Author Topic: Confession to make  (Read 2511 times)

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Online Mr Nick

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Re: Confession to make
« Reply #60 on: April 26, 2019, 21:34:29 »
There's almost a difference in the readings: well balanced!

You've reminded me I was going to buy a 2 cylinder balancer as I'd played with the carb settings so much before tracking down the real issues: off to get one now.
Seems pearl asbo orange is faster after all....

Online Joe Rocket

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Re: Confession to make
« Reply #61 on: April 26, 2019, 22:31:39 »
I hope you could borrow a set like I did?  :icon_wink:

I made sure the choke didn't interfere at all and the cables had sufficient play to allow full shut down to idle. I haven't played inside the carbs at all. There were no 'values' to achieve (sorry, you probably know that) other than they perform the same within given Haynes manual tolerances shown on the guages.

Suddenly, as Rusty Nuts said, it becomes a bike again, not a project. I think today was the day.

Everything going back on again and a real shake down ride this weekend in prospect. I will have to run it in again after totally dismantling the engine back in Winter and I won't take too muck notice of negatives on the Urban Myth thread.........  lol

Online Joe Rocket

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Re: Confession to make
« Reply #62 on: April 27, 2019, 21:42:19 »
Gentle ride for 15 minutes today. Carbs need more work, very reluctant to pull in higher gears and clutch not fully releasing at standstill (put into neutral). However very unworried ride and a pleased smile under my helmet.   :grin:

Offline Dark-Strom

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Re: Confession to make
« Reply #63 on: April 28, 2019, 10:11:37 »
Sounds like a good 1st shakedown Joe  :thumb:
Bikes owned: DT50, CD125T, RD350LC, KMX200, KR1-250, CD125T(again), GSX600F, R80ST, CBX250RSE, ST1050, DL650 AL2

Online Joe Rocket

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Re: Confession to make
« Reply #64 on: June 02, 2019, 19:49:05 »
I promised Mr Nick an update.  :icon_wink:

I mentioned it needed carburation resolved so I took the carbs off and stripped them down to make sure nothing was amiss. I found no blocked passages or jets, diaphragms were fine and slides all functioned fine. One thing wrong was the idle screws' settings , they had all been aligned irrespective of the manual setting of two turns out so anywhere between one and a half to three turns. They are now set to book spec. and the bike runs easier and more fluently. Main jets are standard and I'm runing individual pod filters on each carb. Unfortunately I found a slight leak from the water pump area so have to take off the lower fairing to locate the point of the escape. I'll resolve that before another test ride but into a period of bike trips and tours at the moment so not a priority.

I did bleed the clutch again and gained double the length of resistance in lever travel so I assume the clutch will now release easily at a stop to change into neutral from 1st. I've also checked wiring for the indicators as nothing works on the winker circuit, will keep looking there.

It's a 1987 bike and I've applied for a 'Fédération Française Véhicule d'Epoque' Certificate (collection vehicle being over 30 years old). It will give the bike a recognised vintage status and hopefully keep the bike in standard spec when selling it on. It also offers an advantage of minimal cost to a new owner when changing the registration document, without it it's 95€ but only 4€ if a 'collection' bike. It requires photo record of the bike, engine and frame numbers to support it's authenticity. Two month's wait before that comes through.

Online Mr Nick

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Re: Confession to make
« Reply #65 on: June 02, 2019, 22:14:05 »
Glad to see your fueling issues were just an idle screw adjustment: wish mine were as straightforward...

Next year I can apply for my 2 oldest ones to become historic class & zero tax payable: just needs a form completed declaring the bike's not been substantially modified I think, not the photos you need to provide.
Seems pearl asbo orange is faster after all....

Online Joe Rocket

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Re: Confession to make
« Reply #66 on: June 03, 2019, 08:03:26 »
Yet to see if fuelling issues was just the idle screws. Have to test it pulling in higher gears to see if it lacks extra fuel for the free air flow from the pods. Still might have to upsize the jets, some have suggested trying a DynoJet Stage 3 tuning kit but they're 125€ a go so I'll try everything else first if necessary.

Long terms plans are to look at the state of finish to components and fairing paintwork. I will give it a standard colour scheme. I've some pattern sticker photos to get near original 'decals' printed. Next winter........

Online Joe Rocket

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Re: Confession to make
« Reply #67 on: June 14, 2019, 19:39:40 »
The GPX has been quiet for a little while, the water pump sprung a leak. I've fixed it this week and took the bike out today, it ran well but acceleration stalled beyond 4k in higher gears. There's not enough fuel getting through to meet the free air of the filter pods.

