1971 T350 project

[AgentOrange]

Hi everyone, here is my 1971 (should be a 1972 according to the neck plate) T350. Friend gave it to me for free back in May since it looked pretty rough. No wiring harness, junked gas tank, no lights, bad tires, bad brakes, no title list goes on. So I decided not to restore it since people on ebay are selling NOS parts for an arm and a leg. When I got it I was working on my other bike (zx6r) so that was also sucking up money, basically I wanted to see if it was road worthy. After a carb rebuild kit I had it running. The next thing was to tackle the forks, I took it around the block once and the front was just god awful. It would dive when I got on the brakes, squishy as anything. Figured the forks had no oil so time to do a seal/oil change. Now Ive done fork seals on conventional forks and USD forks but these forks were different. There was no bolt at the bottom to unscrew to remove the inner tube,so with that I chucked them.

When I got it













A few weeks later I found a whole front end off a 92 gsxr1100 for $200, swapped out the stem bearings and races and fit perfectly. I used a CL360 and swapped wheel bearings to fit the 20mm axle. I then had another problem, how am I going to mount the bracket for the front drum brake on my forks? I tried to use 1/8inch steel but there was too much space in between the drum and fork where it would cause the bracket I made to twist. So I decided to convert it to disc brakes. I did some research and found that a GT550 front wheel shares the same bearing size as the CL360 wheel. My forks can only accept a 310mm rotor and the 550 wheel has a 6 bolt pattern at a 78mm circumference. That was only found on 98-99 cbr9XX rotors and 03-06? cbr1100xx rotors. Got the wheel for $25 and the rotor for $65. I had to widen the bolt holes on the rotor and it was a perfect fit. Bought a stainless steel line, 2000 zx6r master cylinder and gsxr caliper for $55. Absolutely solid front brake, I use very light pressure with 2 fingers to brake now.





I upped the slow jet to a 35 and the main to a 115 with the needle clip down 1 notch from stock, plugs are milk chocolate but slightly on the darker side, runs like a dream. I'll admit that I ran that cheap valvoline multi purpose oil for a few rides before I switched to Amsoil dominatior full synthetic.






After I got the front dialed in the rear suspension was terrible. Incredibly stiff to the point where an hour ride would be my max before calling it quits. going into corners the front would feel very planted but then the back would chatter on any minor bump in the road, so as usual I replaced them with a pair of YSS gas shocks, best $300 spent. I have a few other things I will be adding on but I really need expansion chambers. I talked to Jemco and they were trying to sell me a GT250 system for $600. Wasnt going to buy that since its tuned for a GT250 and not a T350. So I have 2stroke wizard 5 to design my own, all I need are some accurate port degree measurements (exhaust port opening, main port opening, secondary port opening, and boost port), if anyone has those measurements that would be great. I painted the tank then I spilt some gas on it by accident (stupid child safety gas cans) so its rough but I kind of like it, it gives it that backyard mechanic feel to it.



I can help anyone out with my exhaust program if they are looking at making their own pipes, I just need some info from your bike.

[Suzukidave]

Maybe some RD350 pipes could be made to fit up ? http://www.ebay.com/itm/DG-Performance- ... be&vxp=mtr" onclick="window.open(this.href);return false;

[AgentOrange]

Maybe some RD350 pipes could be made to fit up ? http://www.ebay.com/itm/DG-Performance- ... be&vxp=mtr" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Im sure I could fit them up but from reading the two stroke tuners handbook, throwing on pipes not matched to your bike wont give you a true tune. Port specs, exhaust temps, timing all matters when it comes to making a true tuned pipe. If I'm going to spend $300+ on pipes I want to know they are done right.

[Suzukidave]

There 200$ and the 350 puts out .. what .. 20hp .. a bit off on the chambers i dont think would matter one way or the other that much .

[AgentOrange]

There 200$ and the 350 puts out .. what .. 20hp .. a bit off on the chambers i dont think would matter one way or the other that much .

$200 isn't bad I've read up on some rd/rz owners that didn't like them too much and went with a 2 stage diffuser for a bigger bang. It might be cheaper for me to make my own since ill only be paying for consumables and and someone to roll the cones. These 350s actually put out 40hp which isn't too bad for a 315cc motor.

[tz375]

JEMCo makes great pipes but the T20 pipes he has are the original Race Kit design and they are not well suited to a street bike. DG are very good pipes for the price and while teh RD350 has more aggressive porting than a T350, the pipes do seem to work. Our own Eric K, Zookie modified a pair to fit on one of his twins and I think he was very happy with them.

Standard modification to DGs is to cut off the rear end (muffler) and fit a stinger and MFactoryWest or Swarbrick mufflers which look more modern. There is no simple mod to the DG design that significantly improves performance but they work well enough on the street and give a wide powerband that stops at a reasonable place. Lomas and others make pipes that are better at the top end and lots of RD guys use Millennium pipes but they are also a race pipe and not great on the street - nice top end but it takes a million revs to start moving. You could also see what's available for Gary at Spec 2. He makes some great RD pipes.

There's a lot of exhaust pipe design software available and all are supposedly based on the work of Dr Gordon Blair. Forget the old Jennings work. He was great for the time, but that was then and this is now and things have changed. I have used MOTA and Wizard and the simulation software doesn't much care for the designs they create. My preference is Bimotion, but it costs more than those DG pipes.......

For sure if you want to get the most out of that package, it will need to be ported, raise compression modify the crank and design pipes for it. By that point the stock 25 or so rear wheel actual HP should be closer to 50. The 550 which is a slightly larger T350 with an extra pot was said to make 50hp @ 6500 but on test it made 35-38HP, so a 350 at 2/3 of that is probably closer to 25 at the rear wheel.

