1981 Suzuki GS450L - Cruiser to Scrambler

Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
trek97 said:
LOL is my sickness showing yet? ::)
You sound about particular as I am so I appreciate the insight and experiences. My bike ran fine enough once I had rebuilt, re-jetted, re-leveled, and synchronized everything but the engineer in me knows that it can probably tuned a little better yet.

All the tuning I did last fall was qualitative (plug color, sound, butt dyno) so it'll be good I think to have some quantitative info (A/F #'s) to tune a bit further with.

It's supposed to get up to 51°F here tomorrow so maybe I can take a break from my house project to make sure my A/F unit is working properly.
 

Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
Finally got some time to tear down the carbs fully after finding that the bike wasn't running quite right after winter storage.

Found that one of the mixture o-rings had been smooshed and split into 3 pieces, probably my fault when I had replaced it last year. So, more o-rings ordered from cycleorings.com. I'm hoping that's the reason for it rev-hanging like crazy.

I had picked up an ultrasonic cleaner this winter, so at least I got a chance to use it again. All the carb pieces got a bath in ChemDip and then 15 minutes in the ultrasonic spa. The bath got pretty murky so it seemed to do a pretty good job.
 

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Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
Was able to get out for the first decent ride of the year and really test the state of the carb tuning with the A/F meter. Two big observations from a couple hours of riding - The carbs are a bit lean in the mid-range and a bit rich on full-throttle. At cruising speed (~3.5k rpm) I'd see an A/F around 16.1 and temps would start to climb. The lowest the Koso gauge will read is 12.2 and at full throttle the A/F was dipping below the minimum reading of the meter.

Regarding my worries about the O2 sensor placement being too far away from the exhaust ports was somewhat valid. The sensor won't get hot enough to give a decent A/F reading until you're up and moving. It doesn't look like it'll give me an idle measurement but I think I'll live.

So, I've got a little more tuning to do. I'll have to see if I can slide another washer under the Jet Needle to richen out the mid range and then I may drop the Main Jet from 137.5 to 135.

Overall still really happy with the bike. The fork rebuild with Progressive springs is really nice. It wasn't bottoming out on big bumps like it had been prior. Wasn't able to get out on the gravel back roads on this ride as was with a good friend on a CBR600rr and they said absolutely not!
 

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Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
Had a very cool experience with the bike this summer. Decided to see what the Rockers Spring Social was about in Minneapolis. I had heard about it from a co-worker who said it was a neat cafe style gathering, so rode the bike there.

Wasn't planning on entering it into the show (I'm kind of shy), but the gate attendant said I really should give it a shot. Well, turns out it got the most votes for "Best Japanese" bike so boy did I get caught off guard. :eek: They had me hop on the stage and say a few words about the bike. There was some disbelief when I said it was my first bike and that all the paint came out of rattle cans in the backyard, so I guess that's about the best outcome I could have imagined for this little GS-L. :p The trophy was really unique... hand-made out of old bike parts. It evens spins around on bearings. Someone put some time into them.

A few pictures from the event to share. You might be able to see a few subtle changes I've made since last posting that include new mirrors, footpegs, and I've got the A/F gauge mounted.

Cheers,
Northish
 

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Maritime

Well-Known Member
Good on you for the win. One of may favorite bikes to come out of here lately as well. Cheers

Maritime
 

rxp1476

Member
I know this thread is a couple months old now but, Awsome build.
I started a simular conversion on a 1980 GS450.

Thanks for sharing
 

Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
rxp1476 said:
I know this thread is a couple months old now but, Awsome build.
I started a simular conversion on a 1980 GS450.
Thanks for the kind words and glad to hear you're tackling the GS450. Which version GS are you working on?
 

scramblerguy

New Member
Thanks for sharing all your experience! I'm building a scrambler on a GS450S and I'm wondering how come you started with such big main jets as 145? My original main jets were 117,5 - that seems like a huge jump up to start with.
Northish said:
The current carb settings are:
Mixture screw - 2.75 turns out
Pilot jet - 22.5
Float height - 22.4 mm
Jet needle - plastic spacer removed, one 0.5 mm washer in its place
Main jet - 137.5
 

Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
scramblerguy said:
Thanks for sharing all your experience! I'm building a scrambler on a GS450S and I'm wondering how come you started with such big main jets as 145? My original main jets were 117,5 - that seems like a huge jump up to start with.
Hey scramblerguy - glad you found my ramblings a bit helpful. I started at 145 on the mains based on other builders' information they posted. I was using K&N pods and a more free-flowing exhaust so figured I'd be pretty lean if I didn't make a big jump. My stock main jet on my "L" model was 115 so it was a huge jump but after reading other ppl's experiences I decided to get some jets centered around the low 140's. I've been pretty happy with the 137.5 so far with my intake and exhaust set up. I see an A/F of around 11 to 13 when running on the mains. Hope that helps.
 