I studied the video I posted on Mr Nick's thread. It says (as a start) up the main jets one size for pods and two sizes for pods and exhaust. The exhausts are back to standard, jets in carbs are standard (112) so I'll get both sizes up from that and try them out, 115 and 118. There is scope to play with needle height and needle jets but I'll go for the simpler route first. Fingers crossed.  :shy:

Online Mr Nick

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Re: Confession to make
« Reply #68 on: June 14, 2019, 22:46:04 »
The 2 different main jet sizes on mine needed different needle heights - the larger jet asked for a lower needle: I'm thinking that's to keep the mixture the same at smaller throttle openings but still allow richer fully open.
Maybe...
Seems pearl asbo orange is faster after all....

Online Joe Rocket

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Re: Confession to make
« Reply #69 on: June 15, 2019, 08:01:08 »
Yes.......maybe.......makes sense.

I can't lower the needles, they have no clip positions. I can only pack them to raise them. Can only try and see.

Online Mr Nick

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Re: Confession to make
« Reply #70 on: June 15, 2019, 09:42:03 »
Looks like we're on the right lines: 1/4 to 3/4 throttle is where the needle jet works.
https://totallyamaha.com/snowmobiles/aaTECH/jetting.htm

If it doesn't adjust then you're kind of stuck with whatever develops - you never know, it might even slightly improve things as most post eco-worriers engines are tuned lean anyway.
Seems pearl asbo orange is faster after all....

Online Joe Rocket

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Re: Confession to make
« Reply #71 on: June 15, 2019, 10:20:23 »
This is a visual guide mentioned in the vid I posted. It says the same thing as your link.

Online Joe Rocket

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Re: Confession to make
« Reply #72 on: July 15, 2019, 21:40:21 »
I have the 'Collection' status for the bike.  :thumb:

Online Mr Nick

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Re: Confession to make
« Reply #73 on: July 15, 2019, 23:44:55 »
 :text-bravo:
Seems pearl asbo orange is faster after all....

Online Joe Rocket

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Re: Confession to make
« Reply #74 on: July 16, 2019, 16:22:14 »
I forgot where I put the 'Attestation'. Here it is:

Online Joe Rocket

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Re: Confession to make
« Reply #75 on: July 16, 2019, 20:32:21 »
Here are a couple of photos looking forward to repaint/refinish work starting in the Autumn (when the weather permits... :icon_wink: )

The double pin stripes are part of an original black livery, with GPX and 750R stickers I'll get made up as the originals were. The lower engine cowl will be in mid-grey.

Online Rusty Nuts

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Re: Confession to make
« Reply #76 on: July 16, 2019, 20:35:25 »
That reminds me my similar age 600 had a pair of 16" wheels. Are the 750s the same? And if so, what choice of tyres is still available?
Sent from my Red Army intelligence-gathering Huawei tablet.

Online Joe Rocket

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Re: Confession to make
« Reply #77 on: July 16, 2019, 21:02:49 »
The 600 wheels are both 16" whereas the 750 has 16" front and 18" rear. (The rear caliper is mounted below the exhaust on the 750) I do have 600 standard exhausts now on my bike so some items in common.

Obviously tyre choices are different and as it's the first I've owned and came with a good pair of Bridgestones I've not searched the possibilities. Sorry, can't say more than that...........for now.   :shrug:  :)

Online Mr Nick

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Re: Confession to make
« Reply #78 on: July 16, 2019, 23:25:57 »
16" and 18" was something Guzzi tried on the Mk2 Spada - it didn't go well & they dropped the idea: the SP3 went back to 18" both ends.
Seems pearl asbo orange is faster after all....

Online Joe Rocket

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Re: Confession to make
« Reply #79 on: July 18, 2019, 19:57:42 »
I've been away from the bike for a while, too much else needing my attention since the end of May.

Today I set about the pilot screws which are accessible from below the carbs so it was always going to be carbs off, adjust, carbs back on then start the bike to see (any) result.

Standard setting - 2 turns. Tick over unstable, acceleration delayed and bogged down above 4K. Won't respond to instant increases.

First change - 2 & 1/2 turns. Reassuring start, stable tick over once warm but resistance to accelerate, had to build up revs from 5K and up but not fluent.

Second change - 2 & 3/4 turns. Good start, had to reduce tick-over. Acceleration nearly broke free on sharp throttle increase. Eases up to 7K with no problem. Slightly bogged down again on sudden throttle increase.

Third change 3 turns. Good start, idle was sounding very good. Fluent acceleration but now close to half throttle.

I'm leaving it there to test ride tomorrow and see if it now lacks main jet fuel input. I think there may be another half turn before pilot jet provides maximum fuel so the input from the main jet is now paramount for half to full throttle.

More tomorrow.  :icon_wink: