Painting engine barrels and overheating
Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan
- tz375
- Moto GP
- Posts: 6210
- Joined: Mon Nov 03, 2008 10:47 am
- Location: Illinois
Re: Painting engine barrels and overheating
If the carbs were virginal, the jets may be ok but if a PO f#*cked with them, the jets may be damaged from poking wires through them and could be oversized. Jets are pretty cheap.
- Suzukidave
- Moto GP
- Posts: 3980
- Joined: Fri Oct 24, 2008 5:55 pm
- Country: US
- Suzuki 2-Strokes: GT750 x2 97 -1200 Bandit 86 GSXR1100
- Location: Lancaster Pa.
Re: Painting engine barrels and overheating
Yeah .. i did forget about the PO'stz375 wrote:If the carbs were virginal, the jets may be ok but if a PO f#*cked with them, the jets may be damaged from poking wires through them and could be oversized. Jets are pretty cheap.

the older i get the faster i was
- Nicholas
- Around the block
- Posts: 96
- Joined: Mon Nov 19, 2012 1:01 am
- Country: United Kingdom
- Suzuki 2-Strokes: Suzuki GT500, SR500, BMW R80, BMW R100S
Re: Painting engine barrels and overheating
Great, thanks for the clarification!
I'm having a hell of a time trying to find the right part number for the needle jets. Do you have advice on where to look?
So my GT500A (VM32SC) has:
Main Jet: 97.5
Needle Jet : P-4
Jet Needle: 5FP17
Pilot Jet: 30
Now I believe for the VM32 I should be looking for a needle jet VM34/05 P-4, 159 Series... Yeah?
Also, on the topic of parts.... One of my oil pump lines broke and looks like the parts are discontinued..
16820-15033 (13), 16840-15033 (14), 16810-15131 (10)
Do you know if it would be easy to fabricate one using PVC tubing? I don't have the bike with me...so I am not sure how the banjo ends could be fitted onto the tubes, I'd imagine this kind of stuff could be ordered... maybe a question for the forum...
I'm having a hell of a time trying to find the right part number for the needle jets. Do you have advice on where to look?
So my GT500A (VM32SC) has:
Main Jet: 97.5
Needle Jet : P-4
Jet Needle: 5FP17
Pilot Jet: 30
Now I believe for the VM32 I should be looking for a needle jet VM34/05 P-4, 159 Series... Yeah?
Also, on the topic of parts.... One of my oil pump lines broke and looks like the parts are discontinued..

16820-15033 (13), 16840-15033 (14), 16810-15131 (10)
Do you know if it would be easy to fabricate one using PVC tubing? I don't have the bike with me...so I am not sure how the banjo ends could be fitted onto the tubes, I'd imagine this kind of stuff could be ordered... maybe a question for the forum...
- Suzukidave
- Moto GP
- Posts: 3980
- Joined: Fri Oct 24, 2008 5:55 pm
- Country: US
- Suzuki 2-Strokes: GT750 x2 97 -1200 Bandit 86 GSXR1100
- Location: Lancaster Pa.
Re: Painting engine barrels and overheating
There are some on ebay http://www.ebay.com/sch/i.html?_sacat=0 ... ion&_rdc=1" onclick="window.open(this.href);return false;
the older i get the faster i was
- Suzukidave
- Moto GP
- Posts: 3980
- Joined: Fri Oct 24, 2008 5:55 pm
- Country: US
- Suzuki 2-Strokes: GT750 x2 97 -1200 Bandit 86 GSXR1100
- Location: Lancaster Pa.
Re: Painting engine barrels and overheating
"I'm having a hell of a time trying to find the right part number for the needle jets ' .... Is this yours ... http://www.oldjapanesebikes.com/mraxl_G ... index.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
the older i get the faster i was
- Nicholas
- Around the block
- Posts: 96
- Joined: Mon Nov 19, 2012 1:01 am
- Country: United Kingdom
- Suzuki 2-Strokes: Suzuki GT500, SR500, BMW R80, BMW R100S
Re: Painting engine barrels and overheating
Hey thanks for your help. No, my bike is a twin, the GT500A (1976)Suzukidave wrote:"I'm having a hell of a time trying to find the right part number for the needle jets ' .... Is this yours ... http://www.oldjapanesebikes.com/mraxl_G ... index.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
http://www.oldjapanesebikes.com/mraxl_G ... Links.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
This is the spec on the carbs for my bike:
http://www.ozebook.com/compendium/t500_ ... pspecs.htm" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
As in the parts manual
http://www.ozebook.com/compendium/gt500 ... arts54.htm" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Now, unless I've got it wrong. I need a 159 Series VM34/05 P-4 needle jet
http://www.motocarb.co.uk/needle%20jets.htm" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Oh, about the oil lines...you think I can just replace the tubes and put some clips on the banjos? The links you sent through were for a GT550, but noticed they had oversized tubes, guessing their not originals. But if they work, then great. I'll just replace the tubes and hopefully reuse the banjos, or maybe they are standard parts that could be ordered?
You do not have the required permissions to view the files attached to this post.
- Suzukidave
- Moto GP
- Posts: 3980
- Joined: Fri Oct 24, 2008 5:55 pm
- Country: US
- Suzuki 2-Strokes: GT750 x2 97 -1200 Bandit 86 GSXR1100
- Location: Lancaster Pa.
Re: Painting engine barrels and overheating
Oh Man .. sorry .. wrong bike .. i dont know how i got side tracked to a 550 

