What a royal kick in the ass T350

[Vintageman]

rocc99,

They look like DG for RD400s like mine. If so those are doubled at the end.

Take pipes off and on the short pipe bolted to engine put high temp silicon (copper colored stuff). Put on pipes. Let set for 24 hours before you start it.

Last I noted Dyr was running 28 mm Flat slides. You look like you are running stock 32mm (me too).


Hmmm 113 mains. No such Mikuni jet. Are you using the Keyster kit main (they provide a 113). And if so did you also uses the Keyster's kit provided Jet Needle? It is for the early carb if I recall, not the 72 version. Verify the Keyster Yxx Needle number

Pods will make it lean versus stock more so as you towards WOT. I run stock box. I know RD Yam for example need several steps on main if no air box. The T350 box has a very large filter so maybe not quite as restrictive as RD in comparison going from Stock Air box to pods.... but may need a few steps still. not sure.

My advice if you go real large on main mix a little oil in gas tank until you get close. If too rich you don't wash injection oil away with straight gas

What do you mean by bogging? for example if you are running 4000-5000 rpm small throttle opening and the crack WOT won't take it? What if you let off a little will it take it then and rev to red line? What if you revving above 6500 RPM (if you can) will it take it then. Please try and describe issue related to throttle position and rpm etc.

[rocc99]

Vintageman - thanks for all the info. I will definitely put some of the high temp silcon on the exhaust, hopefully that helps with some of the oil spray.

As for the carbs, the previous owner replaced some of the jetting before I purchased. I do know that he put new 113 mains in there and I believe the needle is new too, both likely from the keyster kit as you've suggested.

I will try and pull the needle this week to see if there are any markings on it (I guess I'll have to look to see if the needle jet is new as well). If it does happen to be the keyster version, where might I be able to locate the correct, stock needle - looks like it is no longer produced?

I don't have a tach, so I'm not certain of RPM, but it feels like I lose power right around 5,000 rpms in most gears. Anything higher than that and the engine tone drops real low and I don't get any power. It definitely will not accept a WOT crack - backing off and then slowly throttling helps in the mid range, but does nothing once above that 5,000 RPM.

Based on your explanation below, it definitely seems like it is running lean and I need to jump up a few main sizes. When I looked on partzilla I saw availability for a 115 main...do you think this would work? Based on that size, do you still suggest that I mix oil in with the gas? Do you generally just guestimate 32:1 based on how much gas is currently in the tank and then swish around?

Sorry for all of the questions - definitely learning a lot every day! Thanks for the help.

[Vintageman]

Under normal circumstance oil injections is fine. I would not run 32:1 premix in addition to oil injection. I would run ~75:1 just for insurance if i was about to run a main jet couple steps or more beyond OEM. If too rich fuel the plug may foul and you don't want to think it is the added oil causing fouling plug.

I assume your oil injection is working and the injection lines are full of oil with no air pockets?
I assume you verified ignition timing as well? A retarted timed engine can have a similar symptoms

Can you see if there is writing on the jet needle (Mikuni)? After market ones tend to be a more yellow/brass like color metal and OEM is lighter colored metal.

Can you also pop out the needle jet and read numbers on it? Also check the Needle jet for wear. You need to look (magnifying glass) into needle end with light source placed at the jet end. The first 1/8 to 1/4 inch of the needle jet barrel inside is precise and what meters fuel. It should be smooth if not shinny. If it is pitted or looks like the moons surface it is junk.

The ater jet needle and Needle jet are obsolete. However, if the needle jet you have, if it not EOM, but is Keyster it is designed to replace the early T350 carb. As on option you can set up for that model. If the carb kit is from ebay's crusinimage no good for either. I am out of time right now and will come back later with more info

Do you have stock air box.... at least to get it running correct with stock jetting and then try pods?


here is the early manual http://www.oldjapanesebikes.com/mraxl_G ... index.html" onclick="window.open(this.href);return false;
here is the jetting specs versus years -> See bull Spec-6 and Spec- 11

http://www.oldjapanesebikes.com/mraxl_G ... etins.html" onclick="window.open(this.href);return false;

[rocc99]

I assume your oil injection is working and the injection lines are full of oil with no air pockets?
I assume you verified ignition timing as well?

Yes and Yes - these should both be working properly.

I'm hoping to pull jets tonight or tomorrow - I'll let you know what I find.

I do not have the stock air box, though I might be able to borrow one just to test everything.

[Vintageman]

Did you do your jetting homework... compared Suz specification bulletins and the early service manaul.

You'll see that the T305 and 69 T350 had same jetting (some confusion...explained later).

You will see that 70-72 T350 uses another jetting. Some will say the reason for the change is the later T350 added two little extra Exhaust port holes either side of the single large Ex port. I don't think it means squat for jetting. First reason is they made the larger Ex port smaller in area to accommodate the two little extra ports. So really no added area … maybe less me thinks (marketing ploy oto compete with Yamaha’s true extra transfers ?). Secondly, I have run both early and old jetting on both T305 and T350- tried all combinations each worked well

You don't have to believe me. But, then you will need to find a set of 5DH21 Jet Needles. That is what I finally did for believe it was better tuned jetting and better mpg maybe. your running pods so a little rich better maybe

The Keyster needle has stamping mark up by the clips "Y21". The crusinimage kit has no markings. The early OEM needle "5DP2" and is silver in color and aftermarket is brass colored.

The early jet 5Dp2 needle is very close to the Y21 Keyster and crusinimage . I was wrong earlier. the crusinimage is very similar to early OEM jet needle! I just rechecked for you

The early carb calls out for 170 main. I know in the T305 it is a Hex main jet where a 170 hex is about 120 round jet equivalent if you trust conversion chart.

