Saturday, February 21, 2009

Suzuki GT380 Restoration

I haven't used this particular blog for a while for personal reasons and I didn't know whether I should delete it or keep it going. So what I am going to do is use it as a progress report on a motorcycle restoration. When I was 19 I had a Suzuki GT380 which at the time I thought was fantastic. Over the years since I have raced and owned many sorts of motorcycles including road racing sidecars and the quickest of all was a TZ750 Yamaha.

Anyway I came a cross a GT380 about a year and a half ago, it is a 1976 model with a disc brake, I would have preferred a drum brake model but this all I could get at the time, the drum brake models are far and few between nowadays. So I have finally have a garage and some time to play with it, so I have put a couple of pictures of the bike here and as I go I will put on updates of how things are going and what I have done.
Paddy looks good on the bike as well.

So here it is - Unrestored 1976 GT380 Suzuki.


Zac said...

I was just wondering if you have had any progress on your GT380.
I myself bought a 1972 suzuki GT380 that needing restoring when i was 19. The bike really needed minimal work to get it running. Last year it has been tagged was 1974 with a total of 8672 miles on it. Its suprising how good of shape it was in. No cracks in the original seat, minimal rust pitting in the chrome fenders, and the paint and plastics still have a bit of vibrant red left in them. Well im 22 now, And have worked on it here and there, left it untouched for about a year but since its riding season i really wanna push to get it running in a couple months. I just finished cleaning the carbs and putting them back on the bike which was reall all the mechanical work that was needed to get her running. I plan to put fresh fluids and spark plugs in her in the next couple of weeks and possibly try cranking her over for the first time since i bought it. It is a bit exciting to go through the process.
Any ways if you would like to see pics of my GT380 let me know. Plus if you know of a market anywhere of GT380 fanatics that would be interested in buying it let me know. Cant wait to see your progress.

sfw said...

Hi Zac

I'm doing a fairly intensive training course at the moment and I haven't been able to touch the GT for over a month now, it's still sitting as a bare frame. I also need to do a helicoil on the left hand cylinder. I hope to start work onit again in about a months time. I love the sound of your bike it sounds like it's in pretty good condition. Let me know how you go with it etc.

Good Luck


Paul said...

My 1972 is now running beautifully after a winter of work. Have taken it on a handful of rides around the Pennsylvania countryside. Really enjoying this old bike. Best of luck with your restoration. I had trouble with a Creem tank liner application, would not recommend it. Just cleaned out the tank as best as I could and am running with inline fuel filters and hoping for the best. Be careful when messing with the points - there is a nylon points cam gear that breaks very easily. That was one early setback on my project. Enjoy.

sfw said...

Thanks Paul I really wanted a 72 model with the drum brake but they are few and far between, anyway thanks for the advice I will be posting a bit more in the next week or two.

discountbikespares said...


I have a website that may be of interest to you -

I sell a lot of GT parts and I ship worldwide.



Hohmann and Barnard said...

Even though I'm a lifelong dirt bike rider/ex-racer, I was at an estate auction earlier today during the blizzard in New York, and I came across an old (3)cylinder Suzuki street bike. It reminded me of the old GS's I used to fool around on when I was racing my RM250 in the mid 80's. Turned out to be an original owner 1972 GT380 with only 623 miles on it! Even though I didn't know much about this bike, and the flat tires, and that it was 24 degrees and snowing, my son and I loaded into the truck and took it home. After readng your blog, I didn't know if anyone out there would be interested in buying this bike for themselves at a fair price. I don't know what these bikes are worth (dirt bike kind of guy), but if interested,e-mail me with your thoughts. My e-mail is If there's no interest, I'll break out the steel wool, change the fluids, and fire her up in the summer. Hopefully, I can leave questions on this blog if I run into any problems. Thanks, Rich

sfw said...

Hi Rich I'd love to make an offer on the bike it sounds just like what I'm after. Unfortunately at this time of year (Christmas) I'm short of money. If I am travelling better in the New Year I'll let you know. I have a mate in Nth Carolina who sends a container of stuff to Australia twice a year maybe he could fit it in for me. You should take it for a run, they are strange bikes but I just like the looks of them > I raced TZ Yamahas for years and these old Suzukis don't do much right except look Ok.


Jon said...

Maybe one of you guys can help me. I have always ridden yamahe bikes. Well I got rid of my bike a couple of years ago and wanted to get another one now. Well Iinstead of buying a newer one i thought i'd go with a classic. I have my grandfather's 1974 suzuki gt380. Well, They tell me it isn't worth restoring and that I could go and buy one cheaper than what it would take to fix it up. I don't believe that. It doesn't run and no one is really sure what is wrong with it. What I was hoping to do is either find another 380 engine or an engine from another bike, maybe even another manufacturer and mount it to the bike to get it back on the road. Do you have any suggestions or know what engine is comparable to the 380? Thanks

sfw said...

Hi Jon

I help with what I can, you can get in touch with me by going to my profile. Whereabouts are you?

Jon said...