the older i get the faster i was
- ConnerVT
- Novice racer
- Posts: 963
- Joined: Wed Jan 18, 2012 8:01 pm
- Country: USA
- Suzuki 2-Strokes: T500R (now), T500M (40 yrs ago)
- Location: North of Albany, NY
Re: Painting engine barrels and overheating
From what I understand, the 159 series P-4 Needle jets are made of Unobtainium.
There has been some input to a few threads as to another series of jets (with hex head main jets) that can be substituted, but then you are in a trial-and-error mode getting the jetting right.
Unless an inspection of your current Needle Jets shows some abnormal wear, I'd stay with them. The Main Jets and Pilot Jets are easy to find, as well as the Float Needle and Seat. The 5FP17 Jet needles are also available, but takes more hunting to locate (found some about 6 months ago).
There has been some input to a few threads as to another series of jets (with hex head main jets) that can be substituted, but then you are in a trial-and-error mode getting the jetting right.
Unless an inspection of your current Needle Jets shows some abnormal wear, I'd stay with them. The Main Jets and Pilot Jets are easy to find, as well as the Float Needle and Seat. The 5FP17 Jet needles are also available, but takes more hunting to locate (found some about 6 months ago).
- tz375
- Moto GP
- Posts: 6210
- Joined: Mon Nov 03, 2008 10:47 am
- Location: Illinois
Re: Painting engine barrels and overheating
Needle jets are available according to this site
http://www.jetsrus.com/a_jets_by_carbur ... mikuni.htm" onclick="window.open(this.href);return false;
http://www.jetsrus.com/a_jets_by_carbur ... mikuni.htm" onclick="window.open(this.href);return false;
- Nicholas
- Around the block
- Posts: 96
- Joined: Mon Nov 19, 2012 1:01 am
- Country: United Kingdom
- Suzuki 2-Strokes: Suzuki GT500, SR500, BMW R80, BMW R100S
Re: Painting engine barrels and overheating
Yeah, I'll replace them all... I have found a UK Mikuni specialst who sells all the parts I need, including the needle jet. So seems to have worked out... I just need to confirm the actual part numbers stamped on my jets, I dont want to go by what I have transposed from manuals...ConnerVT wrote:From what I understand, the 159 series P-4 Needle jets are made of Unobtainium.
There has been some input to a few threads as to another series of jets (with hex head main jets) that can be substituted, but then you are in a trial-and-error mode getting the jetting right.
Unless an inspection of your current Needle Jets shows some abnormal wear, I'd stay with them. The Main Jets and Pilot Jets are easy to find, as well as the Float Needle and Seat. The 5FP17 Jet needles are also available, but takes more hunting to locate (found some about 6 months ago).