I think the early Needle Jet is a 159 series (Can Still buy these shiny new!!!) and the later T350 is a 188 or 182 (you see for sure when you take it out) same thing but take round main not hex..obsolete I think too in that size?

Here is the confusion. The Spec-11 for 1969 T350 says needle jet is P-6 with 112.5 (round) and 5DP2 needle and early 1969 T350 service manual says is Q-0 with 170 main (hex?) and 5DP2. Maybe spec 11 is correct

My money is it just like the T305 and its a 159-Q0 with 170 hex main with 5dp2 needle (or Keyster Y21 or crusinimage needle!)

This where stock air box is nice


Oh if you do find or have the later 5DL13 and have pitted need jet get a 159 series and do a round to hex main jet size cross or just cross thread a round where the 159 wants hex (works well too)

Wow….. a lot of typing… I hope this helps

[rocc99]

Pulled the slide out this evening to look at the needle. No markings that I could see. Definitely a brass color. Sure sounds like crusinimage. I'll upload a picture of it tomorrow. Hoping to take the carbs completely apart later this week.

I spent most of the evening pulling off the left cover to find a leaking clutch push rod seal. Ordered a new one now just need to wait...any advice on how to properly remove and reinstall?

Finally, started taking off pipes to apply my new high temp silicone. Couple of questions here (I had a guy do this for me originally and now I find myself fixing his mistakes): first, when attaching the d&g coupling to the gt380 flange, what kind of bolts did you use? Normal bolts don't seem to give me enough room to thread the flange all the way down without the heads hitting the fins. Secondly, should the high temp silicone be placed on the threads before threading on the flange? Finally, I assume the silicone should be applied to the outside of the coupling before reattaching pipes, correct? Should I also apply it between the flange and coupling? Sorry for the question overload, just want to do it right this time. Thanks.

[Vintageman]

I am getting nervous about the 1969 T350. even though I don't think the extra little Ex ports matter, the T305 has larger volume transfer passages (not port windows just passages leading to port windows) than a 71 or 72 T350 cyl. I have never seen a 69 T350. Maybe like T305 with respect to transfer passage casting Aluminum.

Not sure why I am doubting, a said I ran t305 carb on 72 T350. And for may thousands of miles I have been running the later T350 carb jetting on my T305. Perfect. And by choice since I have all to make it a T305 jetting

Well if you want later jet needle contact paul miller. I think this is the # 13383-18630.

I got mine off him he may still have more. Not cheep I am sure


You'll have to grind fins off GT380 flange and then screw flange on backwards: Fin side toward cylinder that is. You have to hog out holes a little too to align with RD400 flange. Then use any good bolt. You have to put them in ahead of turning gt380 flange on Ex thread for can't put the bolts in later. You don't need goop on thread for the exhaust gasket fits well between upside down gt380 flange and rd400 flange

don't forget to read my previous post... you posted on top of me

[rocc99]

I read both posts, lots of useful information. Decided to stay up and pull one of my carbs tonight. Like I said before, definitely looks like crusinimage needle (brass no markings). 113 main (brass). And I have no idea how to remove the needle jet, ha. How exactly do I get it out?

[rocc99]

In the meantime, assuming my needle jet is in good shape...how many steps up on the main do you think would be appropriate given the expansion chambers and pods? Currently at 113.

Would you suggest going to 115, 117.5, 120?

Also, pilot jet is 30 - would it make sense to increase this to 35?... I do notice that it takes quite a lot of throttle to get the bike rolling
Thanks.

[Vintageman]

Remove round slide from carb body. Remove main jet and washer below it. You can now take a punch like item and push needle jet from main jet side and it will come out where round slide/jet needle was. Don’t ruin thread were main jet goes in of course


One thing I have learned on old engines is the needle jet inside is usually no good inside. And if I am correct again then that needs to be fixed first. It is critical.

I don't think D&G chamber alone will require any main jet changes. It did not for me at least, others claim you should go up a step at least. Be careful

Stock pilot should be OK. I test pilot circuit by opening throttle very little and on a flat and see if engine will climb up high into RPMs smoothly and without pinging. I start OEM and most the time work richer on jet/ air screw a little. Just the way I like it tuned. It is so fun to street ride if this goal can be achieved. I test other circuits /throttle postion the same way.

If you end up having to go a few step higher on main jet versus stock, I would raise the needle one clip too...to ensure ~¾ throttle pos. not too lean you may have to back main off one step after clip change… maybe not

I have ruined (accelerated ring & cylinder wear) a motor's top end before running too large mains (that's why I say mix some oil in gas tank).

Others are adamant that too lean is bad and start rich. Best to start spot on! Well, IMO you know you are jetting so don't run too long until you know its OK.

I really don't want to tell you what to use for main or even as a guess. You must understand there is a risk if wrong. Also, I have no idea for this setup or I would say what I did with a disclaimer. What you stated for values would be some things to try.

If me i would get stock air box.. at least to get a reference of what works

I will say it can take many tries, careful testing, and patience. I have acquired quite a collection of main jets
There are some good guides on the web of how to tune a VM Mikuni carb .

[rocc99]

Vintageman - all excellent advice. I really appreciate all of your input. I'm going to take a look at the needle jets and then go from there. Hopefully I can remain patient! Thanks again.

[rocc99]

Pulled the needles and they are the originals. But shined a light through them and they look very good, smooth and shiny. Though the washer between the needle jet and main jet was missing on one of the carbs...talk about something that could really mess worth performance. Does anyone know if I could find a washer of the same size in a hardware store? I really don't want to pay $8 shipping for a fifty cent part...

[jabcb]

You could order the washer at your local Suzuki dealer.
Might be a bit more expensive but there won't be any shipping charges.

[Vintageman]

what is stamped on side of needle jet for example 188-P6

[rocc99]

That is exactly what they are...188 p6