I appreciate any help, insight, or information you could provide me with. Like I said before I am having trouble finding a 380 engine for that is in working condition or needs little work, so i was wondering if there was an engine comparable to the 380 measurement wise that I could mount up to the suzuki. I was unable to email you off you profile. I am in North Carolina, USA. My email is


mitch said...

just bought a 1973 gt380 and needs some tlc but every things here and in very nice condition all four pipes are like brand new and it has very good compretion

Zac said...

hey sfw,

So its been quite some time since ive been on this site. i had forgot i even posted something here and came online to try and find what type of oil to put in my 72 gt380. This popped up in my search and made me laugh to read back on things. I still havnt started it yet. alot has happend in the last year. I actually bought a CBR600 for last summer but in november of last year i was riding in the mountains and was sideswiped by a big rig cutting a turn. Messed me up pretty bad, broken pelvis, 2 broken femurs, broken tail bone and left ankle. Spent two months in a wheelchair, and still going through physical therapy to get my stride back but my spirits are still high and ive already got back on a bike since then. Just cant stop riding completely haha. Anyways instead of buying another crotch rocket im really gonna try to finish the GT now and put around on that for the summer. But back to my question. Im tryin to figure out what type of engine oil and tranny fluid to put in the bike. I have a dvd manual i bought off ebay but it doesnt specify and so i was wondering if anyone knew what i should put in her. thanks

sfw said...

Hi Zac

Sounds like you have had some interesting times. Glad you are on the mend now. I stopped riding fast on the roads years ago, I would have killed myself. Why don't you have a crack at road racing, it can be relatively cheap if you pick the right class, it's great fun, you learn that there are a lot of fast riders out there and everyone goes in the same direction with no trucks or cars.

As for the 380 well I'm just putting mine back together. I got the same manual off the internet it's not bad but is a bit light on for details. You ask about oils, well for rngine oil the GT used an oil pump and a separate oil tank. Unless you are sure that your pump is working and is calibrated right I would run premix. Any good quality two stroke oil should do fine, I would mix it at about 25:1 for starters. If you have too much oil all you will get is fouled plugs, not enough and you will wreck your engine.

Like most road bikes the GT uses a wet clutch, I would use any gearbox oil suitable for wet clutches your local motorcycle shop should be able to help you out with that.

Have Fun Zac


Brad said...

I'm trying to resurrect a '74 GT380 from the dead. I have a nice, fat spark at the left plug and breaker, but no spark at the right and center plugs and breakers. I'm trying to trace the break in continuity with a multimeter, but can't find anything.

Any clues?

Also, I don't know the measurements and procedure for actually setting the points gaps. Can you link me to them?


sfw said...

Hi Brad
Sounds strange, I assume you can use a multimeter, you should see 12volts at the points when each one is open. Do this at the one that is working and see if you have the same at the other points, if you do well those points are shot. If you don't get 12v across the points when they are open disconnect the condensers and see if that works, it's unusual but the condensors can short out. If after that you still don't have 12v across the points (when open) take the wire going to the points off and you should have 12v on that, if not then you have a problem in the loom somewhere. Hope that helps.

I have the settings etc for setting the points however to do it properly you really need a Dial Gauge, if you don't you will get it running but performance will be poor. Hope this helps.

Brad said...

Actually...I figured it out. The two that were reading voltage when closed where corroded. I used some sand paper to clean them and then they read 0V when closed. I was actually able to get it to run. It's rough and the left cylinder isn't running well AND and have some fuel dumping from one of the carbs, but there's hope yet! Gonna pull them apart and clean them up.


Brad said...

I rode it today! Not very far, maybe 1/2 mile. The left carb clogs off and on, it had some horrible junk in it! The pilot jet is frozen in the body, and it's nasty anyway, so I'm hunting on eBay for a replacement set.

It's a great feeling!

sfw said...

Sound great Brad, two strokes especially before power valves etc are different ride than modern bikes. The GT's were slow compared to the Kawasakis and yamahas etc but still fun. You really need to set the timing with a dial gauge, otherwise it will not be right. Check that the oil pump is working, if you aren't sure run it on premix just in case. Then the worst you can do is foul the plugs. Whereas without oil it's seize city.

Brad said...

Thanks! I'm ordering a dial indicator with a spark plug adapter today.

I see oil in the lines, and there's lots of smoke coming out, but I do need to pull them off the engine to ensure oil is coming out.

sfw said...

Hi Brad

I'm not sure how to check the oil pump I'll look it up in the manual when I get the chance. Even if the pump is working there is no telling if al the lines and gallerys are clear and that the oil is flowing where it should. Depends on how long the bike has been sitting.

I have put the ignition settings on a new post at the head of the blog, go to there and you should see them.

Bike & Motorcycle Trailers, Tradesman Trailers said...

just wondering for your GT380... good work and thanks to share... for used suzuki parts visit

Kerianne said...

Hi there, have a friend who is restoring a gt380, 1972 model, we are trying to find a crankcase check valve, the sites we have found arent coming up with the type of valve he gave us to look for, was wondering if anyone would know of a good site to check out, have looked at one posted in an earlier post but is not the right valve we are after,

sfw said...

On the last GT Suzuki I had I just disconnected the valves and blocked off where they go in the crankcases. It wasn't a very effective system to start with and the valves and pipes get rotten with age. If you really want them or are trying to do a 'Perfect' bike get on Yahoo, they have a message / discussion board on GT Suzukis. I've found it to be a great source of info. Hope it goes well. I haven't updated my blog for a while due to buying my own business (a motel). I'm hopeful I'll have some time soon to bring it up to speed. If there is anything I can help you with let me know.

Kerianne said...

Hi there, thanks for that, ill pass on the info and will get the partner to suss out the yahoo discussion, he knows what they are looking for better than i do but it doesnt hurt to ask someone does it? Good luck with the business, hope it all comes together for you.