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De-restricting the CB500

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teamwindsor
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De-restricting the CB500

Post by teamwindsor on Tue 26 Jan 2016, 10:01 am

I was wondering if I could ask a bit of advice and determine if I am doing something significantly wrong. 

I have a CB500 v (97) which I bought 6 or 7 years ago- restricted to 33bhp (apparently)- came with a red certificate stating so.

I have had a full license for probably 5 years now and have finally got round to addressing the removing the restrictors. I have had been doing some significant tidying up so it seemed like a good time whilst the bike was is bits. 

After a bit of reading I assume it is just restricted with washers. There is no stamped 33bhp on the carb rubbers. 

I have taken off the easier to remove clips (left in place but fully undone the more fiddly right sided clips) on the rubbers between engine and carbs as well as between the carbs and airbox. Guides say that you are meant to just be able to pull the carbs and airbox back and up to separate the rubbers from between engine and carbs. This is proving difficult- there is no movement whatsoever. I have been on top of the bike and used my weight but still no movement. If I try to prise them off with a large screwdriver is is damaging the rubber. The rubbers move between the carbs and airbox but not the ones further forward. 

The carbs also feel pretty fixed. Should I only need to undo the clips on the rubbers with the little bolts or is there something else that is keeping things fastened down? I have attached a picture of what I assume I should be removing and where others suggest these elusive restrictor plates lie.
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teamwindsor
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Re: De-restricting the CB500

Post by teamwindsor on Tue 26 Jan 2016, 10:01 am

Apologies the picture doesn't seem to want to upload
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ANDYC
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Re: De-restricting the CB500

Post by ANDYC on Tue 26 Jan 2016, 10:57 am

Alas, the rubbers do harden with age. Actually they feel more like steel than rubber in my experience.
Heating them with hot water has worked for me in the past though.
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teamwindsor
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Re: De-restricting the CB500

Post by teamwindsor on Tue 26 Jan 2016, 12:15 pm

Thank you. 

So do you just pour the kettle over the rubbers whilst on the bike? Is the theory to just softened them enough to poke a finger in and fish out whatever is restricting the bike and push back or soften them and pull right off?

My concern is I soften them, get the washers out and they harden up again while I footer about so won't go back on. With them off I would be a little afraid that heating them with water again will get water in the engine...or is there an easier way to do it (heat gun etc.)?
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Re: De-restricting the CB500

Post by eternally_troubled on Tue 26 Jan 2016, 12:49 pm

IMO A kettle is probably better as this limits the heat to 100 degrees. Heat guns can get a bit hot.

Maybe a hair-dryer might be better? (plus you might already have one!)

Any water you (carefully) pour on the carb rubbers will/should just flow down the back of the engine and run off - I don't think you want a torrent, more of a gentle stream Smile

Have you made sure that your bike hasn't been throttle-stop limited - this would make things easier!
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Re: De-restricting the CB500

Post by jerryfudd on Tue 26 Jan 2016, 1:30 pm

....or just by new carb rubbers? OE Honda's are 17ea but you can get pattern ones from the likes of M&P for 22 the pair.



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teamwindsor
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Re: De-restricting the CB500

Post by teamwindsor on Tue 26 Jan 2016, 1:47 pm

Have a heat gun but as you say it tends to burn more than heat sometimes. 

Ideally I wan't to attempt to just pull out the washers. For new carb rubbers I assume the carbs would have to come off? I have had the bike off the road for several months with repairs and was hoping for a quick fix...i'm a slow worker and it's hard in the dark!

I don't see any stop on the throttle but then again I am not sure what if one was in place it would look like?

