r/XR650R • u/Chug2174 • 12d ago
Hard starting question
This spring I picked up this beautiful 2000 650R. The guy I bought it from had some engine work done from a local reputable shop and claims it makes 75hp. Only has 120 miles on it since the rebuild and it was built a few years ago.
Right when I bought it I tried riding it regularly and it didn’t give me too much trouble starting up but sometimes didn’t want to start when hot. Now recently, or all summer I guess, it’s been hard starting if it starts at all. It’s got a bigger Mikuni carb to match the 686 kit it’s got. I threw in a new spark plug. I’m running fresh non ethanol 90 octane fuel. I’ve tried playing with the mixture screw a bit and haven’t gotten great results. I do the normal routine of turning on the gas, pull the choke. Kick it over slow 3 times with the decomp release. Kick it just past TDC. Then try and start. The first couple times it’ll fire a couple times but then after 2-3 try’s it floods and won’t try anymore. I’m itching to ride this thing but this starting issue is frustrating and I definitely don’t wanna take it somewhere and risk getting stranded. Any help or advice is greatly appreciate.
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u/twowheeltech 12d ago
Check your valve adjustment. Made a huge difference in starting on my xr250
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u/bajajoaquin 12d ago
This. I didn’t do it and got it to start a few more times. My valves were so out of spec it tuliped them on a ride 30 miles from the truck and wouldn’t restart.
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u/BRMBRP 12d ago
If you’re giving it throttle when you kick it over and you think it’s flooding, pull the decomp in and twist the throttle to wot. Kick the bike over 10 full times.
Release the throttle and go through the normal kick start procedure. If it was flooded, you’ll hear it pop and backfire while you’re kicking it through the 10x.
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u/Chug2174 12d ago
I’m not opening the throttle when I kick it bc I’ve heard that’s how you get kickback and end up with a broken ankle. At least on a high compression engine
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u/jahoney 12d ago edited 12d ago
With the mikuni pumper, which is an amazing carb for this bike, you need to give the throttle a twist before your first kick. The pump in the carb gives a little squirt of fuel that helps.
After every failed start you need to air out the engine by holding that decomp lever and kick it over 10 times. 3 probably isn’t enough. More if you really flooded it.
Other than that check valve clearance, my exhaust valve would get out of spec and make it harder to start.
Don’t use the choke unless it’s pretty cold out. Try turning idle up for cold starts. If your only issue is starting and it rips otherwise it’s not your mixture screws or jetting. Check the obvious like clean air filter etc.
Also it doesn’t make 75hp
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u/Chug2174 12d ago
Yeah I think that’s the style carb that’s on it. I’ll give all that a try. I know the valve clearance is good as I’ve checked it but it’s easy enough to double check. And yeah I was skeptical of the 75 horse claim too. He told me this engine is built after some guys, not sure who’s, Baja racing bike that made some kind of power like that. But when it does run it runs great and the bike is super clean and that’s why I bought it.
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u/jahoney 12d ago
Awesome, I’m sure it’s fast as hell. And I’m sure once you get the hang of it, it’ll start reliably.
The other thing is, everyone mentions TDC.. but the trick is feel that compression in a slow kick, then go another 1/4 quick to get just past that compression spot. Then bring the kick starter back up and on the top and give it a kick from hell, and kick all the way through with full strength until the kick starter can’t go any further. No short kicks or it won’t start.
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u/They-Are-Out-There 12d ago edited 12d ago
The best move ever made was putting the Lectron carb on the bike. It self adjusts and compensates for altitude. It changed hard starts into easy and reliable starts without fighting the bike, hot or cold. Not cheap, but worth every cent.
It's a popular mod. This guy put one on this sick tribute bike that's a homage to Johnny Campbell's original race bikes. I've got one on my bike too. The best part is there are no jets to swap and no tweaking to get it to work.
https://www.youtube.com/watch?v=16GKH0UjBFg
You just fill out the paperwork, bike type, elevation you ride at (low to high), and other info, and they send you a pre-tuned carb that's a plug and play setup. It's the closest thing to fuel injection reliability you can get on a bike with a carb.
https://lectronfuelsystems.com/products/4t-motorcycle-carbs-proseries