Messages

1

Carburetor, Intake, and Exhaust / Need Jetting help on a new build

« on: September 28, 2016, 03:57:47 PM »

Thanks 2ndmoto!  This was a stock cylinder that BDT ported for me.  It has a +4mm crank for sure, but I can't remember the piston size - seems like it was larger than 66mm (pretty sure the previous piston as 67.5mm).  Beyond that, it has a spacer plate between the case and jug.  BDT said that it would be a 261 Stroker.  I'm actually waiting on the engine to be returned within the next 3 days - can't wait!

Please correct me if I'm wrong - if I go from 165 main (as it is now) to a 175 (or so), then I will probably be a little rich.  So as I'm leaning the main jet, how far should the fuel screw turn in before I drop to the next smaller sized jet (within 1 turn out, or can I go to within 1/2 turn out) - or, where should the fuel screw be if I'm running the correct jet (within 1-2 turns out?)?

If anyone knows of a good instructional site which could walk me through the steps of jetting this carb. then that would be awesome.  I have never messed with carbs, am going into this completely blind with hopes of not damaging this brand new engine.

Thank you.

2

Carburetor, Intake, and Exhaust / Need Jetting help on a new build

« on: September 27, 2016, 04:02:15 PM »

Hi guys!

I am not very good with carburetors and I need some advise on which jets that I should start with for my particular situation.

The is a rebuilt '88, BDT 261 Stroker with V3 Reeds and an FMF Fatty Pipe which is set up to run on race fuel - all parts are new, even the carburetor. The carb. is a 38mm AirStriker PWK. I am in central Georgia, where it's very hot and humid. The temperatures will start to drop soon as we go into winter however - so it will go from burning hot, to 50 degree highs. I would guess I'm about 700-900ft above sea level. At the moment the carb. has a 165 main, 52 pilot and DGH @ 3rd clip.

Thank you!

3

Engine and Bottom End / shifting problem still exists - $2000 later

« on: August 06, 2016, 11:06:05 PM »

Thanks for the responses.  

The shifting problem started suddenly after about 2 years of flawless operation.  I can think of nothing that would have caused this - I was putting around trying to adjust a new carburetor, then realized that it wouldn't shift up without some serious force.  Based on this, I know that the problem wasn't due to something being installed improperly - so I know that that is out of the way.

Yes, this is my first time opening a 250R case (it's an '88 by the way).  I have built car engines, etc, but never opened a 250R case.  All of the testing instructions sound a bit confusing, but as I reassemble, I will keep these instructions in mind and hopefully be able to give it a test as Jerry indicated.

Clutch:  the clutch seems to be about halfway through it's life (it's a Henson Billet Proof).  There are very minimal notches in the basket from the plates - I have heard many people mention to file them a bit - I will do this before re-installing it.  Beyond that, it would roll forward with the clutch was engaged, but only after it warmed a bit - while cold, it would actually stall by engaging 1st gear which the clutch pulled in and at idle.  While warm however, it was fine.  I assumed that this was a typical 250R characteristic and it had never caused my any issue before - it is worth mentioning however.  

So I will go ahead and start reassembly soon.  Lets say I have about $500 more in the budget to spend on the engine - which transmission components should I go ahead and replace in hopes that I find the "bad" item?  Has anyone heard any feedback on the billet steel forks on eBay? I'm afraid to buy OEM, used ones, because they may be more worn than mine.

Thanks guys.

4

Engine and Bottom End / shifting problem still exists - $2000 later

« on: August 04, 2016, 01:20:16 PM »

I am sorry for the bad attitude, but I'm betting ready to sell a $15000 quad because I cannot get it to shift correctly.  I've been on every forum that I could think of and I cannot get any responses at all.

Way too difficult to shift into each gear - shifter hangs up just before engaging into the next gear, then it takes too much force click the shifter up into gear - and this goes for all of the gears.

Engine apart.  All shifter parts are well within specification according to the service manual (forks, fork shaft, shifting drum, all other components).  Is there anything else to look for?

I have spent way too much money - probably $2000 in this engine build alone (including having the top end ported) - what a shame after all of this that it still will not shift.  

Please - someone give some input.  It would be very appreciated.

5

Engine and Bottom End / Bad Shift Forks??

