Mikuni VM38 Questions
Thread Starter
|
Cruiser
Joined: Oct 2011
Posts: 153
Likes: 0
From: Bellmawr NJ
The wood idea is good, thank you. The throttle cable is a motion-pro brand, sorry I threw about the packaging so I don't have a model #, but I purchased it at scooters performance based out of Florida. I can not recommend them though since they repeatedly fumbled my order (claimed they didn't receive CC info, never called until I contacted them a week later, was told they would call again and didn't, was told it would be sent via a faster method and that never happened. After that called up for some tech support which I found on this forum but they were of no help on the phone.) Overall it took three weeks and 3 days to get the carburetor, I went with them because it was a good price ($230 for the whole thing).
Anyway maybe someone will have better luck than me http://www.scootersperformance.com/
I adjusted the slide from what I understood were directions from the PDF file tuning manual, to just raise it slightly off its seat, I judged this by the rear of the slide being a crack open and allowing some light through.
Hopefully will get this bad boy bolted up tomorrow.
Anyway maybe someone will have better luck than me http://www.scootersperformance.com/
I adjusted the slide from what I understood were directions from the PDF file tuning manual, to just raise it slightly off its seat, I judged this by the rear of the slide being a crack open and allowing some light through.
Hopefully will get this bad boy bolted up tomorrow.
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
Oh, I forgot to address the boot and nipple issue.
You should be able to thread the brass nipple all the way into the carb top.
Then the rubber boot is pressed onto the end of the nipple.
The cable goes through the boot and nipple then the elbow seats into the brass nipple.
Here is a pic of mine. My cable/elbow is 1973 so your elbow may be a bit different (not threaded)............
pg
You should be able to thread the brass nipple all the way into the carb top.
Then the rubber boot is pressed onto the end of the nipple.
The cable goes through the boot and nipple then the elbow seats into the brass nipple.
Here is a pic of mine. My cable/elbow is 1973 so your elbow may be a bit different (not threaded)............
pg
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
Regarding you raising the slide with the idle screw so you can see a crack.
I recommend you not do that!
Set the idle screw back to where the slide is all the way down.
Otherwise the engine is going to race when you start it up.
You will be setting the idle after you get it started and warmed up.
While you have your carb off the bike pull out the slide one more time.
Now remove the plate and the needle. You can leave the cable in place.
Is the clip in the needle in the middle slot? This is 3rd from the top or bottom of the 5 notches.
If not, put the clip in that 3rd notch and reassemble the carb. You are good to go.
Also, in case you have no experience with a Mikuni (or for others who may be following this thread) I offer the following.........
A Mikuni uses what they call an 'enrichment system' and this is activated by pushing the lever down.
Many people call this the choke, but it is NOT a choke.
It is a system of jets and passages meant only for the starting of the engine.
So, to start the engine (hot or cold) you.......
(1) Press down the enrichment lever.
(2) Begin kicking or electric starting with the THROTTLE COMPLETELY CLOSED.
The enrichment system is going to take care of getting the fuel to the engine, assisted with a good strong vacuum.
That needed vacuum is produced by keeping the throttle closed.
pg
Thread Starter
|
Cruiser
Joined: Oct 2011
Posts: 153
Likes: 0
From: Bellmawr NJ
By clip in the needle, are you referring to where the needle sits in that plate? I will be sure to check that. Otherwise it looks just like the photos you took of yours. I think I can get my boot on too.
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
pg
Thread Starter
|
Cruiser
Joined: Oct 2011
Posts: 153
Likes: 0
From: Bellmawr NJ
Many thanks again, I took it apart and the needle was in the right groove. I also got the boot over the cable and adjusted the idle so the slide was fully closed. Ready to bolt on when its not raining.
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
Yes, I think it is ready to be installed. Be sure to have no air leaks at the manifold.
Just run a finger over the inside surface of both O rings.
If all feels smooth there will be no leaks.
Just do not over tighten the clamps.
Let us know how much you like the Mikuni and if there are any problems.
pg
Just run a finger over the inside surface of both O rings.
If all feels smooth there will be no leaks.
Just do not over tighten the clamps.
Let us know how much you like the Mikuni and if there are any problems.
pg
Thread Starter
|
Cruiser
Joined: Oct 2011
Posts: 153
Likes: 0
From: Bellmawr NJ
Got the carb on the bike, ran into another brick wall. The ball is too large to fit through the hole on the throttle control housing. Also, the original throttle cable was threaded and the new one is not, and it seems that if the threads were not there the ball would fit. The unsheathed portion of the cable is the same length as stock.
Other issue: The petcock which is a stock replacement does not really fit with the carb, I cannot put the lever on the reserve side due to the carb being in the way.
Tried to start the bike anyways and had not luck due to starter issues, which is another post all together.
Other issue: The petcock which is a stock replacement does not really fit with the carb, I cannot put the lever on the reserve side due to the carb being in the way.
Tried to start the bike anyways and had not luck due to starter issues, which is another post all together.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
Got the carb on the bike, ran into another brick wall. The ball is too large to fit through the hole on the throttle control housing. Also, the original throttle cable was threaded and the new one is not, and it seems that if the threads were not there the ball would fit. The unsheathed portion of the cable is the same length as stock.
Other issue: The petcock which is a stock replacement does not really fit with the carb, I cannot put the lever on the reserve side due to the carb being in the way.
Tried to start the bike anyways and had not luck due to starter issues, which is another post all together.
Other issue: The petcock which is a stock replacement does not really fit with the carb, I cannot put the lever on the reserve side due to the carb being in the way.
Tried to start the bike anyways and had not luck due to starter issues, which is another post all together.
In your throttle control housing there should be a bushing with a split in the side of it.
This bushing goes on the cable and the cable housing fits into one end of the bushing.
The other end of the bushing goes into throttle housing.
But if your lead nipple on the end of the cable will not go through the hole in the housing?
If not, then it must be way too large to fit in the throttle barrel hole too?
This lead nipple should be the same size as the hole in the barrel and flat on both sides. Like the shape of a baby asprin and also about the same size.
For the petcock situation........... Is it possible to remove the petcock and wrap it with 5 turns of yellow Teflon tape.
Then screw it back into the fuel tank?
The idea is to get the petcock to tighten and stop turning leaving the on/off/reserve lever facing away from the carb giving you the clearance you need to operate it.
pg
Thread Starter
|
Cruiser
Joined: Oct 2011
Posts: 153
Likes: 0
From: Bellmawr NJ
So the petcock issue "solved" itself in the malfunction of the valve. It was leaking fuel ever so slowly when in the off position, when I took it apart I found a sizeable tear in the rubber seal. Does anyone have any recommendations on a petcock style? I have had two "oem replacements" crap out on my and I'm not even riding the bike yet.
As far as the throttle cable goes, I filed it down slightly and got it through the hole with a punch and hammer. Major hiccup though is that the end of the sheathing is not threaded, causing the condition you see pictured. Also, when I hold the cable in place the throttle will only lift the slide a bit less than half way.
As far as the throttle cable goes, I filed it down slightly and got it through the hole with a punch and hammer. Major hiccup though is that the end of the sheathing is not threaded, causing the condition you see pictured. Also, when I hold the cable in place the throttle will only lift the slide a bit less than half way.
Last edited by Krazyshark; Nov 20, 2011 at 02:33 PM.