XR650R Thread!

[crypto666]

Originally Posted by rpmwfo

I was thinking of getting a spare flywheel from ebay and lightening it up. Does anyone have any advice on how much or wear to lighten it? I am thinking I can thin the weight out on either side of the rivets. I can probably thin down the actual stamped steel shell some as long as I don't disturb the pick up.

Any ideas?

My question would be why do it? Faster throttle respoonse and less performance in the tight stuff?

I have heard that some racers actualy removed the counter balance. Screw that, fatigue would outweigh the performance gained for me.

[rpmwfo]

Originally Posted by crypto666

My question would be why do it? Faster throttle respoonse and less performance in the tight stuff?

I have heard that some racers actualy removed the counter balance. Screw that, fatigue would outweigh the performance gained for me.

Better throttle response. Make the feel more responsive. I am not concerned with performance in tighter terrain. While the BRP can handle tight and technical, other bikes are easier for me to handle in those situations. Eventually it is probably going to get a rekluse.

I am slowly turning my BRP into a poor man's KTM 690. Lighter(than a DR or KLR) and definitely capable dual sport/adv bike.

[BuRPsa]

Sintax,

I'm at a warm & dry 4500 feet, 27.5 is no problem.
It felt (the ol' bum-meter) it did run better (during back2back tests) with a 25 so that's what I put in. Great pickup, starting etc so it had to be good! Yeah right, it boiled over (the only Pig out of 3) when things got really slow. It does all nigh-on the same with the 27.5 now but for the boiling-over bit, so I'd recommend it. Oh, airjet 1.2, not 1.1.
I think my hoses are the CV4's but they're all the same, very little difference in them. The slippery nature of the silicon requires one to pay a bit more attention than with rubber hoses but that's all basically.

[Desert Scoundrel]

Originally Posted by rpmwfo

I was thinking of getting a spare flywheel from ebay and lightening it up. Does anyone have any advice on how much or wear to lighten it? I am thinking I can thin the weight out on either side of the rivets. I can probably thin down the actual stamped steel shell some as long as I don't disturb the pick up.

Any ideas?

Originally Posted by rpmwfo

Better throttle response. Make the feel more responsive. I am not concerned with performance in tighter terrain. While the BRP can handle tight and technical, other bikes are easier for me to handle in those situations. Eventually it is probably going to get a rekluse.

I am slowly turning my BRP into a poor man's KTM 690. Lighter(than a DR or KLR) and definitely capable dual sport/adv bike.

You'd get better results by not eating breakfast before heading out to ride. I have a lightened FW and you notice nothing, NOTHING! It does not responde better nor does it lack bottom end in the tight stuff. All is does for you is cost $$ by paying for the FW and/or having it machined. Tune the carb right and then it will be more responsive. You just can not remove enough material from the FW to make a noticable difference.

[ride4fun562]

Tire noob here , need some help. I currently have a the maxxis desert it for my rear tire it is a 120/100 18 , I got the bike not to long ago and thats the tire it came with on the back, already worn down pretty good. Sooooo when i look at the mud flap or whatever you call it thats right behind the rear spring it looks like if my tires were new they would have barely any clearance and i can see that the tire was probably rubbing the flap when new. There is actually a hole through it where it looked like the tire rubbed through. So my question is should i go down to a 110/100 18 ?
I have no idea what the tire numbers refer too. 120?/100? i know 18 is the size of my rim but the rest is a mystery to me. Thanks for your help in advance and please forgive my retardation when it comes to motorcycle tires

[PineyMountainRacing]

Originally Posted by ride4fun562

Tire noob here , need some help. I currently have a the maxxis desert it for my rear tire it is a 120/100 18 , I got the bike not to long ago and thats the tire it came with on the back, already worn down pretty good. Sooooo when i look at the mud flap or whatever you call it thats right behind the rear spring it looks like if my tires were new they would have barely any clearance and i can see that the tire was probably rubbing the flap when new. There is actually a hole through it where it looked like the tire rubbed through. So my question is should i go down to a 110/100 18 ?
I have no idea what the tire numbers refer too. 120?/100? i know 18 is the size of my rim but the rest is a mystery to me. Thanks for your help in advance and please forgive my retardation when it comes to motorcycle tires

I believe a 120/80-18 is an 18" tire (fits an 18" rim) that is 120 mm (about 4.7 inches) wide. The 80 is the aspect ratio which means the height (how tall it is) = 80% of 120 mm = 96 mm (about 3.8 inches).

The 110 / 100 is 110 mm wide (about 4.3 inches) and 100 % of 110 tall = 110 mm tall ( about 4.3 inches ). So its 4.3 inches wide by 4.3 inches tall. So a xxx / 100 tire will be the same width as height. The 110/100 will actually be taller than the 120/80. 100% of 110 mm is bigger than 80% of 120 mm.

Some tires are just classified by 1 number, and that implies the aspect ratio is 100%. Like a 4.50 X 18; it's an 18 inch tire that is 4.5 inches wide and 4.5 inches tall.

