T350 first start after restoration questions / problems

[mike1161]

Hey guys, yesterday got my ’70 T350 started for the first time after a total restoration, and I had one “lessons learned” to share, and a few questions for you. Did some searches here, but didn’t see anything matching the issues I’m having.
The “lessons learned” was something that was driving me crazy! When I got the carbs installed, and was checking for proper throttle cable adjustment & carb slide movement, when I twisted the throttle close to wide open, one (or both) of the slides would stick in the wide open position! I would then take off the top screw cap & try to get them to slide free, but they seemed really sticky. Since clearance is tight in there with the carbs mounted, I then took the carbs completely off to see what was up. This went on for a while, very frustrating. The slides seemed just fine with the carbs off the bike. So then I reinstalled both carbs, and the same thing! They hang up again! Then I thought, I’ll just take them off again….As I begin to loosen the first nut holding the carb, I hear the carb slide go “clink” as it frees up! So then I realized that over torqueing the nuts that hold the carbs must be slightly distorting the entire carb body, causing them to seize in there! Hopefully this will help if somebody does the same thing. I guess they really don’t have to be too tight, since they have the O-ring seal, and lock washers. Not something you can get a torque wrench on, either, due to the tight clearance.
Anyway, now for the problems:
1) I’m getting a lot of leaking from around the float bowls. At first I thought the float bowl screws weren’t tight enough, so I re-tightened them, but not much of a difference. And I’m pretty sure it’s coming from around the gaskets, not an overflow problem, since the bike runs fine (at both idle and various rpms, I took it around the block a couple of times), and I double/triple checked the float level setting, and just visually, it seems to be seeping out from the gasket area. They are brand new gaskets (bought off eBay from Cruzinimage). I have had pretty good luck with parts from that guy before. Could they be just bad gaskets? Should I get Suzuki OEM ones instead?
2) I have good oil supply to the pump (no bubbles there), but the output seems to be almost nothing, especially in one of the lines. I just see a lot of air that just doesn’t seem to clear, it does pump some oil through the lines, but it’s really got a lot of air, too. Probably 70% air, 30% oil. All new crush washers, all bolts are tight. As a precaution, I’m running a premix mixture for now, but I know that it doesn’t really do much for the crank bearings. Anyway, I’ve run it at 2000 or 3000 rpms, and held the pump control lever wide open, revved it, etc… but no real change in the output of the pump. I totally rebuilt the pump, with all new seals, too. Could I have a bad pump? Or could some of the check valves be stuck? As part of the restoration, I totally took the oil lines apart, including the check valves, and flushed them out. I did have to replace the small washers near the ball & springs in the check valves, since they got damaged taking them out. I’m thinking maybe it’s a problem with the check valves not opening to allow flow?
Any ideas or help would really be appreciated!

[GT750Battleship]

Hi,in regard to the pump,it is possible on the GT750 to have the pump work the other way around if it's been pulled apart for any reason,& things put back together wrongly, to much oil delivered at small throttle openings & not enough at higher rpm & load ! I have no idea on the workings of the pump on the "twins" If you want to you can look at the "pink possum Site" on the net (Suzuki oil pump) to see how the pumps work on the GT750,info on there about bleeding the lines & purging the pump which may be helpful to you,,sure someone here will come up with a definitive answer to your questions!!
Cheers,
GT750Battleship.

[mike1161]

Thanks for that info - I took a look at the GT750 pumps on the page you suggested, and they look different from the T350 / T500 ones. From what I remember when I had it apart, the internals could only go back together one way (I think...).

[ConnerVT]

I have a similar leak on my LH carb float bowl. Came after I tore the original (to the bike) bowl gasket, on one of the jetting changes I was trying. Replaced it with one of those light brown, paper like gaskets, which I believe may be a real Mikuni gasket. If I leave it on the side stand for a few days, it weeps a little, and I can see the stains on the side cover.

Up here in the Northeast, only have a few more weeks of decent riding weather, so I'm waiting before tearing it apart once again.

[jabcb]

Bloop2 sells oil pump seal kits. Same kit works for the T500, T350, T250 & GT250.
viewtopic.php?f=23&t=8422

Take a look at his pic of the disassembled pump. The bolt with left hand thread is used to prime the pump.

Bloop2 also sells the kit via eBay, which makes orders & payment processing easier.
http://www.ebay.com/itm/Suzuki-T500-T35 ... 0972950654

Suggest you ditch those oil line crush washers & use M6 Stat-O-Seal washers from McMaster-Carr.
viewtopic.php?f=9&t=6094&p=122326&hilit ... al#p122326

The one-into-two junctions on the T-series oil lines are problematic. They can develop air or oil leaks. But can be cleaned & sealed.
Will need to flush the lines so that you get good flow thru both lines & so that the check valves work.
The oil lines weren't designed to be disassembled for repair -- you might end up buying replacements if you try it.
See: viewtopic.php?f=9&t=6827&p=122436

An easy check for function is to fill the oil lines with a different color oil prior to installing them. Then you can easily check for oil flow.

You may find other useful posts if you use search strings like "flush oil line".


Have recently noticed an unexpected result from having multiple problems.
When parked on the side stand for extended periods, the oil can drain from a right cylinder oil line into another oil line.
Had one bike where a right oil line would empty completely when left on the side stand, but then fill back up if I switched to the center stand.

So now to play it safe, I use the center stand for a T-series bike when its parked for more than a few hours.

P.S. for the experts. A sticky topic on T-series pumps & oil line under the Repair Forum would be useful.

