GT550 budget build

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pearljam724
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Re: GT550 budget build

Post by pearljam724 »

Thanks for replies. Coyote, where did you find that grommet for the spark plug hole ?
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Coyote
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Re: GT550 budget build

Post by Coyote »

PJ, the grommets are oem. I got lucky I guess with all the spares I bought before ever starting the build. I had the even niftier ones that fit the plug and the hole. Sort of a hemi look.I had a hard time keeping them in place. Finally ditched them for the ring type that are on it now. The ones in this photo went to Canada. Fred or Ian. Can't remember. I can't tell you if they are early (I think) or later. My ancient parts list shows them for the J,K and L models. Of course they are not available and neither are the rings.

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I was born with nothing and still have most of it left.

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1978 GS1000C
1976 GT550 ongoing money pit.
Cragdog
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Re: GT550 budget build

Post by Cragdog »

Alright , some great news! I got the bike to kick over for the first time! :up:
http://youtu.be/fnRw5hyuUZI

However I haven't got it to idle steadily on its own yet, it seems to be cutting out abruptly, the longest it ran was maybe for 10 seconds or so when I had turned the idle screw up more. One of the times it died, I still had my foot on the kicker, and it felt like it grabbed the kicker gear somehow.. Anybody have any ideas why that might be? Need to adjust the float levels in my carbs still, I did add homemade dust boots like imquattro did to his carbs using some chemical gloves and bench synced. Still have a long way to go, but it was real encouraging to hear the motor turn over for a while.
If you like it, then you should ride it.

1974 Suzuki GT550
1977 Suzuki PE250
1992 Suzuki RM250
1988 Yamaha YZ250
1970 Honda CB750 K0
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Coyote
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Re: GT550 budget build

Post by Coyote »

You must follow through in the kicker and stay followed through. If you let off (retract) the slightest bit, it will grab and kick back at you most every time. Nothing unusual there.
Bike sounds like it's not getting fuel. Have you cleaned the pilot jets and pilot circuit? It won't idle if the pilot circuit is not doing it's job.
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
Cragdog
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Re: GT550 budget build

Post by Cragdog »

Coyote wrote:You must follow through in the kicker and stay followed through. If you let off (retract) the slightest bit, it will grab and kick back at you most every time. Nothing unusual there.
Bike sounds like it's not getting fuel. Have you cleaned the pilot jets and pilot circuit? It won't idle if the pilot circuit is not doing it's job.
Yeah, the first thing I did when I got it was clean out the carbs really well and install new jets. I think I still have a vacuum problem though and my left side exhaust won't match up with the center pipe connector. I was getting some backfiring when it started idling as well.
If you like it, then you should ride it.

1974 Suzuki GT550
1977 Suzuki PE250
1992 Suzuki RM250
1988 Yamaha YZ250
1970 Honda CB750 K0
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Suzukidave
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Re: GT550 budget build

Post by Suzukidave »

Sounded like it was only firing on 1 cylinder , try pulling the plugs and dribble a bit of gas straight into the the engine and then try and see if you get fireing on all three .
the older i get the faster i was
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Re: GT550 budget build

Post by Cragdog »

Suzukidave wrote:Sounded like it was only firing on 1 cylinder , try pulling the plugs and dribble a bit of gas straight into the the engine and then try and see if you get fireing on all three .
I will try that. I am worried its not getting enough oil though by the way it stops so abruptly. I squirted a little 2 stoke oil into the intake of each just to be on the safe side. How can I confirm the oil pump is working? I have been watching this one bubble and it doesn't seem to have moved all the times I've kicked it over..
If you like it, then you should ride it.

1974 Suzuki GT550
1977 Suzuki PE250
1992 Suzuki RM250
1988 Yamaha YZ250
1970 Honda CB750 K0
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Re: GT550 budget build

Post by Suzukidave »

The oil pump (pumps) very slowly at low rpm's so unless the engine is really running you wouldnt see any movement in the lines . I guess you did bleed out the supply line and pump ? If there is a real worry about the startup oil supply you can run premix in a small batch to test start , its likely going to smoke a bunch when you get it going so a bit more due to premix :roll:
the older i get the faster i was
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Re: GT550 budget build

Post by Cragdog »

Suzukidave wrote:The oil pump (pumps) very slowly at low rpm's so unless the engine is really running you wouldnt see any movement in the lines . I guess you did bleed out the supply line and pump ? If there is a real worry about the startup oil supply you can run premix in a small batch to test start , its likely going to smoke a bunch when you get it going so a bit more due to premix :roll:
I did bleed the supply line and pump and primed the all 6 of the lines going to the cylinders and crankshaft, there was only that one very small bubble in one of them. It (the bubble) did seem to move slightly after some time of trying to get it to idle.
Image