Thanks for the help
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Re: De-restricting the CB500

Post by jerryfudd on Tue 26 Jan 2016, 1:51 pm

I'm not really familiar with the restrictors, do they go in the rubbers between the carb and airbox?
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teamwindsor
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Re: De-restricting the CB500

Post by teamwindsor on Tue 26 Jan 2016, 2:12 pm

I'd read that they are meant to be between carbs and engine but could be wrong. It would be good if they were between the carbs and airbox as the rubbers do at least move.
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Re: De-restricting the CB500

Post by jerryfudd on Tue 26 Jan 2016, 2:23 pm

if they are there then I would certainly say the carbs would have to be removed (but maybe out of the bike as that's the really tricky bit!) and if you've got that far then you might aswell just replace the rubbers IMO.

You could probably check if they are present with the airbox and rubbers out the way looking through with a torch and the throttle wide open.
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Jameshambleton
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Re: De-restricting the CB500

Post by Jameshambleton on Tue 26 Jan 2016, 4:31 pm

If I remember correctly, after loosening all of the screwy clips things around the carb rubbers. I popped the rubbers out of the air box to the carbs so that I could move the carbs easier. I then was able to remove the carbs from the rubbers connecting to the engine. Your airbox should move slightly to help this.
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Re: De-restricting the CB500

Post by Alvi on Tue 26 Jan 2016, 9:48 pm

I did it the same way ss James, above. The airbox rubbers are fairly easy to remove. The lips where they fit into the airbox have some sort of sealer, but I've found as long as the rubbers are flexible, they seal back in ok without any assistance. The carbs do take some pulling to get off the inlet rubbers!

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Re: De-restricting the CB500

Post by dado_dassler on Wed 27 Jan 2016, 11:46 am

i don't know if this is the case with your bike, but according to this informative site the 34 hp inlet-stub-limited bikes come with different size jets and springs.
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eternally_troubled
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Re: De-restricting the CB500

Post by eternally_troubled on Wed 27 Jan 2016, 12:36 pm

@dado_dassler wrote:i don't know if this is the case with your bike, but according to this informative site the 34 hp inlet-stub-limited bikes come with different size jets and springs.

Only if they've been limited using the approved Honda kit.

There are other people who just make kits that have washers in.
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jchesshyre
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Re: De-restricting the CB500

Post by jchesshyre on Wed 27 Jan 2016, 10:47 pm

Wow look at the tacho off a Swiss restricted model (on the site in dado_dassler's post): http://www.cb500-wiki.de/lib/exe/fetch.php?cache=&w=900&h=733&tok=a437da&media=motor_und_getriebe:vergaser:dzmschweiz.jpg

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ashcroc
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Re: De-restricting the CB500

Post by ashcroc on Thu 28 Jan 2016, 3:07 am

My gods that's totally blanked off the fun section Shocked
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jerryfudd
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Re: De-restricting the CB500

Post by jerryfudd on Thu 28 Jan 2016, 9:26 am

@ashcroc wrote:My gods that's totally blanked off the fun section Shocked

would give you a buzz to fit the tach to an unrestricted model though - livin' in the red line Cool Cool Cool

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teamwindsor
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Re: De-restricting the CB500

Post by teamwindsor on Mon 01 Feb 2016, 10:42 am

Managed to dig out the restriction certificate that came with the bike:
Restriction device- blade
Device code- 0349
Device details and dimensions- OD 42mm. ID 19mm

From the sounds of it, it appears to be a single washer type with no change to needles. 

Anyway I tried and failed to get off those damn rubbers.

Fully removed the rubbers from the airbox-carbs. Heated the carb-engine rubbers with copious hot water and still absolutely nothing. They got slightly more flexible but are well on there. 

Am moving house in the next two weeks so need to re-assemble the bike to be roadworthy but will re-attempt at a later date. 

With the bike re-assembled (in the dark) it didn't start. Hopefully it is just the battery...new and apparently doesn't need an initial charge (bought it several months ago). Its on the charger as we speak. If not it will be a fault finding mission in the dark- fingers crossed!

Thanks again for the help
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Re: De-restricting the CB500

Post by eternally_troubled on Tue 02 Feb 2016, 1:23 pm

I bet the battery did need charging... good luck with moving house.