[mike1161]

jabcb, thanks for the great info & references. I did get the pump seal rebuild kit back a few months ago when I was in the middle of the restoration, (very nice kit by the way), and totally took the pump apart, flushed it, inspected it, and installed the new seals. So I'm pretty confident the pump is OK....
The bolt you mentioned with the LH thread that's used to prime the pump - exactly how does it prime the pump? I just screwed it back in & left it alone...
I guess the more I think about it, maybe one or more of the little check balls is not working right, but I thought I had them put all back together OK. When I took the oil lines off, some of the fittings were loose or leaking, so I took everything apart, flushed it out, and then glued the fittings back with JB Weld. Seemed to work; the only thing I can think of is that I did replace the small washers that the check balls seat against, since I damaged the old ones getting them out. But you would think that if the ball doesn't seat right, it would cause it to leak oil into the crankcase, vs. not allowing flow.....Oh well, I guess I'll take the lines off & check for good flow, etc, similar to what you said in your post.
Also those Stat-O-Seal washers seem like a great choice, I will probably pick some of those up!
And ConnerVT, thanks for the info on the float bowl leak - yesterday I ordered a pair of genuine Suzuki gaskets from MotoSport; I figured maybe the OEMs might be different / better, so might as well try. They were about $17 shipping included, so worth a try. I'll let you guys know what happens.

[jabcb]

The LH thread bolt is on the top of the pump.
So with everything assembled & oil in the tank, just undo the bolt & the pump will fill with oil.
Passages in the pump are quite small, so it will take a while to fill the pump.

[mike1161]

An update on the problems from above: I went ahead & ordered a set of OEM float bowl gaskets, they should be here in a few days, so that should fix the fuel seeping problem.
As for the oil lines, while I had the carbs off, figured I might as well check the lines again. Took them off, and dis-assembled the check valves again (the T350 style check valves are easy to take apart, unlike the T500). I found that on 1 of the 4, I must have had the spring slightly off the ball when I re-assembled it, and it bent the fragile spring sideways and crushed it, so that check valve is shot. It probably held that ball shut, too, so no oil flow on that line.... The others were fine. So I really needed a new line. Found one (or so I thought) at a small dealer in upper NY, under the right PN (16820-18301), and it arrived yesterday. But when I unpacked it, I knew that somehow in the 30 something years of sitting around in inventory, it had gotten the wrong PN marked on it. It was just in a plain plastic bag with the PN handwritten on it. Below is a photo of one of my old lines, along with what I got!
So, back to the drawing board. I found out that Marcel in the Netherlands had a LH line for the T350, so I just ordered that last night. Hopefully it will be the right one.
In the meantime, I've been reading this thread about making up your own oil lines, seems pretty interesting: viewtopic.php?f=2&t=7226&start=30" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Also, I did use the tip to test out the pump by driving it with a drill, it seems to be pumping fine.

[Vintageman]

I had torque problem too so carbs stuck WOT. If you polish the inside of carb body with Mothers aluminum cleaner it helps. But yes deforms once torqued at all

I have found recently the drain for screw for the bowls, that little gasket leaks. Almost every bike I have has had that issue
So not always main bowl gasket.


Air in lines. Yes one line set is fine on twin and the other has air bubbles. I am always checking now.

To make think quick versus taking a part I will blow out line with 5 PSI only of air and clears up.

I have found if you suck on the check valve (or use about 3 psi) you will feel check valve crack open if not stuck closed or stuck open. Fast test again

If you have not cleaned you oil tank do so. It doesn't take too much to plug lines.

That system relies on all four lines having equal resistance to get equal oil share of pump oil. Scary criteria

Supposedly air is from the line end attached to pump is loose, but not sure if those are bubbles are air or voids.

[mike1161]

Thanks for the info... good to know someone else has had the same experience with the carbs / torque situation, thought I was going crazy! I got the OEM carb bowl gaskets last week, they look WAY better (softer) than the ones that came in the kit I bought on eBay, those seem like just a hard bumpy plastic by comparison.
Also just received the other oil line set from the Suz Classic parts, so will try to get everything back together this weekend & re-start again. Oil tank was completely cleaned out & coated with POR-15 coating kit at the same time as the gas tank, also got new filter screen for it.
I'll get a youtube video up later, too, so you guys can hear how the Higgspeeds sound, they sound pretty good I think!

[mike1161]

Before installing the new LH oil line I got from Suzuki Classic parts, I noticed that although it was right PN this time, and the form factor will fit, the check valve ends are definitely different than what was on my bike. The ones on my bike had an easily re-buildable check valve (just unscrew the brass tips). I had cleaned & re-assembled them, using JB Weld to make sure there was no leaks. This new one looks like the T500 style, "permanently" press fit on, see photo below. Also the banjo fitting that is at the oil pump end is about 3 mm thinner, so the banjo bolt wouldn't seat right, I had to add another crush washer underneath the top of the bolt, so the bolt could be tightened enough and the hole in the bolt would not be obstructed. Everything now installed, though, will try to crank it up again soon & see how it goes!

[mike1161]

Well, today got everything back together, no leaks, oil lines all good, so got the airbox & everything else back on & cranked it up! Didn't hit it too hard, since the motor is pretty fresh, but it seems to have a bit of a flat spot in the midrange, guess I'll work that out later. For now it looks & sounds great. Check the thread over in the "Restorations Photos". Also did a short YouTube video, see here: http://www.youtube.com/watch?v=HzeMSP8DIbI" onclick="window.open(this.href);return false;

[jabcb]

The T305 had the rebuildable oil lines. The T350 had oil lines like the one you got from Suzuki Classic parts.

But given the parts-bin engineering/manufacturing that Suzuki did back then, I would not be surprised if your T350 was manufactured with T305 oil lines.

[mike1161]

Thanks, great tip! I can definitely see that happening, makes perfect sense.