Rieju Rs2 matrix not starting after crash

Luckyfish13 · Renault 5 Driver Joined: 30 Nov 2015 Karma :

Hello people I'm new here this is my intro lol...having a real hard time with this…any help appreciated Smile

bought a a non runner rs2 matrix 125 (2005 - uses the same yamaha engine as the ybr125 just with a spigot mount 20mm mikuni carb) nd apparently it ran fine before he had a front end crash. it started if we squirts fuel into the back of the carb so thought we’ll take it and see…

2 months on we’ve tested everything and still not starting…

checked spark and timing first. Used easy start fluid and it ran fine so timings are ok I think. Still not sure about compression I’m waiting for that compression tester to arrive.

next up the fuel tank..sucked on the vacuum line and then attached to inlet manifold nd both times fuel was flowing. Then attached fuel line to carb and opened float bowl and voila fuel flow…cleaned out the carb with spray left it to soak so all the jets are clear throttle works fine and I think the choke does as well…

ok so there’s no problem in the fuel line, the carb is clean, the engine runs fine with easy start, hook it all up turn it over and…square root of f*{+ all happens….

We tried all the carb adjustments and it doesn’t even want to fire up once on any settings changed the idle screw air screw float settings I really don’t know what else it could be..the only thing I can think is maybe the crash knocked something out of place?

Has anyone had a similar problem?

Burnzy1989 · Nitrous Nuisance Joined: 06 Apr 2009 Karma :

Hmm mm well it could be a number of things like poor fuel in the tank. Send us a picture of what damage the bike has from the accident as it will give us idea of what to look for and see what damage there is as you could have multiple problems and we will be guessing all night

Luckyfish13 · Renault 5 Driver Joined: 30 Nov 2015 Karma :

I couldn't get many photos there isn't much damage. The frame is generally fine there a small bend on the front frame that hold the headlights. The forks were as you can see them front wheel and brake is all fine. It seems like it was a low speed (30mph) crash but maybe it's affected some settings :/

It won't let me attach the photos I took as they're too big so will get back to it this weekend. The one that did attach (from Paul @riejubikers.com) is of the carb connections. A is a vacuum line to the fuel tank petcock. B & D are vents. C is the 'fuel in' pipe. We managed to start it up using easy start then it ran fine for about 20 mins. Refuelled and tried again and nothing at all has happened since. I'm wary about using too much easy start. When it did start up we had connected an extra pipe from the breather valve B (above the electrical heater connections) and hooked it up to the closed off valve next to A. So pumping fuel straight into the inlet manifold.

If I put an inline fuel pump would this also solve the same problem? Thinkin the vacuum is too weak to draw in any fuel....

Burnzy1989 · Nitrous Nuisance Joined: 06 Apr 2009 Karma :

Ok have you cleaned out the carb first, if not do that first and make sure your jets are clear also make sure your choke isn't blocked or stuck open. As well as that you also have air being ducked in through the crank seals which could also be causing hard starting. Try bump (push) starting it to see if that gets it running or firing

Burnzy1989 · Nitrous Nuisance Joined: 06 Apr 2009 Karma :

Ok just seen ur upload my mistake thought it was a 2 stroke . There should be no fuel going into the inlet manifold through that clear pipe only into the carb .

Burnzy1989 · Nitrous Nuisance Joined: 06 Apr 2009 Karma :

Iv never worked on this type of carb so it's hard to explain what to do with out it being in my hands . But B looks like your fuel line into the carb . Best way to tell is take it apart hook a pipe to b and blow down it and see where it's blowing from . If it's coming from the needle jet it's ur fuel in .

Luckyfish13 · Renault 5 Driver Joined: 30 Nov 2015 Karma :

Yeah we've sprayed the carb and soaked in petrol jets are fine...
The clear pipe is a vacuum pump which goes straight to the fuel tank. The fuel tank has 2 lines one for suction one for fuel out. Will check if it's coming out the jets though we hooked it up without the float bowl and and it was spraying fuel out so assuming it's the right one...thanks for the reply man Smile

Burnzy1989 · Nitrous Nuisance Joined: 06 Apr 2009 Karma :

Yha tricky some times . I would rather be there to help as I'm more hands on and trying to explain on here lol

Luckyfish13 · Renault 5 Driver Joined: 30 Nov 2015 Karma :

Hi people this might be a really basic q or not...but if a fuel petcock has a vacuum line to draw fuel into the carb
And I put an inline fuel pump on the fuel side....it's not going to work as it should is it? Because the tap still need vacuum to open...
Can I change the petcock on the fuel tank to gravity feed?

Ariel Badger · Super Spammer Joined: 02 Dec 2006 Karma :

Yes.
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bikenut · World Chat Champion Joined: 21 Nov 2011 Karma :

whats that below b?

an electrical connection?? an electrical fuel cut off?? you have a spare wire ?? see the bikes wiring diagram to verify....

may be its an electrical air valve??

also brass distance piece on carb clamp, air leak there or all good there??
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Luckyfish13 · Renault 5 Driver Joined: 30 Nov 2015 Karma :

Thanks, nat able to get back to garage til Tuesday bit am quite excited with this info and a fuel pump lol maybe it will fire up this time....

The electrical connectors are for carb heater it should run fine without them connection attached if I'm not mistaken. Hasn't though of checking for air leaks will give it a shot on tues as well. Cheers!