250R NA Build - Ultimate

[EMSRacer07]

Originally Posted by mgentz

Any more ideas?

I would ask @RacerX because with your cams, headwork, pistons things could be very close in clearances. Something could be binding someplace. U using a manual tensioner or the stock one for the cam chain?

[bruce71198]

Originally Posted by mgentz

The tightness is not in the valves.cams. I dettached the cams and turned over the motor only to find the same thing. I would have no idea what on the lower end could cause this.

So it's on TDC for cylinder 2 every time the pistons at TDC, not just the exhaust stroke or compression stroke ? You custom made your head gasket ? Could it be a little out of shape and hanging into the combustion chamber? How bad does it hang up? Is it smooth as you rotate it or does it feel like something's scraping?

[mgentz]

It happens when the 2T| mark aligns with the notch in the case....that's it. Happens without the cams so its not the valves. No funny noises....just tight.

[Racer x]

And no spark plug I assume. How tight?Just some resistance or does it stop?

[Racer x]

Better pull the head and temporarily bolt the block steady. Then test again. No guessing. If it does not feel right find out why. If you start with a tight spot. It will turn red hot in seconds. Maybe go away maybe not. At this stage you just have to go back and check. Really not unusual. Why it takes patients.

[cuong-nutz]

Do you have the spark plugs out?

The headgasket won't catch the piston regardless since the piston edges do not protrude past the bore.

Did you align the balancer shaft with the crank? There are alignment marks on the sprockets/gears so that they are "in phase". I can't remember if the a lobe on the balancer shaft would contact the crankshaft if it's out of line. Maybe @Racer x knows more.

So the crank hangs when it hits 2T every 360* of crank rotation?

[mgentz]

Just higher resistance. It does not stop.

It is not the head gasket as the piston never gets that high.

[mgentz]

Yes the shafts are aligned.

[tubarney]

Originally Posted by mgentz

Just higher resistance. It does not stop.

It is not the head gasket as the piston never gets that high.

Have you checked your piston side wall clearance? Check clearance and pull the pistons out and have a look at them an see if there is scuffing anywhere on the piston or bore.

If everything is fine I bet it is nothing to worry about.

[tubarney]

I bet its got something to do with where you are applying your torque to the crank. As you are referring to the "feel".

Its the only thing I can think of. The wrench or drill is placed on the end which is the furthest point from piston #2. It is further than the distance from piston #1.

The piston is applying force to the crank. As you know the distance it is applied multiplies the force.

[mgentz]

Originally Posted by tubarney

I bet its got something to do with where you are applying your torque to the crank. As you are referring to the "feel".

Its the only thing I can think of. The wrench or drill is placed on the end which is the furthest point from piston #2. It is further than the distance from piston #1.

The piston is applying force to the crank. As you know the distance it is applied multiplies the force.

Hmmm. I will say that it turns and continues to turn once moving. There are no scratches scuffs or anything on the walls and I checked ring end gap and piston clearance.

You may be right on this whole force thing but someone would need to go out and spin their motor with a wrench for me. @Racer x any chance you could do this for me? Please

Again ocd is in full force.

[tubarney]

Originally Posted by mgentz

Hmmm. I will say that it turns and continues to turn once moving. There are no scratches scuffs or anything on the walls and I checked ring end gap and piston clearance.

You may be right on this whole force thing but someone would need to go out and spin their motor with a wrench for me. @Racer x any chance you could do this for me? Please

Again ocd is in full force.

Yeah. I'm pretty sure the force thing is correct. Apply the torque from the other side and you will find piston #1 has more resistance.

My assembly didn't go so well so I can't help you for at least a week. I snapped a bolt with less than the required 12 N.m of force. And its HIGH TENSILE!!. I can't drill it out because it is so hard. It is harder than the crank.

How I snapped it I don't know. The bolt was obviously weakened by a crack or excessive heat so I am probably lucky I snapped it off because my transmission will have more than 10 N.m of torque going through it.