« on: July 29, 2016, 09:57:26 AM »

I am still trying to solve my gear shifting problem.

Very difficult to shift into the next gear - especially from 1st to 2nd, but also through the rest of the gears - 3rd is a bit easier than 2nd, 4th easier than 3rd.....I have to apply so much for to click into the next gear, that I was afraid of breaking something.

I have the cases split and am using this opportunity to rebuild.  I see nothing wrong in the transmission - at all.  The forks are the only possible cuprit.  See picture of the "R" fork - you can see that one side of the pad is worn just a bit more than the other.  You can also see the slightest bend in the arm (slight bend down as seen in picture 1).  

I can't imagine what would be causing this difficulty in shifting.  Prior to this sudden problem, my transmission was slippery like butter.

6

Engine and Bottom End / Transmission Problem

« on: July 26, 2016, 11:20:52 AM »

Thanks Tbone.  I had another buddy check last night and he has this amount of free movement on the Counter Shaft as well.  

I have questions about the transmission too (this is my first time opening the case).  If you have some advice for me regarding the tranny then I sure would appreciate it.  I have the case split now, but I haven't pulled any gears out because I don't know what to look for.  While riding, my shifter was getting stuck just before engaging the next gear.  It would go into gear, but I had to put way too much upward force to do it.  Same with all of the other gears, but it seemed to get a bit easier with each gear progression.

7

Engine and Bottom End / Rebuilding Transmission - what should I expect?

« on: July 26, 2016, 11:16:16 AM »

I really need your input if you have any - this is my first time with opening the engine - so far it's been lots of fun!

I have no clue what to expect when I start pulling the gears, and gear mechanism.  I know that something is wrong here, but I don't know what.  Although the bike will shift, the shifter gets hung at the very top of the up-motion, then only snaps into the next gear with a lot of force and a harch snap.  It gets a bit easier as you move up the gears, but it's definitely not a good thing.

Now that the engine is one my bench, it's stuck in first gear and I don't have the leverage to move through the gears in hopes to find where the binding is.

• What should I look for in regards to worn out parts ( I only know about the forks and drum - should I be looking also for something else)?
• Again, this is my first time is a motorcycle case - ever.  I'm confident that I can do the work, but I just have some questions

As always - you guys rock!  I couldn't have gotten this far.

8

Engine and Bottom End / New Crank and Bearings?

« on: July 26, 2016, 11:08:57 AM »

I have all of the correct tools - crank puller/case separator, etc.  

I also need to get top, case saver mounting hole repaired - it still works because there are enough threads deeper into the hole.  I would rather get this fixed.  I have heard that some of the guys out west can fix this - is this something that perhaps a local machine/weld shop could do?  While we're on the subject, should I paid or powdercoat the case?

Thanks everyone - this has been a huge help.  Now I will create another post regarding what I can expect when I dig into the gears, forks, etc.

9

Engine and Bottom End / New Crank and Bearings?

« on: July 25, 2016, 07:57:53 PM »

Thanks for your input jto1.  A new crank is $300 though - phew!  Would it be better to send my crank out to be rebuilt?  The budget for rebuilding this bottom end is becoming sky high.

10

Engine and Bottom End / New Crank and Bearings?

« on: July 25, 2016, 04:46:36 PM »

Hello everyone!

I have my engine torn down in an attempt to determine a transmission issue (another tread).

While I have the engine apart, is it normal to not change the crank and bearings?  I realize that it would normally be recommended, but in my case, everything is fresh and looks/performs like new.  

Is there a surefire way to check my crank to see if it needs replaced (hot rods long rod)?  There is the slighted bit of left/right motion where the rod meets the crank, but very little at all - almost unnoticeable.  There is no up/down motion.  

Just wondering.

Thank you!

11

Engine and Bottom End / Transmission Problem

« on: July 25, 2016, 11:35:33 AM »

How much backlash should there be between gears?

I have my engine on my bench, inspecting the bottom while the top is away to be ported.  Seems that I have too much backlash between the gears.  I noticed that the shifter became very hard to snap into gear just before removing the engine.  I haven't split the cases yet to check out what's going on in the shifting mechanism, but in the meantime I have realized that have about 1/8 rotation of backlash at the Counter Shaft (or where the small sprocket was).

Thanks in advance for your help.