Riverduk

New Member
Hey Northish,

I have thoroughly enjoyed reading about your build, also very encouraged to have a go myself, I have a '88 GS 450 E, different tank / seat and side covers but basically the same bike. I have been trying to find something a little different to have a go at and have just started looking at scramblers when I found this blog. Congrats on your prize win at the bike show, well deserved, your bike has a very professional look to it so I can understand your pride in your first build. I also appreciate the amount of time you took to record, not only the build but also all of the additional info to help other builders on their journey to a successful build, cheers, Ross
 

themountain

New Member
I really enjoyed reading your "ramblings" :D
I will soon start a gs250 and I really hope the outcome will be half as good as yours!
Mayor kudos for your first build...its amazing!

Cheers from cold Lima/Peru
Andy
 

Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
Riverduk said:
I have thoroughly enjoyed reading about your build, also very encouraged to have a go myself, I have a '88 GS 450 E, different tank / seat and side covers but basically the same bike. I have been trying to find something a little different to have a go at and have just started looking at scramblers when I found this blog.
Riverduk - thanks for saying Hi! Glad you found all the notes helpful; that was my hope. Also glad to hear from another GS450 guy. I hope your build goes well for you; riding the finished bike is great, but the build is the most memorable part. Best of luck; hope to see your build on DTT!

themountain said:
I really enjoyed reading your "ramblings" :D
I will soon start a gs250 and I really hope the outcome will be half as good as yours!
Mayor kudos for your first build...its amazing!

Cheers from cold Lima/Peru
Andy
Thanks man; glad to hear from someone all the way in Peru! A GS250 has to be so light and nimble! Let me know if you have questions on something; I'm no expert but I'd be happy to try to help. Get that project rolling!
P.S. My name is Andy too
 

rekidiw

New Member
Northish said:
Well, I am happy to say that I have now put about 70 miles on the bike in the last few days and not one thing has fallen off :p It's been on a cafe run and a commute to work and no issues to speak of!

The current carb settings are:
Mixture screw - 2.75 turns out
Pilot jet - 22.5
Float height - 22.4 mm
Jet needle - plastic spacer removed, one 0.5 mm washer in its place
Main jet - 137.5
hey northish, im working through my 81 gs450 right now and was just curious if these ended up being your final settings or? nice work and glad to see the gs450 getting some quality love
 

Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
rekidiw said:
hey northish, im working through my 81 gs450 right now and was just curious if these ended up being your final settings or? nice work and glad to see the gs450 getting some quality love
Hey, thanks for the kind words, good to hear from another GS450 owner! Yes, I'm still using those settings. I've been pretty happy with them for my setup.
 

rekidiw

New Member
Northish said:
Hey, thanks for the kind words, good to hear from another GS450 owner! Yes, I'm still using those settings. I've been pretty happy with them for my setup.
would you happen to know your wet fuel height measurement? like the clear tube out of the drain plug reading.
 

Northish

If you know what you're doing, you're not learning
DTT BOTM WINNER
rekidiw said:
would you happen to know your wet fuel height measurement? like the clear tube out of the drain plug reading.
I don't have that measurement and the bike is drained for winter now, but I did record my float heights. I finally settled with 23.5 mm for them after checking my notes, so that is the one difference from my noted settings.
 

rekidiw

New Member
Northish said:
I don't have that measurement and the bike is drained for winter now, but I did record my float heights. I finally settled with 23.5 mm for them after checking my notes, so that is the one difference from my noted settings.
alright thanks for that. if youre running the same carbs/floats and all that as me thats a pretty high fuel level! could be some different stuff though. it seems there are about 3 different settings for the gs450. i think that would be around a 3.5mm fuel level. Im currently at 26.6 with a 6.5mm fuel level. not sure what that means exactly but ive been fighting finding the best height since the manuals are all mixed up..so thanks i may try raising mine a bit. I was thinking that would be way too high but you seem to be running fine on that.
 
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