If you've got the airbox -> carb rubbers off have you tried removing the carbs from the other rubbers? or are you trying to remove the whole lot (carbs + rubbers) from the engine?

It might be easier in small chunks.

You might have to face the fact that you might need to buy new rubbers...

If you look here:

http://www.lingshondaparts.com/honda_motorcycle_parts_selection_pfk.php?block_01=13MY5WEA&block_02=E__0200&block_03=1612&block_04=xx&block_05=hmc

They don't seem as expensive as I thought they might be.
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teamwindsor
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Re: De-restricting the CB500

Post by teamwindsor on Thu 04 Feb 2016, 9:33 pm

Thanks for the link- they are not too bad considering the cost of some of the other small parts!

My goal now is to try and get it started as it's being stubborn! I have 8 days to get it running before the move (plus packing) so it is going to be tight!

I removed the battery and stuck it on an optimate charger for a little over 24 hours but still no success. 

Lights, indicators and horn all work fine. 

It sounds like it is trying to start, just doesn't quite get there. It sounds close and the longer I try the poorer it gets. If I wait a couple of minutes it sounds better but still never gets there which makes me think it is still the battery despite the recent charge. 

It has been off the road since November and kept outside under a cover. 

I have replaced the spark plugs, oil and filter. The battery is new. I had part taken the carb rubbers off but the engine-carb rubbers never budged- I was trying to take carb and rubbers off together. I have seated the airbox-carb rubbers again and tightened everything down so don't think I have an air leak. 

Had a quick look at the fuses (couldn't get the main fuse cover off in the dark- but will look at this later) and they are ok. 

I took out and re-sited the spark plugs. HT leads are on reasonably well. 

Can anyone else think of something I am missing? It started and ran fine prior to the recent work/me pissing it off. 

I still have it on it's centre stand so havent tried wheeling it in gear but there isn't any reason I can think of that the engine should be seized. 

I plan to try and jump it and see if it rears to life but this will have to wait to the weekend now unfortunately.
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Re: De-restricting the CB500

Post by Jameshambleton on Thu 04 Feb 2016, 9:51 pm

I had the same problem before, the carbs were not sitting in the correct place and it was causing an air leak so one silinder wanted to start as the other didn't. I have to reseat them a few times before she started it fire up correctly.
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teamwindsor
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Re: De-restricting the CB500

Post by teamwindsor on Thu 04 Feb 2016, 10:14 pm

Thanks for the reply will take another look but had thought they look fairly well set. The front rubbers never came off. The back rubbers went back on fine and tightened down. I know they are meant to have some form of sealant to prevent air leaks - what can be used for this purpose? Silicon?

The other thought I had was I drained the carb bowels using the side screws. Is there an way to easily prime the carbs?
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Re: De-restricting the CB500

Post by Jameshambleton on Thu 04 Feb 2016, 10:25 pm

Did you remember to re-screw up the circlips on the rubbers? 

To get your carbs full of magical, boom, boom, BANG! fuel, suck on the vacuum tube leading from the rear of the engine to the fuel tap, if you don't like the taste of petrol then maybe don't suck on it for too long. 
It's the small rubber tube that's on the left side of the engine, just remember to have your fuel tap on and to place the tube back on the thingy when you've done sucking on it creating a vacuum to get fuel into the carbs.
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jchesshyre
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Re: De-restricting the CB500

Post by jchesshyre on Thu 04 Feb 2016, 11:22 pm

How old's the petrol?
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teamwindsor
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Re: De-restricting the CB500

Post by teamwindsor on Fri 05 Feb 2016, 8:13 am

Petrol has been in the tank since it came off the road so about 3-4 months. It is practically a whole tank which is less than ideal.

So that is suck on the vacuum tube on the left side of the engine. Is it the tube that goes to the back of the fuel tap or the brass coloured stub it connects to on the side of the carbs?

All the carb clips are tight as they will go. Rubbers appear well seated with no visible gaps.

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