Nice project BTW.

[AgentOrange]

Thanks. I have seen a few T350's with the DG's on them, not a fan of them aesthetically really, one forum that I frequently visit had stock baseline and DG pipe dyno numbers on a T350. Went from 25rwhp to 32rwhp. Not bad but I wasnt sure how much those pipes adjusted the powerband if any, since its a single stage I'd imagine it pushed the powerband up slightly. But I have a degree wheel, the software, and cold weather approaching so hopefully I can get the port measurements to build these pipes relatively soon.

[AgentOrange]

So I tried to get someone local to roll the cones for the exhaust I'm building, no one wants anything to do with it. I had a guy on another forum but he couldn't do it. So finally I found a group up in Wisconsin called Aaen Performance that will roll each cone for $20-25 each for 10 cones, (not bad considering another place wanted $300 not including materials for 8 cones) but I'm not sure if that includes the 6 sections in the header as 1 cone. I used 2 strokewizard where I put down 50bhp for my peak at 7500rpm which I think its reasonable since the DG pipes added around 7rwhp, all I wanted was a broader band with a little extra power up top.

I'll have to run the pipes in between the frame rails and cut out the center stand mounts (its dead weight anyway) so I don't sacrifice the pipes on the pavement when I lean. I sketched this out in my knockoff autocad just to get an idea of what the complete system would look like. Horizontal line is the frame rail, line perpendicular to it over the convergent cone is the original exhaust mount which I plan to use. Frame rail ends just before the belly of the exhaust. Hopefully it turns out pretty well.





Made a seat out of deer skin, better than sitting on bare metal.

[tz375]

Aaen are two stroke gurus but I think their quote is per individual cone, so 6 pieces for the header is 6 cones a side, but check with them.

A couple of caveats for you to ponder. 2 stroke wizard is not a great design program, but it's worth what it costs.

Unless you are planning on extensive porting that motor is unlikely to make 50 HP at the crank at 7,500. And a tapered header favors narrow powerbands and higher peaks. For the street, a parallel header is usually better. The picture appears to suggest that you are planning on using large belly section diameter and that means large included angles which again favors top end - as a rule.

Going back to DGs for a moment, a 7 hp increase with just a pipe change is 28% improvement which ain't too shabby.

I would be very interested to see your results if you go ahead and have those cones rolled. Good luck.

[AgentOrange]

I'm hopefully ordering the cones this week but I'm thinking about having someone hydroform them. tz350 any recommendations on porting for the T350's? I found this for the T500 but I'm sure mine would be a bit different.





Side note, I picked this up for $100 on sunday. not sure what year (67'?) but its a YDS-3, turning it into a TD2 look-a-like.

[Vintageman]

I run D&G on my T305. I had done this on a T350 too. I am npw making a T350 swap now into a another GT250 I have.

I was going to run D&G again on that one too, but not much difference then between my T305 in a 74GT250 and my 76GT250 with a T350. I run the later t350 heads on both so look the same too. More fin area for cooling. I never checked to see if the T305 heads was smaller diameter (hmmm I should check... I still have...). Maybe I'll put T305 head back on T305

About a year ago now John Easton (jemco) had a T350 in his shop and was making a set of pipes for it's owner. I asked him if these where race pipes or something more broad range street pipes. He said broad ranged like the T500 style chambers he makes I have not called since. Just to be different I may get these. D&G are well under $300. And, I all ready have set too. I think they D&G look nice. I did not notice any bottom end power loss. Since this post shows the T5000 factory article On my T305 I now run pistons with 2mm off skirt and the T350 is going to have 1/16" off. That's enough porting for me and so easy to do. I had good luck with T305 and hope the T350 is the same

AgentOrange. Do you have the post link that shows the dyno of T350 with D&G added? Was that all I know on Yam R5 and RD400 D&G add similar increase. They are very good pipes.

[AgentOrange]

I called jemco and he said he never had a T350 to make pipes for and only made pipes for the GT250 and a few other suzuki series. it was $600 for those but he said those were designed more towards racing so I didnt buy them. I still never got to getting these pipes done since I was side tracked by buying a KDX200, YDS-3 and an engine for my ZX6R. then I decided to go back to school, so right now school is priority #1 and motorcycles are #2. I sound like a big puss but I'm having separation issues from my bikes. I'm used to killing time by working on them for about 5-7 hours on days off, now its books and student loans to work on.

Vintage: unfortunately they didnt post any pictures of the dyno runs

http://www.2strokeworld.com/forum/index ... pic=5363.0" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[Vintageman]

AgentOrange

Thanks for the post link. Too bad pics are gone. "Pay attention DG haters" to quote that post. DGs are not adhoc design and sure wake up Yams. You sure can pay a lot more for others

It is trivial to put on DG pipe on a T350 or GT/T250. I have both sets for RD350 and RD400. They are very similar in cone design and cone lengths differed maybe < 3/8" Maybe that is on purpose or just tolerance during mfg. I have never compare the exhuast timing between the two Yams

I choose RD400 for the bracket to mount was in a better spot and did not have to move.... that is trivial.

Yes go back to school. You are going to need a lot of money if you choose to play with the old oxidized, dried up obsolete stuff.... and if you make a lot of money save up and buy a new Yamaha FZ-09 triple and Kawasaki Ninja 300

[AgentOrange]

I found some rz350 stock pipes on ebay for $50. They have very similar dimensions to the pipe I "designed". These should work better than my stock pipes correct?

[tz375]

Possibly, but at that price it's worth trying them out to see.