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Post by 4l04ever on Jan 16, 2019 19:36:12 GMT 1
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Post by Tobyjugs on Jan 16, 2019 19:42:25 GMT 1
Nice Idea but i do like big nipples  |
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Post by Tobyjugs on Jan 17, 2019 21:00:34 GMT 1
With the engine build for this project i will be using a dry clutch system, here's a small taster.   |
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Post by Tobyjugs on Jan 28, 2019 20:09:48 GMT 1
Not too much to show at the moment. I have been too busy to get the bike back to Nico Bakker as the days he has been open i have been working, so that still needs to happen. At the moment my attention has turned to the engine. I am now trying to work out which gears to use. I have a choice of YPVS or Banshee or may be a mixture of both. Below is a box with the different ratios of both boxes. I have marked the gear ratio's i want to use with an Asterix but i still have to find out if it is possible to mix and match the gears. | Gear | YPVS gears | YPVS gear ratio | Nova gear ratio | Banshee gears | Banshee gear ratio | | 1st | 36/14 | 2.571 | 1.889 | 32/13 | 2.461* | | 2nd | 32/18 | 1,777* | 1.450 | 29/16 | 1.812 | | 3rd | 29/22 | 1.318* | 1.227 | 27/18 | 1.5 | | 4th | 26/24 | 1.083* | 1.083 | 25/20 | 1.25 | | 5th | 25/26 | 0.961* | 1.000 | 23/22 | 1.045 | | 6th | 24/27 | 0.888 | 0.923 | 21/24 | 0.875* |
If i use a dry clutch system my first gear ratio will be 2.5 with a 36/14 gear/input shaft. If i use a wet clutch i will go with the banshee first gear. Any comments on the above are most welcome as i have never built a track bike or an engine purely for track use. |
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Post by jon on Jan 28, 2019 21:31:17 GMT 1
Personally I don’t see the difference in using a hybrid YPVS and Banshee box based on the above ratios is worth it.
Personally I’d just stick to the YPVS box.
The Nova box is massively different to the other 2. Making 1st gear nearer 2nd on a YPVS box and the other 5 closer.
I understand this as on a track your never going to use first gear more than once.
Jon
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Post by marrcel on Jan 28, 2019 21:43:13 GMT 1
I read somewere that 5th and 6th banshee ratio are to long and it is difficult to reach topspeed.
I think you should put the ratios in a spreadsheet. And for track use choose the close ratio setup.
There are a lot of classic racers in Holland with a ypvs motor. Maybe you can ask in the 2stroke thread of motorforum.nl
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Post by Tobyjugs on Jan 29, 2019 8:34:00 GMT 1
Personally I don’t see the difference in using a hybrid YPVS and Banshee box based on the above ratios is worth it. Personally I’d just stick to the YPVS box. The Nova box is massively different to the other 2. Making 1st gear nearer 2nd on a YPVS box and the other 5 closer. I understand this as on a track your never going to use first gear more than once. Jon Hi Jon, you're not too far off the mark i think. After looking at all the ratio's and comparing them to the Nova ratio's i thought about only using the YPVS gears except for first. I have been informed first gear is very important and that it should be long. |
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Post by Tobyjugs on Jan 29, 2019 8:44:47 GMT 1
I read somewere that 5th and 6th banshee ratio are to long and it is difficult to reach topspeed. I think you should put the ratios in a spreadsheet. And for track use choose the close ratio setup. There are a lot of classic racers in Holland with a ypvs motor. Maybe you can ask in the 2stroke thread of motorforum.nl Hi marrcel I'm guessing the large jump between the ratio's in the last two gears in the Banshee box has got something to do with it. The first time i tinkered with an LC engine after reading how to tune it in a magazine produced a very quick bike. Which unless you were revving it's nuts off would fall away in the last two gears due to the peaky engine. |
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Post by Tobyjugs on Jan 29, 2019 23:25:45 GMT 1
I have changed my mind and have decided to use the Power valve gear cluster for this project. Just out of curiosity i did make the hybrid gear box and used the 1st and 6th gears from the banshee and the rest from YPVS gears. Sometimes i forget how bad a condition the gear wheels can be. I don't think many people split the gears and examine them. I found the bronze bush on the 1st gear from the YPVS cluster loose in the gearwheel another gear wheel 3rd had picked up on the shaft and one shim was worn very thin. Maybe my spares are all bad because they came from two retired racer's. Below is a picture of the hybrid gears. 