Anyway, I have to take it to a shop with a drill press and see if they can drill it out and tap a new 7mm thread (1mm bigger). If I need to go any bigger than that I will need new cases which I can get for 200 bucks at wreckers.

Will have assembled by end of this week.

[mgentz]

Oh boy...that sucks. Sorry. Which bolt was that?

[Racer x]

I wish I could.I don't have pistons in yet.

[mgentz]

Umm...anyone have a working motor that could test this?

[EMSRacer07]

Originally Posted by mgentz

Umm...anyone have a working motor that could test this?

Ill be servicing my swing arm today so ill take a wrench to the crank and see where and if it gets tight on cylinder 2

[mgentz]

Cool. Its a 14 mm socket needed for the bolt that is behind the plug on the alternator cover. If possible please use a 3/8" socket wrench that is normal or less than 8"in length. If I use a larger wrench is just rolls on by....

[EMSRacer07]

Originally Posted by mgentz

Cool. Its a 14 mm socket needed for the bolt that is behind the plug on the alternator cover. If possible please use a 3/8" socket wrench that is normal or less than 8"in length. If I use a larger wrench is just rolls on by....

Ok ill use those. Let you know here in an hour or so if someone doesnt do it first.

[mgentz]

Cool. Thanks.

Will someone else try as well? It would be nice to get multiple opinions.

[EMSRacer07]

Originally Posted by mgentz

Cool. Thanks.

Will someone else try as well? It would be nice to get multiple opinions.

used the same wrench set up and it does have a more resistance feel than cylinder one. Cylinder one just seems to go by fine but cylinder two seems to resist just a tad more. Idk if thats what your feeling. I did mine from a cold engine.

[mgentz]

Hmmm. Yea that is what I am feeling. It does not stop...there is just more resistance there. THANKS! !!!!

Thank you for the help. I still extend my plea to anyone else that can help me. The more people that test this the better.

It might just be my ocd but I know I checked everything at least twice.

[tubarney]

Originally Posted by mgentz

Hmmm. Yea that is what I am feeling. It does not stop...there is just more resistance there. THANKS! !!!!

Thank you for the help. I still extend my plea to anyone else that can help me. The more people that test this the better.

It might just be my ocd but I know I checked everything at least twice.

I think everything is normal. Your taking your measurements (feel) from a specific point. This measurement is going to change depending on where you take it from.

The bolt I snapped holds the transmission shift forks in. It uses a little bracket to hold them in. The bracket has 2 holes.

I took it down to Duncan Foster Engineering. He is going to drill it out and put the same size thread back in (6mm). Not sure how that is possible but I'm just really happy I don't have to modify the cases or the bracket.

[tubarney]

For anyone interested. I have been in contact with Brad Penn about their Break-in oil SAE 30. I have 3 litres so I might use it instead of the motul mineral oil depending on what I get back in response. Should have an email back in a couple of days.

Here's the first email reply:
"Brad,

The Brad Penn PG 1 Break-In Oil was designed and tailored specifically as a 'break-in' oil only, but has been used successfully in various applications, including motorcycles. However...it would not be on my list of appropriate lubricants for motorcycle applications.

Is their any specific reason why you would like to run the break-in oil? We do carry a great line of motorcycle specific oils and if you would kindly provide me with some information on your bike, I will research and recommend accordingly.

I look forward to your response.

Ken Tyger
Tech Services
American Refining Group, Inc"

[mgentz]

I am using straight 30W oil....cheap stuff thst I will run for about 100 miles. Then I will run regular moto oil

[tubarney]

Mike, since you have ocd tendencies like myself, here is some math to back what what I am referring to.

When you put the wrench on the end of the crank you are taking moments from that point.

Lets assume that no other forces are acting on the crank other than the weight of the piston. which is what is happening when you crank it manually without the spark plug or cams.

You are taking moments from a point which is 100mm from Piston #1 and 175mm from Piston #2. Measurements taken off our crank.

Assuming your pistons weights 140.00 grams.

The moments(force) would be 0.14*0.10 = 0.014 Kg.Nm for Piston #1.

