I need some help diagnosing/fixing - Honda Motorcycles - FireBlades.org
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post #1 of 12 Old 07-07-2017, 7:25 AM Thread Starter
 
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I need some help diagnosing/fixing

Hi all

I've run into my first mechanical issues with my RR-X. Recently it's been using a bit of oil (it's needing a top-up about every 1000 miles) and yesterday I went out for a blat and at first everything was fine but later in the ride it started to feel a bit low on power - felt a bit like the fuel starvation you get when it's time to switch to reserve tank - and by the time I got home she was feeling pretty gutless.

Tomorrow I'm going to remove and clean the carbs. I've never done this before so what should I look out for?
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post #2 of 12 Old 07-07-2017, 9:02 AM
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Re: I need some help diagnosing/fixing

Hi, the overhaul of the carbs is in the manual, but before you take them off take out the plugs and have a look at them, see if their the right colour, and with the carbs still on do a compression test(spark plugs still out) and then perhaps the carbs, if the compression test is alright your valve clearances should be within scope, just follow the manual for the carb clean
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post #3 of 12 Old 07-07-2017, 10:58 AM
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I'd do one carb at a time,you'll be less likely to lose bits or mix up jets (inner jets are different to the outers)
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post #4 of 12 Old 07-07-2017, 12:25 PM Thread Starter
 
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Re: I need some help diagnosing/fixing

Thanks for the tips guys. Valves were done just recently at 38000 miles, she's on 45899 now. Need her tip top for the Nurburgring at the end of next month!
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post #5 of 12 Old 07-10-2017, 2:55 PM Thread Starter
 
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Re: I need some help diagnosing/fixing

Quick update: went out Saturday morning and spent 25 on a can of carb cleaner, a can of compressed air, gloves, wipes etc then sat down in the garden in the sun to start The Big Clean

...which soon turned into The Big Disaster as the first float bowl screw I came to was seized solid. I sprayed it liberally with WD40 and thought I'd check the pilot screw settings while I waited for it to soak in. The second pilot screw was also seized and the half the head snapped off the moment I tried to undo it.

So I walked the carbs up to my local bike shop to be ultrasonically cleaned. 100 and I pick them up tomorrow. What a ballache
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post #6 of 12 Old 07-10-2017, 3:06 PM
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Re: I need some help diagnosing/fixing

A leaking petcock can also cause running problems, might be worth checking especially with the tank off the bike.
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post #7 of 12 Old 07-10-2017, 3:17 PM Thread Starter
 
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Re: I need some help diagnosing/fixing

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Originally Posted by Gunk View Post
A leaking petcock can also cause running problems, might be worth checking especially with the tank off the bike.
Thanks, that's a good shout. I think I found at least part of the problem - the clips securing the carbs to the inlets weren't very tight and would have been allowing air in
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post #8 of 12 Old 07-13-2017, 11:10 AM Thread Starter
 
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Re: I need some help diagnosing/fixing

Ok so I've put the bike back together and it's running like a peach! I've set the mixture screws at the stock 2 turns out plus an extra quarter turn for safety as I have a Yosh RS-3 end can.

The bike now fires up with no throttle, which it didn't before. It also picks up the front in 1st on about 90% throttle, which it would previously only do on full throttle and then only if I shifted back in the seat. I haven't balanced the carbs but it doesn't feel like they need it.

It's going on a dyno on Saturday morning so I'll have a look at the fuelling then. I'm very happy indeed
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post #9 of 12 Old 07-17-2017, 12:57 PM Thread Starter
 
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Re: I need some help diagnosing/fixing

Dyno results are in

I haven't had them by email yet but she made 117.34 at the wheel. Add 10% for the crank figure and it's a very healthy 129ish so I'm very pleased. The fuelling is a bit lean around 4-8k so I'm going to shim the needles up a touch to sort it. It's fine once it's on the main jets

I need a bit of advice on oil use though. When it's on the dyno there's a bit of dark smoke out of the exhaust at the top of the rev range. The bike's only on 46k miles so I don't think it's piston rings and I'm thinking maybe valve stem seals? Has anyone had a similar experience? If so would you recommend a head refurb?
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post #10 of 12 Old 07-17-2017, 2:22 PM
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It's more likely to be valve guides, personally I would leave it for the time being and just check oil consumption per 1000 miles before you made a decision to tear it apart
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post #11 of 12 Old 07-17-2017, 3:14 PM
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Re: I need some help diagnosing/fixing

Dark smoke typically indicates running rich, oil smoke has a blu-ish tint to it. Worn valve guides/seals also show themselves under vacuum (i.e. which pulls oil down the guides) rather than at sustained full throttle, you normally see a puff of smoke after rolling the throttle off and then back on again.

A leak down test would show how well the rings are sealing.
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post #12 of 12 Old 07-19-2017, 9:39 AM Thread Starter
 
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Re: I need some help diagnosing/fixing

Thanks guys. I'm off to the Alps next month and coming home via the Nurburgring where I want to push for a better lap time than last year so I really want the bike tip top as I use a lot of over-rev into some of the corners. With that in mind I've booked it in to have the oil use diagnosed. It didn't previously use any oil at all between services so something's definitely changed and I'd like to be certain it's not something that's about to let go in an exciting way if you know what I mean
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