I'm currently running a 140/80-18 on the rear, but its a Pirelli Scorpion, MT90 - more or a dual sport tire. I think the last knobby I ran was a 120/80. Pretty sure a 140/80 knobby would not have enough clearance, it would be too tight with the knobs. It's all kinda confusing until you start mounting lots of tires and see them side by side. Plus you gotta convert the metric to inches, unless you're on the other side of the pond.

[jesusgatos]

That's sort of a chronic problem if you want to run the rear wheel towards the front of the adjustment slots (handles better). But we're making some carbon/kevlar mudflaps that should pretty much solve that problem. Only thing is I can't tell you when they might be available or how much they'll end up costing...

[ride4fun562]

Thanks for your help guys, and i like that mudflap . I was assuming that it would be bad/annoying sounding for the rear tire to rub on the flap but it seems like from what you are saying that it does more damage to the mudflap than it would to the tire ? I think a 120/90 18 would be perfect but just my luck maxxis doesent make them that size. So i guess ill go with the same tire 120/100 and just deal with replacing mud flaps alot

[jesusgatos]

No, nothing to worry about.

[Shibby!]

Originally Posted by ride4fun562

Thanks for your help guys, and i like that mudflap . I was assuming that it would be bad/annoying sounding for the rear tire to rub on the flap but it seems like from what you are saying that it does more damage to the mudflap than it would to the tire ? I think a 120/90 18 would be perfect but just my luck maxxis doesent make them that size. So i guess ill go with the same tire 120/100 and just deal with replacing mud flaps alot

Just stop replacing them. They won't wear any more but replacing it will wear out within 10 miles of a new tire. Trust me, I've gone through a few and just stopped.

Keep an eye on your swingarm for wear, but even that can be fixed with some JB weld. The tire shouldn't hit the frame, but the cut portions of the flap could cause a bit more friction in places the swingarm wasn't designed for it. Layer of epoxy on this would make the epoxy wear and not the aluminum. Not really an issue just comes into affect after A LOT of miles.

I have 24000 km on "worn" mudflaps. No issues.

[lstzephyr]

Alright gents I need a couple extra opinions on my current situation. I can't get my bike to start again after it died the other day. It was running fine on a new engine rebuild until I turned into the bar and it sputtered and died. I figured it was low on fuel and didn't bother with it. When I went to leave I couldn't get it to start. It hasn't started since.

I have:

1. New fuel
2. new petcock
3. new fuel line
4. new spark plug
5. Checked for spark(has spark on spark tester and when holding plug to head)
6. Top end is fresh(new piston/rings/valves/seals/tensioner/cam chain etc less than 8 engine hours ago)
7. Checked cam chain, cam timing, valve clearance(all in spec)
8. Checked wiring
9. Cleaned the carb thoroughly ( tore it down completely and had it dunked over the weekend by the local machine shop)
10. Attempted bump starting (the bike only locks the back tire, I need a bigger hill)

After the carb cleaning it would periodically fire 3-4 revolutions then die. Barely more than the spin of the kick. Starting fluid has no effect other than raising the amount of backfires.

I swapped on my recently rebuilt HS40 Carb (mikuni tm40) to see if it was still a plugged pilot circuit. No change except it will fire 3-4 revolutions every other kick now. I think that is because the accelerator pump allows me to toss fuel in. I didn't want to add another variable(new carb) but I wanted to rule out the stock carb as the issue.

So my thinking is that it could be one of a few things:

Unlikely:

1. Loss of compression(it is still more difficult to kick than before rebuilt so it appears to have compression)
2. CDI(only failure symptoms I can find say that there is no spark with a dead cdi, I have spark so probably not cdi)
3. Stator(the wires to the stator appear fine and I could not find any cuts or abrasions)
4. Plugged pilot circuit in both carbs (I checked both thoroughly, especially the hs40)

Probable:

1. Misadjusted idle in both carbs (I have moved the idle screws around while trying to start it)
2. Coil

My current thinking is that I have spark but the bike won't fire more than 3-4 revolutions so the spark may be weak causing it to only be able to overcome compression at low rpm. High rpm blows out the weak spark. That makes me think that the coil is the issue. It could be the idle is so out of whack it won't start or the pilot circuit is still clogged. I'm completely guessing at this point though and I'm leaning toward coil.

Can the coil or stator be tested?

Any other ideas?

[Kiko]

Did you check the ground wire on the coil to frame connection? Try to find another CDI and swap it out. Test the pick up coil.

[ZXRaziel]

Originally Posted by jesusgatos

I like that , very good idea ,
i just bought new mudflap rode the bike for 10 minutes and its all scratched already - bad design , it is too soft and it moves when you ride then the wheel and the chain eat it away fast , one solution would be to take it out and put something on the back of it ( plastic plate ) to make it stronger/stiffer to stop it from flapping around .

[Desert Scoundrel]

Does anyone has any experience with the Acerbis Sahara underseat tank? I see a few websites still have some in stock. I know you need the seat to fit the tank aswell. I was wondering about the seat height, is it higher than stock? and how well does the tank fit? Any other problems?

[Sean-0]

seat is highr than stock ..they fit ok from what i have seen .. they have been known to split

weight is high ..not a good idea IMO