Perhaps a good resource for others in the UK
http://www.motocarb.co.uk/" onclick="window.open(this.href);return false;
- ConnerVT
- Novice racer
- Posts: 963
- Joined: Wed Jan 18, 2012 8:01 pm
- Country: USA
- Suzuki 2-Strokes: T500R (now), T500M (40 yrs ago)
- Location: North of Albany, NY
Re: Painting engine barrels and overheating
This is good to know. Even Sudco wasn't listing a part number for the Needle Jets anymore, and I do remember a couple of conversations on the forum here about converting them over to a hex head equivalent.tz375 wrote:Needle jets are available according to this site
http://www.jetsrus.com/a_jets_by_carbur ... mikuni.htm" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Especially with it likely already jetted for your chambers, checking what is currently in the carbs and starting from there, is a wise choice. I have two sets of carbs (one came on my '71 engine, one from an unknown year eBay purchase). The '71 carbs had a P-4 and a P-5 Jet, with old style needles. The unknown set also had P-4 and P-5 Jets, but with late style needles. Neither match the combinations stated in Suzuki's Tech Notices.Nicholas wrote:I just need to confirm the actual part numbers stamped on my jets, I dont want to go by what I have transposed from manuals...![]()

- Nicholas
- Around the block
- Posts: 96
- Joined: Mon Nov 19, 2012 1:01 am
- Country: United Kingdom
- Suzuki 2-Strokes: Suzuki GT500, SR500, BMW R80, BMW R100S
Re: Painting engine barrels and overheating
Good point, I did not check the other carb.ConnerVT wrote: Especially with it likely already jetted for your chambers, checking what is currently in the carbs and starting from there, is a wise choice. I have two sets of carbs (one came on my '71 engine, one from an unknown year eBay purchase). The '71 carbs had a P-4 and a P-5 Jet, with old style needles. The unknown set also had P-4 and P-5 Jets, but with late style needles. Neither match the combinations stated in Suzuki's Tech Notices.

http://www.ozebook.com/compendium/t500_ ... pspecs.htm" onclick="window.open(this.href);return false;
That site has been brilliant for looking up facts and part info.... Oh, I also discovered some more ulgy news on the oil line fiasco and they have check valves...... I might put it in my question as this thread is getting confused...there is some good carb stuff here and I started the question with painting engine barrels...

- ConnerVT
- Novice racer
- Posts: 963
- Joined: Wed Jan 18, 2012 8:01 pm
- Country: USA
- Suzuki 2-Strokes: T500R (now), T500M (40 yrs ago)
- Location: North of Albany, NY
Re: Painting engine barrels and overheating
1971 is the T500R -- Both P-5 with 5PF8 needles, per this tech bulletin: http://www.ozebook.com/compendium/techb ... %206-9.pdf
The other set (from eBay) also came with a P-4 and a P-5, with 5PF17 needles -- and no bike was spec'd from Suzuki using the 5PF17 needle with the P-5 jet.
And one always has to watch for what previous owners may have done -- they had nearly 40 years to screw things up.
It all has worked out well for me, as now I have a full collection of jets and needles to experiment with. I can now tear down the bike, re-jet the carbs, and have everything installed and ready to run, in 1 hour.
The other set (from eBay) also came with a P-4 and a P-5, with 5PF17 needles -- and no bike was spec'd from Suzuki using the 5PF17 needle with the P-5 jet.

And one always has to watch for what previous owners may have done -- they had nearly 40 years to screw things up.

It all has worked out well for me, as now I have a full collection of jets and needles to experiment with. I can now tear down the bike, re-jet the carbs, and have everything installed and ready to run, in 1 hour.

- tz375
- Moto GP
- Posts: 6210
- Joined: Mon Nov 03, 2008 10:47 am
- Location: Illinois
Re: Painting engine barrels and overheating
They are probably 159 series with large hex jets
If they are large round jets, they use 188 series. They are the same AFAIK and are tapped foe different main jet threads.
The series # is marked above the P-4 size stamp.
If they are large round jets, they use 188 series. They are the same AFAIK and are tapped foe different main jet threads.
The series # is marked above the P-4 size stamp.
- Nicholas
- Around the block
- Posts: 96
- Joined: Mon Nov 19, 2012 1:01 am
- Country: United Kingdom
- Suzuki 2-Strokes: Suzuki GT500, SR500, BMW R80, BMW R100S
Re: Painting engine barrels and overheating
You are spot on! I took both out and they are 188s! Glad I did not order the 159 models! Thanks very much for putting doubts into my head!tz375 wrote:They are probably 159 series with large hex jets
If they are large round jets, they use 188 series. They are the same AFAIK and are tapped foe different main jet threads.
The series # is marked above the P-4 size stamp.

My setup with AllSpeeds and K&Ns (if tunned right... :-/)
VM32SC
Main Jet: 97.5
Needle Jet: 188 P-4
Jet Needle: 5FP17-4 (Stock is -3)
Pilot Jet: 30
Slide: 2.5
Going to order 2 sets of these things before the disappear!