The moments(force) would be 0.14*0.175 = 0.0245 Kg.Nm for Piston #2.

This is why the force you are experiencing is greater for piston #2 than #1. The force is nearly double.

[mgentz]

I am going to put a torque wrench to this and get some numbers tomorrow.

[tubarney]

Originally Posted by mgentz

I am going to put a torque wrench to this and get some numbers tomorrow.

You will need to multiply my numbers by 9.81 for gravity. Any additional force will be from friction. A few things are creating friction; rings, bearings, sprockets. You could work out how much force the friction is creating. All I need to include is the weight of your rods. Measure the torque. I will take some measurements and do some calculations to see if the forces (torque required) are in the correct ratio.

So. 0.014 Kg.Nm * 9.81 = 0.137 Kg.Nm or 1 ft/lbs
0.0245 Kg.Nm * 9.81 = 0.240 Kg.Nm or 1.74 ft/lbs


I just thought of the best way to remove that bolt I snapped. I should have got the die grinder out with a pointed carbide burr and grinded a screwdriver slot in it.

Simon at Duncan Foster mentioned the use of a die grinder with a diamond tip carbide burr to even things out then drill it, I will find out exactly how he did it in-case it happens to anyone else or to me again.

Apparently you come across weakened bolts every now and then. The bolt was obviously cracked because it sheared off unevenly below the beginning of the thread. Try and twist any other bolt with less than 12 N.m of force, not going to happen, especially a high tensile bolt.

Also the bolt was too hard to centre punch. This what also made it impossible to drill with a hand drill.

[mgentz]

some recent pics

[cuong-nutz]

What did you do to the air box?

[mgentz]

I cannot tell the tone of that question. Is it an inquiry or more of wtf did you do?

Either way I opened up the box for more flow while keeping the stock intake runners and panel-type filter. This avoids dirt and water better and also helps resonance. I needed the flow but I also left myself an out (or in?) By creating a way to fix a panel to the back of the box to return to stock...that's what the little holes are for.

[Racer x]

I think it was a question. More than a WTF. I was wondering about the holes. Are you going to screen over them or maybe block them if needed? I like the air box. I just wish it was easy to remove.

[mgentz]

Definitely not easy to remove.

So..three people have told me that they feel various tight spots...

[choneofakind]

FWIW, that's what Leo Vince suggests doing to the air box with the install on an EFI bike. I bet you'll be fine. Smart thinking making it reversible.

[mgentz]

Originally Posted by choneofakind

FWIW, that's what Leo Vince suggests doing to the air box with the install on an EFI bike. I bet you'll be fine. Smart thinking making it reversible.

Winner..winner...chicken dinner

Stand on the shoulders of giants my friend

[tubarney]

I had to post this. Its 1.5m long by 40cm high. The journals are so big I can't wrap my hands around them.

[cuong-nutz]

Sorry about the vague post! It was meant as a question. I was on my phone but had to leave so just went ahead and posted it. I did spin the crank. It spins relative freely and then kind of catches but that's normal. All cranks do that because of the counter weights which helps with transferring all the energy generated from the fuel burning pushing the piston down.

[tubarney]

Mike, did you have a way to measure what degrees the camshaft opens and closes the valves?

You might be able to do it by sight, a dial indicator is much better and easier.

Will be a lot easier to find out which cam actually has the longer duration, sort out this 0.050 stuff.

[mgentz]

I will run the crank counter-clockwise tonight and see what I feel. this is the direction of rotation so I will see if there is a difference.

[mgentz]

I have a degree wheel and indicators, but I would need to pull the motor all apart to check this.

[mgentz]

Originally Posted by cuong-nutz

Sorry about the vague post! It was meant as a question. I was on my phone but had to leave so just went ahead and posted it. I did spin the crank. It spins relative freely and then kind of catches but that's normal. All cranks do that because of the counter weights which helps with transferring all the energy generated from the fuel burning pushing the piston down.

No problem. If I recall correctly those are 2.5" - 3" holes. That is the biggest I could go. The snorkel is also removed from the far right. After cutting I beveled all of the edges.