In the YPVS gears the first gear wheels are thin and sixth gear wheels are wider. The Banshee Gears are the opposite first is wide and sixth is thin. Third and fourth gear are one part on the input shaft so these two ratios will always be together, either YPVS or Banshee. |
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Post by midlifecrisisrd on Jan 30, 2019 8:56:14 GMT 1
My first thought was use the tallest 1st and second then the closest 4-6 but the thin top would worry me
I've had a couple that whine in top or seen them discoloured from heat
I've also found the knackered first gear. Was about to close an engine up that I'd fitted a new crank in when I noticed what looked like a little bit of dwarf on the side of the gear but when I pulled it there was quite a long bit between the gears
Stripped the cluster and the bronze inner was half the width it should be and fell out
I'll always check now
Steve
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Post by 4l04ever on Jan 30, 2019 11:29:31 GMT 1
The wide 6th gear of the YPVS looks more useful/robust on a track bike than a wide 1st gear.
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Post by Tobyjugs on Jan 30, 2019 12:16:45 GMT 1
The difference between the 6th gears is just over 2 mm and the 1st gears is 3mm. I wonder why Yamaha changed the sizes.
It does sound logical to beef up the first gear. I will ask a gearwheel specialist for his opinion.
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Post by midlifecrisisrd on Jan 30, 2019 13:26:35 GMT 1
I reckon it's because of the different uses
A ypvs on long journeys will spend a lot of time in top gear but minimal time in first
Also a limit on how much you can stress 1st gear. It will either be in 1st for a few seconds or flip the bike
A banshee however will not spend as long "cruising" in top but think of the abuse it will take on uneven terrain or with 2 wide knobbly tyres
Steve
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Post by Tobyjugs on Jan 30, 2019 13:48:28 GMT 1
I reckon it's because of the different uses A ypvs on long journeys will spend a lot of time in top gear but minimal time in first Also a limit on how much you can stress 1st gear. It will either be in 1st for a few seconds or flip the bike A banshee however will not spend as long "cruising" in top but think of the abuse it will take on uneven terrain or with 2 wide knobbly tyres Steve Very true. It does make me curious about the gears from Nova. Just to remind everybody i will be using the YPVS set in this project and put the hybrid gears in my special 4LO engine. |
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Post by mouse on Jan 30, 2019 21:13:27 GMT 1
Flip, this is a mammoth project, but i love it.
Keep it going Tobyjugs
ATB
Mouse
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Post by Tobyjugs on Jan 30, 2019 21:29:12 GMT 1
Flip, this is a mammoth project, but i love it. Keep it going Tobyjugs ATB Mouse Now you know the fate of your old engine casing. If it all works out it will be the new home for a modified TZ 2505KE clutch with an extra set of plates. |
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Post by mouse on Jan 31, 2019 17:40:21 GMT 1
Flip, this is a mammoth project, but i love it. Keep it going Tobyjugs ATB Mouse Now you know the fate of your old engine casing. If it all works out it will be the new home for a modified TZ 2505KE clutch with an extra set of plates. Ahh, glad i could return the help ATB Mouse |
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Post by Tobyjugs on Jan 31, 2019 18:33:50 GMT 1
Now you know the fate of your old engine casing. If it all works out it will be the new home for a modified TZ 2505KE clutch with an extra set of plates. Ahh, glad i could return the help ATB Mouse We're just helping each other. Why butcher a perfectly good casing  |
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Post by Tobyjugs on Jan 31, 2019 20:01:39 GMT 1
Hello chaps, I need some advice and opinions about gearbox bearings.
I have read here and there that people fit heavy duty bearings in the gearbox of their big bore engine. What does this consist of? And where are they available?
My own experience of these engines is only finding the large ball bearing on the clutch side of the input shaft worn all the rest seem to have been good.
Basically I don't want to waste money on bearings which I think are good enough. Unless told otherwise.
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Post by midlifecrisisrd on Jan 31, 2019 20:40:49 GMT 1
I fitted them on my 385 as I was naive
I reckon new standard bearings are fine
The HD bearings just have more balls and rollers like the uprated crank main bearings
I swear my clutch bearing had more play in it from new than the used bearing I took out
I've chased the dreaded bottom end clank with the engine since it was built and that's the only thing that I can see
Either that or the tss crank clang on the bearings
Steve
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Post by Tobyjugs on Jan 31, 2019 20:53:20 GMT 1
Personally I think the standard needle bearings are strong enough, it's just that one bearing next to the clutch, I'm not sure about.
