Hoping someone can help? New to Locost Builders site.

I have an MNR Vortx with a 2003 Yamaha R1 engine. I have a problem with second gear.

When under fairly hard acceleration the I loose drive once or twice for a split second. It never completely jumps out of gear. It always continues to accelerate following the sudden loss.

I live in Glossop just outside Manchester and could do with recommendations as to someone who can fix the second gear.

I simply do not know of anyone who could take on the job and give a fair, honest price.

Any advice would be very much appreciated. Cheers.

Strange symptoms. If it was jumping out of gear I would suspect selector forks.

Does it rev wildly or does the engine die when the loss of drive occurs?

If the latter then it s sounds more fueling/electrical.

Are you happy with your clutch, sidestand, tipover shortouts?

- Jim

Hi, thanks for the response.

The loss of drive and back is so instant it is almost like a machine gun effect.

There is no time for the engine to race.

It also only happens in second gear. Absolutely no sign of it at all in any other gear.

I do have a power commander and did think it could be the fuel map but it feels so mechanical when it occurs.

Sounds more fuelling/electrical to me. Killing the spark or fuelling will give the driveline a shunt a bit like kangarooing the clutch but worse.

Has it just started occuring or always been that way?

I would start looking at clutch, sidestand, tipover shortouts. And your ignition switch. Do you have one of those FIA cut-off swiches (ebay specials). I have seen those cause a few problems.

Did you build the car yourself?

- Jim

Do the revs pick up when it looses drive? If so it sounds like clutch slip...or wheel spin. Or is it like the engine cuts? Which would sound electrical in nature. Or does it jump out of gear and you have to select gear again? Which would sound like the 'box.

I'm in Stalybridge (where I run a garage) and I'd be happy to take a look and give a second opinion. I'll u2u my address/No.

I think I might have seen you on the road last year; I was in my R1 engined Fury???

adrian

ps. welcome to the mad house!

[Edited on 8/4/10 by adithorp]

Hi. My MNR was built by Marc & Chris at the factory.

It is kind of like the engine cutting out but the cut out is so quick.

I never have to re-engage into gear - it always remains in gear.

Revs have no time to die or race.

Sounds silly, BUT, what fuel level are you running?

I had similar when running low fuel and getting fuel surge on track, you the hardest of gears cause the surge and drop in power?

When it first started happening I tried brimming the tank with fuel.

I think I need someone in the know, like Adithorp, to come out in it and get a real feel for what is happening.

I am just hoping it isnt something too costly. Not been the best time recently finance wise.

I am glad I joined the forum though as I have got a lot further on here than me simply popping into to local motorcycle shops.

Has it just started occuring or always been that way?

- Jim

I think it has always been that way.

It is only as I have become more used to driving it and so can push a little more that it is much more frequent and harsh.

I know I can plug my laptop into the power commander and alter fueling in second gear but do not want to cause more harm than good.

If it is a 2003 (5PW) R1 I am not aware of a link between fueling and gear selection via the powercommander.

- Jim

Did you get to the bottom of this?

It sounds like the problem I currently have - except mine is in 3rd gear. 2nd gear is normally the one to go first though.

Anyway my theory for this is that the dogs or corresponding "holes" (can't remember the proper name!) are slightly worn BUT not all of them. Under hard acceleration it slips around until it gets to a combination that is not so worn.

This reflects my situation where it doesn't always slip in 3rd as I've struck lucky with the shift first time. Whereas other times it will slip once or twice.

My "slips" are accompanied by a loud transmission clunk - similar to that when you change down to first gear. But it never completely jumps out of a gear just a momentary loss of drive with a clunk or two.

Once it reaches a good "mate" it won't slip again no matter how hard I mash the pedal.

Anyway if your problem is the same as mine then its gearbox rebuild time unfortunately.

Interested to hear if you think your situation is the same?

You are absolutely right.

On mine every single cog on one shaft was worn and all 3 shifter forks where showing hefty wear.

Was quoted £750+VAT just for parts! I bought a second hand box and got that put in. Saved me a fortune.

Still had quite a bill for labour though. All is well now.

The high level of wear was caused by the paddle shift throwing each gear change slightly too far I believe. The gear change now is so much slicker.

I used a chap at Heights Engineering not too far from Manchester. I could not rate him high enough - very sound chap.

You have u2u

Reading this has worried me.... im just at the end of setting up my paddle shift from stick.

I dont want to over throw the gear change too far.

I may be wrong but I think the problems regarding overshifting are related to powered electric shifters.

Mechanical paddles can be no worse than a stick IMHO. And not any better in reality other than gimmick (I have had both).

- Jim

Dans clunk/knock would do it again and again if you hit just the right amount of load. IE. accelerate in second on moderate throttle and it'd clunk. Back off and then accelerate again and it'd do it again. I managed to get it to go clunk, clunk, clunk... but only once.

Good to hear you got it sorted, Dan.

adrian

[Edited on 3/6/10 by adithorp]

Hi Adrian

I wouldn't have known where to even start getting it fixed without you checking over the electrics, etc and test driving it.

I will pop over to Stalybridge soon to say hi.

Are you arranging any regular meets as yet?

Daniel

Also, if anyone needs to know who I found to fix the gearbox problem send me U2U for details.

I would certainly recommend them.