths there.
For the Yam portmaps to compare, look at Erlenbachracing.net he have all the R + RD range port maps on his site.

For now i will modify the std jugs, and mill the heads until they fit, making the Squish 1 deg steeper than the piston Crown.

BTW did you do the mod to your DG stinger / silencer?

[Vintageman]

I have rod lengths for T305 and is allegedly same as T20, T250 T350, GT250, GT380. I think 110mm . I'll check when home and update if wrong


The port map for Yam... you still don't know port timing degrees for you need deck height, piston dimensions and rod length as you know

No its casting flaws on intake bridge. No casting is perfectly smooth and varies jug to jug. And Since no Al divider they were made skinny too. I think any less than 1mm or 1.5mm?? thick would break. Seen some early T500 jugs on eBay with broken intake casting. Guys that bore this area need to feed depth slowly. In fact I would offset bore a little towards Ex if you get too thin last possible bore

Yes I put DGs on my GT250/T3xx So easy to do if you use RD400, DG for RD350 work too just need to move rear bracket... search my posts, or give a chance to find them. They work well no funny areas. It boosts power too, but not as much as when put on RD/YR5, but Yam is tuned hotter than T/GT my guess.

I am not sure what you are trying to make. But, I sure would like to know how R5 and RD350 port timing compare to T350. if milder I would go R5... too much Ex timing, is nice, but you can never drive easy why I am puting t350 in place of GT250A. That's why we need more than one bike! Same with RD400 versus GT550 curious port timing

I am going to pull my T350 jugs off and lower that intake 1mm (window area too small we learned vs 32 mm carb). I never had any problems with stock head and note T350 claims 6.8: 1 compression which is higher than RD. What I really should do is rubber mount engine. If my Ex is 32mm like your that's good for me. And if 33mm may just leave it alone too (we'll see).