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-   -   My COMET GT250!! Done just 1400Kms!!! (https://www.team-bhp.com/forum/motorbikes/52919-my-comet-gt250-done-just-1400kms-9.html)

hey buddy! well if your carbs aren't balanced then some cylinders are working harder than the others! power output won't be optimum, may cause vibration also!
well for a 4 cyl you'll need either a specific carb sync tool or a little extra work!

OK i shall post the procedure for anyone who'd like to DIY it! so here goes:

Materials Needed:

1. yard stick (something long around the 3 ft to 4 ft range)
2. Approx. 12 to 15 ft of clear 1/4" id tubing (can be found at hardware stores)
3. Tie wraps
4. Vacuum tube connectors and t-joints(straight connectors used to connect two 1/4" id hoses together)
5. motor oil or Automatic transmission oil(which i heard works better)
6. Marker


Assembly:

1. Take the clear tubing and mark down about 24 inches on one end.
2. Start to run the tubing down the yard stick, using the tie wraps to hold it in place.
3. When you get to the bottom of the stick, go back up the other side, once again using the tie wraps to hold it in place. (be sure not to kink the hose towards the bottom... make the loop gradual)
4. Cut the hose to it's even with the other side. (the device made should look like a "U" with a stick in the middle)
5. Place one end of the hose into the oil and use the other end of the hose to suck the oil into it. CAUTION: Do not ingest oil!!
6. You want to suck in enough oil so that you are about a 1/3 of the way up the stick on each side of the tubing. (if you suck in too little oil the first time around, then try to suck more oil in, you will create an air pocket. This air pocket can be tough to get out. Blow the oil back out and start over.)
7. Be sure there are no air pockets in the hose when finished.
8. When the oil settles in the hose, mark on the stick where the two lines meet each other.


Synchronizing:

1. Because you have 4 carbs, and only two hoses on this tool, you need to sync your carbs in sections.
2. Connect one end of your manometer to the 1st cylinder using the vacuum connectors, and the other end to the 2nd cylinder. (be sure the hoses from cylinder 3 and 4 are still plugged off)
3. Start the bike and watch the oil rise on one side and fall on the other. (if the bike isn't sync'ed correctly)
4. Adjust the screw between the two carbs to make the oil level equal with the mark you made previously on the stick.
5. Shut the bike off, plug the hose for cylinder 1 and 2, and repeat the same process for cylinder 3 and 4.
6. At this point, you should have two sets of carbs that are sync'ed, but not necessarily with each other.


7. Tee cylinder 1 and 2 together with a T-joint. Do the same for cylinder 3 and 4.

8. Hook up the manometer to each T fitting and start the bike. Adjust the screw between carb two and three so that the oil level is inline with the mark on the stick.

Optional:

7. Plug the hose from cylinder 1 and cylinder 4. Hook up the manometer to the hose from cylinder 2 and 3. Start bike and adjust the screw so that the oil level is equal.

Congrats people! You have just made a manometer and successfully sync'ed your carbs


Hope that helps!

Hey Speedo, yes the Bike does vibrate a little till about 5000-6000 rpm, & then it becomes BUTTER SMOOTH. I think I'll get the exhaust made by the same guy as you did, b'coz my mech's a little busy these days. I'm currently using AGIP Full Synthetic oil for my bike, It's been pretty good after using it.

CHEERS,
G D

Awesome attempt D..! clap: Couldn't have asked for anything better.. I guess I'll try that with full preparation sometime..
Thanks again, and keep rolling! :)

you dont need to thank me buddy! if you need any help i'm free on mondays and out with my tools in my garage, tinkiering with something or the other to do, so if you need any help walk in! ;)

I greatly appreciate that.. :) It's always beneficial to have a better set of hands and minds at work.. :D
I guess I have your number, so would buzz you if the need be.

Cheers!
J.

guys how do i increase the preloasd setting of the monoshock? it seems imposible to get in there, someone said a C spanner does get in there, any other way, using some other tool?

guys how difficult is it sourcing jets for the mikuni BDS carbs on the comet!? are they model specific? I mean are mains universal or is the threading different?

I don't think jets should be that much of a problem for Mikuni carbs.
Once you know the specs and size, there are many jets available here that fit your bill.
I got mine changed for the Katana, with oversized ones, worked absolutely fit!! Karol bagh is the place..!

thanks buddy! anywhere specific in KB?

Getting those Jets was hell in US atleast. I went to scores of places in California asking for size 100 jets for the mikuni BDS26 carb. They just couldnt pronounce Hyosung right! :) Then they would pull out the mikuni manual and the smallest it listed was BS30. No mention of the BDS26. :) Let me know if you can find one. There are 3 options when it comes to the jets. small hexagonal, small circular, large circular, make sure you know. i think they are circular but just not sure if they are large or small or what ever.
if you find a place to get size 100 jets, do let me know.

need to mention that i'm no biking guru but i googled to find the carb name etc before i walked into the stores. so i hope BDS26 is not another BS!

hey buddy! as far as I've heard mains are not too much of trouble as they're quite universal, they are circular jets, button type with flat head type screw head on it. if i find them and its a matter of small or large I'll buy both ;) actually i was thinking of experimenting with 95/97.5, 97.5/97.5 or 100/100, pilots are a little tough to get though.
will keep you updated if i find them. :) they're the same as suzuki's ive heard.

hey guys was thinking on checking my valves as ive noticed the vibration im experiencing comes at around 4.5k rpm while accelerating but at round5.5-6k while decelerating! tried reverting to old astock endcan but no difference in vibration, so basically if it was some weight imbalance then it would be at the same RPM hence the doubt on the exhaust and now on the valves! what say?
Also need your inputs on adjusting the rear shock! cant seem to reach it to adjust it!!

You can possibly scour the local market for finding the main jets. Mikuni BS carb's jets would suit 99%. After all the BDS is a BS Downdraught that's where the D comes from. Almost all the CV carbs on Indie bikes are Mikunis, except the Hondas. What is the size of the pilot jet? You won't have to change it prolly, half a turn or one turn richer setting with the fuel screw will take care of the pilot.

Thanks for the gyan. :-) The pilots are size 20.

Speedy -- I got a two bros titanium exhaust on my way back from US. I know most would scoff at this wasteful expenditure but hell it looks good! Thats the reason why i was looking for the size 100 jets. I got the 22.5 pilots along since those i found in US but just couldnt find the size 100. And i didnt look for size 100 for the BS ones cause until Sankar pointed out that BDS is a BS, i didnt know! :( nyways. will install the pipe this weekend. Didnt get the db diffuser (Power tip is what they call) so i'm sure its going to be louder than i want. Guess will have to make someone get it for me.

sounds amazing! pics please!! do you have a stock airfilter? desnorkeled/ aftermarket? if its stock i doubt you'd need the 100/100 setup! i feel two sizes up should suffice, then again no dyno around to actually test it, try the butt dyno and see what works for you, i'm going to get different sizes and then see what feels best, along with reading the plugs for a fair idea of your mixture!