Thanks for your frank input Steve
Oh I've chased after the same rattle as well. I thought it was clutch orientated but now I have another theory, which is in progress
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Post by Tobyjugs on Feb 5, 2019 19:21:25 GMT 1
Ok i did a bit of research on bearings and i have decide to go with the original set up. My reason being this engine is not going to be that reliable and will need frequent checks. Having a dry clutch means its easy to spot any play on the bearing which is most vulnerable in the gearbox. (in my opinion)
From the picture of the bearing i have seen classed as a heavy duty bearing for our gearboxes i would be very weary of it. To increase the radial load properties more balls are added which means smaller diameter balls. This will be ok if there is no or little axial load i.e. straight cut primaries, but i would not use it with standard primaries due to the axial load they create.
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Post by Tobyjugs on Feb 10, 2019 12:03:48 GMT 1
As i'm still waiting for my dry clutch parts to arrive, i thought i would build the engine up "Dry" so that i can check the squish height and the uncorrected compression ratio. At first i just fitted one piston ring on one piston but this felt a bit strange when turning the engine so i ended up fitting another piston ring to the other piston. First i put some solder on top of the piston crowns and measured the squish height. The pieces of solder were found to be slightly tapered and measured 1.00 mm this was using a 0.6 mm base gasket.  The top of the outside edge of the pistons was covered with grease to help the top piston ring seal. The cylinder head was refitted and i put the pistons in TDC and measured the amount oil used to fill up both cambers to the top of the thread hole. After a little bit of maths i worked out the Uncorrected Compression Ratio of 12:1 which is ok for now.   The cylinder head is from Chariot and the domes are 26 ml. Pistons used are Wiseco 68 mm |
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Post by tsa on Feb 10, 2019 12:45:44 GMT 1
The wider gears are due to how much the torque available is amplified/multiplied through the box. You accelerate faster in first because there is more torque being amplified/multiplied so it needs more metal to distribute the forces. The Banshee is thicker because it is used to accelerate in deep muddy/sandy conditions
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Post by Tobyjugs on Feb 19, 2019 22:59:02 GMT 1
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Post by donkeychomp on Feb 19, 2019 23:13:13 GMT 1
Can you not use that or will it ruin the handling?
Alex
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Post by oldbritguy on Feb 20, 2019 1:42:50 GMT 1
Will the wider tyre setup have an adverse effect on the chain run also?
You are showing some fine engineering skills here and I know you said you will cover the offset later in the thread, but this must surely be a massive offset to level out. Don't want to lose all your weight saving gains with big spacers or outriggers and bearings etc up front.
Absolutely cracking build though. I'm totally hooked
John
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Post by marrcel on Feb 20, 2019 12:34:27 GMT 1
I think a 150 can cope with 100hp easy.
With 200hp then look at 190mm.
For the looks? Looks like a HD size on a beautiful nimble 2stroke.
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Post by Tobyjugs on Feb 20, 2019 14:34:14 GMT 1
Can you not use that or will it ruin the handling? Alex There does seem to be two different opinions about this size wheel on such a small bike. Most say over kill. The other opinion is more choice of rubber available. The plan is to use a a smaller tire maximum size being 165. I think Marrcel summed it up pretty good. "Looks like a HD size on a beautiful nimble 2stroke." My thoughts were it looked more like a monkey bike with a balloon tyre. I can't tell you what it does to affect the handling, but i can tell you my other RD feels better to ride with a 140 size tyre than a 150 size tyre. Hopefully some of the track lads will comment upon it. |
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Post by Tobyjugs on Feb 20, 2019 14:44:44 GMT 1
Will the wider tyre setup have an adverse effect on the chain run also? You are showing some fine engineering skills here and I know you said you will cover the offset later in the thread, but this must surely be a massive offset to level out. Don't want to lose all your weight saving gains with big spacers or outriggers and bearings etc up front. Absolutely cracking build though. I'm totally hooked John The way the bike is set up there is no need for mods, but i am still busy with the offset. There is a roller on the bike for supporting the chain.  |
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