SuzukiSavage.com - Speedtractor - ST400 - Bringing it back to life

Werdna

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Speedtractor - ST400 - Bringing it back to life
06/25/23 at 19:53:15

Hi Everyone,

I have joined the forum because I have just pulled my S400 Tempter out of storage and I'm going to try and get it running again. Novice, so here to get some much needed advice.

I got the bike from Japan, the shop created the custom model was called Speedtractor, I don't think they are still going.

It's turning over, I have new fuel & filter, but no dice. I pulled the plug today and it was black so I will replace tomorrow and see if that does the trick.

Any other advice would be great.

I will post a link and some pictures when the forum allows me (newbies can't do it)

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ohiomoto Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 2772	Re: Speedtractor - ST400 - Bringing it back to li Reply #1 - 06/26/23 at 16:35:16 Super cool!!!! A lot of us here are interested in the ST400 Tempter, but it was never offered here in the States. (We got the GR650 Tempter instead.) I am familiar with Speedtractor's work. Here is a post with one of their ST400 (maybe this is yours): https://www.bikeexif.com/suzuki-st400-tempter
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Re: Speedtractor - ST400 - Bringing it back to li
Reply #2 - 06/26/23 at 16:41:29

As for your no-start issue...

Don't jump the gun and start "rebuilding" the carb and don't open up more than one can of worms at a time. It will just make everything harder in the long run. But you have the right idea by starting with the spark plug.

Here is an excellent video about this topic. Once you start the process, we will be able to help you more.

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Re: Speedtractor - ST400 - Bringing it back to li
Reply #3 - 06/26/23 at 16:56:35

Lastly, most of us don't know much about the ST400, let alone one that has been modified. But, there are a few things we know about the LS650 that might apply to your bike.

You need a strong battery to get these to produce enough spark to start.
The stock fuel petcock is prone to failure, so make sure you check for flow before removing or cleaning the carb.
The cam chain tensioner can fail. Check yours once you get your bike running. (We will point you in the right direction when the time comes.)

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Werdna YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 10	Re: Speedtractor - ST400 - Bringing it back to li Reply #4 - 06/26/23 at 18:58:11 Yep, that's my bike. Thanks for sharing the link, I was trying to do that last night but I was not able to, I think because I am still new. I am going to try and post a couple of pictures now and then an update on the starting after 3 - 4 years standing.
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Werdna YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 10	Re: Speedtractor - ST400 - Bringing it back to li Reply #5 - 06/26/23 at 18:59:11 Here are some pics (hopefully)
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Werdna YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 10	Re: Speedtractor - ST400 - Bringing it back to li Reply #6 - 06/26/23 at 19:00:48 and more.....
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Werdna YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 10	Re: Speedtractor - ST400 - Bringing it back to li Reply #7 - 06/26/23 at 19:03:00 I'm not sure how to put several pics in a single post, but here is another
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28886 L.A. California Gender:	Re: Speedtractor - ST400 - Bringing it back to li Reply #8 - 06/26/23 at 19:06:07 If you can, give us some close ups of the how they did the pegs. kinda looks like my brother in laws kawasaki.
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Werdna

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Re: Speedtractor - ST400 - Bringing it back to li
Reply #9 - 06/26/23 at 19:15:45

Update on Starting.

I changed the plug and with a little start fluid in the air box we have some life, but it's very lumpy and weird. I can also really hear the piston going up/down, maybe that's normal but I wondered what other checks I should do.

A bit of history....

I had it serviced by a shop in Phoenix about 3 years ago. When I collected it the mechanic (nice chap) said that he was not happy about how it was running and he's done the best he could. The basic symptoms were, it started strong and at low rev's everything was hunky dory but when you gave it some gas it jittered and spluttered.

Anyways, I only rode it for about 30mins before (due to life's challenges) it went back into storage.

So now when I can (eventually) start it, it idles just about but when given any gas it stalls (most of the time).

With my limited knowledge it would seems to be a Carb issue and that aftermarket pipe (which I want to ask for advice about changing, it's insanely loud (another post maybe)....the service guy felt like the pipe could be compounding the carb balance (that's above my pay grade to agree/disagree).

My plan is to get it running and in tip top shape, changing out some of the parts to make it more enjoyable to ride (be gone loud pipe) and further enhance the aesthetic.

Small steps. Thanks for the feedback so far, I'm really pleased to be able to share the bike with people who are interested.
Grin

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Re: Speedtractor - ST400 - Bringing it back to li
Reply #10 - 06/26/23 at 20:37:12

Werdna wrote on 06/26/23 at 19:15:45:

With my limited knowledge it would seems to be a Carb issue and that aftermarket pipe (which I want to ask for advice about changing, it's insanely loud (another post maybe)....the service guy felt like the pipe could be compounding the carb balance (that's above my pay grade to agree/disagree).

yes you got a carb problem and it's not unusual.
clean, blow out all passages with air, try it.
still got a problem, repeat try harder until good.

take a look at the numbers of the jets.
we won't know exactly what yours should be, but we can guess.

yes an open pipe will make it lean and loud.
adding a baffle can help both
look at http://suzukisavage.com/cgi-bin/YaBB.pl?num=1609379913/0

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Ruttly Serious Thumper Offline Thumpers Rule Posts: 5106 Manteca , CA Gender:	Re: Speedtractor - ST400 - Bringing it back to li Reply #11 - 06/26/23 at 22:54:08 I like the 4 shoe double leading front brake , super cool Those are fantastic looking bikes stock !
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Re: Speedtractor - ST400 - Bringing it back to li
Reply #12 - 06/27/23 at 05:51:37

Make sure you check out all of the mechanical parts of the fuel system before doing any jetting or mods.

If your bike has a vacuum operated petcock, make sure it is working properly. They present a lean condition when they are failing.

Confirm that the slide opens properly. It's vacuum operated. If it is not opening properly it will not deliver the proper amount of fuel when the throttle plate opens. You can remove the air box and observe the slide's movement with the bike running. If it's not moving or getting stuck you may need to clean or replace the slide.

Another issue with the slide is that people will sometimes mix up the air jets with the fuel jets. The air jets (located at the top of the carb) are much larger than the fuel jets. This creates a very rich condition (you mentioned a black spark plug). So make note of the air jet sizes when you are inspecting the slide.

Then move on to the bottom of the carb. Make a note of the jet sizes. If things look clogged take the jets out for cleaning and note the placement of any washers. I believe there should be one under the main jet.

As for jet sizes... Since you have a 400cc motor, find out what the stock jetting for the bike should be and adjust from there. Don't blindly take our recommendations, since we have 650cc bikes.

If the bike ran well when you got it, the goal is to get it back to its original operating condition BEFORE addressing performance and sound issues.

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Werdna YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 10	Re: Speedtractor - ST400 - Bringing it back to li Reply #13 - 06/27/23 at 10:58:40 Here are the pegs,
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Ruttly Serious Thumper Offline Thumpers Rule Posts: 5106 Manteca , CA Gender:	Re: Speedtractor - ST400 - Bringing it back to li Reply #14 - 06/27/23 at 16:28:54 Must handle real good with those tires !?
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