I couldn't for the life of me get the old spark plugs off, I even went and bought a 22mm deep socket and it just barely didn't fit somehow.. :wth: so I ended up just taking the head off to take a look at the plugs and get some gas in the cylinders as Dave recommended. The plugs looked fine so I didn't continue trying to budge them off, I was worried I'd break a cooling fin using my crescent wrench or vice so I gave up on them. After I got the head back on, I didn't notice any difference with gas in the cylinders, it actually didn't want to idle at all at that point. My garage was getting extremely full of exhaust smoke at that point so I had to get out of there for a while and breath some fresh air. With the heads off, the kicker operated very smoothly and the pistons seemed to be traveling very easily in the cylinders without any issues (just carbon on their tops, skirts and rings looked good).

I feel as though my problem is mainly due to the carbs, I need to do a better job of sealing off the vacuum lines, they seem to be pouring gas out of the overflows either from the left or middle depending on how the bike is standing.
My exhaust is far less than ideal as well. I wish I had a picture, but there is like a 1 inch gap between the left pipe and where it is supposed to mate with the center pipe. If I try to force it to fit, then the header doesn't match up with the exhaust port and won't seal properly, I think the pipe may be warped or twisted somewhat. I also need to get all new exhaust seals and hardware (right side flange bolts was stuck and I had to drill it out so that one will need a tap as well). Really wish I was rather just getting a set of Jemcos for Christmas! HA! :roll:
If you like it, then you should ride it.

1974 Suzuki GT550
1977 Suzuki PE250
1992 Suzuki RM250
1988 Yamaha YZ250
1970 Honda CB750 K0
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Suzukidave
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Re: GT550 budget build

Post by Suzukidave »

Not saying this is the problem with the plugs but what can happen is if the wrong plugs have been installed with threads protruding into the combustion chamber , these threads can get carboned up and not want to come back out .
the older i get the faster i was
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Re: GT550 budget build

Post by Cragdog »

Suzukidave wrote:Not saying this is the problem with the plugs but what can happen is if the wrong plugs have been installed with threads protruding into the combustion chamber , these threads can get carboned up and not want to come back out .
Well I sure hope that's not the case! They were pretty darn stuck on there tho.. :?
If you like it, then you should ride it.

1974 Suzuki GT550
1977 Suzuki PE250
1992 Suzuki RM250
1988 Yamaha YZ250
1970 Honda CB750 K0
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Suzukidave
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Re: GT550 budget build

Post by Suzukidave »

Too bad we didnt know about this problem before you put the top end back together .. bad plugs can even cause these engine to refuse to start and they dont seem to like Champion plugs either .
the older i get the faster i was
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Re: GT550 budget build

Post by Cragdog »

Suzukidave wrote:Too bad we didnt know about this problem before you put the top end back together .. bad plugs can even cause these engine to refuse to start and they dont seem to like Champion plugs either .
I believe they are NGK B6ES plugs
If you like it, then you should ride it.

1974 Suzuki GT550
1977 Suzuki PE250
1992 Suzuki RM250
1988 Yamaha YZ250
1970 Honda CB750 K0
Cragdog
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Re: GT550 budget build

Post by Cragdog »

"B" translates to 20.8mm, no wonder my socket didn't fit.. ONE OF THESE DAYS I will have all the tools needed to do this stuff without making a trip to the hardware store! :twisted: haha, no but seriously, being only a hobbyist mechanic has some annoying drawbacks..
If you like it, then you should ride it.

1974 Suzuki GT550
1977 Suzuki PE250
1992 Suzuki RM250
1988 Yamaha YZ250
1970 Honda CB750 K0
Cragdog
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Posts: 267
Joined: Mon Oct 14, 2013 2:25 pm
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Suzuki 2-Strokes: GT550L, PE250B, RM250N
Location: Southern California

Re: GT550 budget build

Post by Cragdog »

Hope everyone had a great Christmas! I did a little bit of work on the GT on Christmas Eve, got the old plugs off, they looked to be in really good shape still, but replaced them anyways. Still couldn't get it to idle, couldn't even get it started anymore, just smoke filling up the pipes and backfiring. My battery seems to be getting drained very quickly now when I try to start it..
If you like it, then you should ride it.

1974 Suzuki GT550
1977 Suzuki PE250
1992 Suzuki RM250
1988 Yamaha YZ250
1970 Honda CB750 K0
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