Stumped experts: BRP Carb touched, won't start

[Zapp22]

If I slow kick mine through the compression stroke, it will backfire on the second or third kick. But it starts fine. I'm no expert, but you've got me stumped also. If I weren't down by Galveston, I'd like to see exactly what's happenin'. I know you said you only replaced the carb jet. There's no chance your timing chain is loose enough that it could have jumped a tooth is there?

what size pilot are you running? i assume you're uncorked... The only backfires I have ever had on any bike [real backfires, not carb fires] have been on running bikes that ran poorly. a fouled plug on my now-sold DRZ caused a lot of backfiring, but AFTER the engine was lit. I can never recall a true backfire flame-belcher like this on a non-starter.

I guess ANYTHING might happen at random but the most likely 'Occam's Razor' is that I inadvertently changed/moved/lost/misplaced something.

Something I never got an answer to, guys: is there a tiny O-ring or something inside the channel the Pilot screw screws into? anything that could have fallen out unnoticed?

tomorrow with luck i'll have a loaner carb

[phil_j]

Re: backfiring, just to add to the mix - I just got a brand new, corked up brp, and while slowly kicking it through this morning (no intention to start it, just idly pushing the kickstarter through while talking to someone), the cannon went off after about 4 slow kicks. Stock corking, stock 68P and 125 main, I can only assume. Took me by surprise, for sure.

that said, it starts and runs fine when I actually do give it a good kick.

Good luck with it.

[jbird710]

I didn't see any O-ring when I did mine. I've got a 68s Pilot, a 175 main (main jet from the HRC kit) and uncorked. Pretty much followed:

http://www.xr650r.us/tech/thewrench.jpg

I just looked at the diagram in the factory Honda manual and it doesn't show any O-ring.

If you send me a PM with your email address, I'll send you the exploded view of the carb.

[exaresix]

Every now and then, I see similar posts, and in almost all cases, the bike finally starts after having it soaked in carb dip. There is another channel in the carb's idle circuit that can not be cleaned out by spraying carb cleaner, but will clear if soaked in carb dip. You can not start the bike if this circuit is clogged. How would it get clogged? Just taking the jet out and replacing it could do it. I would have your expert disassemble the carb and do the dip. Some disassembly is necessary for a proper dip since you have to remove all the non metallic parts. When he does the disassemble and reassemble, he may also notice if there is something wrong in your assembly. The whole thing should cost between 100-120 bucks.

[roryscott30]

Tow it with another vehicle round the block, for me if it is almost there ie firing then a rapid tow usually always works. I have a '86 600R and i find it the most tempramental beast. There is an absolute knack to starting it ie with no throttle, in fact if my hand is too close to the throttle it'll object and flood. I'm a great believer in setting fuel screws/air screws when the engine's running and have always had limited success pre-setting. I know that is what this thread is about trying to start the little lady but i would tow it before i stripped it down again, it'll take 5 minutes.

Hope that makes sense and doesn't p*ss too many people off.

thanks

[angrycookieman]

Did you get it started? What was it?

[Zapp22]

yep way back.

you won't believe how simple, and yet effective [that is, at rendering unstartable].....

idle too high.

long story, but its a reminder that when you go to deliberately CHANGE something so critical, change ONE thing at a time. the BRP will NOT start with the throttle partly opened like that.....

Did you get it started? What was it?