Paging Kurlon - XR100R

[breakdirt916]

btw - I usually buy my jets from rockymountainatv because the Pro-X aftermarket ones are $3.21

if you're just buying 2 jets, shipping kills the deal, but anytime I get a new-to-me bike, I usually have to get some starter maintenance items (well, ok...on this bike it's just an air filter and spark plug) and in my head it averages out

edit - nvm...if you are already there, you start looking at other items sold for that bike - FMF Power Core IV w' S/A...I had one on my last XR100, and it made it sound remarkably deep for a 100cc lawnmower engine, lol

edit: @Kurlon - I did not realize there was a difference b/w BT45 and BT45V - I thought they were all BT45's!

so the options are:
BT45V
110/90-16 ($121)
120/80-16 ($125)

BT45
100/90-16 ($88)

so you're running 110/90 front and rear? 120 rear? did the tire profile change too much to allow you to drag knee?

I had a 120 on the back of the CR80R, and it was too fat for my tastes...you could only use about 70% of the tires, and the profile "pudged" out so it didn't really like to lean very far...if I can I'd even run a 90 width front

[Kurlon]

I'm running a 110/90-16 rear and a 110/80-17 front.

Heats 6/6 - 22photos

Nope, no issues cranking it over so far.

[breakdirt916]

NICE!

ahh, I didn't realize you ran a 17" front and that the TTR came with a disc front...that's a hot setup!

the XR actually has a 19" front - and the BT45V comes in a 100/90-19 front...why wouldn't I just slap that on the factory rim instead of scavenging for an XR80 front rim?

[Kurlon]

The TTR LE came with a 19" disc front, I swapped the entire front end out for a YZ80 setup, 17" disc included.

People do run the 19" front with a BT45V, but the geometry seems to be better overall with a 16" front on the XRs based on most racer's reports.

[nhbubba]

Dear god that looks like fun. Possibly more fun than LRRS.

[Kurlon]

GET OUT HERE AND TRY IT!

August 7th is a school before the double header that weekend, if I have project Stupid ready come and play on the TTR a bit.

[breakdirt916]

coo...I am down...I just setup an automated search for [(XR80,XR80R,"XR 80") front (rim,wheel,mag)]

gonna run 110 front/rear...$240 rubber on a $400 dirt bike

[nhbubba]

August 7th is a school before the double header that weekend, if I have project Stupid ready come and play on the TTR a bit.

Okay.

[loudbeard]

Boxshop looks like a blast, I'll have to check with the missus and see if I can play that weekend, she's the keeper of the calendar.

So I have a bit more progress with my carb. I opened it up and discovered what I thought was a 35 pilot was actually a 38. Luckily when I was at bettencourts I picked up a 38 and a 42. I plugged in the 42 and it does idle better now with some adjustments. I started at 1.5 out on my AI screw and I'm at about 1 out as of now.

No adjustment on the main jet, I picked up a 98 and a 105, but he gave me hex head jets and I needed the stubby ones with the flat head. My bad, I forgot which they were.

On to an interesting issue. About 100% certain this is a replacement carb. The bike has taken a really hard shot on the right side, looks like directly on the carburetor. The frame directly behind the carb is dented in and the right side subframe support is also dented in.

I'm wondering if I may not have the correct carburetor for my bike. Reason I say this is the gasket between the float bowl and carb body doesn't fit perfectly. It's the correct shape, but maybe 2% larger than it should be. I used a bit of motor oil to get the gasket to stay in its seat but its definitely not correct.

My Keihin carb is a PD series and has 80CBPE stamped on the carb body.

[TheIglu]

I'm wondering if I may not have the correct carburetor for my bike. Reason I say this is the gasket between the float bowl and carb body doesn't fit perfectly. It's the correct shape, but maybe 2% larger than it should be. I used a bit of motor oil to get the gasket to stay in its seat but its definitely not correct.

That's pretty typical. Rubber expands from gasoline. I wouldn't look into it much further.

[breakdirt916]

My Keihin carb is a PD series and has 80CBPE stamped on the carb body.

lemme check mine...

[loudbeard]

OK so we'll go for some more input now. Barring a few minor tweaks, she's idling well now. I'd like to get it a bit lower, but its well within acceptable.

I have to 105 main in there now. At first I thought it was still bogging at WOT, and it is...but...it seems like the entire span of my throttle control is 0-10%. At about 10% throttle it will rev to peak engine speed and hold it there with now problems (haven't tested it under load yet.) Above 10% it will start to bog and sputter again.

I have removed the needle and moved the clip one notch up to drop the needle in further, not really a ton of change. I started in the center position of the needle (3 of 5) and moved up one.

Thoughts?

[TheIglu]

Sounds like exactly how my XR80 ran.

[Kurlon]

Ignore any behavior involving the throttle and the bike sitting in neutral. You're chasing ghosts. Climb aboard, click it into gear and flog it up and down the gearbox, THEN adjust based on how that goes.

[loudbeard]

Copy that, going for a quick buzz around the 'hood. Hope they're not too sensitive about dirt bikes on public roads in the Boston area lately

[loudbeard]

OK so under load it pulls well to about half engine speed and then bogs. Before my previous post I had already moved the needle to the last position. As of now about the first 40% of the throttle is functional.

[cdovego]

we're so close to spree/xr100 hot laps around the neighborhood!

[loudbeard]

Success! It was getting flooded with fuel. I also picked up a 100 main yesterday so I pulled the 105 out and she rips!

So, ready to ride on Saturday. I'll wait for gearing as its just practice but I need to figure out what guys are running.

Kurlon, if you have any insight as to what guys are running at Boxshop that would be awesome. I'll be on 16" wheels (the front arrived today) running BT45V's, 110/90 front, 130/90 rear.

Thanks for all the help guys, she's ready to ride now!

[Kurlon]

I'm running stock gearing on my TTR, can't imagine the XR will be too far off from stock?

[loudbeard]

I have no idea to be honest. I'm just in need of a new chain, I figured I'd put correct gearing on while I had it apart.

[cdovego]

congrats on getting it running

[breakdirt916]

oh mannn...I missed the whole discussion!

but ya - Paul-ED covered it in one of my threads...the WOT stuff is all the main jet...if it bogs/sputters, then it's too rich...so dropping down to that 100 got it just right!

btw - stock pipe?

and maybe an even bigger pilot jet to idle better?

[loudbeard]

Yep, stock pipe. I'll leave as is for the remainder of the year, this winter she'll get a 120 kit, pod filter, and a nice exhaust. Really like the Outlaw series from engines only.

So here's the scoop. I won't be sumo'ing this bike. Spent the day at Wachusett Valley Riders Club in Winchendon and this girl is going to be a flat tracker. As it turns out, its better to run 19/16 wheels on a flat tracker. Going to be running Trail Wings as well.

Flat track is a stupid amount of fun, I'm hooked. They also have a ton of events, you can basically ride every weekend. I want to give the mini Supermoto thing a try too, but the bikes are way to different setup wise to ride a catch all machine. I'll be looking for another bike that's a good candidate to sumo soon.

I now know I can do this stuff on the cheap. With tires I'll be less than $600 into my XR. Gotta just be on the CL hunt for non/poorly running cheapo bikes because they're stupid easy and cheap to fix. Maybe I'll get lucky and find a 150R in that state.

[TheIglu]

I was told by Roger that 150R's aren't allowed in the 100-160 class.

[loudbeard]

Makes sense, that's 25+ horsepower vs my 6.5. I'm more thinking of a 150R for sumo, but they're pretty big money. Haven't seen one on CL for less than $2k.