Winter project: upgrading time! (R6 forks and more...)

Did some testing yesterday, it running great! The idle is really stable ones warmed up, which is nice. No more traffic lights anxiety haha.

Did some minor tweaking of the mix screws and throttle slide screws.

Only the cold starting is still hard. It doesn't accept any choke while starting. Leaving me to kick it without and a low rpm at idle.
 
the cold starting is still hard. It doesn't accept any choke while starting
My VM equipped bike REQUIRES choke for cold start and warm up, about the first minute's running is dodgy unless I am nursing (I have two separate) chokes/enricheners.
I fought poor sealing float needle valves for quite a while on several VM carbs.
There are also a couple different float settings depending on when the VM was built older carbs used a different setting.
Just a heads up if purchasing replacements, there are several VM float valve throat sizes.
 
Before I changed the cam chain (to what I believe is the right tooth), I tried the VMs. I do remember they started only with choke.

I to have two separate choke levers.

And jerry from heiden tuning recommended using the chokes for starting. He prepared these carbs. I don't know what floats I have.
 
Just reading the general mikuni VM manual. Maybe its not super weird i dont need to use the choke (enricher) at the current temperature?


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Hi, i'm from NL too.
My XS starts 1st time on choke witch CVK's.
What needles and jets do you use?
 
Hi, don't recall maybe it's in the topic somewhere. However my problem was have the timing one tooth off 🙈

Running mikuni VMs now, maybe I'll try the cvk again next year.

Where are you located in the Netherlands? I'm in Zwolle
 
Hi, don't recall maybe it's in the topic somewhere. However my problem was have the timing one tooth off 🙈

Running mikuni VMs now, maybe I'll try the cvk again next year.

Where are you located in the Netherlands? I'm in Zwolle
I'm from Burgm Frl. My next project will be a R6 fork. Will alse have to make som disk spacers. Were yours 14.5mm also?
 
Just reading the general mikuni VM manual. Maybe its not super weird i dont need to use the choke (enricher) at the current temperature?


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Sounds like it may be a tad rich on the pilot jet or mixture screw. Note that on a VM carb, mixture screw IN gives a slightly richer idle mixture, screw OUT will make it leaner. This is OPPOSITE to how it works on the stock CV carbs.
The "rule of thumb" regarding idle jet size and mixture screw is that you want to end up with the mixture screw between 1 or 2 turns out from seated.
And the basic method is to find the idle mixture that gives the highest idle rpm. So with a fully warmed up engine, tweak the mixture screws to see where you get the highest rpm. If that happens with the mixture screws more than 2 turns out, you need smaller idle jets. And with highest rpm with the screws less than 1 turn out indicates a need for larger idle jets.
And as always: Before attempting any carb tuning, the engine must be in decent condition and adjusted correctly. That means good compression, correct cam timing and timing chain tension, correct valve clearances, new or clean air filters, and correct ignition timing
 
Time for some forum posts, did a major engine rebuild this spring. Was aiming for a winter rebuild but started too late lol.

First time diving into the engine this deep! Kinda scary but i learned a bunch.

Want to share some of my shed adventures, maybe ask some questions. These are old'ish pics. The engine is back together and running.

I had the engine inspected, mainly to inspect the crank. Feeling wise I had quite a lot of vibrations. Since I have no experience in building cranks, I figured I have somebody else do this. The crank was probably original and had about 60k km on it.

It wasn't completely shot but some interesting things were found!

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First dual engine mitsubishi colt 🤣
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This was bringing it to the shop. Got it back in parts.

The crank had some misalignment. Not major, but not insignificant either. The small ends showed pitting and the whole crank was rebuilt. After some consideration I decided to go the 277° route. Main reason being I would like to reduce vibrations at higher RPM. This was THE moment to do it since everything was apart.

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The gearbox was also inspected and the 5th gears showed a lot of pitting. So both were replaced. I went with the overdrive 5th.



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Keeping all the worn parts. Maybe make some art out of it later.
 
Since its winter again I feel like it's time to update. I finished the engine rebuild during the summer. Had some struggles but in the end I managed to drive quite a bunch this season.

Here some pics of the rebuild and other stuff I've been working on:

I got an 750 Kitt
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I had a really though time fitting the piston clips. Before destroying shit in anger I made a tool that works great!
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Love this picture where the last rays of sun only hit the engine
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The 277 setup requires a different ignition, went with the vape system after using that for 360 before.

Not the biggest fan of the location of all the parts, I fitted the ignition boxes under the tank, super close fit but I don't like that the boxes are in the heat of the engine. Might relocate them later. Same for the coils, don't hate it, but don't love it either
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Riding time:
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